WO2000013513A1

WO2000013513A1 - Masa-based products comprising polyglycerol fatty acid ester and/or modified starch

Info

Publication number: WO2000013513A1
Application number: PCT/DK1999/000465
Authority: WO
Inventors: Viggo Norn; John Seeberg; Allan Sandbeck
Original assignee: Nexus A/S
Priority date: 1998-09-04
Filing date: 1999-09-03
Publication date: 2000-03-16
Also published as: AU5408499A

Abstract

Method of retarding the loss of flexibility of masa-based products including tortillas, soft tortillas, tacos, burritos, enchiladas, tortilla chips and snacks is based during storage on the addition to the masa of an emulsifier such as a polyglycerol fatty acid ester, and/or a modified starch. A synergistic effect is obtained when both active components are added. The shelf-life of tortillas can be extended by at least 3 days, relative to tortillas not containing the active components.

Description

MASA-BASED PRODUCTS COMPRISING POLYGLYCEROL FATTY ACID ESTER AND/OR MODIFIED STARCH

FIELD OF THE INVENTION

The present invention relates to the field of preparing food products based on lime treated corn kernels, i.e. masa. Specifically, there is provided means of improving the storage stability of such products including tortillas by adding to the masa an emulsifier such as e.g. a polyglycerol fatty acid ester and/or a chemically modified starch.

TECHNICAL BACKGROUND AND PRIOR ART

Tortillas, taco shells and other masa-based products are popular food products originating from Mexico. Tortillas in the form of pancakes and taco shells are often consumed with a filling comprising e.g. vegetable materials and other foodstuffs. The masa-based products are made from a special flour prepared from maize (corn) which has been subjected to alkaline conditions at elevated temperatures, and subsequently dried and milled, resulting in a flour being denoted as nixtamalized flour or limed flour. The dough formed from nix- tamalized maize flour is generally referred to as masa.

Presently, industrially produced tortillas and other products based on masa are often prepared and sold as pre-cooked products in order to enable the end consumer to fill and roll the tortillas and subjecting these to a final cooking step. However, a major problem facing food manufactures producing such pre-cooked masa-based products is the limited period of time wherein the products retain their flexibility. Loss of flexibility is generally believed to be due to the association of the amylopectin of the starch, a phenomenon known as retrogradation or staling.

The industrially produced tortillas hence loose their mechanical strength even after a few days of storage. This loss of flexibility results in a product which, when it is rolled or bent, will crumble easily, crack or even break, meaning that such products have a relatively short shelf-life. This short shelf-life inherently impedes the distribution of such products and results in the discarding of a relatively high proportion of the products. The above technical problem related to the limited shelf-life of masa-based products has given rise to different attempts to solve this problem.

Thus J.C. Yau (Cereal Foods World, 1994, vol 39, pp.397-402), who reported on the ef- feet of adding different ingredients to corn flour tortillas. The addition of native maize starch was seen to negatively affect the rollability i.e. the flexibility of the tortillas, whereas the addition of crosslinked-stabilized waxy corn starch did not result in any positive or negative effect. The addition of sorbitol increased the storage stability but had the negative effect of an increased stickiness of the dough, and the addition of proteins in the form of gluten, whey, denatured whey and sodium caseinate affected the tortillas negatively by causing burned spots on the surface of the cooked tortillas. The best results regarding extended storage stability obtained in this study was the combined addition of sodium carboxymethylcellulose (CMC), gluten and sorbitol which prolonged the shelf-life of tortillas by nine days as compared to a control. However, the addition of protein in the form of gluten, gave rise to burned spots on the tortillas surface which is an highly unwanted effect. These authors also reported that addition of monoglycerides and lipids did not affect flexibility properties of corn tortillas

I.C.F Aida (International Journal of Food Science and Technology, 1996, 31 :505-509) re- ported that the addition of a fungal alpha-amylase to masa used for the preparation of tortillas delayed staling and hence had an improving effect on the shelf-life. US 3,655,385 discloses the use of hydrocolloids such as locust bean gum and carboxymethylcellulose as having an improving effect. However, as also found in the above study of Yau (1994), the effect was very limited. T.J. Twillman et al. (Cereal Chemistry, 1988, 65(3):253-257) and US 3,563,915 describe the effect of adding emulsifiers in the form of mono- and di- glycerides to maize tortillas, which apparently results in more Tollable tortillas and retarded staling during storage. However, the addition of mono- and diglycerides in the preparation of tortillas has been tested by the present inventors and it was found to give a very limited effect on retardation of loss of flexibility, confirming the above observations of Yau et al. It was also found that these emulsifiers can only be added in very limited amounts, as higher doses give rise to a shortness of the tortillas and has the undesirable effect that the tortilla is easily broken, which is the same effect as also seen in baked goods containing high amounts of lipids. The above mentioned studies all result in a very limited prolongation of the period of time wherein the tortilla is flexible, i.e. a limited extension of the shelf-life. Furthermore, some of the applied additives result in negative effects on both the appearance and the texture of the tortilla.

According to the present invention, there is now provided a method of preparing a masa- based product, that overcomes the above mentioned disadvantages and results in an improved shelf-life as a result of an enhanced retardation of loss of flexibility, as compared to presently used methods.

SUMMARY OF THE INVENTION

Accordingly, the present invention relates in a first aspect to a method of preparing a masa-based product, the method comprising adding to the masa a polyglycerol fatty acid ester and/or a chemically modified starch in an amount that results in a retardation of loss of mechanical strength of the masa-based product and optionally, at least partially cooking the masa.

In a further aspect, there is provided a composition for preparing masa-based products, the composition comprising a polyglycerol fatty acid ester and a chemically modified starch.

In still further aspects the invention pertains to a masa-based product that is obtainable by the above method and to the use of the composition according to the invention and to a method of preparing such a composition.

DETAILED DISCLOSURE OF THE INVENTION

The primary objective of the present invention is to provide the means of providing masa-based products having improved storage stability characteristics including such product that are at least partially cooked.

The term "masa" is used herein to designate the traditionally used starting material for the production of a range of corn-based food and snack products. Masa is obtained by steeping whole kernels of white and yellow corn (maize) of the dent type in a hot lime solution to soften the outer hull and partially gelatinize the starch in the endosperm. The degree of gelatinazation is generally about 10%. This steeping is typically carried out by adding the kernels to a vat containing heated water and a proportionate amount of lime. The mixture is heated to the boiling point, the heat is turned off, and the contents of the vat are allowed to stand for 10-20 hours. The lime loosens the pericarp from the endosperm so that water can reach the starch and the pericarp can be removed. The corn kernels generally have a moisture content of at least about 50 wt% by the end of the steeping step. The heating and steeping steps result in hydration and partial hydrolysis of the corn hulls. The corn hulls are removed from the steeped kernels by washing and subsequently, the washed kernels are ground in a stone mill into a dough containing about 50 wt% or more of moisture, known as masa. The steeping and heating process is also referred to as nixtamalization. In industrial production of masa-based products, the relatively moist masa is dried and milled into a dry, free-flowing powder that is also referred to as masa flour.

In accordance with the invention the loss of mechanical strength or flexibility of any type of masa-based product during storage can be improved. Such products include tortillas which are prepared from the moist masa material or a dough prepared by adding water to masa flour, and optionally adding other ingredients and preparing flat discs of dough of diameter 10-20 cm and height 1 ,5-2 mm either by hand or by use of any mechanical equipment which squeezes or presses pieces of dough. After they have been made, the flat discs of dough are cooked on a flat plate whose temperature typically varies between 200 and 300°C. In the cooking process, each face or side of the disc is alternately ex- posed to the heat for 15-30 seconds, after which the first side is again exposed for an additional 15-30 seconds. The cooked tortillas have a moisture content of 40-50 wt%. It is also possible to apply less heating to the discs whereby are obtained "pre-cooked" tortillas which are sold to the consumers in moisture tight, closed packages containing a number of such pre-cooked tortillas which must be subjected to a final cooking step prior to eating. Alternatively, the raw, uncooked masa product can be packaged as such and stored at low temperatures including temperatures below the freezing point for the product.

Other masa-based products that can be improved in accordance with the invention include "burritos", "enchiladas", flavoured tortillas, "wraps", tortilla chips, taco shells and masa-based snack products. In the present context, the expression "at least partially cooked masa-based products" refers to any of the above products which during processing have been subjected to a heating step which, in relation to the appropriate heating state when the products are eaten, can be partial or complete. Thus, as an example the above pre-cooked tortillas represent a partially cooked masa-based product.

As mentioned above, masa-based products such as tortillas are soft and flexible when fresh and this characteristic is an essential part of the quality of such products. However, even when kept under conditions in which no moisture is lost, the products loose their mechanical strength and become hard and inflexible with the passage of time and break or crumble easily when flexed, rolled or bent. As used herein the expression "mechanical strength" refers to the ability of masa-based product to resist breaking when subjected to flexing, rolling or bending as it is defined in the following examples. The term "flexibility" is used herein interchangeably with "mechanical strength". Hardening or loss of flexibility of masa-based products is believed to be due to physico-chemical change in the starch con- stituent which is known as retrogradation. Due to this hardening phenomenon, the shelf- life of packaged masa-based products is relatively short, typically only a few days. It is therefore an important aspect of the invention that the hardening or retrogradation process can be retarded so that the shelf-life of the products can be extended.

In determining the flexibility of a disc shaped masa-based product such as a tortilla, the product is bent around a bar representing a rod-shaped cylindrical element, of known radius and this is done with successively smaller bars until a bar is found which is the smallest around which the tortilla just breaks when it is bent. A more flexible tortilla will just break when it is bent around a smaller bar than a less flexible bar.

In one aspect of the invention there is provided a method whereby the loss of mechanical strength of masa-based products can be retarded. The method is based on the finding that adding an effective amount of an emulsifying agent including a polyglycerol fatty acid ester or a mixture of such esters or a chemically modified starch can retard the hardening process and thereby significantly retard the loss of the mechanical strength or flexibility of the products. In this connection, the retardation of the loss of the mechanical strength is to be understood as implying an improvement of the storage stability of the product in the sense that the point in time during storage where the hardening of the products has progressed to an extent where the product will break when tested for flexibility as defined above, is delayed. Although it has been found that fatty acid esters of polyglycerols are highly useful in the invention, it is contemplated that other surfactants or emulsifiers used in the food industry can be used, optionally in combination with a polyglycerol fatty acid esters. Examples of such other emulsifiers include lecithin, modified lecithin, monoglycerides, diglycerides, ethoxylated monoglyceride, sorbitan monostearate, a polysorbate, succinylated monoglycerides, sucrose esters, lactic acid esters of mono- and diglycerides, propylene glycol esters of fatty acids, sodium stearoyl lactylate, diacetyl tartaric acid, acetic acid or citric acid esters of mono- and diglycerides and salts of fatty acids.

In the present context, the term "polyglycerol fatty acid ester" refers to a group of non- ionic surfactants consisting of an oligomeric or polymeric glycerol moiety which is esteri- fied with one or more fatty acids through the free hydroxyl radicals. Thus, the degree of polymerization of the polyol moiety can vary e.g. between 2 and 20 glycerol groups such as 2 to 10 glycerol groups. The fatty acids which are used for esterifying these glycerol condensates include long chain fatty acids such as C₆.₂₄ fatty acids, presently preferred fatty acids being selected from C₁₆.₁₈ fatty acids. The fatty acids may be saturated, mono- or polyunsaturated depending on the desired characteristics of the polyglycerol fatty acid ester. It will be appreciated that the expression "polyglycerol fatty acid ester" includes mixtures of species hereof having varying numbers of glycerol moieties and varying fatty acids. In this connection, useful polyglycerol fatty acid esters include such compounds having HLB values in the range of 5 to13 such as in the range of 8 to 12.

In useful embodiments of the invention, the amount of polyglycerol fatty acid esters which is added to the masa is in the range of 0.01-10 wt% including the range of 0.05-5 wt% such as in the range of 0.1 to 3 wt%.

In accordance with the invention, the retardation of loss of mechanical strength of the products can also be achieved by adding an effective amount of a chemically modified starch including any such starch product that can be used in the manufacturing of edible products. In the present context, the term "chemically modified" includes any enzymatic modification of native starch. Presently available modified starches include oxidized starch, monostarch phosphate, distarch phosphate, phosphated distarch phosphate, acetylated distarch phosphate, acetylated starch, acetylated distarch adipate, hydroxy propyl starch, hydroxy propyl distarch phosphate, acetylated oxidised starch, crosslinked starch and starch sodium octenyl succinate. Additionally, the term "chemically modified starch" as used herein include partially hydrolysed starch products such as maltodextrins. It will be understood that mixtures of any of such modified starches can be used. One presently preferred modified starch is acetylated distarch phosphate which e.g. can be derived from tapioca.

Typically, the modified starch is added to the masa dough in an amount that is in the range of 0.01-30 wt% including the range of 0.01-20 wt% such as in the range of 0.01 -10 wt%, e.g. in the range of 0.05-5 wt%.

When both of the above active components are added in combination, the ratio between the amount of polyglycerol fatty acid ester and the modified starch is typically in the range of 1 :1 to 1 :100, e.g. in the range of 1 :1 to 1 :50 including the range of 1 :1 to 1 :30.

As mentioned above, a substantial retarding effect on the loss of mechanical strength of masa-based products was found with either of a polyglycerol fatty acid ester and a chemically modified starch. However, it was surprisingly found that the addition of a mixture of these compounds results in a much higher effect than could be expected by simply adding the effects of the compounds. In other words, a strong synergistic effect was observed when combining a polyglycerol fatty acid ester compound and a chemically modified starch compound as it is illustrated in the below examples.

In one specific embodiment, the method of the invention is one wherein the retardation of the loss of mechanical strength results in that the period of time where the at least partially cooked masa-based product is flexible, is increased by at least 3 days such as at least 4 days e.g. at least 5 days relative to that of an otherwise similar masa-based product not containing a polyglycerol ester and/or a chemically modified starch, said flexibility being measured at time intervals by rolling a sample of the masa-based product around a rod shaped cylindrical element having a diameter of about 10 mm and recording the time at which the at least partially cooked masa-based product can no longer be rolled onto the cylindrical element without breaking.

The active components, the polyglycerol fatty ester and/or the modified starch can, in accordance with the invention, be added to the masa in varying forms. Thus, in one embodiment the polyglycerol fatty acid ester is added to the masa in the form of a melt, e.g. having a temperature in the range of 30 to 100 °C. In other embodiments, the active com- ponents are added separately or as a mixture in the form of a granulate or a powder, e.g. in the form of an extruded powder. Alternatively, the active component(s) is/are added to the masa in the form of a paste such as a paste having a moisture content in the range of 5 to 50 wt%.

In a further aspect, the invention provides a composition for preparing masa-based products, the composition comprising a polyglycerol ester as defined above and a chemically modified starch as also defined above. In such a composition, the amount of polyglycerol fatty acid ester or chemically modified starch is in the range of 0.01-90 wt% including the range of 0.05-50 wt% e.g. an amount which is the range of 1 to 25 wt%. Examples of specific compositions according to the invention are given in the below examples.

In addition to the above active components, the composition may contain further components such as a monohydric, dihydric or polyhydric alcohol including as examples glyc- erol, 1 ,2 propanediol (propylene glycol), a fatty acid including stearic acid and a base such as e.g. potassium hydroxide.

In accordance with the invention the composition is provided in any convenient form including a paste, a powder, a granulate, a suspension, an emulsion or a slurry. It will be appreciated that the present composition may also contain the masa components such as e.g. nixtamalized corn flour. In such an embodiment, the composition can be provided as a dry pre-mix possibly containing all ingredients for manufacturing masa-based products. The composition is prepared by any conventional methods of making the above composition forms, which method may include an extrusion step.

The invention will now be explained in further details in the following, non-limiting examples.

EXAMPLE 1

Preparation of tortillas using compositions containing polyglycerol fatty acid esters and modified starch

Cooking experiments were set up in order to investigate the effect of applying polyglycerol fatty acid esters, modified starch or a combination of polyglycerol fatty acid esters and modified starch on the characteristics of pre-cooked tortillas.

The polyglycerol fatty acid esters and/or the modified starch were added to a masa dough as a paste or a powdered composition. The preparation and formulation of the paste compositions (B98-029, B98-175) and the powdered composition (E98-515) can be found in the below Examples 3 and 4.

In these experiments the following two different types of com (maize) flour was used:

Masa Minsa: Instant corn flour, USA. Contains nixtamalized, stone ground corn flour, fu- maric acid, sorbic acid, propionic acid, and calcium in trace amounts, and

Maseca: Nixtamalized corn flour, Mexico not containing additives.

The modified starch product used was Purity 69A (acetylated distarch phosphate), National Starch, Manchester, England and the polyglycerol fatty acid ester product used was Palsgaard 1024, Palsgaard Industry A/S.

The recipes for the preparation of the tortilla doughs are shown in the below Tables 1.1 and 1.2. The amounts are given in units of weight.

TABLE 1.1

TABLE 1.2

The ingredients were mixed using a Hobart N50 mixing apparatus provided with a spatula, operated in first gear for 3 minutes. The finished dough was separated into pieces having a weight of 32 g. The dough pieces were formed into to a disc shaped form having a diameter of 15 cm. The disc formed dough pieces were cooked immediately on a hot plate at 220-240°C for 24 sec, turned around and heated on the other side for 24 sec and then flipped back to be heated for a further 24 sec. The resulting tortillas were stacked and stored in moisture-proof plastic bags at room temperature (20-22°C). The flexibility of the tortillas was tested after 1 , 5 10, 15 and 20 days of storage by wrapping them around a rod shaped bar of known radius, repeating this with successively smaller radii and detecting when the tortilla was breaking. The test was performed by using round sticks of a length of 30 cm and radii of 20, 16 and 10 mm, respectively.

The results of this test are summarised in the below Tables 1.3 and 1.4, where "-" designates a broken tortilla and "+" designates a perfect and not broken tortilla.

TABLE 1.3: Results of flexibility test of tortillas of the recipes in Table 1.1

TABLE 1.4: Results of flexibility test of tortillas of the recipes in Table 1.2

As it can be seen from the above Tables 1.3 and 1.4, the addition of modified starch to the tortilla dough significantly increases the flexibility of the pre-cooked tortillas. In e.g. Table 1.3, recipe No. 2, the tortilla is flexible after 20 days of storage using a bar diameter of 20 mm, whereas the control (recipe No. 1 , Table 1.3) without addition of modified starch is breaking after the same period of storage. Likewise it can be seen from Table 1.4, recipes Nos. 1 (control) and 2 (addition of modified starch) that the control tortillas brake already after 15 days of storage (bar diameter 20 mm), whereas the tortillas containing modified starch are still flexible or reliable after the same period of time.

It also appears from Tables 1.3 and 1.4 that the addition of polyglycerol fatty acid esters to the tortilla dough has a significant improving effect on the flexibility and rollability of precooked tortillas. In e.g. recipe No. 3, Table 1.3, the addition of polyglycerol ester results in a pre-cooked tortilla that is not breaking after 20 days of storage (diameter 20 mm), whereas the control (recipe No. 1 , Table 1.3) is breaking after 15 days of storage. Likewise, the tortilla prepared with addition of polyglycerol ester in recipe No. 3, Table 1.4, is also flexible (20 mm) after 20 days of storage, whereas the control is only flexible/rollable until 10 days of storage.

The combined effect of adding both polyglycerol ester and modified starch to a tortilla dough can be seen from Tables 1.3 and 1.4. When e.g. comparing recipe No. 4 (Table 3.3) with the control (recipe No. 1) it is clear that the combined addition has a highly improving effect on the flexibility of pre-cooked tortillas. The tortilla of recipe No. 4 was flexi- ble/rollable after 20 days of storage at all bar diameters (20, 16 and 10 mm) whereas the control was breaking at day 20 (20 mm), day 15 (16 mm) and day 5 (10 mm), respectively. Similar results can be seen in Table 1.4 where the combined effect is also clearly seen from the results of recipe No. 4 as compared to the control (recipe No. 1).

Furthermore, it appears from Tables 1.3 and 1.4 that the combination of polyglycerol fatty acid ester and modified starch has an synergistic improving effect on the flexibility of the tortillas. This synergistic effect can be seen from e.g. Table 1.3 by comparing recipe No. 4 with recipe No. 2 (addition of modified starch) and with recipe No. 3 (addition of polyglyc- erolester). The effect is clearly not just an additive effect.

The data in Tables 1.3 and 1.4 illustrates the effect of adding the polyglycerol fatty acid ester and the modified starch in the form of a powder (recipe No. 5) which is also see to clearly enhance flexibility after storage as compared to the control (recipe No. 1). Furthermore, it is also seen in Tables 1.3 and 1.4 (recipe No. 6) that the addition of polyglycerol ester and modified starch in the form of a paste product improves the flexibility of the pre-cooked tortilla after being stored, as compared to the control.

EXAMPLE 2

Preparation of tortillas using compositions containing polyglycerol fatty acid esters and modified starch products

Cooking experiments similar to the above were set up in order to investigate the effect of applying two different modified starch products both of the type acetylated distarch phosphate.

The modified starch products were SMS747 (acetylated distarch phosphate), Siam Modi- fied Starch Co., Ltd, and SMS757 (acetylated distarch phosphate), Siam Modified Starch Co., Ltd.

The recipes for the preparation of the tortilla doughs are shown in the below Tables 2.1 and 2.2. The amounts are given in units of weight. The tortillas were prepared as de- scribed in Example 1.

TABLE 2.1

TABLE 2.2

The results of this test are summarised in the below Tables 2.3 and 2.4, where "-" designates a broken tortilla and "+" designates a perfect and not broken tortilla.

TABLE 2.3. Results of flexibility test of tortillas of the recipes in Table 2.1

TABLE 2 4 Results of flexibility test of tortillas of the recipes in Table 2 2

The above results generally confirmed the results obtained in Example 1 The effect of the two modified starches was substantially identical

EXAMPLE 3

Preparation of compositions in paste form containing polyglycerol fatty acid esters and modified starch

The following formulations of paste compositions were prepared

TABLE 3 1

The paste products were prepared by melting the polyglycerol fatty acid ester emulsifier and adding to the melt a heated aqueous phase containing the water soluble ingredients at a temperature above that of the emulsifier. The addition of the aqueous phase was done under continuous mechanical processing i.e. stirring and optionally circulation using a mechanical pump until a homogeneous product was obtained. The modified starch can be added via the aqueous phase or it can be added in a separate process step after the aqueous phase containing the remaining water soluble ingredients are added to the melt of the polyglycerol fatty acid ester.

EXAMPLE 4

Preparation of compositions in powder form containing polyglycerol fatty acid esters mixed with modified starch

The powdered compositions were prepared as described in US 4,748,027 using an extruder, type BC 45 (Clextral Framatome). in the below Table 4.1 the compositions of the extruded compositions are summarized:

TABLE 4.1

In addition to the fatty acid polyglycerol esters the extruded compositions contain glycerol and optionally, 1 ,2 propanediol.

Claims

1. A method of preparing a masa-based product, the method comprising adding to the masa a polyglycerol fatty acid ester and/or a chemically modified starch in an amount that results in a retardation of loss of mechanical strength of the masa-based product and optionally, at least partially cooking the masa.

2. A method according to claim 1 wherein the amount of polyglycerol ester is in the range of 0.01-10 wt% including the range of 0.05-5 wt%, of the masa.

3. A method according to claim 1 wherein the amount of the chemically modified starch is in the range of 0.01-10 wt% including the range of 0.05-5 wt%, of the masa.

4. A method according to claim 1 wherein the retardation of loss of mechanical strength results in that the period of time where the masa-based product is flexible, is increased by at least 5 days relative to that of an otherwise similar masa-based product not containing a polyglycerol ester and/or a chemically modified starch, said flexibility being measured at time intervals by rolling a sample of the masa-based product around a rod shaped cylindrical element having a diameter of about 10 mm and recording the time at which the masa-based product can no longer be rolled onto the cylindrical element without breaking.

5. A method according to claim 1 wherein the masa-based product is selected from the group consisting of a tortilla and a taco product.

6. A method according to claim 1 wherein the polyglycerol fatty acid ester is added to the masa in the form of a melt.

7. A method according to claim 1 wherein the polyglycerol fatty acid ester and/or the chemically modified starch is added to the masa in the form of a powder.

8. A method according to claim 1 wherein the polyglycerol fatty acid ester and/or the chemically modified starch is added to the masa in the form of a paste.

9. A method according to claim 1 wherein the chemically modified starch is acetylated distarch phosphate.

10. A method according to claim 9 wherein the acetylated distarch phosphate is derived from tapioca.

1 1. A composition for preparing masa-based products, the composition comprising a 5 polyglycerol fatty acid ester and a chemically modified starch.

12. A composition according to claim 1 1 wherein the amount of polyglycerol fatty acid ester is in the range of 0.01-90 wt% including the range of 0.05-50 wt%, of the masa.

10 13. A composition according to claim 11 wherein the chemically modified starch is selected from the group consisting of oxidized starch, monostarch phosphate, distarch phosphate, phosphated distarch phosphate, acetylated distarch phosphate, acetylated starch, acetylated distarch adipate, hydroxy propyl starch, hydroxy propyl distarch phosphate, acetylated oxidised starch, crosslinked starch and starch sodium octenyl succinate.

15

14. A composition according to claim 11 comprising a further component selected from the group consisting of an alcohol, a fatty acid including stearic acid and a base including potassium hydroxide.

20 15. A composition according to claim 14 wherein the alcohol is selected from the group consisting of glycerol and 1 ,2 propanediol.

16. A composition according to claim 11 which is in the form of a paste.

25 17. A composition according to claim 11 which is in the form of a powder.

18. A composition according to any of claims 11-17 that comprises nixtamalized cereal flour.

30 19. A masa-based product obtainable by the method of any of claims 1-10.

20. Use of a composition according to any of claims 11-18 for preparing a masa- based product.

21. Use according to claim 20 wherein the composition is added as a premix comprising all dry ingredients for preparing the masa-based product.

22. A method of preparing a composition according to any of claims 11-18.

23. A method according to claim 22 comprising a step of shear stress treatment including an extrusion treatment.