Starch grains PART 2
Alpha-galactosidase is not active in the germinated seeds, but it’s activated by germination. The higher activity was observed after three days of germination. Who prepares homemade soy milk or other soy preparations, to try the french authors’ suggestion: to let the beans to germinate for 3-4 days.
Another problem, related to soy milk and other products, is the somewhat unpleasant taste. Lipids or fats from soy are a major source of compounds responsible for the unpleasant taste. In the forming of less pleasant smell and taste, lipoxygenase enzyme plays an important role, which deteriorates the palatability when soy is processed under conditions of much moisture (such as the preparation of soy milk with traditional methods).
Lipoxygenases are enzymes which use molecular oxygen to produce hydroperoxides of fatty acids. These enzymes can be found widespread in nature. Dried soy beans contain at least 6 lipoxygenase.
Lipoxygenase are involved in various aspects of the plant physiology, including growth, development, resistance to pests, aging and the response to pathogenic infections.
Short germination period can substantially improve the smell and taste of soy flour with whole fat content by decreasing the lipoxygenase activity in the process of germination. Thus, fat flour of germinated grains can be preserved longer without rancid.
Germination of 24 hours leads to a massive decline in the lipoxygenase activity. In fact, 1 day germination presents and other advantages too: simplifies the beans wrapper removal (shell), lowers the level of oligosaccharides (stachyose and raffinose), ie non-digestible starch, and reduces the browning phenomenon, darkening color during the heat treatment by raising the level of ascorbic acid and reducing lipoxygenase activity.
The quality and biological value of a protein depends on its digestibility and the essential amino acids amount; must not contain harmful substances or factors that influences olfactory and gustatory qualities. Structural features and amino acids sequence can influence also the value or the use of amino acids in the protein.
The amino acid profile of the soy protein is particularly well made up for the vegetable protein. The high content of lysine soy protein makes it very suitable to supplement proteins from cereals that are low in lysine.
Not only that soy is a complete protein, with nothing inferior to albumin, but its consuming with other vegetable protein, especially proteins from cereals, improves their quality, making it serve as a complete and well-balanced source of amino acids to meet the needs of human physiology.
French authors recommend that before the thermal preparation, soybeans to be germinated about three days, after that to proceed to the milk or other products manufacture.