METHOD OF MAKING FOOD COATINGS, FILLERS AND PELLETS

Abstract: A less costly and quicker way to make food coatings, filler and pellets by using ingredients such as grains and/or pulses with an average moisture content of less than 14 % then directly extruding the gelatinised elastic-like mass with such a low moisture content that drying is not required.

Description: METHOD OF MAKING FOOD COATINGS, FILLERS AND PELLETS This invention relates to a method for manufacturing a dry coating used in such products as crumbed fish fingers, chicken pieces, etc., fillers used in smallgoods, such as sausages, and food ingredients, such as a component of muesli and food pellets. BACKGROUND ART Breadcrumbs used domestically are usually manufactured from reprocessed, stale bread and vary widely in terms of colour, flavour, grain size, hardness, absorption, moisture content and general properties which affect their ability to adhere to trie basic food item comprising poultry, fish or meat. When crumbs are applied commercially it is necessary to control the above factors within critical tolerances. Specification of cereal products used as binders or fillers in smallgoods is also critical - particularly in relation to water absorption ability. For both coating crumbs and fillers the specification calls for a moisture content of less than 10%. The conventional method for manufacturing coating crumbs involves the following operations - making dough (moisture content approximately 30%), fermentation, baking a loaf (moisture content approximately 18-20%), slicing, drying to 7-10% moisture, milling and screening. A particular type of filler, commonly referred to as yeastless rusk, is made from lean biscuit dough having a moisture content over 18% which is not fermented but normally aerated using a combination of sodium bicarbonate and acid phosphate and/or ammonium bicarbonate. After baking, the biscuit is subject to controlled drying which reduces the moisture to approximately 2% without charring or serious discolouration. The rusk is them milled and screened to a range of particle sizes dependant on application and end use. In recent years a new process has been developed which avoids production of a baked loaf or biscuit by employing a steam extrusion process.' Finely ground wheat flour is mixed with water and/or steam to make a containing 18-30% moisture, which is extruded under high pressure in dies. The dough is then cut into smaller pieces through a mill using rotating blades, dried to less than 10% moisture, ground and screened. There is another process which is employed in the manufacture of extruded snack foods. Directly expanded snacks are extruded from a starch base to which moisture has been added to bring the level up to about 18%. This mixture is then extruded through an orifice to give a product of a specific final shape - considerably expanded to approximately 15 times its original volume. The product is then dried to a moisture content of approximately 1% prior to being flavoured with an application of oil, seasoning, etc. DISCLOSURE OF INVENTION This invention differs from the above processes in a number of ways:- (i) There is no formulation of dough, (ii) No additional water is added for pre-conditioning. (iii) No post extrusion drying required, (iv) Controlled expansion of extrudate is possible and hence control of ultimate nature of finished product. (v) Ingredients are mixed in dry state with consequent"improvement in uniformity and texture of the product, (vi) It is possible to develop more satisfactory methods for the control of colour of the finished product. A particular feature of the new invention is that ingredient materials are mixed in a dry state with a moisture content of less than about 14% and then directly extruded, thus avoiding the necessity to make a dough or to remove moisture after extrusion. Following extrusion, the product has only to be ground and screened into appropriate sizes for use as .coating crumbs or fillers with a finished moisture content of 4-10%. A further advantage of the new process is that a wide range of crumb textures can be produced which satisfy varying specifications of products - e.g. fish fingers which must be cooked, frozen, thawed and then reheated require a harder crumb than does a product which is crumbed and cooked for immediate eating. The new process handles a wide range of ingredient materials, such as semolina, whole grains such as wheat, peas, lentils, as distinct from the other process for manufacturing crumbs which traditionally use wheaten flour. This facilitates blending of materials to achieve finished products with desired characteristics of hardness, textures, flavours, water absorbency, etc. The term ingredients used in this specification and claims is defined as whole grains, pulses and the like and derivatives thereof. This invention in one broad form comprises a method of manufacturing food coatings, fillers or pellets comprising the steps of feeding the ingredients into an extruder, said ingredients having an average moisture content of about 8-14% (preferably 9-12%), processing the * ingredients through the extruder at a * temperature and pressure which cause the starches present to gelatinise to form a dense elastic-like mass and extruding this mass having 4-10% (preferably 5-9%) residual moisture. BEST MODE OF CARRYING OUT THE INVENTION Though it is not necessary, the ingredients, may be preground to obtain even size which improves even distribution of the ingredients and their characteristics, such as colour, taste, etc. The ingredients are mixed or blended to obtain a uniform consistency either in a ground or whole form. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to the drawings in which: Figure 1 is a sectional view of part of the extruder. Figure 2 is a view along- section line II-II of Figure 1. The ingredients are mixed in a dry state according to the fermentation which will produce the desired end product. The ingredients are then fed into the extruder 1 and the auger or screw 2 applies friction and shear as the ingredients are forced towards the die 3. The length to diameter ratio of the auger can be 2 to 1 to 4 to 1. The internal wall of the extruder may take the form of a female auger 4 whose spiral curves in the opposite direction to the spiral on the male auger 2. This gives improved friction and shear. A number of combinations of extruder design, speed of auger and residence time can produce a satisfactory product. As a guide barrel temperature of 200 Q C, auger speeds of 350-400 RPM, internal temperature at the end of the extruder of 160oC to 230oC and residence time of 8 seconds have been found to give satisfactory results. Internal pressures in front of the die-plate of 2000-2500 psi have been noted under these conditions. Operation includes the ability to control the auger speed and to control temperature along the length of " the extruder. Initial startup of the extruder requires pre-heating of the barrel, but thereafter a balance of internal pressure within the extruder determines the properties of the extruded mass. For adequate control of the shear-induced exotherm, control of barrel temperature, internal pressure, auger speed and residence time is desirable. MACHINE CHARACTERISTICS AND DRAWINGS To obtain the above conditions, it is necessary to design the appropriate combination of auger, barrel and die configuration. In combination with auger design, appropriate internal pressures can be controlled by means of a breaker plate 5 similar in design to normal plastic extruders and/or by means of a restricting gap 6 between the breaker plate 5 and a spacer ring 7. Further pressure regulating can be obtained by a further gap 8 adjacent the die orifices 9 and between the spacer ring 7 and the die 3. The face of the breaker plate 5 may have grooves 10 to improve the grinding effect and to help move the ingredients towards the die 3. The extrudate undergoes comminution to provide products of the required size range. These are then separated by screening. Because of the low moisture content there is no appreciable expansion of the extrudate. In order to achieve control over density and tenderness of certain crumbs it is preferable to include in the ingredients products which include fat and emulsifiers. This can be achieved by incorporating approximately 2-5% of full fat soya flour which contributes fat and lecithin in the required proportions. FORMULATIONS A typical formulation for a tender crumb by this process is:- Whole wheat - 48.2% Semolina - 47.5% Full fat soya flour 2.5% Salt - 1.5% Dextrose - 0.3% INDUSTRIAL APPLICABILITY The new process can be used to produce a broad range of products : (1) Crumbs - These cannot be truly described as "bread crumbs" because at no time in the process is bread made. Texture, flavour and colour is varied according to requirements of the end product. (2) Rusk - Conventional rusk is made from a yeastless biscuit so that it has longer shelf-life and is dried to minimum moisture level to enhance moisture absorbency as well as improving shelf-life. The new process facilitates production of hard, low moisture granules which retain their individuality when incorporated with sausage mixes, etc. and have very high water absorbency - over 3:1 compared with flour of, say, less than 1:1 and conventional rusk of say, 2.5:1. (3) Flavoured/Coloured Coatings - The new process facilitates production of different flavours and colours due to the ease of varying formulae, the low content during the process and the short processing time which has minimal effect on losing or distorting added flavour and colour. Thus it is possible to extend the market applications either by addition of artificial or natural flavours or by using different basic ingredients. For example, by using whole wheat it has been shown that crumb with a decided nutty flavour results which can be enhanced by addition of a nut flavour to the grain being fed into the system. The resulting product can be marketed as a nut replacer or extender for application to the outside of ice cream, in cake recipes, sweet confectionery, etc. Similarly, split peas and soya beans can be extruded to give characteristic flavoured coatings. (4) Croutons - The new process will extrude shapes simulating conventional croutons - a coating of fat and/or flavour being applied by continuous spray onto the hot extrudate. Apart from quality advantages arising from use of * the new process, there are substantial savings in energy consumption both in the extrusion operation and in the absence of drying equipment. Capital expenditure and floor space requirements are also considerably lower than for the previously accepted processes. The flexibility of the new process facilitates production of a high density crumb when required. This results in a thinner layer of crumbs on the outside of a finished product for the same weight application - often allowing the manufacturer to apply crumbs with a single enrobing process, compared with the double operation necessary when crumbs of lower density are applied. The process facilitates production of a crumb with particularly high water absorbency properties. Consequently, smallgoods can be manufactured with a higher meat/cereal ratio than with a conventional rusk type binder.

Claims: CLAIMS 1. A method of manufacturing food coatings, fillers or pellets comprising the steps of feeding the ingredients into an extruder, said ingredients having an average moisture content of about 8-14%, processing the ingredients through the extruder at a temperature and pressure which causes the starches present to gelatinise to form a dense elastic-like mass and extruding this mass having 4-10% residual moisture. 2. A method as claimed in Claim 1 wherein the mass extruded is ground to the required particle size. 3. A method as claimed in Claim 1 or 2 wherein the extruder is preheated to a barrel temperature of about 200°C, auger speeds are 350 to 400 RPM, residence time of the ingredients in the extruder is about 8 seconds and internal pressures are 2000 to 2500 psi. 4. A method as claimed in Claim 1, 2 or 3 wherein the internal pressure is regulated by varying the gap between a breaker plate and spacer ring situated between the auger and the die of the extruder. 5. A method as claimed in any preceding claim wherein the average moisture content of the ingredient is 9 to 12% and the extruded mass has a moisture content of 5 to 9%. 6. A method as claimed in any preceding claim wherein 2 to 5% of full fat soya flour is added to the ingredients. 7. A method as claimed in any preceding claim wherein the ingredients are whole wheat 48.2%, semolina 47.5%, full fat soya flour 2.5%, salt 1.5% and dextrose 0.3%. 8. Crumb type coatings and fillers, rusks, croutons, flavoured and/or coloured coatings when made by the method of any preceding claim. 9. A method of manufacturing crumb type coatings or fillers substantially as herein described with reference to the accompanying drawings.

Inventors: CAMERON WILLIAM DOUGALL DAVID, CAMERON, WILLIAM, DOUGALL, DAVID
Applicants: D & S MFG PTY LTD, D & S MANUFACTURING PTY. LTD.
Application year: 1982
Main classification: A23L1
IPC codes: A23L1, A23P1