Soybean fatty acid protein

Flavor is one of the major characteristics that restricts the use of legume flours and proteins in foods. Processing of soybeans, peas and other legumes often results in a wide variety of volatile compounds that contribute flavor notes, such as grassy, beany and rancid flavors. Many of the objectionable flavors come from oxidative deterioration of the unsaturated lipids. The lipoxygenase-catalyzed conversion of unsaturated fatty acids to hydroperoxides, followed by their degradation to volatile and non-volatile compounds, has been identified as one of the important sources of flavor and aroma components of fruits and vegetables. An enzyme-active system, such as raw pea flour, may have most of the necessary enzymes to produce short chain carbonyl compounds. 

On average, a ton of soybeans yields about 18% oil, 72% protein meal, 7% hulls, and 3% loss. A listing of the primary fatty acids found in soybean oil is provided in TABLE 12-5. 

Soybean -dewatering of [DEWATEFJNG] (Vol 8) -fatty acid source [CARBOXYLIC ACIDS - ECONOMIC ASPECTS] (Vol 5) -lecithin m [LECITHIN] (Vol 15) -protein m dairy substitutes [DAIRY SUBSTITUTES] (Vol 7) -protein source [FOODS, NONCONVENTIONAL] (Vol 11)... 

Erucic acid is a fatty acid that has toxic properties and has been related to heart disease in humans. Glucosinolates give rise to breakdown products that are toxic to animals. These characteristics make rapeseed products unsuitable as animal feedstuffs but canola, like soybeans, contains both a high oil content and a high protein content and is an excellent feedstuff for poultry. 

The earliest efforts to modify the composition of milk fat used an insoluble formaldehyde-crosslinked protein to encapsulate unsaturated vegetable oils. In numerous studies using this approach, linoleic acid was increased to as high as 35%, w/w, of the total milk fatty acids (reviewed by McDonald and Scott, 1977). Bitman et al. (1973) fed increasing amounts of safflower oil encapsulated in formaldehyde-treated casein. The content of milk fat increased linearly from 3.5 to 4.6% as supplemental protected oil was increased from 0 to 1320 g/day per cow. The concentration of linoleic acid increased to 33% of total milk fatty acids, with a compensating decrease in Ci6 o and a smaller decrease in Ci4 0. The concentration of milk fat decreased to lower than pretreatment levels when the supplement was removed, a common observation (Pan et al., 1972). A typical milk fatty acid profile from cows fed a protected sunflower/soybean (70/30) supplement is shown in Table 2.1. 

Soybeans are comprised of (w/w), 40% protein, 30% carbohydrates, and 20% oil (5, 4). Currently, about 95% of soy protein is used in feed and 4% in food (for human consumption) applications. On the other hand, about 94% of soybean oil is used in food and only about 4% in industrial applications. Soybean oil is a triglyceride, which is a triester of glycerol and three fatty acids. The main fatty acid composition of soybean oil is (w/w) linoleic (54), oleic (23), and linolenic (8), (5). These fatty acids contain 1, 2, and 3 double bonds, respectively, in their hydrocarbon chains. These double bonds or unsaturations are reactive sites and allow for the development of soybean oil for various applications. 

The effects of two commercial rumen inert fats and whole roasted soybeans on yield of milk and its fatty acid profile were evaluated (99). Fatty acid profiles of the three fat sources are shown in Table 19. Whole roasted soybeans produced more total and 3.5% FCM milk, total protein, and total fat than the two rumen inert fat sources (Table 20). However, Megalac produced the milk with the highest fat... 

Defatting. When tofu, a protein curd made from whole soybean, was treated with Molsin, in addition to volatile compounds, nonvolatile fatty materials were liberated including triglygerides, fatty acids, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol, sito-steryl-D-glucoside, genistein, saponins, etc. (84). 

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