WO2010068990A1

WO2010068990A1 - Composite protein-rich materials for aquaculture feeds

Info

Publication number: WO2010068990A1
Application number: PCT/AU2009/001641
Authority: WO
Inventors: Robert John Pearce; Peter Richard Simpson; Salah Salem
Original assignee: Shoalhaven Starches Pty Ltd
Priority date: 2008-12-18
Filing date: 2009-12-17
Publication date: 2010-06-24

Abstract

There is a protein-rich material disclosed which is manufactured from at least one wheat protein ingredient and at least one lupin protein ingredient, said protein-rich material being prepared as a composite material to provide complementary nutrition and functionality suited to use in aquaculture feeds.

Description

COMPOSITE PROTEIN-RICH MATERIALS FOR AQUACULTURE FEEDS

Field of the invention

The present invention relates to protein-rich materials manufactured from wheat protein ingredients and lupin protein ingredients that have been prepared as a composite material to provide complementary nutrition and functionality suited to use in aquaculture feeds, to a process for manufacturing said materials and to the application of said materials in aquaculture feed products.

Background to the invention

The consumption of seafood species is increasing globally for cultural and health reasons. Wild catch is unable to sustain the demand and in response an aquaculture industry is developing rapidly. There is a high demand for species including salmon, trout, halibut, eel, crustaceans and molluscs. As the aquaculture industry has developed a demand has arisen for high quality, nutritious feed suited to the species, stage of growth and feeding habit.

There is therefore a need to provide aquaculture feed containing required nutrient ingredients in a format that allows maximum yield of seafood species, maximum utilisation of feed and minimum environmental contamination through un-consumed feed or excessive excrement. The use of high levels offish meal and fish oil in aquafeed is predicted to be unsustainable, therefore, nutrient materials from vegetable sources in particular have been identified as essential for sustainability Glencross et al (2007).

Yeast cells are a potential rich source of nutrients. US Patent No. 5, 158,788 describes a process wherein a highly digestible feed for aquaculture use involves a treatment wherein yeast cells are the external layer of the cell wall is at least partially hydrolysed without damaging the wall itself.

The majority of seafood species are carnivorous which implies that fat and protein are the major constituents of their diets. Protein is required for structural growth, for metabolism and as a source of energy. In natural feed organisms the protein content typically constitutes about half the dry matter. In fish and other species raised in aquaculture as in other animals, the quality of dietary protein is determined by its constituent amino acids and by their digestibility and availability.

For the majority of aquaculture feed applications a sinking feed is most desirable in that it allows the natural tendency to bottom feed. Methods have been employed to make a satisfactory aquaculture feed by compressing ingredients into pellets without cooking, however, such pellets may quite rapidly lose their integrity in water. Addition of a binder derived from wheat or corn adds little nutrition but additional expense. US Patent No 4,935,250 describes the use of an alginate gel in the pellet forming process. US Patent No 6,805,884 describes the use of agar to provide an aquafeed which is stable for a long time, is insoluble and does not load the water chemistry. US Patent No 6,303,175 describes a gel-like feed for aquatic animals that contains a gel former which may be one of several substituted cellulose ethers, polysaccharides, vegetable gum, collagens or mixtures thereof. US Patent No 6,168,815 describes a method for continuous production of dry feed for fish and shell fish based on fresh fish and addition of dry carbohydrate materials, vitamins, antioxidants and binding agents. US Patent No 5,863,586 provides for a fish feed in the form of pellets with a high fat content and superior physical properties made by immersing feed pellets in a hot oil bath to achieve drying and fat absorption followed by cooling to give dry free flowing particles. US Patent 4,981,71 1 describes the use of extrusion cooking as a means to producing a sinking shrimp and fish food in which the cooked mass contains up to 60% vegetable protein. During extrusion the protein within the mixture is developed into laminar striations that ultimately develop into a layered, open celled high protein product with specific gravity greater than 1.00 and which will not decompose in water.

British Patent No 2,217,175 describes the use of gelatine or caseinate as the proteinaceous ingredient. US Patent No 6,685,980 provides for a low pigmented, highly digestible white protein meal from corn gluten to be used in aquafeed. Norwegian Patent 179 731 utilises the binding characteristics produced by the coagulation of native proteins. In order to produce covalently bonded pellets that do not lose their shape US Patent No 6,399,117 describes a process using the enzyme transglutaminase to catalyse cross-linking between proteins in the feed ingredients. US Patent No 6,528, 100 claims an aquafeed product obtained by the use of the transglutaminase enzyme-based process.

Wheat gluten can act both as a source of protein nutrient and a functional pellet binder. For species such as Atlantic salmon with limited ability to digest starch, farinaceous binders cannot be utilised to any great extent ( Hemre 1995a,b). Use of indigestible hydrocolloid binders results in reduced digestibility of protein and fat ( Storebakken, 1985 , Storrebaken et al 1987). The use of wheat gluten as a binder does not cause such problems as it is substantially digestible. (Fagbenro and Jauncey, 1995; Yamamoto and Akiyama, 1995). US Patent No 5, 102,671 describes a feed pellet manufacturing process without heat using wheat gluten to act as both binder and nutrient.

Wheat gluten is highly digestible and can replace a large proportion offish meal in diets of rainbow trout, provided that the diets are supplemented with lysine, the first limiting amino acid in gluten, as demonstrated by Pfeffer et al (1992, 1994) who found an apparent digestibility of 99% for crude protein when feeding a diet of 92.7% gluten and 1.45% lysine to rainbow trout. Wheat gluten had the numerically highest value with respect to apparent digestibility of dry matter and protein when compared to several fish meals, poultry by-products, and vegetable sources in rainbow trout.

Sugiara et al (1997) showed that wheat gluten ranked among the best ingredients with respect to availability of Ca, Fe, K, Mg, P, Sr and Zn. Vegetable protein-rich feed ingredients such as soy bean meal and corn gluten resulted in lower absorption of several elements.

Storebakken et al (2000) showed that there was a trend toward increased apparent digestibility coefficients of fat and energy in diets of Atlantic salmon enriched with wheat gluten, and the diet with 25% wheat gluten was ranked significantly higher than the fish meal control. The apparent digestibility coefficients of crude protein and apparent absorption coefficients of all amino acids except alanine and lysine increased with increasing proportion of dietary protein from wheat gluten. Absorption of amino acids from wheat gluten was between 94 and 100% Wheat gluten is low in lysine but their results indicated that the requirement for lysine was almost met and the requirement for all other amino acids was met even at 50% wheat gluten inclusion due to the supplementing effect of the amino acid profile offish meal.

Helland and Grisdale-Helland (2006) showed that wheat gluten is a suitable replacement protein source for fish meal at a high inclusion level of 20% of Atlantic halibut diet. Further increase should be done with caution up to 30% wheat gluten unless the diet is supplemented with lysine. The lysine content of the diets were 4.0, 3.6 ,3.1 and 2.6% respectively at 0, 10, 20 and 30% wheat gluten. Fish growth and feed efficiency were not influenced by dietary wheat gluten level. The whole-body protein concentration and crude lipid concentration increased with dietary wheat gluten.. It was concluded that the diet containing 2.6% lysine was deficient in this amino acid.

Supplementation of diets with lysine is undesirable because of the high solubility of the lysine in water and the cost. Van Barneveld (1999) indicated that complementary ingredients of consistent and reliable quality can be blended together to provide nutritionally complete diets. Williams (2007) has compared the crude protein content, gross energy and apparent digestibility in several marine species. US Patent Application No 20030180415 describes a highly digestible protein concentrate from corn gluten of a number of grains, plant protein meals, and marine protein meals. US Patent No 5,936,069 describes a process for an improved soy protein concentrate having little or no indigestible oligosaccharides from genetically modified soybeans.

Of plant protein ingredients, lupin protein is one that has been shown to provide some potential as a valuable ingredient in aquaculture diets due to its significant level of lysine but is limited in its use by the low level of methionine. Lupin meals are being used in commercial diets and especially that of lupin kernel meal because of the higher protein content and reduced fibre. To enhance the dietary benefit of lupin protein further, lupin protein concentrates made from lupin kernel flour have been described as prototypes with further increase in protein content to about 70% and further reduction of fibre (Glencross et al (2005). These lupin protein concentrates were produced by a method mimicking the production of soy protein concentrates. The protein content was increased by extracting the oligosaccharides from lupin flour using 70% aqueous ethanol. When included at up to 40 % into a typical salmonid diet formulation and supplied to rainbow trout, no significant effects of inclusion of such lupin protein concentrate on any fish performance criteria such as feed intake or growth was identified relative to a reference diet. Lupin protein concentrate was highly palatable at inclusion levels up to 40% of the diet. Manrique (1977) described extensively parameters that affect the extractability of soluble components from lupin. King et al (1983) described an aqueous extraction method for solubilising much of the protein from lupin meal which can be used as the basis for preparing lupin protein concentrates and isolates.

It has now been shown to be possible to combine the nutritionally complementary aspects of wheat protein and lupin protein with their desirable physical and functional attributes in pellet binding in order to provide a cost-effective composite ingredient for aquaculture feed formulation. In addition, novel manufacturing technology is disclosed that includes an alternative procedure for preparing lupin protein concentrate with low fibre content and procedures for blending the protein-rich components and for drying and pelletising a composite product.

Objects of the invention

It is an object of the present invention to provide novel composite protein-rich materials from ingredients rich in wheat protein and ingredients rich in lupin protein that provide a source of complementary nutrition and desirable functionality in feeds designed and constituted for aquaculture.

Another object of the present invention is to provide novel composite protein-rich materials from ingredients rich in wheat protein and deficient in insoluble fibre and ingredients rich in lupin protein and deficient in insoluble fibre that provide a source of complementary nutrition and desirable functionality in feeds designed and constituted for aquaculture. A further object of the invention is to provide a novel process for the manufacture of novel composite protein-rich materials from ingredients rich in wheat protein and ingredients rich in lupin protein that provide a source of complementary nutrition and desirable functionality in feeds designed and constituted for aquaculture.

A further object of the invention is to provide applications for the novel composite protein-rich materials from ingredients rich in wheat protein and ingredients rich in lupin protein that provide a source of complementary nutrition and desirable functionality in feeds designed and constituted for aquaculture.

Description of the invention

In accordance with a first aspect of the invention a protein-rich composite material for use in aquaculture feed is disclosed, said material including wheat gluten and lupin protein concentrate which are combined in proportions to provide nutrition as ingredients rich in protein and functions of cohesion and integrity in said feed.

In another aspect the invention also discloses an aquaculture feed which includes the aforementioned protein rich composite material.

Preferably said feed is in a compacted or pelleted form.

It is further preferred that said wheat gluten in vital wheat gluten has a protein content greater than about 65% (N x 5.7) and an insoluble fibre content less than about 10% wherein and hereinafter such contents of protein and fibre should be construed to refer to estimations on a weight-for-weight basis in relation to dry solids content. .

It is further preferred that said vital wheat gluten has a protein content greater than about

75% (N x 5.7) and an insoluble fibre content of less than about 5%. Most preferred is that said vital wheat gluten is of a grade manufactured for and suited to the baking industry having protein content greater than about 75% (N x 5.7) and an insoluble fibre content of less than 1%

It is further preferred that said lupin protein concentrate has a protein content greater than about 50% (N x 6.25) and an insoluble fibre content of less than about 20%.

It is further preferred that said lupin protein concentrate has a protein content of greater than about 60% (N x 6.25) and an insoluble fibre content of less than about 5%.

Most preferred is that said lupin protein concentrate has a protein content of greater than about 65% (N x 6.25) and an insoluble fibre content of less than about 5% and has been manufactured from lupin seed or dehulled lupin meal that has an alkaloid content less than 200mg/kg considered suitable as a human food ingredient.

It is further preferred that said vital wheat gluten and lupin protein concentrate are mixed in about equal quantities.

In accordance with a further aspect of the invention a process is disclosed for the manufacture of a protein-rich composite material for use in aquaculture feed, said process including the step of combining wheat gluten and lupin protein concentrate in proportions to provide nutrition as ingredients rich in protein and functions of cohesion and integrity in said feed.

Preferably required amounts of vital wheat gluten powder and lupin protein concentrate powder are blended with for example a ribbon blender and the mixture provided as a powder or preferably delivered to forming or extrusion machinery to achieve the desired form of product.

In an alternative preferred process required amounts of vital wheat gluten powder and liquid lupin protein concentrate dispersion are blended in a suitable mixer and the blend introduced into a drier suitable for drying wheat gluten products such as a ring drier. Such dried composite protein-rich product is preferably delivered to forming or extrusion machinery to achieve the desired form of product.

In another alternative preferred process required amounts of wet vital wheat gluten directly recovered from wheat flour processing or from re-hydration of dry vital wheat gluten and liquid lupin concentrate dispersion that may have been further concentrated by a process such as evaporation using a swept surface evaporator are blended in a suitable mixer and the blend introduced into a drier known to be suitable for drying wheat gluten products such as a ring drier. Such dried composite protein-rich product is preferably delivered to forming or extrusion machinery to achieve the desired form of product.

The method of preparation of liquid lupin protein concentrate dispersion or its dried form is not limited other than that that it is rich in protein and deficient in insoluble fibre having a protein content greater than 50% (N x 6.25) and preferably greater than 65% (N x 6.25) and an insoluble fibre content of less than 20%, preferably less than 10% and most preferably less than 5%. The feedstock for preparation of lupin protein concentrate is not limited and may be from any of whole lupin seeds or meals or de-hulled lupin seeds or meals. Efficiency of preparation may be optimised by selection of average particle size in the meal suited to the processing machinery. A suitable method for the preparation of liquid lupin protein concentrate is provided in one of the following non- limiting Examples,

Examples

Example 1. Preparation of liquid lupin protein concentrate. Method

De-hulled lupin flour from Lupimis angustifolia having protein content of approximately 36% on a dry basis determined on a Nitrogen content x 6.25 was selected and dispersed with vigorous agitation into aqueous suspension with the addition of sodium hydroxide solution to maintain the pH in the range 8.5 to 9.0. The dispersion was extracted through a 3 -tank counter-current extraction system with intermediate decanters to separate heavy and light phases. The initial flour solids to water extraction ratio was 5: 1.

Results

Solids content of final lupin extract = 18% w/w

Protein content (N x 6.25 dry solids basis) = 65%

Example 2. Water removal from lupin protein concentrate by evaporation

Lupin protein concentrate (5000kg) as prepared in Example 1 was continuously introduced into a swept surface vacuum evaporator. The operating conditions of the vacuum evaporator were selected so that the vapor temperature in the evaporator was in the range of 45 to 55°C. Water was continuously removed until the evaporated product would still flow at about 50C and then collected continuously.

Results

Volume of water removed by evaporation = 2500kg

Solids content of evaporated lupin protein concentrate = 36% w/w

Example 3. Preparation of a composite dispersion rich in wheat gluten and lupin proteins.

Method

Liquid lupin protein concentrate ( 5000kg) prepared as in Example 1 was stirred with high shear in a tank and the pH adjusted to 7.0 by addition of hydrochloric acid (16%w/w). To this mix was added vital wheat gluten ( 900kg on a dry basis, 7% moisture content) until uniformly mixed.

The thick, highly hydrated paste was supplied continuously to a high speed pin worker acting as a blender in the re-cycle loop of a ring drier such that the wet paste was vigorously mixed with almost dry material being returned to the blender. The product was recovered continuously from the ring drier and continuously milled and sieved to provide a uniform powder product. Results

Solids content of final wet lupin extract-wheat gluten mix = 30% w/w

Total protein content of mix = 70%

Ratio of lupin protein : wheat gluten protein = 1 : 1.15

Example 4. Preparation of a composite dispersion rich in wheat gluten and lupin proteins.

Method

Liquid lupin protein concentrate ( 2500kg) prepared as in Example 2 was stirred with high shear in a tank and the pH adjusted to 7.0 by addition of hydrochloric acid (16% w/w). To this mix was added wet vital wheat gluten ( 900kg on a dry basis, 68% moisture content) until uniformly mixed.

The thick, highly hydrated paste was supplied continuously to the blender of a ring dryer as in Example 3 and to yield a uniform powder product

Results

Solids content of final wet lupin extract-wheat gluten mix = 36% w/w

Total protein content of mix = 70%

Ratio of lupin protein : wheat gluten protein = 1 ; 1.15

Example 5 Preparation of pelleted lupin-gluten composite aquafeed ingredient

A composite dispersion of liquid lupin protein concentrate and wheat gluten was prepared as in Example 4. The lupin-wheat gluten composite powder was supplied with steam to a pelletising press and formed into 5mm diameter rigid pellets that were cooled on a perforated belt and then packaged.

Result

Moisture content of pellets = 7.3% O

Bulk density of pellets. = 71.5g/l 0OmL

It will thus be appreciated that this invention at least in the form of the examples disclosed provides a novel and improved form of protein rich composite material for use in aquaculture feed. Clearly however the examples disclosed are only the currently preferred forms of the invention and modifications and improvements may be made following further development work by the inventors.

References Cited [Referenced by) U.S. Patent Documents

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Sipsas, S. (2005) Evaluation of the digestible value of lupin and soyben protein concentrates and isolates when fed to rainbow trout {Oncorhyncus mykiss)\ising either stripping or settlement faecal collection methods. Aquaculture, 245:211 - 220.

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Claims

The Claims:-

1. A protein-rich material manufactured from at least one wheat protein ingredient and at least one lupin protein ingredient, said protein-rich material being prepared as a composite material to provide complementary nutrition and functionality suited to use in aquaculture feeds.

2. The protein-rich material as claimed in claim 1 wherein said at least one wheat protein ingredient is in the form of a vital wheat gluten.

3. The protein-rich material as claimed in claim 1 wherein said at least one lupin protein ingredient is in the form of a lupin protein concentrate

4. The protein-rich material as claimed in claim 2 wherein said vital wheat gluten has a protein content greater than 65% on a dry basis and an insoluble fibre content of less than 10%.

5. The protein-rich material as claimed in claim 2 wherein said vital wheat gluten has a protein content greater than 75% protein on a dry basis and an insoluble fibre content of less than 5%.

6. The protein-rich material as claimed in claim 2 wherein said vital wheat gluten is of a grade manufactured for and suited to the baking industry and has a protein content greater than about 75% (N x 5.7) and an insoluble fibre content of less than 1%.

7. The protein-rich material as claimed in claim 3 wherein said lupin protein concentrate has a protein content greater than 50% on a dry basis and an insoluble fibre content of less than 20%

8. The protein-rich material as claimed in claim 3 wherein said lupin protein concentrate has a protein content greater than 60% on a dry basis and an insoluble fibre content of less than 5%.

9. The protein-rich material as claimed in claim 3 wherein said lupin protein concentrate has a protein content of greater than about 65% (N x 6.25) and an insoluble fibre content of less than about 5% and has been manufactured from lupin seed or dehulled lupin meal that has an alkaloid content less than 200mg/kg considered suitable as a human food ingredient.

10. The protein-rich material as claimed in Claim 1 wherein said at least one wheat protein ingredient is in the form of a vital wheat gluten and said at least one lupin protein ingredient is in the form of a lupin protein concentrate and said vital wheat gluten and said lupin protein concentrate are mixed in proportions that provide complementary nutrition with respect to the contents of constituent essential amino acids in the composite material, said proportions being defined by the dietary requirements of the species and stage of development of the organisms in said aquaculture.

11. The protein-rich material as claimed in claim 1 wherein said at least one wheat protein ingredient is in the form of a vital wheat gluten and said at least one lupin protein ingredient is in the form of a lupin protein concentrate and said vital wheat gluten and said lupin protein concentrate are mixed in about equal proportions with respect to protein content.

12. A process for manufacturing a protein-rich material as claimed in claim 1 said process including the step of combining wheat gluten and lupin protein concentrate in proportions to provide nutrition as ingredients rich in protein and functions of cohesion and integrity in said feed.

13. The process as claimed in claim 12 wherein required amounts of vital wheat gluten powder and lupin protein concentrate powder are blended uniformly to form a mixture and said mixture is delivered to forming or extrusion machinery to achieve a desired form of product

14. The process as claimed in claim 12 wherein required amounts of vital wheat gluten powder and liquid lupin protein concentrate are blended uniformly to form a mixture which is dried in a drier and the dried mixture delivered to forming or extrusion machinery to achieve a desired form of product

15. The process as claimed in claim 14 wherein said drier is a ring drier.

16. The process as claimed in claim 12 in which required amounts of wet vital wheat gluten and liquid lupin protein concentrate are blended uniformly to form a mixture which is dried in a drier and the dried mixture delivered to forming or extrusion machinery to achieve the desired form of product.

17. The process as claimed in claim 16 wherein said drier is a ring drier.

18. A protein-rich material for use as an aquaculture feed, said material being substantially as described herein with reference to the examples.

19. A process for manufacturing a protein-rich material for use as an aquaculture feed, said process being substantially as described herein with reference to the examples.