Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES, NOT OTHERWISE PROVIDED FOR; PREPARATION OR TREATMENT THEREOF
  • A23L11/00—Pulses, i.e. fruits of leguminous plants, for production of food; Products from legumes; Preparation or treatment thereof
  • A23L11/30—Removing undesirable substances, e.g. bitter substances
  • A23L11/31—Removing undesirable substances, e.g. bitter substances by heating without chemical treatment, e.g. steam treatment, cooking

Definitions

• This invention relates to soybean products for human consumption.
• soybeans contain a high proportion of protein and a valuable oil content- Soybean crops are grown in very large tonnages in many regions of the world.
• the major proportion of the world soybean crop is used for the extraction of oil with the consequent production of huge tonnages of defatted soy meal or cake. Most of this meal or cake is used as stockfood.
• Defatted soy meal while high in protein, has an unacceptable flavour for use in human food, having a strong beany or bitter flavour and only as the result of expensive and capital-intensive further processing can this meal be converted into forms which are more acceptable to human taste. Even so, a residual beany flavour usually persists which substantially reduces its consumer acceptance.
• special steps are taken in the oil extraction and associated steps to improve the flavour, however the resultant meal still suffers to some degree from the above mentioned disadvantages.
• whole soybeans are simply ground to a meal or flour, the flavour is objectionable being described as "green”, “painty” and “raw” such flavours being a consequence of the enzymatic activity in the full-fat soy flour so prepared. What is more, raw soybeans or flour prepared therefrom contain certain anti-nutritional factors which affect digestion and absorption of food. It has been proved that it is very important to reduce substantially such factors in such soybean products for human consumption.
• flavours are generally unsuitable for human food unless used as a very low proportion ingredient in food and/or used in conjunction with flavouring substances which will hide the "objectionable”, flavours.
• OMPI _ considered preferable for health reasons over more saturated fats.
• soy flours could be added to foods in any desired proportion without encountering the problem of off-flavours referred to and without the necessity of adding supplementary flavouring substances for the purpose of masking objectional flavours.
• soybeans to produce full fat soy flour, meal or grits in such a way that the end product, hereafter referred to processed soy material (PSM) is free or substantially free of the mentioned "beany”, “bitter”, “painty”, “raw” or “green” flavours, and of such bland character that it may be used as or in food products suitable for human consumption in substantial proportion so that significant improvement in protein content thereof is achieved.
• PSM processed soy material
• the nutritional quality of the PSM is maximised for human food use so that there be no problems from residual anti-trypsin factors or other anti-nutritional factors.
• the process be economical to carry out and not require the use of expensive or specialised equipment. It is a further object of the invention that the process has low energy requirement and be capable of being operated by persons of reasonable skill but not requiring perons having a high degree of technical training and specialised skills.
• the PSM when dried should be stable under atmospheric conditions and able to be stored for long periods of time in a dry state without significant deterioration.
• the PSM should be capable of being used in the manufacture or preparation of more-or-less conventional foods which have a ready acceptance in all or most parts of the world. This is an important consideration since it is often found very difficult or impossible to introduce foods of special nutritional quality to peoples in need of such nutrition unless the foods are similar to or identical with the styles of foods with which such peoples are familiar.
• the invention accordingly resides in a process of producing PSM wherein whole or preferably split soybeans are treated w ⁇ th live steam or water under atmospheric pressure at temperatures ranging between 85 to 100°C for 2 1/2 to 20 minutes, preferably 2 1/2 to 15 minutes or for an equal or shorter period under steam pressure in excess of atmospheric pressure such combination of time and temperature under ste-am7-under pressure in excess of atmospheric pressure which results in a degree of blandness in the resultant PSM as is about equivalent to the blandness which results from the stated treatment under atmospheric pressure.
• the preferred method of heating the beans is by the use of steam.
• the beans thereafter may be dried by passing through the beans hot air at temperatures below 95°C, the lower the better.
• the invention also resides in PSM produced in accordance with the mentioned process.
• the beans are first de-hulled and the loose hulls separated before the beans are subsequently processed.
• the treated beans are then steamed in the manner described and are then ground to a flour, meal or grits as required.
• the beans are reduced in size for example by rolling as they exit from the steam treatment. The reasons for this are that the beans are softer when they are steaming hot so that less energy is needed for size reduction. Additionally, it is more economical and quicker to carry out a subsequent drying step (where this is required) after the beans have been so reduced in size.
• a further advantage is that less heat is generated during grinding because the beans have already been partly pulverised.
• the preferred stage and method is that after steaming, the softened beans are compressed. For example, they may be passed between smooth rolls in a roller mill set at a gap of 0.6-1.0 mm. The beans will exit from the mill in a well flattened but in otherwise intact form.
• the flattened beans while still hot may be subjected to the percolating and extracting action of water, preferably hot, either on a batch basis, or preferably in a continuous operation for example by counter current extraction.
• water preferably hot
• the use of a basket centrifuge or a continuous centrifuge is a convenient final step before drying.
• OMPI sintered structure induced in them as a consequence of the hot rolling operation, the soluble oligosaccharides are readily eluted.
• the flattened beans remain intact.
• the extracted soybeans may then be further pulverised and/or dehydrated as described, or may be used directly in the preparation of other food products.
• the treatment will need to be long enough to avoid green, painty or raw flavours developing in the PSM on storage, but short enough so that beany or bitter flavours do not develop in the PSM.
• the PSM produced according to the invention generally has a protein content of about 40-42% and a fat content of about 20-21% when prepared from dehulled beans depending on the composition of the original soybeans.
• the PSM thus produced represents an important source of high quality fat, as well as protein.
• Example 1 Soybeans used were of sound quality, well cleaned and free from extraneous weed seeds and other materials. In carrying out the dehulling operation the following steps were followed:
• the beans were first heated in a stream of hot dry air at a temperature 90°C for 5-8 minutes, or until the hulls become a little loosened from the cotyledons. It is only necessary that the hulls have become loosened to the extent that the entire hull can be easily removed by rubbing in the palm of the hand.
• the warm surface-dried beans are passed through a hulling machine in which the beans are abraided against
• OMPI_ ⁇ themselves and also against an abrasive element which is included in such machines. It has been found that an abrasive rice whitener is very suitable for this purpose. Machines manufactured by Satake Engineering Co. Ltd. of Tokyo, Japan, in particular model HS-2B have been found suitable for the dehulling step. It is important that the hulls are separated with a minimum of mechanical damage being done to the cotyledons, such as scratching, cracking or breaking. Avoidance of mechanical damage is especially important if the hulled soybeans are to be stored from some period of time prior to further processing.
• the dehulled soybeans are then separated from the hulls as completely as possible, using aspiration equipment. At the same time the dehulled soybeans may be cooled down, which is especially important if the dehulled material is to be stored for some period of time before further processing.
• the dehulled soybeans were then subjected to a controlled heat treatment.
• the degree of heating of the beans is determined to some extent by the use to which the ultimate PSM will be put.
• the dehulled soybeans are placed in a well insulated batch-type steamer so arranged that the steamer is filled from the top, and emptied from the bottom at the end of the steaming period.
• Live steam is fed into the soybeans through a vertical perforated tube running almost the full vertical length of the steamer.
• a supply of dry potable steam at atmospheric pressure is passed through the soybeans until the beans reach a temperature of 100°C, as indicated by a thermometer as well as by the observation that live steam is escaping from the top of the mass of beans.
• the steam flow is maintained so that the beans are held at 100°C for ten minutes. Then the steam is turned off and the hot steaming beans are dropped from the steamer into an insulated container.. While still very hot the soybeans were passed between smooth rollers in a roller mill with the gap between rolls set at 0.4mm. The soybeans exit from the mill in a flaked condition, the flakes having a plurality of cracks and fissures throughout. The soybeans cool down to some degree during rolling due to loss of steam from the beans, especially as they are flattened by the rolls.
• the soybean flakes were further dried in a forced draft dehydrator using hot air at an inlet temperature of 90°C.
• the temperature of the flakes is kept below 80°C. Because the flakes are very thin, and have a fractured structure they dry very rapidly in the • dehydrator.
• the soybeans are dehydrated to about 3-4% moisture content and cooled to 30°C or less: they may then be pulverised in a grinder to a degree of fineness suitable for further use applications.
• the dehulled and split soy beans are fed at a uniform rate through a trap into a continuous steamer. This consists of a well insulated horizontal trough in which is turning a helix and paddles, the speed of which can be varied by an appropriate speed controller.
• Potable steam is injected into the base of the trough through a plurality of orifices.
• the split soybeans are subjected to rapid heating by live steam and are simultaneously mixed by the paddles to ensure uniform heaing and are transported through the steam zone.
• the speed of rotation of the helix is adjusted so that the residence time of the dehulled and split soybeans at 100°C is 10 minutes.
• the treated beans exist from this continuous steamer directly into the nip of the smooth rolls of a roller mill described above, then are further processed by drying and pulverising as described.
• the pulverised PSM produced from the flaked dried soybeans had almost no flavour, being quite bland.
• the minimal flavour which could be detected is a pleasant slightly sweet, buttery, egg-like flavour.
• the PSM was completely lacking in any beany or bitter flavour, and was also lacking in painty or green flavour.
• Dehulled soybeans were treated as in example 1 except that the final dehydration step was omitted.
• the cooled flaked soybeans were frozen and packaged for further use then used as required in the preparation of various food products, for example for inclusions in high protein bread doughs. Alternately, the cooled flaked soybeans were used directly as an ingredient in high protein biscuits
• Dehulled soybeans were processed as in example I except that the time of steaming at 100°C was varied to cover a range of periods of time, as shown. In each case the dried soya flakes were reduced to a fine meal using a laboratory grinder. The resultant soy flours were compared for flavour and appearance.
• Dehulled and split soy beans were prepared as in example I (A,B,C) and were then subjected to a controlled heat treatment in heated water instead of in live steam.
• the dehulled soybeans were added to an excess of water held at the temperatures and for the times shown in the results hereunder. The times of exposure were measured from the time at which the temperature of the water returned to the stated temperature after addition of the dry dehulled beans.
• the dehulled and split soybeans were fed continuously and at a controlled rate, into a continuous rotary water blancher in which the water was maintained at 95°C.
• the speed of rotation of the screw section of the water blancher was controlled so that the beans were at 95°C for a total of 15 minutes before being lifted from the hot water by the emptying device on the blancher.
• the beans so treated passed across a dewatering screen, then fed while still very hot to a roller mill and were further processed as in example I to produce a dried and pulverised meal.
• the resultant product had a light straw colour and a completely bland flavour and aroma.
• Dehulled soybeans were processed as in example 1 except that instead of being steamed at atmospheric pressure at 100°C, the beans were steamed under pressure at 120°C for periods of 2 1/2, 5, 10 and 20 minutes. The following observations were made:
• Dehulled split soybeans were steamed in batches as described in Example I, except that the beans were held at 100°C for quite short periods, ranging from 30 seconds to 2 1/2 minutes, with an unheated control treatment.
• the heat-treated beans were flaked, dried and further pulverised as described.
• the unheated control was simply pulverised in the raw state.
• There was a marked range of flavour characters in the treatments as follows:
• Dehulled soybeans were processed as in example VI except that instead of being processed in steam under pressure in excess of atmospheric pressure at a temperature of 120°C, the beans were processed at higher temperatures. To achieve this on a batch basis, it was necessary to use a small pressure vessel with a quick release lid.
• flavour quality of a soy flour produced in steam at 100°C and described as bland is of superior flavour as compared to the bland treatments produced at higher temperatures. It is believed that this may be because the surface of an individual soybean reaches a higher temperature when treated at, say 130°C before the centre of the bean reaches a temperature adequate to prevent development of a raw flavour in the centre tissue. At that stage, the surface tissue may have then
• OMPI already developed a degree of beany flavour.
• the final flour may thus be a mixture of different flavour qualities to a greater extent than for treatments carried out at a lower temperature.
• the foregoing examples are illustrative of the invention only and it will be appreciated that various times, temperatures and pressures may be selected within the ranges disclosed which will result in the production of a satisfactory product.
• the various samples of processed beans prepared as referred to herein were incorporated into a liquid formulation, in which form any flavour changes became very perceptible to the palate.
• the liquid formulation used was in the nature of a milk-like beverage.
• the hulled soybeans variously treated and at 4% moisture content (103.

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• Life Sciences & Earth Sciences (AREA)
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Citations (14)

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• 1983
  • 1983-07-21 GB GB08408341A patent/GB2135566B/en not_active Expired
  • 1983-07-21 WO PCT/AU1983/000095 patent/WO1984000476A1/en unknown
  • 1983-07-21 JP JP58502431A patent/JPS59501494A/ja active Granted
  • 1983-07-27 CA CA000433360A patent/CA1247929A/en not_active Expired
  • 1983-07-28 ZA ZA835518A patent/ZA835518B/xx unknown
  • 1983-08-05 FR FR8312981A patent/FR2531319B1/fr not_active Expired
• 1987
  • 1987-09-19 SG SG755/87A patent/SG75587G/en unknown

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