AN EXPANDED SNACKFOOD AND A PROCESS FOR PREPARING SAID EXPANDED SNACKFOOD

Abstract: The invention provides cereal snackfoods of the expanded variety such as crisps and the like. The snackfoods of the invention comprise discrete cooked portions of a dough composition comprising gelatinised starch and added cereal bran other than rice bran, and contain at least about 5% by weight and preferably no more than about 30% by weight of oil or fat. The snackfoods may be produced from a half pro­ duct comprising at least some gelatinised starch and added cereal bran by frying or by immersion in a bed of hot particu­ late material followed by spraying with fat or oil. Even when fried the snackfoods have a lower energy value than compar­ able known products and the bran content provides a useful source of fibre in any diet.

Description: An expanded snackfood and a process for preparing said expanded snackfood. The present invention relates to expanded snackfoods such as crisps and like foods obtained by cooking discrete portions of a dough composition. An essential requirement to obtain such expanded snackfoods is that before cooking at least some of the starch in the dough should be gelatinised. Gelatinisation of the starch is typi­ cally achieved by cooking it in the wet state, whence a physical change takes place in its structure such that it becomes more viscous. It is believed the presence of gelatinised starch is necessary to trap the steam produced on cook­ ing so as to give the necessary expanded struc­ ture. Various processes for preparing expanded snackfood products have been described by Willard, Snack Foods, 62, pages 52 to 54, 1973, (see also U.S. Patent Specification No. 3, 997, 684) and Matz, Snack Food Technology, The AVI. Publishing Company, Inc., Westport, Conn., U.S.A., pages 144 to 149). The processes using dough can generally be grouped into three categories and summarised as follows: (1) The dry collett process: In this process a thin portion of dried starch-­ based gel is expanded by a short immersion in hot fat or, as recently described in British Patent Specification No. 2,008,924 A, by cooking in a hot bed of, for example, salt or calcium carbonate. Typical of such a process is that disclosed in British Patent Specification No. 888,689 which describes the manufacture of a potato-based foodstuff in which potato flour is mixed with powdered potato starch, water is added to form a dough, and the dough is cooked so as to gela­ tinise the starch, the swollen dough being dried to form a product having a rubber-like con­ sistency. After drying the dough can be sliced, the slices further dried, and then cooked in boil­ ing fat to provide potato crips. In another such process described in U.S. Patent Specification No. 4,140,803 starch is gelatinised by feeding an aqueous slurry containing starch on to a hot double roller dryer, and the multilaminar film obtained is cut into small pieces and fat fried. In other such processes as described in, for example, British Patent Specifications Nos. 1,358,097 and 1,484,455, a dough containing some pre-gelatinised starch is extruded through a die such that the temperature and pressure conditions lead to further gelatinisation; the small pieces of this dried material are then fried as before. (2) Frying a wet completely gelatinised dough: In this process a wet dough containing about 30 to 85% solids is cut into desired shapes, and then fried, the starch in the dough being completely gelatinised before it is fried. Some of the products made in this category are described in U.S. Patent Specifications Nos. 3, 539, 356; 3, 297, 450; 3, 451, 822; and 4, 007, 292; and Canadian Patent Specification No. 871, 648. (3) Frying a wet dough containing some ungela­ tinised starch: In this process the dough contains a mixture of gelatinised and ungelatinised starch, and consists of about 30 to 70%, usually 40 to 50%, by weight of solids. The dough is formed into pieces and fried. With such a dough, for expamle, as described in U.S. Patent Specifica­ tion No. 3, 97, 684, the expansion is only about 1.6 to about 3.0 times the original volume com­ pared with the over three times expan­ sion obtained by the processes of the two pre­ vious categories. In the production of baked or toasted cereal products of the kind used as breakfast foods, and in the production of biscuits and cookies, it is known to employ a dough mixture including bran in various proportions of up to about 100% of the product. Examples of such foods are disclosed in British Patent Specifications Nos. 344, 055; 1, 561, 190 and 2, 010, 656A. In addition, British Patent Specifications Nos. 1, 465, 843 and 1, 544, 843 disclose snack­ foods including rice bran material, particularly in the latter case to afford a rice cracker flavour. According to the present invention there is provided an expanded snackfood in the form of discrete cooked portions of a dough composi­ tion comprising gelatinised starch, the snack­ food containing at least 5% by weight of oil or fat and characterised in that the snackfood includes from 15 to 70% by weight of added cereal bran selected from wheat bran, barley bran, oats bran, rye bran, maize bran and mixtures thereof. The expanded snackfood of the present invention is intended to be a crisps-like pro­ duct. That is to say it should have a "fried" flavour imparted to it by the presence of at least 5% by weight of saturated or unsaturated oil or fat, whether incorporated by frying or other­ wise e.g. by spraying onto the cooked product. In addition, the bran employed must not in itself nor in the amount in which it is employed impart to the snackfood organoleptic proper­ ties which significantly detract from a crisps-­ like feel and/or flavour. Thus, the bran used should not be rice bran which has a distinctive character and flavour sufficient to detract from the properties required, and it is to be under­ stood that the term "cereal bran" as used herein and in the claims does not include rice bran. Moreover, the snackfood must be expanded, that is the dough portions from which it is derived are expanded by frying or other cook­ ing processes generally to at least 1.25 times their original volume, preferably to at least 1.5 or 1.6 times, more preferably to at least 2 ties e.g, 2.5 or 3 ties their original volume. Sur­ prisingly the incorporation of bran does not lead (as was expected) to a crisps-like snackfood in which the expansion is kept to an undesirably low level. Thus, with a product containing 50% by weight of bran the mean expansion may be, for example, about 1.5 times. The present snackfood is highly palatable and can contain a high content of bran, generally a content higher than that present in whole wheat flour (about 13% by weight of bran), and always a content higher than that of whatever starch source is employed. Thus, the snackfood of the invention comprises from 15 to 70% by weight of bran, preferably from 20 to 50% by weight of bran. The inclusion of bran in a snackfood provides a highly palatable means of including fibre in a diet, the necessary level of fibre often lacking in the diets of Western populations. The snackfood may be in any of the many usual discrete portion forms, e.g. thin wafers such as crisps, rings, straws, chips, small sausages and the like. The gelatinised starch may be used alone or in admixture with ungelatinised starch and may be incorporated in the dough in any convenient form. Thus, at least some of the starch may be pregelatinised or at least some of the starch may be gelatinised by cooking once the dough composition has been prepared. By way of example, the starch may be one obtained from wheat, oats, barley, rye, maize, rice, cassava, potatoes, tapioca, sago, legumes and/or arrowroot. Preferably, the starch is one provided by incorporating a cereal flour, in par­ ticular wheat flour, in the dough. n an especially preferred aspect the wheat flour is one in which the starch has been pre-gela­ tinised e.g. one made by taking white wheat flour, making it into a slurry with water, and then spraying the mixture on to hot rollers. The dried material is scraped off and remilled to give a fine powder which can later be reconstituted with water into a dough. A similar technique can be applied to flours from sources other than wheat to afford the necessary pre-gelatinised material. In another preferred aspect, the gelatinised starch is provided by dehydrated cooked potatoes. Preferably the cereal bran used in the pre­ sent invention is wheat bran. However, other forms of cereal bran may be used where these are available and can produce the desired fibre content, for example, barley, oats, rye or maize bran. Wheat bran usually provides about 45% by weight of fibre and accordingly a snackfood containing 15% by weight or more of wheat bran will contain a significant and useful amount of fibre. Preferably the bran is heated before it is added to the dough composition, so as to gelatinise any residual starch, and to destroy enzymes such as amylase. Another unexpected property imarted to the snackfood of the present invention by the incorporation of cereal bran is the ability to have a relatively low fat content compared with known crisps or the lik, even when frying is used for cooking. One drawback of potato cisps and other fried snackfoods is their high energy value, and it is a significant advantage of the present snackfood that its energy value can be much less per unit weight than other such foods not containing bran. Thus, the present snackfood is advan­ tageous in that it provides a good source of fibre in any diet, it is highly palatable, it has a fried flavour, and yet since it can contain fewer calories than comparable known products not containing bran, it can be produced in a for acceptable to those on slimming diets. The expanded snackfood of the present invention may be prepared by any process which comprises mixing starch e.g. wheat flour, and bran, and treating the mixture by any tech­ nique which affords the necessary instan­ taneous, severe, localised heating conditions to provide discrete cooked portions of said dough expanded to the necessary level. For example, the snackfood may be prepared by any of the processing techniques in categories (1) to (3) described above. Thus, for example, such a process may com­ prise adding water to a mixture of bran and ungelatinised starch or a source thereof to form a dough, cooking the dough to gelatinise at least some of the starch, sub-dividing the resulting dough composition e.g. by slicing and drying the sub-divided dough to for discrete portions of a "half product" which can be cooked either by frying in fat or oil or, for example, by immersion in heated salt or calcium carbonate. The "half product" can also be made by mixing bran with pre-gelatinised starch and water to form a dough which is cut or other­ wise sub-divided and then dried, or by forming a slurry of bran and ungelatinised starch or a source thereof, which is then hot roller dried, and the thus-formed sheet of dried dough sub- divided e.g. cut, into discrete portions. Such cut portions may be cooked as such or ground, and reconstituted with water to make a dough, which itself is cut or otherwise sub-divided and dried. As another example the process of the inven­ tion may comprise forming a dough comprising bran and starch, some of which is gelatinised, extruding the dough through a die under condi­ tions of temperature and pressure which lead to gelatinisation of more of the starch, sub-divid­ ing the extruded dough into discrete portions, and cooking the portions. Preferably the snackfood of the invention is prepared by a process using pre-gelatinised starch suitably in the form of a gelatinised wheat flour or potato flour. An advantage of employing pre-gelatinised starch is that flavouring and other materials can be incorporated in the dough and there is much less likelihood of these materials being destroyed than might be the case when the dough is cooked to provide gelatinisation. In the processes of the invention frying may be accomplished in hot fat or oil, typically hot cooking oil, for a cooking time preferably of from 5 to 100 seconds within the usual temperature range of from 160°C to 215°C, and it is an advantage of the dough used in the present invention that it can be cooked at temperatures below the upper end of the range e.g. at 190 to 195°C (typically about 193°C). This is advantageous in that the oil will be further from its boiling point and will tend to smoke less. Alternatively, "half products", preferably of 10 to 15% moisture content by weight, can be cooked by heating the "half-product" by immer­ sion in a bed of hot articulate material such as salt or calcium carbonate, and separating excess articulate material from the expanded cooked product. The cooked product can then be sprayed or otherwise treated to incorporate the necessary amount of oil or fat which affords the desired flavour. A variety of additives may be included in the snackfood of the present invention to provide the required visual and organoleptic properties. Such additives may be included either in the dough, especially in the case where a pre-gela­ tinised starch is employed, or by spraying on to the cooked food. Thus, the palatability of the snackfood can be improved by adding flavour­ ing agents, amongst the preferred being salt and vinegar, cheese and/or onion, bacon, eat, fish, tomato, chicken and ham. Such flavouring agents are commercially available and may comprise hydrolysed vegetable protein, mono­ sodium glutamate, common salt spices, syn­ thetic flavours and/or natural flavours, to give the required flavour and aroma. Typically up to 30% by weight of flavouring agent may be incorporated in the dry mixture from which the dough is prepared by adding water, and the pre­ ferred level is about 10% by weight. Currently, Health Authorities are tending towards a policy of wishing to limit salt in dietary products and the like. Accordingly, if desired a snackfood according to the invention for use in conjunction with a low-salt or salt-­ free dietary regime may have a "salty" taste provided by the inclusion of potassium and/or amonium chloride in approximately the same amount by weight as (and as a whole or partial substitute for) sodium chloride. In addition the snackfood may be supple­ mented by including a proteinaceous supple­ ment and typically up to 75% by weight of proteinaceous material may be incorporated in the dry mixture from which the dough is pre­ pared. Typically such proteinaceous materials are milk proteins, especially caseinates, soya, wheat and corn gluten. The inclusion of protein­ aceous material improves the nutritional value of the snackfood. To achieve the necessary level of bran in the final product up to 75% by weight of bran may be included in the dry mixture from which the dough is prepared. However, the especially pre­ ferred range for palatability is from 30 to 40% by weight of bran in the mixture. As mentioned above the expanded snack­ food of the present invention can contain less fat or oil, than similar known snackfoods. In par­ ticular, typical snackfoods in accordance with the present invention will contain no more than 35%, preferably no more than 30%, more pre­ ferably no more than 25%, and still more pre­ ferably no more than 20% by weight of fat or oil e.g. 8 to 20% by weight fat or oil. The following Table I gives typical bran and fat contents for snackfoods in accordance with the present invention compared with a snack­ food containing no bran. The following Examples illustrate the pre­ aration of expanded snackfoods according to the present invention. All of the expanded snackfoods described had an oil or fat content of at least 5% by weight and were expanded to at least 1.25 times the volume of the original dough portions. (A) Examples of dry collet processes Example 1 A mix was made of the following ingre­ dients: Gelatinised wheat flour 60 g Flavouring 10 g Wheat bran (heated) 30 g To 100 g of this mix were added 80 ml of water and the whole mixed well into a dough. The dough was formed into a cylindrical rod of 25 mm diameter and cut into thin slices 1 mm thick. The latter were dried in a war room overnight. The dried slices were then cooked in hot vegetable fat at 193°C for about ten seconds. Example 2 A mix was made of the following ingre­ dients: Gelatinised wheat flour 60 g Flavouring 10 g Wheat bran (heated) 20 g Soya protein isolate 10 g A snackfood was prepared from this mix as described in Example 1. Example 3 Potato flour was produced by washing and peeling raw potatoes, then boiling them and mashing after straining and rejecting the water. The mashed potato was rolled dry over hot rollers as a powder of moisture content 4 to 5%. Wheat starch in fine powder for and wheat bran were mixed with the potato flour in the following proportions: Potato flour 20 g Wheat starch 40 g Bran (unheated) 30 g Sufficient water was added to make a dough (80 l). The dough was extruded into a cylin­ drical rod, cut into lengths of about 30 m, placed in boiling water and allowed to boil for 45 minutes. The gelatinised product was cut with a sharp knife into thin wafers, which were then dried in a warm room overnight. The slices were fried in oil at 193°C. Example 4 The following ingredients were intimately mixed according to the formula below: Potato granules (gelatinised) 30 Potato starch (no-gelatinised) 30 g Pre-gelatinised potato starch 7 g Wheat bran (heated) 30 g Salt 3 g The ingredients were mixed for 8 minutes in a vertical mixer and the moisture content adjusted to about 35% by weight by addition of water. After mixing the material was extruded through a standard pasta press at a tempera­ ture of 55 to 65°C at a pressure of from 88 to 108 bar (190 to 110 kg/cm²). The die produced spiral shaped pieces approximately 30 mm in length, 1 cm diameter, with a wall thickness of 1 mm. After extrusion the pellets were slowly dried in a drum drier at a temperature of from 36 to 55°C for about 6 hours. The final moisture content of the "half product" was about 11% by weight. The "half product" was fried in oil at 205°C for about 15 seconds. Example 5 The following ingredients were mixed into a slurry: Wheat flour 20 g Wheat bran (unheated) 8 g Flavouring 2 g Water 70 g The slurry was fed on to a double roller dryer operated at about 2.39 bar (20 p.s.i.g.) steam pressure, and the drums allowed to rotate 9 times until a film of approximately 0.5 mm thickness had built up. The multi-layer film was removed as a sheet with a blade and cut into 2.5 cm × 4 cm rectangles containing about 11% by weight moisture. These were deep fried for 10 seconds in fat at 170°C. In the above Example the wheat flour can be replaced by pea flour. Example 6 The above Examples were repeated except that the dried "half product" was cooked by immersion in hot articulate salt instead of by frying to produce a cooked, but fat-free product. For each repeat Example, a snackfood having an oil content of a magnitude which gave a palatable product was produced from the cooked product by spraying with a vegetable oil. In this way there were produced five batches of snackfood having respectively an oil content of 35%, 30%, 25%, 20% and 15% by weight. (B) Examples of frying wet completely gelatinised dough: Example 7 A mix was made as described below of the following ingredients: Potato granules (gelatinised) 600 g Isolated soya protein 300 g Wheat bran (heated) 300 g Salt 60 g Glycerol monostearate 20 g Water 700 g The water, salt and glycerol monostearate were mechanically blended and the remaining dry ingredients mixed in a Hobart mixer. The wet blended ingredients were then added to the dry mixed ingredients and mixed until the mass was free flowing. The mixture was then extruded in a press using a 1.25 mm by 2.5 cm ribbon die at a temperature of 74°C. The extruded ribbon was stretched by 30 to 40% and cut into 3 cm lengths and fried at 190°C for 45 seconds. Example 8 A potato dough was made from the follow­ ing composition: Potato granules (gelatinised) 70 g Wheat bran (heated) 27 g Guar gum 1.5 g Salt 1.5 g The above dry ingredients were mixed together and then uniformly mixed with about 226 ml water at 60°C to form a dough of about 30% by weight solids content. The dough was fed through a piston extruder with a die of 1 cm × 1 cm and cut into portions 7.5 cm long. The formed units were discharged into a deep fat fryer at 170°C for about 90 seconds. The part-fried material was stored deep frozen until required. To prepare for consumption the frozen units were toasted in a standard bread toaster for 1 to 3 minutes. Example 9 The following ingredients were mixed in a Hobart mixer to form a dough. Potato flakes (gelatinised) 200 g Bran (heated) 100 g Hydrolysed soyabean oil* 5 g Ascorbic acid 1 g Water 200 g * containing 40% monoglycerides, 40% diglycerides and 20% triglycerides. The dough at a temperature of 45°C was passed through a two roll mill to give a sheet 0.4 thick which was cut into elliptical pieces 7.5 cm × 5 cm diameter. These were deep fried in cottonseed oil at 175°C. Example 10 A mix was made of 97% by weight of rice flour and 3% by weight of salt. About 700 of the mix was then cooked with 300 ml of water in a pressure cooker. The cooked rice dough was extruded through holes 3 mm diameter and cut into pellets 1.5 mm to 3 mm length. The pellets were then mixed with dehydrated mashed potatoes and bran as follows: Rice pellets (32% by weight moisture) 25 g Mashed potato (gelatinised) 25 g Bran (heated) 25 g Water 18 g The overall moisture content was 32% by weight. The mixture was finely chopped and blended and the granular material fed through rollers to form a sheet 0.75 mm thick from which ellip­ tical shaped chips were cut. These were fried in coconut oil at 200°C for 15 to 20 seconds. (C) Examples of frying a wet dough containing some ungelatinised starch: Example 11 The following ingredients were combined in a 5 quart Hobart mixer using a paddle turning at low speed for 1 minute: Dried potato flakes (gelatinised) 100 g Potato starch (ungelatinised) 100 g Wheat bran (heated) 100 g Salt 7 g During an additional one minute 347 ml water at room temperature were added and mixing continued for one minute thereafter. The mixture was then placed in a piston extruder. By application of force the mixture was extruded through a die opening 2.5 cm by 1 mm thick. The extruded dough was cut with a knife into pieces approximately 5 cm long, and as cut the pieces were allowed to fall into a standard fryer containing hydrogenated vegetable oil at 190°C where they were fried for 90 seconds. In the above example potato starch can be replaced by tapioca starch with excellent results. Example 12 A dough was prepared as in Example 11 and rolled into a sheet 0.5 mm thick using a pasta roller. The sheet was then rolled to a thickness of 1.5 mm and cut into pieces 7.5 cm long. The product when fried had the appearance of potato chips.

Claims: 1. An expanded snackfood in the form of discrete cooked portions of a dough composi­ tion comprising gelatinised starch, the snack­ food containing at least 5% by weight of oil or fat and characterised in that the snackfood includes from 15 to 70% by weight of added cereal bran selected from wheat bran, barley bran, oats bran, rye bran, maize bran and mixtures thereof. 2. A snackfood according to claim 1, contain­ ing from 20 to 50% by weight of bran. 3. A snackfood according to claim 1 or claim 2, wherein the starch is gelatinised before the dough composition is formed. 4. A snackfood according to any one of the preceding claims, wherein the gelatinised starch comprises starch obtained from wheat, oats, barley, rye, maize, rice, cassava, potatoes, tapioca, sago, legumes and/or arrowroot. 5. A snackfood according to any one of the preceding claims, wherein the bran is wheat bran. 6. A snackfood according to any one of the preceding claims, wherein the bran is heated before it is added to the dough composition. 7. A snackfood according to any one of the preceding claims, wherein the dough composi­ tion includes ungelatinised starch. 8. A snackfood according to any one of the preceding claims, which contains up to 35% by weight of fat or oil, preferably from 8 to 20% by weight of fat or oil. 9. A snackfood according to any one of the preceding claims, wherein the dough portions are expanded to at least 1.25 times, preferably at least 1.6 times, more preferably at least 2.0 times their original volume by cooking. 10. A process for preparing a snackfood according to any one of claims 1 to 9, which process comprises cooking discrete portions of a dough composition comprising gelatinised starch and added cereal bran selected from wheat bran, barley bran, oats bran, rye bran, maize bran, and mixtures thereof to expand the dough portions to at least 1.25 times their ori­ ginal volume, the process including a step whereby an oil or fat content of at least 5% by weight is imparted to the dough portions, the cooking preferably being achieved (a) by frying in oil or fat, or (b) by immersion in a bed of hot particulate material, the cooked snackfood being subsquently treated after step (b) to provide the required level of fat or oil, pre­ ferably by spraying. 11. A process according to claim 10, comprising either (a) mixing bran with ungela­ tinised starch or a source thereof, adding water to form a dough, cooking the dough to gela­ tinise at least some of the starch, sub-dividing the resulting dough composition into discrete portions, drying the portions and cooking them, or (b) mixing bran with pregelatinised starch and water to form a dough, sub-dividing the dough into discrete portions, drying the por­ tions and cooking them, or (c) forming an aqueous slurry of bran and ungelatinised starch or a source thereof, drying the slurry on one or more hot rollers to form a sheet of dried dough, sub-dividing the dried dough into discrete por­ tions, and cooking the portions, or (d) forming an aqueous slurry of bran and ungelatinised starch or a source thereof, drying the slurry on one or more hot roller to form a sheet of dried dough, sub-­ dividing the dried dough into discrete portions, grinding the portions, reconstituting the ground dough with water, again sub-dividing into discrete portions, drying and cooking the por­ tions, or (e) forming a dough comprising bran and starch, some of which is gelatinised, extruding the dough through a die under condi­ tions of temperature and pressure which lead to gelatinisation of more of the starch, sub-divid­ ing the extruded dough into discrete portions and cooking the portions.

Inventors: HOWARD, ALAN NORMAN
Applicants: THE HOWARD FOUNDATION
Application year: 1981
Main classification: A23L1
IPC codes: A21D13, A21D8, A21D2, A23G3, A23L1