Soya processing

Gavin, A.M. Deodorization and finished oil handling. Proceedings of the World Conference on Soya Processing and Utilization hOCS Press Champaign, IL, 1981 pp. 175-184. 

During soya processing, volatile degradation compounds (hexanal, etc.) with a bean-like aroma defect are formed because of the enzymatic oxidation of unsaturated fatty acids. These defects can be eliminated by the enzymatic oxidation of the resultant aldehydes to carboxylic acids. Since the flavor threshold values of these acids are high, the acids generated do not interfere with the aroma improvement process. 

Clarity. In some soya processing plants, high levels of TI or HI matter may partition with the lecithin gums on separation from the oil. This lipid-insoluble material can cause haziness in fluid lecithins. With modem miscella and oil filtration techniques, clear transparent-looking lecithins with very low, or even no, TI contents can be produced. Additionally, moisture of over 1% can also contribute to lack of clarity. Haziness can result in sediments over time solid particles may appear on the bottom of an otherwise clear liquid lecithin. 

Of these materials zein, the maize protein, has been used for plastics on a small scale. It can be cross-linked by formaldehyde but curing times are very long. Complicated bleaching processes have led to the production of almost colourless samples in the laboratory but the process cannot readily be extended to large-scale operation. The cured product has a greater water resistance than casein. Proteins from soya bean, castor bean and blood have also been converted into plastic masses but each have the attendant dark colour. 

Soya bean Soya bean processing and food industries... 

This, then, was the scene in which SCP projects were planned in Europe. The need for alternative foods and feedstuffs was clear and, in the UK and elsewhere, oil and gas seemed a plentiful and cheap resource from which to produce them. North Sea gas fields were being exploited and research had shown that natural gas or its derivatives could be used to produce SCP feed of superior protein content to conventional feedstuffs. The economics of such processes seemed very promising. In 1971 the European prices for fish meal and soya meal were 200 and 100 per ton respectively. In 1973 oil price rises and a failure in the Peruvian fish meal supply pushed these prices up to 550 and 300 respectively. With such prices for the major feedstuffs it was considered that SCP feeds could be produced competitively. 

SAQ 4.15 Use the data in the Resource Material to answer the following question. It is 1977. The bacterial SCP from methanol plant referred to in Table 4.9 does not produce protein at a price that competes with soya protein. By how much would the cost of methanol have to fall in order that the protein from such a plant can be produced competitively with soya protein You can assume i) that the SCP processes referred to in Tables 4.7 and 4.9 to 4.15 are of 2 x 10s tons annual capacity, ii) that yield on methanol is 0.5kg biomass per kg methanol, iii) bacterial SCP contains 60% protein. 

If methanol costs are discounted altogether, the remaining production cost of bacterial protein is still 0.36 kg 1, ie more than the cost of soya protein. At these levels the particular SCP process in question is clearly not competitive. 

The main limitation to the clinical use of the MAOIs is due to their interaction with amine-containing foods such as cheeses, red wine, beers (including non-alcoholic beers), fermented and processed meat products, yeast products, soya and some vegetables. Some proprietary medicines such as cold cures contain phenylpropanolamine, ephedrine, etc. and will also interact with MAOIs. Such an interaction (termed the "cheese effect"), is attributed to the dramatic rise in blood pressure due to the sudden release of noradrenaline from peripheral sympathetic terminals, an event due to the displacement of noradrenaline from its mtraneuronal vesicles by the primary amine (usually tyramine). Under normal circumstances, any dietary amines would be metabolized by MAO in the wall of the gastrointestinal tract, in the liver, platelets, etc. The occurrence of hypertensive crises, and occasionally strokes, therefore limited the use of the MAOIs, despite their proven clinical efficacy, to the treatment of atypical depression and occasionally panic disorder. 

There have been a number of reports of the use of enzymes in the extraction of oils from sources such as fish, rape seed, yeast, palms, and soya beans. Celluloses and pectinases are used in pdm oil extraction. In soya bean and fish, much oil has been found to be associated with protein, so that addition of proteases increases the yield of oil and protein. Use of thermostable proteases is preferred, but m general the use of enzymes is limited by the minimal water contents of the various process streams. Trichoderma uride and A niger celluloses, hemicellulases and proteases have been used to extract hydrocarbons from Euphorbia plants 39 40) and similar enzymes used to extract sapogenins from Helleborus 41). 

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