CA2085793A1 - A quality preserving material of fresh food - Google Patents
A quality preserving material of fresh foodInfo
- Publication number
- CA2085793A1 CA2085793A1 CA 2085793 CA2085793A CA2085793A1 CA 2085793 A1 CA2085793 A1 CA 2085793A1 CA 2085793 CA2085793 CA 2085793 CA 2085793 A CA2085793 A CA 2085793A CA 2085793 A1 CA2085793 A1 CA 2085793A1
- Authority
- CA
- Canada
- Prior art keywords
- water
- aluminum
- fresh food
- whiskers
- alloy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
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- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F3/00—Tea; Tea substitutes; Preparations thereof
- A23F3/06—Treating tea before extraction; Preparations produced thereby
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B7/00—Preservation or chemical ripening of fruit or vegetables
- A23B7/14—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10
- A23B7/144—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10 in the form of gases, e.g. fumigation; Compositions or apparatus therefor
- A23B7/148—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10 in the form of gases, e.g. fumigation; Compositions or apparatus therefor in a controlled atmosphere, e.g. partial vacuum, comprising only CO2, N2, O2 or H2O
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B7/00—Preservation or chemical ripening of fruit or vegetables
- A23B7/14—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10
- A23B7/153—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10 in the form of liquids or solids
- A23B7/157—Inorganic compounds
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/10—Treating roasted coffee; Preparations produced thereby
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/10—Treating roasted coffee; Preparations produced thereby
- A23F5/105—Treating in vacuum or with inert or noble gases; Storing in gaseous atmosphere; Packaging
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
- A23L3/34—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals
- A23L3/3409—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals in the form of gases, e.g. fumigation; Compositions or apparatus therefor
- A23L3/3418—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals in the form of gases, e.g. fumigation; Compositions or apparatus therefor in a controlled atmosphere, e.g. partial vacuum, comprising only CO2, N2, O2 or H2O
- A23L3/3427—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals in the form of gases, e.g. fumigation; Compositions or apparatus therefor in a controlled atmosphere, e.g. partial vacuum, comprising only CO2, N2, O2 or H2O in which an absorbent is placed or used
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
- A23L3/34—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals
- A23L3/3454—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals in the form of liquids or solids
- A23L3/358—Inorganic compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
- B65D65/38—Packaging materials of special type or form
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Nutrition Science (AREA)
- Inorganic Chemistry (AREA)
- Wood Science & Technology (AREA)
- Zoology (AREA)
- Mechanical Engineering (AREA)
- Storage Of Fruits Or Vegetables (AREA)
- Food Preservation Except Freezing, Refrigeration, And Drying (AREA)
Abstract
ABSTRACT
This invention is related to a quality preserving material of fresh food, which enable to keep the quality and freshness of fresh food in a good state, and which comprises a base with aluminum or its alloy material, numerous voids or pores formed in the outer surface of the base and penerating through the base, aluminum oxide whiskers being formed in the voids or pores and an active water being retained by the whisker.
This invention is related to a quality preserving material of fresh food, which enable to keep the quality and freshness of fresh food in a good state, and which comprises a base with aluminum or its alloy material, numerous voids or pores formed in the outer surface of the base and penerating through the base, aluminum oxide whiskers being formed in the voids or pores and an active water being retained by the whisker.
Description
2~ 7~
TITLE OF THE INVENTION
A QUALITY PRESERVING
MATERIAL OF FRESH FOOD
FIELD OF THE INDUDSTRIAL UTILIZATION
This invention relates to materials for preserving the freshness or quality of fresh foods and~ more particularly, to a quality preserving material, which can keep the quality and freshness of fresh foods in a good state for long time.
When is the material used for storing fresh food at a low temperature state, by using is a refrigerator9 it can allaviate over-cooling ambience in the neighborhood of a cool air outlet inside the refrigerator, and also quickly recover temperature drop into an improved state of temperature at the time of opening and closing the door of the refrigerator and make an uniform flow of cool ambient air circulating in the refrigerator, thus eliminating the over-cooling of the stored fresh food and keeping the quality or freshness of the fresh food in a good state!
The quality preserving material according to ~he invantion can ba effectiv01y used for general food and particularly sff0ctively used for fresh foods or the like including vegetables, fruit, meat, fish and shellfish, favorite foods such as coffee and green tea~ and such plants as cu~ flowers and s~sds~
PRIOR ART STATEMENT
For keeping the quality or freshn~ss of foods, such as fish and shellfish, maat, vegetables3 agriculturAI products and other fresh foods, various methods, davices and -.. --. - - :
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,,, ' , ., ' 2~57~3 apparatuses have been proposed and used in practice~ In this connection5 endless e~forts have been paid for researches and developments. Up to date, there are various proposals of techniques ~or keeping fresh food in a good state thereof, instead of canning or thermally sterilizing them9 resulted in providing wide variations and great benefit in consequence of our eating life style, by utilizing the proposal techniques~
The proposal techniques for preserving the food quality are roughly classified into two groups~
The former group is for suppressing cellular function of the fresh food7 and the latter group is for stopping or preventing the progress of maturing or corrosion of tha fresh food.
The former group techniques is further classified into two groups~ The one group is for keeping the food quality in a good state by cooling and the other group is for keeping the food quality in a good state by freezing~
The freezing quality preservation is a method, in which the fresh food is preserved at a temperature lowsr than normal temperature, that is, by cooling the ~ood without causing freezing of water content in the food~ These techniques include commonly term0d cooling and chilling. In this quality preservation techniques~ the quality and ~reshness of the fresh food are kept in a good state without effecting thHrmal sterilization, drying or without use of any salt or sugar for preservation, and activity and propagation of bact0ria concerning th0 corrosion or maturing are suppressed to keep tha quality and freshness of the ~ood in a good state~ The m0thod has recently been improved greatly to have a feature that it permits preservation of fresh food quality without spoiling the quality and freshness thereof~
- The fre0zing quality preservation is a method, in which the frash food is cooled down to a temperature below the , , , . ~ ,. . .
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temperature of freezing of water and also to such an extent that the center temperature of the food is -18 C or below.
This method provides a preservation for long time of food quality7 and consequently it is used for food preservation on ships on the sea or for long time~ However, freezing quality preservaition is liable to destroy the food structure or texture, thus posing problems in the sense of eating and quality of the food after de-freezing~
The latter group techniques is predicated in the fact that among the fresh food vegetables and fruit emit ethylene during maturing and that $he emitted ethylene has an effect of causing enhanced breathing of the vegetables and fruit and thus helping the maturing~ In this method3 the connection of ethylene ~o the maturing is cut~ and the preservation atmosphere is adjusted using, for instance7 carbon dioxide, More specifically, ethylene is removed to stop progress of the maturing of vegetables and fruit9 or ethylene is removed from matured fruit or vegetables to stop further progress of maturing~
This techniqua has a certain effect of preventing the corrosion of fresh food~ However, it is not for keeping the quality or freshness in a good stateg and it does not permit preservation of fresh food in the raw state, Recently~ it has been noted that water contained in food has a closad connection with th0 quality and freshness of food. Gonsequently, there have been proposed a preservation techniques which adjust the character or structure of water contained in the fresh food to thereby keep the quality and freshness of the food in a good state~
Thesa techniques are proposad in a form that active water subjected to electric treatment in an electric or magnetic field is utilized for the preservation of fresh food, growth of plants and manufacture of food~ EspesialIy~ it has bean .
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reported that utili~ation of the active water has specific effects for the growth of plants~ preservation of the quality or the freshness of fresh food and adjustment of the atmosphere surroundin~ the food.
In this technique, however~ the effect goes ahead of theoretical analysis related thereto. Nevertheless, it has been proved that the active water with variation in structure thereof can provide satisfactory biological activity to animals and plants~ In addition to this9 the active water provides results, such as an increase in the hen egg laying, a protection against bacteria of cow by enhancing cow physical strength and a promo$ion of growth of plants.
More specificallyg water containing in fresh food, more particularly, water existing around the cells of fresh food, consists of three layers9 i~e~ 9 those of free water, bonded water connected with the cells and non-frozen water, and the quantity of these kinds of water reaches substantially 80 to 85 %c Particulary, as fresh food or plants are said to be "juicy", water contained in the food has a connection directly closed to the quality and freshness of the food~
According to a recent review~ non-frozen water contained in protein is said to have a melting point of -80 C ~ It is also well known that water contained in food is evaporated slowly compared to ordinary drinking water~
The free water9 bonded water and non-frozen water have respectively clusters with difference of water molecular number~ The bonded water cluster has water moleculer numbers ~reater ~han those of the non -frozen water cluster and smaller than those of the free water clusterc Conseqently, "juicy" of the frash food can be preserved for a long time by an adjustment or an activation of structure and character of the free water, or by a replacement of the free water by an active water with pre -controlled structure~ From these .. , :,. . ..
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points of view, it is necessary to make use of already proved active water for keeping the freshness of fresh food~
In other words~ the prior art techniques of keeping the freshness of fresh food, as noted before~ are to store fresh food in a cold or frozen state or seal carbon dioxide gas or remove ethylene~ It is desired for keeping the freshness of fresh food to make use of active water having adjusted structure or character along with the above freshness keeping techniques~
However, in spiee of the fact that it is very effective for keeping the quality and freshness of fresh food to adjust the structure or character of water and $hus render water to be active, substantially no means or device of adjustment has been developed~ At present9 therefore~ it is impossible to improve the freshness keeping beyond the conventional level.
PROBLEMS TO ~E SOLVED ACCORDING TO THE INVENTION
The present invention is completed in the light of the above background, and it seeks to provide a freshness keeping material, in which mainly active water retained in alumina whiskers has effects of preventing oxidization of fresh food and hence prevent the deterioration of the quality of the food, such as freshness7 taste and flavor and suppressing emission of ethylene gas from fruit or the like as well as adjusting tha structure or character of water contained in the fresh food via the water content in air or like function~ thus permitting long preservation of fresh food~
MEANS FOR SOLVING THE PROBLEMS
According to the invention~ there is provided a material for keeping the freshnass of fresh ~ood, which comprises a base made of alminum or an alloy thereof and having numerous Yoids ~ormed adjacent the outer surface or in , - . .. . . . . . .. . . ..
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2~ 7~3 the inside, some or all thereof being accommodated with one another~ whiskers mainly compose~ of aluminum oxide being formed in at least some of pores formed by the voids, active water having fine structures being retained by ~he whiskers~
In this material, the base made of aluminum or an alloy thereoF consists of a sintered body of aluminum or an alloy thereof in a powdery or fibrous form or of an aggregate of fibrous aluminum or an alloy thereof or a foamed body of aluminum or an alloy thereof.
Further, the base made of aluminum or an alloy thereof, consists of a sintered body of aluminum or an alloy thereof in a powdery or fibrous form for retaining fine structure water via the whiskers.
More specifically, the freshness keeping material according to the invention is a porous material of aluminum or an alloy ~hereof.
The porous material of aluminum or an alloy thereof is manufactured from a powdery or fibrous material of aluminum or an alloy thereof by sintaring or foaming~ the method of manufacture being well known and disclosed in Japanese Patent Publication NOA 47322/1985.
Whiskers mainly compGsed of aluminum oxide are formed in at least some of infinite pores in the porous material~
The whiskers may be formed by a commonly termed boehmite process. In this case, however7 it is necessary to use pure water~ More specifically, pure water is boiled or vapori~ed and~ in this state, act~d on the porous material to thereby form innum0rable very fine whiskers comprising aluminum oxide hydrats on the surfacs and in the pores of the porous material.
The whisker is a very thin elongate member like the "whisker"
on the face~ and very small gaps are formed between adjacent whiskers. Thus fine structllre water, iOe~, very small film of active water~ can be retained between adjacent whiskers.
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The water which is thus retained via whiskers, includes commonly termed active water, which is different in the structure or character from ordinary supply water of distilled water~
Generally, water is expressed by the molecular ~ormula of H~O. Although it may be considered that individual water molecules of H,O are found distinctly, recently it is thought that individual water molecules are bonded to one another into groups of molecules~ These groups of water molecules are called clusters o~ water molecules (or aggregates of water molecules)~ It is said that ordinary water such as supply water and distilled water is found as clusters, in which manu water molecules are bonded to one another in a bar -like or linear form~ and thus has low activity.
In contrast~ by adjusting the structure or character of water, the crystalline structure of water, comprising water molecules bondad to one another into a bar-like or linear form~
is changed into clusters each comprising several water molecules or, according to some theoriesy into a cyclic structure comprising water molecul0s bonded cyclically to one another or a three -dimensional structure, in which such cyclic structures are compounded~ Water having such structures is greatly different in the character or the like from ordinary water. Natural spring water is slightly different structurally from ordinary waterg and thus is different in the taste and flavor. Further~ it is said that water in the cells of a healthy man has a cyclically bonded structura and has high activity~
The adjustment of the structure or character can be obtained by (1) a magnatic field process, (2) an electric field process~ (3) a microwave process, (4) an ultrasonic process, (5) a c0ramic process, (6) an ozone process, (7) a ~
(pai) process, (8) a nuclear magnetic resonance process, (9) - , '.: . ~ : . ' .
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a far infrared radiation process, (10) an electric oven process and (11) a natural stone process~
The constitution and function of these means will now be described in detail with reference to the drawings~
Fig~ 1 is a view with an enlarged scale, showing a potion of the surface of one embodiment of the freshness keeping material according to the invention;
Fig. 2 is an enlarged -scale view showing whiskers formed on the wall surfaces of pores formed between adjacent particles of aluminum or an alloy thereof as the material of the surface keeping material;
Fig~ 3 is a graph showing the relation between the vapor pressure of water retained by the whiskers and the radii of the pores with the whiskers formed therein.
Fig~ 4 is a graph showing the relation between ethylene concentration and the time of maturing in the re~rigerater according to the invention and a prior art refrigerator; and Fig. 5 is a graph showing the relation between the refrigerator inside temperature the door open peirod with the refrigerator according to the invention and a prior art refrigerator, Referring to Fig. 1; refarence numeral 1 dasignates a base of aluminum or an alloy thersof in the freshness keeping material according to tha invention, The base 1 is a porous mat0rial of aluminum or an alloy thereof~ The ~ase 1 has pores 2 communicating three-dimensionally with one anothar~
The percentage in Yolume o~ the pores ~ is desirably 20 to 70 %~ In manufacture~ powd~r of aluminum or an alloy thereof is used as a skeleton material, and a binder m~tal powder having a lower melting point than that of tha powder of aluminum or an ailoy thereof is added~ The mixture powder is disposed without pressure application and sintered in a non-oxidizing atmosphere at a temperature between tha melting point of the " . .; . . - . . .
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binder metal and the melting point of the powder of aluminum or an alloy thereof as ~he skeleton material~ At this time~
the percentage of the pores 25 i~e.~ the porosity, can be adjusted by selecting the shape or grain size of the particles of aluminum or an alloy thereof as the skeleton material~
It is possible to prepare the base 1 by other means than sintering as well1 for instance by compression molding fibrous aluminum or foaming fused aluminumL
Tha base 1, which is thus produced from a porous material of aluminum or an alloy thereof with infinitely bent internal pores 2, has material characteristics such that it is light in weight and excellent in the heat conductivitya Structurally~ it has a complicated surface shape and has innumerable inner pores. Thus~ it has a large surface area and can sufficien$1y dissipate heat~ When it is used to line refrigerator inner surfacesy it can suppress over-cooling of the neighborhood of a cool air outlet and ~reatly alleviate tsmperature changes at the time of opening and closing the refriseratorn In addition, the surface area is actually increased to about lO,000 to 500,000 times the surface area of a flat plate by ~locks of very fine whiskers. Thu~y an effect of adsorbing smell and deteriorating componants can be obtained.
Whiskers 4 are produced on the inner wall surfaces of pores 2 formed between adjacent particles 3 of aluminum constituting the skelaton as well as on the outer surface of the base 1~ as ~hown in Fig, 2~ They are formed by boiling the base 1, which comprises a porous material of aluminum or an alloy thereof~ in water and then heating it in atmosphere at 100 C or above~ The individual whiskers 4 mainly comprise the hydrate of aluminum oxide. Some of them~ however~
are naturally grown as single crystals of Al~0, as beohmite _ g _ .
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2 ~3 ~ 3 is partly caused to undergo a dehydration reaction by heating in atmospheren By adding organic amines, sulfuric acid, etc.
during the boiling process, these components may be provided in the hydrate. The whiskers 4 which are produced in this way are as thin as about 0.01 ~ m in diameter and spaced apart by a distance of about 0~03 ~ m~ They are produced such as to cover the surfaces of aluminum particles 3, which are three-dimensionally continuous to one another.
Then7 active water 5 is retained in the form of fine particles in the base 1 having the above structure via the whiskers 4 which are formed on the surface and in the inside of the base~ This is done by impregnating the base 1 with ac~ive water usually by dipping or spraying and then drying, if necessary, at about 100 C~ In this way, the active water 5 can be retained without evaporation~
More specificalIy~ water having fine structures is retained in the interstices of the whiskers 4~ This is made over the entire wall surfaces of the pores 2~ which are internally three-dimensionally con~inuous to one another. As noted before, a majority of active water is found in $he interstices o~ the whiskers. However, some active water is re -bonded to whiskers to form crystalline structure water, and other is adsorbed in micropores in whiskersn Water 5 such as active water can be retained via whisker 4 irrespective of the ambient atmosphere owing to the fact that the interstices among the whiskers 4 are very fine.
The fall of the vapor pressure of liquid~ for instance watar7 in micropores is governed by the Kelrin's formula.
Figure 3 shows the solution of the formula with respect to wat~r. In the Figure~ curve (a) is obtained at 100 ~, and curve (b) at 20 C. As is seen from the Figure~ while water is boiled at 100 C under 1 atm~, with a micropore diameter of 0.01 ~ m it is condensed rather than boiled~ Thus, with ,,, . ~ .
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such very fine interstices among the whiskers 4 as about 0,01 ~ m, the water provided by the impregnation can be retained stably. In addition~ even when the system is heated at a low temperature after the impregnation with water~ the water that is retained via the whiskers can be evaporated very slightly and remain stably, StructuralIy~ the base 1 has innumerable pores, in which fine whiskers are provided. Thus, it has 10,000 to 500, 000 times the surface area of a flat plate of the same size and hence has an extraordinarily increased heat transfer constant~ Thus, when this material with whiskers is used in a refrigerator~ as cold air passes through the refrigerator~
the flow is un!foYmalized to prevent deterioration of the freshness that might otherwise result from local over-cooling of or lack of uniformity of the temperature distribution in the fresh food.
Further, aluminum or an alloy thereof constituting the base itself can very readily store heat and emit coolness~
In addition5 since it has a large surface area owing to the above structure, at the cold air outlet of a refrigerator, it serves the role of alleviating the cold air to pr0vent over -cooling in the neighborhood of the outlet.
The freshness keeping material having the above structure can keep the quality and freshness of fresh food as follows~
In the first placa, the above structure can block the maturing of vegetables and fruit, Vegetables and the like were matured in the pr~sence of the freshness keeping material of the above structure to find that in comparison to the casa of absence of the material substantially no ethylene gas was gensrated during tha maturing~ Thus1 an effect of blocking the maturing itself can be attained~ The reason for this is not clear in detail, but tha effect is thought to be .
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attributable to ~he adsorbing action of the whiskers 4~ In addition~ ~he base 1 of aluminum or an alloy thereof generates far-infrared rays forming a far-in~rared ray field~
It is thought that the effect is more or less attributable to this far -infrared ray field~ Further, active water retained by the whiskers has influence on the water content in air or like atmosphere, and this effect can be elevated whe~ active water is retained by the alumina whiskers.
When an atmosphere containing ac~ive water is formed around fresh food~ it makes up for the aging of water contained in the fresh food, for instance free water on the surface (the free water being structurally close to ordinary water), thus keeping the freshness of the fresh food~ The reason for this is not clear, It is thought that when active wa~er is retained by whiskers, it provides an effect of keeping the freshness of the food.
The formation of such atmosphere has an effect of suppressing the oxidi~ation of the surface of fresh food and1 in case of coffee or the like with the flavor thereof being important, it has an effect of suppressing the scattering of the flavor.
EXAMPLES
Example 1 An aluminum porous sintered material was prepared by sintering aluminum particles~ This porous sintered material was boiled for one hour at 100 ~C and dried for 1R5 hours to at 150 C to generate whiskers in it. Theng it was impregnated with samples of diluted solutions (diluted from material water) as a kind of ~ (pai) processed water containing iron ions and sodium chloride, disclosed in Japanese Patent Application Public Disclosure No~ 283612/1990 ,. " , ' , ' ~ . -by spraying the solutions~ followed by drying at 40 C for 8 hours~ These two materials were used to keep perched coffee grains in respective containers for one weekl and the freshness of the coffee was examined~ The results were shown in Table 1. The evaluation was done with reference to the following:
Evaluation mark:
1: No flavor change and satisfactory 102: Slight deterioration of flavor 3: Slight deterioration of flavor and weakened taste 4: Slight deterioration of flavot and very weakened taste 5: Defective Table 1 = _ Days The invention material The invention past used in vessel material not used ~ ~ ~ 3 _ _ .
30A: Far-infrared radiation treatment B: Magn~tic field treatment C: Electronic oven treatment D: Ultra-sonic wave treatment - ,: . . . , . . , - .
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Example 2 In lieu of the coffee in Example 1 green tea contained in a vacuum pack was charged into a can~ and it was ~hen processed in a manner as in Example 1 by using active water samples obtained from supply water by the magnetic field process, far -infrared process, electronic oven process and super-sonic wave process~ The results are shown in Table 2.
Table 2 _ _ _ ~. .
Days The invention The invention past material used in vessel material not used 8 . ~ 2 _ The evaluation was done under the same conditions as in Example 1~ Clear differences of effect could be obained with any treated water compared to non-treated watery The coffee, black tea9 green tea, etcO are foods likad 25by individuals3 their distinct flavorg taste and other sofisticated characters are required. Among these linkings, the coffee is subject to its quality and grade depending on the conditions of perching its grains~ Of course9 it has various features depending on the districts of its production~
30Its typical example is blue mountain produced in Jamaica, which is liked by many people in Japan as wellO Blue mountain is liked for its miId flavor~
Further) when serviny coffee, perched coffee grains are "
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~ ~3 ~ 3 ground into flour right before serving, ~hus providing coffee having good taste and flavor~ However, coffee flour obtained from coffee grains is subject to subtle changes in its taste and flavor when it is le~t or held in a usual sealed metal containerO The perched coffee is mainly composed of coarse sugar component (in which tannin is present in the form of glycoside, and the sugar component of which comprises sucrose and grape sugar)~ coarse protein, fat, caffein7 coarse fiber~
ach component. These components as a whole influence the flavor and taste. It is not clear which ones of these components particularly have to be retained by suppressing the denaturing. Generally, it is necessary to prevent oxidization and dispersing of the flavorO
By using the freshness keeping material according to the invention~ however, the freshness of coffee could be maintained, and also it was possible to prevent subtle oxidation of the coffee in spite of the fact that the flavor~
sourness and bitterness are subject to very ready oxidization by oxygen in air~ -Examle 3 20 apples were stored in a refrigerator$ which was lined by the freshness keeping material in Example 1 of the invention~ Meanwhile, 20 apples were stored in a conventional refrigerator as such.
Fig~ 4 shows the results of comparative examination of the shift of ths ethylene concentration with the lapse of time.
In the examination, the sole apples are contained in the refrigerators~ the inside temperature thereof was held at 8 + 0~5 ~ with the refrig0rator doors held closed, and 10 ml of the inside gas was extracted ~rom each refrigerator via a gas tube disposed therein~ The extracted samples of the gas were subjectsd to gas chromatography to determine the . . .
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ethylene concentration~ It was found that in the case of the conventional re~rigerator as such the ethylene concentration raised with the lapse of time~ whereas with the re~rigerator according to the invention the ethylene concentration, which was close to the value in the case of the conventional refrigerator, was reduced with the lapse of time and down to an equilibrium value after about 5 hours and could be held at a low value subsequently. The apple is well known as a plant which can emit ethylene greatly~
Fig~ 5 shows the results of comparative examination of the inside temperature shift with refrigerator according to the invention and a conventional refrigerator by holding the refrigerator door held at 8~5 C and held fully open for 10 seconds. With the conventional refrigerator, the the inside temperature was increased up to 17 C maximum, and it took about 110 seconds after closing the door to restore a preset temperature of 8.5 C ~ In contrast~ with the refrigerator according to the invention the inside temperature is increased only by 14 ~, and it took only about 40 seconds after the door closure to restore the preset temperature.
Thus~ high coldness keeping function was recognized. Fur$her, the inside temperature distribution was examined at a certain preset temperature~
Thus, high coldn~ss keeping function was recognized~ Further, ~5 the inside temperature distribution was examined at a certain preset temperature and with the door closed.
A thermostat was turned on to detect the preset temperature and then turned off. The inside temperature is raised naturally for a certain period of time~ With the refrigerator the temp~ratur0 was not raised so much~ With the conventional refrigerator the temp~rature was raised very much. In experiments conducted by setting ~5 C 3 the temperature change was 3~5 C with the refrigerator lined .
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with the material according to the invention while it was 7 C
with $he conventional refrigeratora Table 3 ._ . _ After 1 After 2 After 3 After 4 After 5 week weeks weeks weeks weeks Invention Normal Normal Partial Loss of Loss of yellow leaves stem tips ~ ends Prior Art Partial Loss of Subs-yellow leaves tanti-ing of ally leave rottrn ~ . .
Table 3 shows the results of o~servation of spinach stored in the refrigerator according to the invention and in a conventional refrigerator for 5 weeks, the refrigerators being held at ~ C c In the prior art case, yellowing of leave tips was recognized after one we~k, and almost all the leaves were rotten after 3 weeks~ In contrast~ according to the inv~ntion yellowing of leave tips was recognized only after 3 weeks, indica~ing that it is possible to preserva food for a long period of 3 weeks~
In this ~xperiment, in viaw of the facts that the r~frigerator door was not opened in other times than when the refrigerator inside was observed for every week and that spinach is a plant which does not substantially 0mit ethylene~
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i~ is difficult to explain the resu!ts of experiment with the coldness keeping effect or ethylene emission suppression effect alone~ It has to be considered that the alumina whiskers retaining active water have an effect of keeping the freshness.
As has been described in the foregoing, the material For keeping the freshness of fresh food comprises a base made of aluminum or an alloy thereof and has numerous voids adjacent the outer surface and/or in the inside, some or all of the voids being communicated with one another, whiskers mainly composed of aluminum oxide being formed in at least some of pores formed by the voids, active water having fine structures being retained by the whiskers.
Thus9 in the presence of the freshness keeping material according to the invention the quality of freshness of fresh food can be maintained effectively for long time. More specifically~ when the material is used for preserving fresh food in a refrigerator or the like, it is possible to alleviate over-cooling of the neighborhood of the cold air outlet in ~he refrigeratorp quickly absorb temperature changes when the refrigerator is opened and closed, make the flow of cold air in the refrig0ra~0r uniform and thus cool the stored fresh food without over-cooling~ Further, water content or the like in the atmosphere may be caused to act on the fresh food or water content therein to keep the freshness of the quality or character of the fresh food.
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TITLE OF THE INVENTION
A QUALITY PRESERVING
MATERIAL OF FRESH FOOD
FIELD OF THE INDUDSTRIAL UTILIZATION
This invention relates to materials for preserving the freshness or quality of fresh foods and~ more particularly, to a quality preserving material, which can keep the quality and freshness of fresh foods in a good state for long time.
When is the material used for storing fresh food at a low temperature state, by using is a refrigerator9 it can allaviate over-cooling ambience in the neighborhood of a cool air outlet inside the refrigerator, and also quickly recover temperature drop into an improved state of temperature at the time of opening and closing the door of the refrigerator and make an uniform flow of cool ambient air circulating in the refrigerator, thus eliminating the over-cooling of the stored fresh food and keeping the quality or freshness of the fresh food in a good state!
The quality preserving material according to ~he invantion can ba effectiv01y used for general food and particularly sff0ctively used for fresh foods or the like including vegetables, fruit, meat, fish and shellfish, favorite foods such as coffee and green tea~ and such plants as cu~ flowers and s~sds~
PRIOR ART STATEMENT
For keeping the quality or freshn~ss of foods, such as fish and shellfish, maat, vegetables3 agriculturAI products and other fresh foods, various methods, davices and -.. --. - - :
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,,, ' , ., ' 2~57~3 apparatuses have been proposed and used in practice~ In this connection5 endless e~forts have been paid for researches and developments. Up to date, there are various proposals of techniques ~or keeping fresh food in a good state thereof, instead of canning or thermally sterilizing them9 resulted in providing wide variations and great benefit in consequence of our eating life style, by utilizing the proposal techniques~
The proposal techniques for preserving the food quality are roughly classified into two groups~
The former group is for suppressing cellular function of the fresh food7 and the latter group is for stopping or preventing the progress of maturing or corrosion of tha fresh food.
The former group techniques is further classified into two groups~ The one group is for keeping the food quality in a good state by cooling and the other group is for keeping the food quality in a good state by freezing~
The freezing quality preservation is a method, in which the fresh food is preserved at a temperature lowsr than normal temperature, that is, by cooling the ~ood without causing freezing of water content in the food~ These techniques include commonly term0d cooling and chilling. In this quality preservation techniques~ the quality and ~reshness of the fresh food are kept in a good state without effecting thHrmal sterilization, drying or without use of any salt or sugar for preservation, and activity and propagation of bact0ria concerning th0 corrosion or maturing are suppressed to keep tha quality and freshness of the ~ood in a good state~ The m0thod has recently been improved greatly to have a feature that it permits preservation of fresh food quality without spoiling the quality and freshness thereof~
- The fre0zing quality preservation is a method, in which the frash food is cooled down to a temperature below the , , , . ~ ,. . .
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temperature of freezing of water and also to such an extent that the center temperature of the food is -18 C or below.
This method provides a preservation for long time of food quality7 and consequently it is used for food preservation on ships on the sea or for long time~ However, freezing quality preservaition is liable to destroy the food structure or texture, thus posing problems in the sense of eating and quality of the food after de-freezing~
The latter group techniques is predicated in the fact that among the fresh food vegetables and fruit emit ethylene during maturing and that $he emitted ethylene has an effect of causing enhanced breathing of the vegetables and fruit and thus helping the maturing~ In this method3 the connection of ethylene ~o the maturing is cut~ and the preservation atmosphere is adjusted using, for instance7 carbon dioxide, More specifically, ethylene is removed to stop progress of the maturing of vegetables and fruit9 or ethylene is removed from matured fruit or vegetables to stop further progress of maturing~
This techniqua has a certain effect of preventing the corrosion of fresh food~ However, it is not for keeping the quality or freshness in a good stateg and it does not permit preservation of fresh food in the raw state, Recently~ it has been noted that water contained in food has a closad connection with th0 quality and freshness of food. Gonsequently, there have been proposed a preservation techniques which adjust the character or structure of water contained in the fresh food to thereby keep the quality and freshness of the food in a good state~
Thesa techniques are proposad in a form that active water subjected to electric treatment in an electric or magnetic field is utilized for the preservation of fresh food, growth of plants and manufacture of food~ EspesialIy~ it has bean .
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reported that utili~ation of the active water has specific effects for the growth of plants~ preservation of the quality or the freshness of fresh food and adjustment of the atmosphere surroundin~ the food.
In this technique, however~ the effect goes ahead of theoretical analysis related thereto. Nevertheless, it has been proved that the active water with variation in structure thereof can provide satisfactory biological activity to animals and plants~ In addition to this9 the active water provides results, such as an increase in the hen egg laying, a protection against bacteria of cow by enhancing cow physical strength and a promo$ion of growth of plants.
More specificallyg water containing in fresh food, more particularly, water existing around the cells of fresh food, consists of three layers9 i~e~ 9 those of free water, bonded water connected with the cells and non-frozen water, and the quantity of these kinds of water reaches substantially 80 to 85 %c Particulary, as fresh food or plants are said to be "juicy", water contained in the food has a connection directly closed to the quality and freshness of the food~
According to a recent review~ non-frozen water contained in protein is said to have a melting point of -80 C ~ It is also well known that water contained in food is evaporated slowly compared to ordinary drinking water~
The free water9 bonded water and non-frozen water have respectively clusters with difference of water molecular number~ The bonded water cluster has water moleculer numbers ~reater ~han those of the non -frozen water cluster and smaller than those of the free water clusterc Conseqently, "juicy" of the frash food can be preserved for a long time by an adjustment or an activation of structure and character of the free water, or by a replacement of the free water by an active water with pre -controlled structure~ From these .. , :,. . ..
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points of view, it is necessary to make use of already proved active water for keeping the freshness of fresh food~
In other words~ the prior art techniques of keeping the freshness of fresh food, as noted before~ are to store fresh food in a cold or frozen state or seal carbon dioxide gas or remove ethylene~ It is desired for keeping the freshness of fresh food to make use of active water having adjusted structure or character along with the above freshness keeping techniques~
However, in spiee of the fact that it is very effective for keeping the quality and freshness of fresh food to adjust the structure or character of water and $hus render water to be active, substantially no means or device of adjustment has been developed~ At present9 therefore~ it is impossible to improve the freshness keeping beyond the conventional level.
PROBLEMS TO ~E SOLVED ACCORDING TO THE INVENTION
The present invention is completed in the light of the above background, and it seeks to provide a freshness keeping material, in which mainly active water retained in alumina whiskers has effects of preventing oxidization of fresh food and hence prevent the deterioration of the quality of the food, such as freshness7 taste and flavor and suppressing emission of ethylene gas from fruit or the like as well as adjusting tha structure or character of water contained in the fresh food via the water content in air or like function~ thus permitting long preservation of fresh food~
MEANS FOR SOLVING THE PROBLEMS
According to the invention~ there is provided a material for keeping the freshnass of fresh ~ood, which comprises a base made of alminum or an alloy thereof and having numerous Yoids ~ormed adjacent the outer surface or in , - . .. . . . . . .. . . ..
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2~ 7~3 the inside, some or all thereof being accommodated with one another~ whiskers mainly compose~ of aluminum oxide being formed in at least some of pores formed by the voids, active water having fine structures being retained by ~he whiskers~
In this material, the base made of aluminum or an alloy thereoF consists of a sintered body of aluminum or an alloy thereof in a powdery or fibrous form or of an aggregate of fibrous aluminum or an alloy thereof or a foamed body of aluminum or an alloy thereof.
Further, the base made of aluminum or an alloy thereof, consists of a sintered body of aluminum or an alloy thereof in a powdery or fibrous form for retaining fine structure water via the whiskers.
More specifically, the freshness keeping material according to the invention is a porous material of aluminum or an alloy ~hereof.
The porous material of aluminum or an alloy thereof is manufactured from a powdery or fibrous material of aluminum or an alloy thereof by sintaring or foaming~ the method of manufacture being well known and disclosed in Japanese Patent Publication NOA 47322/1985.
Whiskers mainly compGsed of aluminum oxide are formed in at least some of infinite pores in the porous material~
The whiskers may be formed by a commonly termed boehmite process. In this case, however7 it is necessary to use pure water~ More specifically, pure water is boiled or vapori~ed and~ in this state, act~d on the porous material to thereby form innum0rable very fine whiskers comprising aluminum oxide hydrats on the surfacs and in the pores of the porous material.
The whisker is a very thin elongate member like the "whisker"
on the face~ and very small gaps are formed between adjacent whiskers. Thus fine structllre water, iOe~, very small film of active water~ can be retained between adjacent whiskers.
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The water which is thus retained via whiskers, includes commonly termed active water, which is different in the structure or character from ordinary supply water of distilled water~
Generally, water is expressed by the molecular ~ormula of H~O. Although it may be considered that individual water molecules of H,O are found distinctly, recently it is thought that individual water molecules are bonded to one another into groups of molecules~ These groups of water molecules are called clusters o~ water molecules (or aggregates of water molecules)~ It is said that ordinary water such as supply water and distilled water is found as clusters, in which manu water molecules are bonded to one another in a bar -like or linear form~ and thus has low activity.
In contrast~ by adjusting the structure or character of water, the crystalline structure of water, comprising water molecules bondad to one another into a bar-like or linear form~
is changed into clusters each comprising several water molecules or, according to some theoriesy into a cyclic structure comprising water molecul0s bonded cyclically to one another or a three -dimensional structure, in which such cyclic structures are compounded~ Water having such structures is greatly different in the character or the like from ordinary water. Natural spring water is slightly different structurally from ordinary waterg and thus is different in the taste and flavor. Further~ it is said that water in the cells of a healthy man has a cyclically bonded structura and has high activity~
The adjustment of the structure or character can be obtained by (1) a magnatic field process, (2) an electric field process~ (3) a microwave process, (4) an ultrasonic process, (5) a c0ramic process, (6) an ozone process, (7) a ~
(pai) process, (8) a nuclear magnetic resonance process, (9) - , '.: . ~ : . ' .
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a far infrared radiation process, (10) an electric oven process and (11) a natural stone process~
The constitution and function of these means will now be described in detail with reference to the drawings~
Fig~ 1 is a view with an enlarged scale, showing a potion of the surface of one embodiment of the freshness keeping material according to the invention;
Fig. 2 is an enlarged -scale view showing whiskers formed on the wall surfaces of pores formed between adjacent particles of aluminum or an alloy thereof as the material of the surface keeping material;
Fig~ 3 is a graph showing the relation between the vapor pressure of water retained by the whiskers and the radii of the pores with the whiskers formed therein.
Fig~ 4 is a graph showing the relation between ethylene concentration and the time of maturing in the re~rigerater according to the invention and a prior art refrigerator; and Fig. 5 is a graph showing the relation between the refrigerator inside temperature the door open peirod with the refrigerator according to the invention and a prior art refrigerator, Referring to Fig. 1; refarence numeral 1 dasignates a base of aluminum or an alloy thersof in the freshness keeping material according to tha invention, The base 1 is a porous mat0rial of aluminum or an alloy thereof~ The ~ase 1 has pores 2 communicating three-dimensionally with one anothar~
The percentage in Yolume o~ the pores ~ is desirably 20 to 70 %~ In manufacture~ powd~r of aluminum or an alloy thereof is used as a skeleton material, and a binder m~tal powder having a lower melting point than that of tha powder of aluminum or an ailoy thereof is added~ The mixture powder is disposed without pressure application and sintered in a non-oxidizing atmosphere at a temperature between tha melting point of the " . .; . . - . . .
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binder metal and the melting point of the powder of aluminum or an alloy thereof as ~he skeleton material~ At this time~
the percentage of the pores 25 i~e.~ the porosity, can be adjusted by selecting the shape or grain size of the particles of aluminum or an alloy thereof as the skeleton material~
It is possible to prepare the base 1 by other means than sintering as well1 for instance by compression molding fibrous aluminum or foaming fused aluminumL
Tha base 1, which is thus produced from a porous material of aluminum or an alloy thereof with infinitely bent internal pores 2, has material characteristics such that it is light in weight and excellent in the heat conductivitya Structurally~ it has a complicated surface shape and has innumerable inner pores. Thus~ it has a large surface area and can sufficien$1y dissipate heat~ When it is used to line refrigerator inner surfacesy it can suppress over-cooling of the neighborhood of a cool air outlet and ~reatly alleviate tsmperature changes at the time of opening and closing the refriseratorn In addition, the surface area is actually increased to about lO,000 to 500,000 times the surface area of a flat plate by ~locks of very fine whiskers. Thu~y an effect of adsorbing smell and deteriorating componants can be obtained.
Whiskers 4 are produced on the inner wall surfaces of pores 2 formed between adjacent particles 3 of aluminum constituting the skelaton as well as on the outer surface of the base 1~ as ~hown in Fig, 2~ They are formed by boiling the base 1, which comprises a porous material of aluminum or an alloy thereof~ in water and then heating it in atmosphere at 100 C or above~ The individual whiskers 4 mainly comprise the hydrate of aluminum oxide. Some of them~ however~
are naturally grown as single crystals of Al~0, as beohmite _ g _ .
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2 ~3 ~ 3 is partly caused to undergo a dehydration reaction by heating in atmospheren By adding organic amines, sulfuric acid, etc.
during the boiling process, these components may be provided in the hydrate. The whiskers 4 which are produced in this way are as thin as about 0.01 ~ m in diameter and spaced apart by a distance of about 0~03 ~ m~ They are produced such as to cover the surfaces of aluminum particles 3, which are three-dimensionally continuous to one another.
Then7 active water 5 is retained in the form of fine particles in the base 1 having the above structure via the whiskers 4 which are formed on the surface and in the inside of the base~ This is done by impregnating the base 1 with ac~ive water usually by dipping or spraying and then drying, if necessary, at about 100 C~ In this way, the active water 5 can be retained without evaporation~
More specificalIy~ water having fine structures is retained in the interstices of the whiskers 4~ This is made over the entire wall surfaces of the pores 2~ which are internally three-dimensionally con~inuous to one another. As noted before, a majority of active water is found in $he interstices o~ the whiskers. However, some active water is re -bonded to whiskers to form crystalline structure water, and other is adsorbed in micropores in whiskersn Water 5 such as active water can be retained via whisker 4 irrespective of the ambient atmosphere owing to the fact that the interstices among the whiskers 4 are very fine.
The fall of the vapor pressure of liquid~ for instance watar7 in micropores is governed by the Kelrin's formula.
Figure 3 shows the solution of the formula with respect to wat~r. In the Figure~ curve (a) is obtained at 100 ~, and curve (b) at 20 C. As is seen from the Figure~ while water is boiled at 100 C under 1 atm~, with a micropore diameter of 0.01 ~ m it is condensed rather than boiled~ Thus, with ,,, . ~ .
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such very fine interstices among the whiskers 4 as about 0,01 ~ m, the water provided by the impregnation can be retained stably. In addition~ even when the system is heated at a low temperature after the impregnation with water~ the water that is retained via the whiskers can be evaporated very slightly and remain stably, StructuralIy~ the base 1 has innumerable pores, in which fine whiskers are provided. Thus, it has 10,000 to 500, 000 times the surface area of a flat plate of the same size and hence has an extraordinarily increased heat transfer constant~ Thus, when this material with whiskers is used in a refrigerator~ as cold air passes through the refrigerator~
the flow is un!foYmalized to prevent deterioration of the freshness that might otherwise result from local over-cooling of or lack of uniformity of the temperature distribution in the fresh food.
Further, aluminum or an alloy thereof constituting the base itself can very readily store heat and emit coolness~
In addition5 since it has a large surface area owing to the above structure, at the cold air outlet of a refrigerator, it serves the role of alleviating the cold air to pr0vent over -cooling in the neighborhood of the outlet.
The freshness keeping material having the above structure can keep the quality and freshness of fresh food as follows~
In the first placa, the above structure can block the maturing of vegetables and fruit, Vegetables and the like were matured in the pr~sence of the freshness keeping material of the above structure to find that in comparison to the casa of absence of the material substantially no ethylene gas was gensrated during tha maturing~ Thus1 an effect of blocking the maturing itself can be attained~ The reason for this is not clear in detail, but tha effect is thought to be .
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attributable to ~he adsorbing action of the whiskers 4~ In addition~ ~he base 1 of aluminum or an alloy thereof generates far-infrared rays forming a far-in~rared ray field~
It is thought that the effect is more or less attributable to this far -infrared ray field~ Further, active water retained by the whiskers has influence on the water content in air or like atmosphere, and this effect can be elevated whe~ active water is retained by the alumina whiskers.
When an atmosphere containing ac~ive water is formed around fresh food~ it makes up for the aging of water contained in the fresh food, for instance free water on the surface (the free water being structurally close to ordinary water), thus keeping the freshness of the fresh food~ The reason for this is not clear, It is thought that when active wa~er is retained by whiskers, it provides an effect of keeping the freshness of the food.
The formation of such atmosphere has an effect of suppressing the oxidi~ation of the surface of fresh food and1 in case of coffee or the like with the flavor thereof being important, it has an effect of suppressing the scattering of the flavor.
EXAMPLES
Example 1 An aluminum porous sintered material was prepared by sintering aluminum particles~ This porous sintered material was boiled for one hour at 100 ~C and dried for 1R5 hours to at 150 C to generate whiskers in it. Theng it was impregnated with samples of diluted solutions (diluted from material water) as a kind of ~ (pai) processed water containing iron ions and sodium chloride, disclosed in Japanese Patent Application Public Disclosure No~ 283612/1990 ,. " , ' , ' ~ . -by spraying the solutions~ followed by drying at 40 C for 8 hours~ These two materials were used to keep perched coffee grains in respective containers for one weekl and the freshness of the coffee was examined~ The results were shown in Table 1. The evaluation was done with reference to the following:
Evaluation mark:
1: No flavor change and satisfactory 102: Slight deterioration of flavor 3: Slight deterioration of flavor and weakened taste 4: Slight deterioration of flavot and very weakened taste 5: Defective Table 1 = _ Days The invention material The invention past used in vessel material not used ~ ~ ~ 3 _ _ .
30A: Far-infrared radiation treatment B: Magn~tic field treatment C: Electronic oven treatment D: Ultra-sonic wave treatment - ,: . . . , . . , - .
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Example 2 In lieu of the coffee in Example 1 green tea contained in a vacuum pack was charged into a can~ and it was ~hen processed in a manner as in Example 1 by using active water samples obtained from supply water by the magnetic field process, far -infrared process, electronic oven process and super-sonic wave process~ The results are shown in Table 2.
Table 2 _ _ _ ~. .
Days The invention The invention past material used in vessel material not used 8 . ~ 2 _ The evaluation was done under the same conditions as in Example 1~ Clear differences of effect could be obained with any treated water compared to non-treated watery The coffee, black tea9 green tea, etcO are foods likad 25by individuals3 their distinct flavorg taste and other sofisticated characters are required. Among these linkings, the coffee is subject to its quality and grade depending on the conditions of perching its grains~ Of course9 it has various features depending on the districts of its production~
30Its typical example is blue mountain produced in Jamaica, which is liked by many people in Japan as wellO Blue mountain is liked for its miId flavor~
Further) when serviny coffee, perched coffee grains are "
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~ ~3 ~ 3 ground into flour right before serving, ~hus providing coffee having good taste and flavor~ However, coffee flour obtained from coffee grains is subject to subtle changes in its taste and flavor when it is le~t or held in a usual sealed metal containerO The perched coffee is mainly composed of coarse sugar component (in which tannin is present in the form of glycoside, and the sugar component of which comprises sucrose and grape sugar)~ coarse protein, fat, caffein7 coarse fiber~
ach component. These components as a whole influence the flavor and taste. It is not clear which ones of these components particularly have to be retained by suppressing the denaturing. Generally, it is necessary to prevent oxidization and dispersing of the flavorO
By using the freshness keeping material according to the invention~ however, the freshness of coffee could be maintained, and also it was possible to prevent subtle oxidation of the coffee in spite of the fact that the flavor~
sourness and bitterness are subject to very ready oxidization by oxygen in air~ -Examle 3 20 apples were stored in a refrigerator$ which was lined by the freshness keeping material in Example 1 of the invention~ Meanwhile, 20 apples were stored in a conventional refrigerator as such.
Fig~ 4 shows the results of comparative examination of the shift of ths ethylene concentration with the lapse of time.
In the examination, the sole apples are contained in the refrigerators~ the inside temperature thereof was held at 8 + 0~5 ~ with the refrig0rator doors held closed, and 10 ml of the inside gas was extracted ~rom each refrigerator via a gas tube disposed therein~ The extracted samples of the gas were subjectsd to gas chromatography to determine the . . .
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ethylene concentration~ It was found that in the case of the conventional re~rigerator as such the ethylene concentration raised with the lapse of time~ whereas with the re~rigerator according to the invention the ethylene concentration, which was close to the value in the case of the conventional refrigerator, was reduced with the lapse of time and down to an equilibrium value after about 5 hours and could be held at a low value subsequently. The apple is well known as a plant which can emit ethylene greatly~
Fig~ 5 shows the results of comparative examination of the inside temperature shift with refrigerator according to the invention and a conventional refrigerator by holding the refrigerator door held at 8~5 C and held fully open for 10 seconds. With the conventional refrigerator, the the inside temperature was increased up to 17 C maximum, and it took about 110 seconds after closing the door to restore a preset temperature of 8.5 C ~ In contrast~ with the refrigerator according to the invention the inside temperature is increased only by 14 ~, and it took only about 40 seconds after the door closure to restore the preset temperature.
Thus~ high coldness keeping function was recognized. Fur$her, the inside temperature distribution was examined at a certain preset temperature~
Thus, high coldn~ss keeping function was recognized~ Further, ~5 the inside temperature distribution was examined at a certain preset temperature and with the door closed.
A thermostat was turned on to detect the preset temperature and then turned off. The inside temperature is raised naturally for a certain period of time~ With the refrigerator the temp~ratur0 was not raised so much~ With the conventional refrigerator the temp~rature was raised very much. In experiments conducted by setting ~5 C 3 the temperature change was 3~5 C with the refrigerator lined .
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with the material according to the invention while it was 7 C
with $he conventional refrigeratora Table 3 ._ . _ After 1 After 2 After 3 After 4 After 5 week weeks weeks weeks weeks Invention Normal Normal Partial Loss of Loss of yellow leaves stem tips ~ ends Prior Art Partial Loss of Subs-yellow leaves tanti-ing of ally leave rottrn ~ . .
Table 3 shows the results of o~servation of spinach stored in the refrigerator according to the invention and in a conventional refrigerator for 5 weeks, the refrigerators being held at ~ C c In the prior art case, yellowing of leave tips was recognized after one we~k, and almost all the leaves were rotten after 3 weeks~ In contrast~ according to the inv~ntion yellowing of leave tips was recognized only after 3 weeks, indica~ing that it is possible to preserva food for a long period of 3 weeks~
In this ~xperiment, in viaw of the facts that the r~frigerator door was not opened in other times than when the refrigerator inside was observed for every week and that spinach is a plant which does not substantially 0mit ethylene~
- : . . . . , .
- . . . . -, ,,, , . . , . , : :: .
- . .. . . , . :
. - -' ', ' ' .. ' ~ ,:, , . ,: :
.: ~.. ' ~ ,. '' . ' , . ..
i~ is difficult to explain the resu!ts of experiment with the coldness keeping effect or ethylene emission suppression effect alone~ It has to be considered that the alumina whiskers retaining active water have an effect of keeping the freshness.
As has been described in the foregoing, the material For keeping the freshness of fresh food comprises a base made of aluminum or an alloy thereof and has numerous voids adjacent the outer surface and/or in the inside, some or all of the voids being communicated with one another, whiskers mainly composed of aluminum oxide being formed in at least some of pores formed by the voids, active water having fine structures being retained by the whiskers.
Thus9 in the presence of the freshness keeping material according to the invention the quality of freshness of fresh food can be maintained effectively for long time. More specifically~ when the material is used for preserving fresh food in a refrigerator or the like, it is possible to alleviate over-cooling of the neighborhood of the cold air outlet in ~he refrigeratorp quickly absorb temperature changes when the refrigerator is opened and closed, make the flow of cold air in the refrig0ra~0r uniform and thus cool the stored fresh food without over-cooling~ Further, water content or the like in the atmosphere may be caused to act on the fresh food or water content therein to keep the freshness of the quality or character of the fresh food.
.
:
Claims (3)
1. A quality preserving material of fresh food comprising a base made of aluminum or an alloy thereof numerous voids or pores formed in the outer surface of said base and penetrating through said base, some or all of said voids being communicated with each other, whiskers mainly composed of aluminum oxide being formed in at least some of pores comprising said voids, and an active water with fine or precise size being retained by said whiskers.
2. The quality preserving material of fresh food according to claim 1, wherein said base made of aluminum or an alloy thereof consists of a sintered body of aluminum or an alloy thereof in a powdery or fibrous form.
3. The quality preserving material of fresh food according to claim 1, wherein said base made of aluminum or an alloy thereof consists of an aggregate of fibrous aluminum or an alloy thereof or a foamed body of aluminum or an alloy thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20840492A JPH0630744A (en) | 1992-07-13 | 1992-07-13 | Material for keeping freshness of perishable food |
| JP208404/1992 | 1992-07-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2085793A1 true CA2085793A1 (en) | 1994-02-01 |
Family
ID=16555690
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2085793 Abandoned CA2085793A1 (en) | 1992-07-13 | 1992-12-18 | A quality preserving material of fresh food |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH0630744A (en) |
| CA (1) | CA2085793A1 (en) |
| DE (1) | DE4323006A1 (en) |
| GB (1) | GB2269524B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2767645A1 (en) * | 1997-09-03 | 1999-03-05 | Henri Louis Marie Drean | PRESERVATION PRODUCT FOR LIVING MATERIALS PROCESS AND DEVICE FOR OBTAINING SAME |
| JP5138664B2 (en) * | 2008-12-09 | 2013-02-06 | 直志 門馬 | Sprout training system |
| KR101156050B1 (en) | 2010-01-15 | 2012-07-03 | 한국전력기술 주식회사 | Load measurement apparatus acting on pipe support |
| CN104738225A (en) * | 2015-03-31 | 2015-07-01 | 张松波 | Processing technology of high-fragrance oolong |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63154341A (en) * | 1986-12-18 | 1988-06-27 | 川崎製鉄株式会社 | Far infrared radiator |
| EP0493373A2 (en) * | 1987-11-30 | 1992-07-01 | Nippon Yakin Kogyo Co., Ltd. | A production process of ferrite stainless steel covered with oxide whisker |
| JP2693180B2 (en) * | 1988-08-05 | 1997-12-24 | 大阪瓦斯株式会社 | Stainless steel plate with excellent water repellency |
| JPH0634678B2 (en) * | 1990-07-25 | 1994-05-11 | エヌデーシー株式会社 | Material for long-term preservation of fresh food |
-
1992
- 1992-07-13 JP JP20840492A patent/JPH0630744A/en active Pending
- 1992-12-18 CA CA 2085793 patent/CA2085793A1/en not_active Abandoned
-
1993
- 1993-07-11 DE DE19934323006 patent/DE4323006A1/en not_active Withdrawn
- 1993-07-13 GB GB9314509A patent/GB2269524B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| GB2269524A (en) | 1994-02-16 |
| DE4323006A1 (en) | 1994-01-20 |
| GB2269524B (en) | 1996-04-24 |
| GB9314509D0 (en) | 1993-08-25 |
| JPH0630744A (en) | 1994-02-08 |
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