GB2030438A - Novel, starch containing food products and process for preparing same - Google Patents

Abstract

Commercially prepared dry food products, prepared for ultimate consumption by being added directly to boiling aqueous liquid and cooked therein, contain a thickening agent comprising a root starch or tuber starch having retarded-thickening properties, particularly heat-moisture-treated potato starch, tapioca starch or arrowroot starch. The product may be vanilla custard sauce, white sauce with vegetables, lentil broth, brown gravy mix or dumplings with sauce. <IMAGE>

Description

SPECIFICATION Novel, starch containing food products and process for preparing same This invention relates to a novel class of food products which include starch as a thickening agent. More specifically, the invention relates to commercially prepared, dry (i.e., non-aqueous) food products which are prepared for ultimate consumption by adding them directly to boiling aqueous liquids (such as water, milk, boullion etc.) and cooking them in the boiling liquid, wherein the thickening agent consists of a root starch or tuber starch having retarded thickening properties, preferably a heat-moisture-treated potato starch.

The term "heat-moisture-treated starch" is well known in the art, and is commonly used to refer to a starch which has been subjected to a heat treatment under controlled moisture conditions, the conditions being such that the starch undergoes neither gelatinization (i.e., exhibits substantially no loss of bire-fringence) nor dextrinization. Louis Sair, in Methods In Carbohydrate Chemistry. Vol. IV, R.J. Whistler Ed., Academic Press N.Y. (1964) pp. 283-285, describes laboratory-scale methods for heat-moisture-treated starches, and also describes various properties of starches so treated.

As is known, heat-moisture-treatment affects various properties of all amylose-containing starches, but perhaps the most dramatic alteration takes place when root or tuber starches, particularly potato starch, are subjected to such a treatment. As has been reported in the literature, when measured as a function of time as with a Brabender Viscograph the "viscosity peak", i.e., the point of maximum viscosity increase during gelatinization, is delayed and also lowered. A starch whose viscosity peak has been delayed in this manner will be referred to throughout the instant specification and claims as a starch having "retarded thickening properties".

It should be noted that retarded thickening properties can be imparted to root starches by various means.

One method is to heat an aqueous slurry of starch at just below its gelatinization temperature. This method requires very careful temperature control in order to avoid gelatinization of the starch, and therefore it is less practical than the preferred method in which granular starch is treated at temperatures above the gelatinization range, under conditions of moisture and temperature which avoid gelatinization and dextrinization. A recently reported method is disclosed in U.S. Patent 3,977,897 to Wurzbu rg which involves heating an aqueous slurry of starch at from 500c. to 1 00"C., gelatinization being avoided by including in the slurry an appropriate amount of a suitable inorganic salt which raises the gelatinization temperature of the starch.Needless to say, starches so prepared must be thoroughly washed to remove the salts prior to using them in food products.

The most practical commercial method for preparing starches having retarded thickening properties for use in the instant invention is simply to heat starch, at its normal moisture content (or with some added moisture, if desired, but not in aqueous slurry) in a closed heating device, to give the desired degree of heat-moisture-treatment. Specific suitable conditions, and "guide-lines" for selecting suitable conditions, will be presented hereinafter.

Retarded-thickening properties can also be imparted to starch by means of chemical modification, but such methods are costly and may also employ chemicals which are undesirable or even prohibited in food.

Because the instant invention relates solely to products intended for human consumption, these last-mentioned chemically-modified starches are generally not considered suitable for use in the invention.

Specifically, the invention comprises a commercially prepared dry food product containing a thickening agent, which food product is prepared for ultimate consumption by adding it directly to boiling aqueous liquid and cooking it in same, wherein the thickening agent consists of a root starch or tuber starch having retarded-thickening properties. Most preferably the thickening agent consists of a heat-moisture-treated potato starch.

Typical examples of such food products include sauce or gravy bases, comprising starch plus flavouring and/or colouring materials, dry soup mixes containing dehydrated vegetables and/or meat plus a thickening agent and other food products which include at least one main ingredient which must be cooked in boiling water plus a sauce base, containing a starch thickening agent, which also must be cooked in boiling water.

Examples of these last-mentioned food products are pasta or dumplings plus sauce.

Referring first to the sauce or gravy bases, it is well known that if one simply adds starch, or a base mix containing same, to a boiling liquid such as water or milk, the starch will rapidly form lumps which cannot be dispersed even with the most vigorous and extended stirring. This is because upon contact with the hot liquid the outer portion of the starch clusters immediately gelatinize, and this "coating" of gelatinized starch forms a barrier against water penetration into the clusters. Many methods have been proposed to delay the dehydration of starch until it has fully dispersed in the hot liquid, including adding to the starch-containing base mix a dispersing agent such as lactose or malto-dextrin, or coating the starch with fat.It has now been discovered that a potato starch with suitable retarded thickening properties, when added to boiling liquid with a slight amount of stirring, will disperse completely in the liquid prior to any actual thickening taking place. Therefore, a sauce or gravy base containing such a starch as the thickening agent can be reconstituted for consumption by merely adding it directly to boiling liquid and stirring gently for one or two minutes until the desired viscosity is reached, resulting in a smooth, lump-free, sauce or gravy.

In the area of products such as dumplings-plus-sauce combinations the use of a root starch having retarded-thickening as the thickening agent produces truly dramatic results, as will be seen in the Examples. Normally, such products are sold as "combination" packages, the dumplings being separate from the sauce base. To prepare the meal the consumer must boil the dumplings in water for the requisite period of time and prepare the sauce in a separate cooking utensil by cooking the base mix in water. One could not normally cook both the sauce and the dumplings simultaneously in the same kettle, because the suace base, upon thickening, would immediately take up and "bind" a good portion of the water, leaving insufficient free water to cook completely the dumplings.However, to prepare such a product which has been made in accordance with the invention the consumer can merely add all of the ingredients, the dumplings and the sauce base, directly to a single kettle of boiling water and permit it to cook for the requisite period of time.

During the first stage of cooking no substantial thickening of the sauce takes place, thereby leaving all of the water free to hydrate and cook completely the dumplings. Then, during the last few minutes of the cooking time the sauce thickens, after which the complete meal is ready to be served and eaten.

By applying appropriate conditions of heat-moisture-treatment potato starches of different gelatinization characteristics (e.g., time required for commencement of thickening and extent of ultimate thickening) can be prepared; therefore such starches can be "tailor-made" to meet the requirements for any specific food product application. Following are some general principles regarding heat-moisture-treating of potato starch (as well as other root starches).

(1) The moisture present can be as low as about 16% and should not exceed 35% be weight. Frequently potato starch at its "normal" moisture level at ambient temperature and relative humidity, i.e., 18-21% moisture, can be employed without any additional water being added.

(2) The temperature can be as low as 55,C., and should not exceed about 135"C; excessive temperatures results in secondary changes, e.g., dextrinization. Temperatures within the range of 90"C. are suitable for most degrees of modification.

(3) The time of treatment will depend upon the desired degree of modification and also, of course, upon the equipment used, which equipment used will define, of course, the quantity of starch being treated and the time at which the starch itself reaches treatment temperature.

(4) Other conditions being equal, the extent of the modification of the starch (i.e., delay in reaching viscosity peak and lowering of the ultimate viscosity) is increased with increases in any of the three variables of water content, temperature and time.

(5) Because gelatinization of the starch (including any substantial loss of birefringence) must be avoided, relatively low temperatures must be employed at high moisture levels, while high temperatures (up to about 135"C.) may be used at lower moisture levels.

Following are descriptions of two specific heat-moisture-treatments to produce starches having desireable properties for different food applications. The equipment used was a laboratory-scale, slowly rotating jacketed cylindrical autoclave which rotates in the horizontal axis. The outlet of the autoclave was insulated to prevent localised temperature differences which would cause condensation and partial gelatinization of the starch. The volume of the cylinder was 9 litres, and the heating medium used in the jacket was glycerine.

The autoclave was hermetically sealed during treatment.

In each case the autoclave was brought to the desired temperature, 3 kg. of native potato starch, containing 19.2% moisture content was introduced into the autoclave, the autoclave was closed and the starch treated for the requisite period of time. The starch was then removed from the autoclave and spread out in a thin layer at room temperature to facilitate cooling and drying. After reaching room temperature the starch, which had a moisture content of about 15%, was sieved. Before use in the Examples, all of which exemplify dry food mixes, the starch was dried to a moisture content of about 8%.

The first starch, designated as STARCH A, was treated to render it suitable for use as a thickening agent for a sauce or gravy base. For such products extensive modification is neither necessary nor desirable; the gelatinization time need not be delayed for more than a few seconds (just long enough to permit the starch to become fully dispersed in the boiling liquid), while a fairly high final viscosity is required. Therefore, this starch was subjected to a relatively mild treatment conditions, specifically a temperature of 1 03 C. for a period of 115 minutes.

The second starch, designated as STARCH B, was prepared for use as a thickening agent in soup mixes or sauce mixes which were to be used in conjunction with other dried food products requiring relatively long cooking time. For such products one needs a starch, the thickening of which is delayed for several minutes, i.e., sufficient time to permit the other ingredients to become fully cooked. For starch B the treatment conditions selected were 100"C. for 195 minutes.

The drawing gives the Brabender curves for the untreated potato starch and starches A and B.

Starches Aand B were then employed as thickening agents in various dried food products formulations, as set forth in the following examples. The examples are presented for illustrative purposes only and the skilled practitioner will readily be able to select optimum starches and recipe formulations for a wide variety of food products.

EXAMPLE I, BROWN GRA VYMIX Recipe la (Invention) Ingredient Amt. (gms) Percentage STARCH A 259 46.25 Malto-dextrin 51 9.11 Rice flour 18 3.21 Lactose 70 12.05 Flavourings & 138 24.64 colourings Sunfiower oil 24 4.29 TOTAL 560 100.00 Recipe Ib (Comparison) This was identical to Recipe la except the STARCH A was replaced by 259 gms. native (untreated) potato starch.

Recipe Ic (Comparison) This was identical with Recipe la except STARCH A was replaced by 373 gms. of wheat flour. In this example, and in other examples wherein the wheat flour is employed for comparative purposes, the amounts of wheat flour are adjusted so as to give a product having the same final viscosity as the product prepared in accordance with the invention, when both products are reconstituted for consumption under identical conditions, by adding the product to cold aqueous liquid and then heating to effect the gelatinization and thickening.

Reconstitution of the Base Mixes for Comsumption In each case 250 ml. water was brought to boiling and the base mix (15 gm. each of recipes la and Ib, and 18 gm. of recipe Ic) were added directly to the boiling water with stirring. The products were then simmered with occasional stirring for about 1 > minutes. The products were then removed from the heat and poured through household strainers into bowls.

Observations and Results Recipes Ib and Ic thickened immediately upon being introduced into the boiling water, with the formation of large lumps which did not disperse during the simmering period, even with stirring. Ia showed no thickening upon being introduced into the water, but gradually began to thicken about 5-10 seconds later, and had fully gelatinized and thickened by the end of the cooking time of 16 minutes.

Gravy la contained no lumps whatsoever, and had an excellent, smooth, short texture. Gravy Ib contained a number of lumps, which were retained by the strainer, and the texture of the strained gravy was glutinous and stringy, although relatively smooth (the lumps having been all retained on the strainer.) Gravy Ic contained a great many lumps of various sizes, the large ones being retained by the strainer, the smaller ones passing through thereby rendering the strained gravy lumpy as well. Furthermore, the strained gravy was substantially less thick than gravies la and Ib, and had a decidedly watery texture.

EXAMPLE II, VANILLA CUSTARD SAUCE Recipe ila, illustrating the invention, was prepared by mixing together 170 gms. of STARCH A, 120 gms. of fine crystal sugar, 120 gms. powdered sugar and 6.3 gms. of flavourings and colourings. Recipe ilb was also prepared for comparative purposes, consisting of a mixture of 160 gms. of maize starch, 120 gms. fine crystal sugar, 120 gms. powdered sugar and 6.2 gms. of flavouring and colouring. As was the case with the wheat starch in Example I, the respective amounts of STARCH A and maize starch were adjusted to give products of identical final viscosity when prepared in conventional manner, i.e., adding to cold milk and then cooking.

The two sauce mixes were then prepared for consumption by bringing 250 ml. of milk to boiling, stirring 20 gms. of each mix directly into the boiling milk, and simmering, with occasional stirring, for 12 minutes. The finished sauces were then strained into bowls, as in Example I.

Observations and Results Sauce mix llb thickened immediately upon being introduced into the boiling milk, and formed large lumps which could not be dispersed with stirring. Sauce mix Ila showed no noticeable thickening for the first few seconds, and then gradually thickened to a smooth lump-free sauce.

Sauce Ila passed through the strainer without leaving any residue other than a few small particles of burned milk, and the strained custard had an excellent smooth thick texture. When Sauce llb was strained into the bowl the large lumps of starch were retained on the strainer and the strained suace contained small lumps and "fish-eyes". The strained sauce was substantially less thick then sauce Ila, and did not have a smooth homogenous texture.

EXAMPLE Ill WHITE SAUCE WITH VEGETABLES Dehydrated vegetables normally require several minutes cooking time in boiling water for complete dehydration. Therefore, packaged products containing such dehydrated vegetables plus a dry sauce base normally contain separate packets, or pouches, of the ingredients, and the consumer must cook the sauce base and the dried vegetables in separate cooking utensils. This example shows such a product wherein all of the ingredients may be packaged together and cooked for ultimate consumption in a single step and in a single cooking utensil.

Recipe Illa (Invention) White Sauce Base Ingredient Amt. (grams.) STARCH B 180 Hydrolyzed veg. protein 10 Fat powder (dried veg. 110 fat emulsion) Sodium Phosphate 10 Salt 50 Onion powder 10 MSG 32 Sugar 8 Citric Acid 2 TOTAL 412 To 40 gms. of the white sauce mix was added 4 gms. each of the following dehydrated (air-dried) vegetables; the average dimensions of the dehydrated vegetables, in centimetres, are given in parenthesis: leek (3.0 X 2.0 X0.1), celery (2.5 X 0.4 X 0.4), green beans (3.0 X0.7 X 0.7). The aforementioned dehydrated vegetables normally require a cooking time, in boiling water, of about twenty minutes for complete rehydration.

Recipe Illb (Comparison) This was identical to Recipe Illa except STARCH B was replaced with 180 gms. of native potato starch.

Recipe Illc (Comparison) This was identical with Recipe Illa except 200 gms. of wheat flour was used in place of the STARCH B, and 44 gms. of the base mix was combined with the 12 gms. dehydrated vegetables.

Preparation for Consumption In each case 700 ml. of water was brought to a boil and the sauce-plus-vegetables mix (52 gms. each of Recipes Illa and Illb, 56 gms. of Recipe Illc) was stirred directly into the boiling water, after which the cooking pans were partially covered and the product allowed to simmer for 25 minutes. The products were stirred occasionally during the cooking time. At the end of the cooking time the products were poured into bowls.

Observations and Results Recipe Illa did not thicken at all upon being added to the boiling water, and no observable thickening whatsover took place during the first 5 minutes of the cooking time. After about 5 minutes a very slight thickening could be observed, which increased very slowly, the moisture still being thin after 10 minutes cooking time. The thickening progressed gradually during the last 15 minutes of cooking time until a smooth thick product resulted.

Both mixes Illb and Illc thickened, and formed lumps, immediately upon being introduced into the boiling water. These finished products, i.e., after the full cooking time, both retained lumps, sauce Illb containing more lumps than sauce Illc.

Finished sauce Illa had an excellent, smooth, thick, "short" texture. Sauce Illb also had a thick, but a "long" texture, in addition to containing a large number of lumps. Sauce Illowas substantially thinner than Illa and Illb, and had a somewhat "slimy" texture.

Upon tasting the finished products it was noted that the vegetables in Illa were all fully rehydrated and cooked, while those of sauce Illb were definately less tender, indicating incomplete rehydration. The vegetables in sauce Illc were also not fully rehydrated, but were somewhat more tender than those of Illb.

In addition, taste differences were observed which could not be attributed solely to the differences in the textures of the sauces and degrees of rehydration of the vegetabis. The flavour of product Illa was substantially better than that of either of the other two products, indicating that the free water available for the cooking of sauce Illa acted not merely to rehydrate fully the dehydrated vegetables but also to release their flavour as well as the flavourings of the seasonings employed in the mix.

EXAMPLE IV LENTIL BROTH Thick "chunky" soups and broths, containing large pieces of vegetables and/or meat in a thick base, are extremely popular food products, but the manufacture of dry mixes for such products, and the ultimate preparation of same for consumption, present problems because the dry "chunky" portions need to be rehydrated in free water. Following is a a recipe for such a dry product which can be packaged in a single package and prepared for consumption in a single cooking utensil.

Recipe IVa (Invention) (1) Base Mix Ingredient Amt (gms) STARCH B 108.0 Lactose 85.0 Lentil Flour 220.0 Streaky Bacon 135.0 Flavourings (including yeast powder, tomato powder, onion flour, salt & spices), flavour enhancers & olourings 346.0 TOTAL 894.0 (2) Vegetable Mix (average dimensions in mm., shown in parenthesis) Ingredient Amt. (gms.) Quick-cooking lentils 270 Air-dried potato 15(16x 16x 2) Air-dried carrots 6(10 x 10 x 1) Dried grated onions 4 Air-dried leek 1(15 x 15 xl) Beef fat 4 TOTAL 300 For a single portion 33 gms. base mix were combined with 90 gms. of the vegetable mix.

Recipe IVb (Comparison) The base mix was identical to the base mix of Recipe IVa except that, as the thickening agent, STARCH B was replaced with 75 gms. of wheat flour and 21 gms. of guar gum. The vegetable mix was identical to that used in Recipe IVa, and, as in Recipe IVa, a unit portion was made up by mixing together 33 gms. of base mix with 90 gms. of vegetable mix.

Preparation for Consumption 500 ml. of water was brought to a boil and the dry mixes (123 gms. each) were stirrred directly into the boiling water.. Each kettle was then partially covered and the product allowed to simmer for 10 minutes, with occasional stirring (the vegetable mix itself would normally require a cooking time in boiling water of about 8 minutes for full rehydration). Atthe end of the cooking time both products were poured into bowls.

Observations and Results During the first 5 minutes of cooking time Recipe IVa remained substantiallythinnerthan Recipe IVb, after which it gradually became thicker during the last 5 minutes of cooking. After the product had been poured into bowls it was observed that the kettle in which Recipe IVb had been cooked still contained a fair amount of "burned-on" product No "burning-on" occured during the cooking of Recipe IVa.

Both finished products were very similar in appearance, i.e., both being very thick broths. Substantial differences, on the other hand, were detected upon tasting the two products. In the case of broth IVa the lentils and other vegetables were extremely tender and were fully cooked and rnhydrated; the vegetables in both IVb were not fully rehydrated and therefore were substantially less tender. Furthermore, the overall flavour of broth IVa was substantially better than that of broth lVb, again indicating that the free water available during the major portion of the cooking time had effectively released the flavours of the vegetables and other ingredients of the total mix.

EXAMPLE V, DUMPLINGS WITH SAUCE Dry dumplings, having an average diameter of 1 > cm. and containing protein, cereals, flavourings and fats, which dumplings are normally cooked by adding them to boiling water and simmering for about 8 minutes, were combined with a tomato base having the following composition.

Ingredient Amt. (gms.) Tomato powder 400 STARCKB 192 Salt 76 Sugar 72 Fat 160 MSG. 42.4 Fat powder 56 Spices, flavourings, 83.6 colourings TOTAL 1082.0 49 gms. of the sauce mix was mixed with 45 gms. of the dumplings, and added directly to 400 ml. of boiling water. The pan was partially covered and the product was simmered for 10 minutes. No noticeable thickening of the sauce occurred during the first 5 minutes of the cooking time; then a slight thickening began, and the thickening gradually continued for the last half of the cooking period until, at the end of the 10 minutes, the sauce was thick and very smooth. The finished product had an excellent appearance and taste, the dumplings being completely cooked and hydrated.

For comparative purposes a similar mix was prepared by combining and dumplings with a commercially available "instant" tomato sauce base having, as the thickening system, native potato starch, guar gum and flour. The commercial mix also contained lactose as a diluent to impart to the mix its "instant" character. The combination of dumplings and commercial sauce base was added directly to boiling water After the 10 minute cooking time the dumplings were decidedly "under cooked" and insufficiently hydrated. The product was then subjected to an additional 5 minutes cooking time, during which time a substantial amount of the product burned-on the bottom of the kettle. In spite of the additional 5 minutes cooking time the dumplings were still under cooked and not fully hydrated.

Examples illustrating starches other than potato The invention can be practiced, as been stated, with any root starch or tuber starch having retarded-thickering properties (such retarded thickening properties advantageously being imparted by a heat-moisture treatment); Examples I-V illustrate practice of the invention employing the preferred starch, which is potato starch. It should be noted, however, that potato starch is preferred merely because it is generally more readily available and less expensive than other operable starches. Examples VI, VII and VIII, to follow, illustrate the applicability of other starches as well.

Tapioca and arrowroot starches were selected for the additional examples, and three different heat-moisture treatments, all using the same equipment, and the same general process, as STARCHES A and B described previously. The specific treatments, all designed to produce starches suitable for use in gravy or sauce mixes, were as follows.

STARCH C was prepared from tapioca starch having an original (normal) moisture content of 13.6%. The moisture content was raised to 22.7% by spraying water from a fine nozzle onto the starch while mixing it.

2.5 kg. starch was then placed in the autoclave and treated for 3 hours at 1 OO"C. The treated starch was cooled and sieved as were STARCHES A and B. The moisture content of the cooled starch was about 18%. As was the case with STARCHES A and B, STARCH C (as well as STARCHES D and E, to be described) was dried to about 8% moisture before use in a food mix.

STARCH D was prepared from arrowroot starch having an original moisture content of 13.7%, which moisture content was raised to 24.2% before treatment. 2.5 kg. starch was treated for 50 minutes at 95 C.

After cooling the moisture content was about 19%.

STARCH E was also prepared from arrowroot starch, all conditions being identical to those of STARCH D except the time of treatment was 70 minutes instead of 50 minutes, Example VI, Brown Gravy Mix, Tapioca Starch A mix very similar to that of Example I was prepared, using STARCH C as the thickening agent; for comparison purposes a second mix employing untreated, native tapioca starch was prepared. The following table sets forth the compositions of the mixes.

Ingredient Amounts in Grams Comparative Invention Example STARCH C 301 Native tapioca starch 301 Malto-dextrin 51 51 Rice flour 18 18 Lactose 70 70 Flavourings & olourings 138 138 Sunflower oil 24 24 Gravies were prepared from the mixes exactly as is Example I except 16 gms. of each mix were added to the 250 ml. boiling water.

The observations and results were virtually identical to those is Example I. The mix containing the native tapioca starch thickened immediately and formed large lumps; the final gravy was similar to Recipe Ib. The mix containing the treated starch behaved as did Recipe la, resulting ina smooth, short-textured gravy.

Example VII, Brown Gravy Mix, Arrowroot Starch Brown gravy mixes employing STARCH D and, for comparison purposes, untreated arrowroot starch, were prepared. The recipes were identical to those of Example VI except 339 grams of each starch instead of 301 gms., were used.

Preparation of the gravies was the same as in Example VI except 17 grms. of each mix was added to the boiling water.

The obervations and results were the same as in Example VI.

Example VIII, Vanilla Custard Sauce, Arrowroot Starch Mixes similar to those of Example II were prepared, using STARCH E and, for comparative purposes, untreated arrowroot starch. The exact composition of the mixes are set forth below.

Ingredient Amounts in Grams Comparative Invention Example STARCH E 250 Native arrowroot starch 160 Fine crystal sugar 240 240 Flavourings & Colourings 6.3 6.3 Sauces were prepared with boiling milk (250 ml.) as in EXAMPLE II; 25 gms. of the mix containing STARCH E and 20 gms. of the mix containing the native starch being used.

The observations and results were very similar to those of Example II, the mix prepared in accordance with the invention forming an excellent, smooth, lump-free, short-textured sauce, the mix containing untreated arrowroot starch behaving very much like Recipe llb.

The term "arrowroot starch", as used above, means starch from the species Maranta arundinacea; the term "tapioca starch", as used above, refers to native starch from the Cassava root (Manihot utilissima).

Claims (11)

1. A commercially prepared dry food product containing a thickening agent, which food product is prepared for ultimate consumption by adding it directly to boiling aqueous liquid and cooking it in same, wherein the thickening agent comprises a root starch or tuber starch having retarded-thickening properties.

2. The product of Claim 1 wherein the starch is potato starch, tapioca starch, or arrowroot starch.

3. The product of Claims 1 or 2 wherein the thickening agent is a heat-moisture-treated potato starch, tapioca starch or arrowroot starch.

4. The product of Claim 3 wherein the thickening agent has been prepared by heating native potato starch, having a moisture content of 18%-21 %, in a closed system, at a temperature within the range of 90"C.

and 1200C., for a time period sufficient to impart to the starch the desired degree of retarded-thickening.

5. The product of Claim 3 wherein the thickening agent has been prepared by heating native tapioca starch, having a moisture content of 20%-25%, in a closed system, at a temperature within the range of 90"C.

and 1 200C., for a time period sufficient to impart to the starch the desired degree of retarded-thickening.

6. The product of Claim 3 wherein the thickening agent has been prepared by heating native arrowroot starch, having a moisture content of 20%-25%, in a closed system, at a temperature within the range of 90"C.

and 120"C., for a time period sufficient to impart to the starch the desired degree of retarded-thickening.

7. The product of any of the preceding claims consisting of a sauce or gravy mix containing flavourings and/or colourings plus the thickening agent wherein the starch is one which will not begin noticeably to thicken until at least about 5 seconds after being introduced into boiling water.

8. The product of any of Claims 1 - 6 consisting of a complete mix for thick soups or broths containing a thickening agent plus vegetables and/or pieces of meat, wherein the starch is one which will not begin noticeably to thicken until at least 5 minutes after being introduced into boiling water.

9. The product of any of Claims 1 - 6 consisting of a complete mix for a sauce containing vegetables, wherein the starch is one which will not begin noticeably to thicken until at least about 5 minutes after being introduced into boiling water.

10. The product of any of Claims 1 - 6 consisting of a sauce mix plus at least one foodstuff which needs to be cooked in free aqueous liquid for at least 5 minutes, wherein the starch is one which will not begin noticeably to thicken until at least about 5 minutes after being introduced into boiling water.

11. The product of Claim 10 consisting of a packaged mix including dry dumplings and a sauce base.