Study On Enzyme Modification Of Soybean Phospholipids Powder

Phospholipids is a type of phosphoric multi-lipids. As a type of natural amphoteric surfactants, soybean phospholipids has been widely used in food, cosmetics, medical treatment, health products, weave and feed industry. However the weakness of easy oxidation and low hydrophile limited it application. For raising the ability of antioxidation and hydrophile, follow work have been successfully studied with phospholipase A₂ (EC 3.1.1.4) sourced from actinomycetes.The enzyme phospholipase A₂ was acquired from the fermentation supernatant fluid, 10 percent substrate concentration was based on. The optimum conditions of phospholipids enzyme-hydrolysis were: initial reaction pH value 7.5, reaction temperature 40°C, Ca²⁺concentration 10mM and hydrolysis time 19h, under this condition the ratio of hydrolysis was up to 44.75 percent.The best preparing process of enzyme-hydrolyzed phospholipids was that adding 12 volume times acetone solution (without water content) to the reacted system, stirred 30 minutes. The acetone insoluble substance was then dried under 60°C condition after repeating 4 times former treatment.The TLC analysis was operated on silica gel G (made in Qingdao ocean factory) plate, used chloroform: methanol: distilled water (65/25/4) system saturated 30mins. The operation temperature was 30°C, and the phospholipids concentration was 20mg/ml in chloroform, 5μl sample getting to the plate, iodine gas was used to dye after the separation was over.The relative emulsification ability of raw phospholipids (RPL) was 769 seconds at the concentration of 0.24 percent. The ability of enzyme-hydrolyzed phospholipids (EHPL) was higher than that of RPL while the concentration was only half of RPL. It could be up to 1176 seconds when concentration was 0.6 percent, and no obvious difference was observed with the concentration increasing.The relative stability of emulsified layer of EHPL was much better than that of RPL under neutral 25°C condition during 24h periods. If observed at 96h, its relative ability to soybean oil was 38.7 percent, about 3 times of RPL.The relative stability of emulsified layer of EHPL observed at the time of 24h was 25.3 and 61.5 percent at pH 5 and pH 9 respectively, about 1.69 times and 1.22 times compared with that of RPL, and 32.1 and 25.1 percent at 4°C and 80°C condition respectively, about 1.99 times and 1.86 times compared with RPL. When the Na⁺and Ca²⁺ ion stress concentration was 20mM and 10mM, it was 23.4 and 30.7percent respectively,...