用酶水解结合盐溶解的方法制备丝素肽

Preparation of Silk Fibroin Peptide by Enzymatic Hydrolysis Combined with Salt Bath

以家蚕茧壳为原料,采用胰蛋白酶水解结合盐溶解的方法制备丝素肽。通过单因素试验、正交试验优化蚕丝蛋白纤维脱胶、酶水解、盐溶解和真空冷冻干燥全流程主要工艺条件为：蚕丝蛋白纤维以2.5 g/L Na2CO3＋2.5 g/L NaHCO3的混合液脱胶30 min;在脱胶丝素蛋白纤维与8×10^5U/m L胰蛋白酶液的质量比为1∶100、酶解液pH 7.5、温度50℃的条件下酶解4 h;98℃下用200 g/L CaCl2溶液（浴比1∶120）溶解反应6 min;液态丝素肽在真空度60～70 k Pa条件下,进行-42℃3 h→60℃5 h→70℃4 h分段式真空冷冻干燥。在此工艺条件下,丝素蛋白的水解度为19.7%,获得的丝素肽样品呈粉末状,颜色洁白,无异味,可溶性指数接近100%,具有较好的商品性能与应用性能。

In this study,we prepared silk fibroin peptide from mulberry silkworm（ Bombyx mori） cocoon shell by using the methods of trypsin hydrolysis combined with salt bath. Through single factor experiment and orthogonal test,the main technological conditions including degumming of silk fiber,enzymatic hydrolysis,salt bath and vacuum freeze drying were optimized as： degumming of silk fibers in 2. 5 g / L Na2CO3＋ 2. 5 g / L Na HCO3 mixed solution for 30 min,digestion of degummed silk fibers with 8 × 10^5 U / m L trypsin at 30 ℃ for 4 h under the conditions of the mass ratio of silk fibers to trypsin solution 1∶ 100,enzymatic hydrolysis solution pH 7. 5,and enzymatic hydrolysis temperature 50 ℃,dissolved in 200 g / L Ca Cl2solution（ bath ratio 1∶ 120） at 98 ℃ for 6 min,and staged vacuum freeze drying of liquid silk fibroin peptide at-42 ℃ for 3 h,60 ℃ 5 h and 70 ℃ 4 h under the vacuum degree of 60-70 k Pa. Under this optimal condition,the hydrolysis degree of prepared silk fibroin was 19. 7%. The obtained silk fibroin peptide sample has the characteristics of powdered form,white,nounpleasant smell,and good solubility（ soluble index was close to 100%）,showing good product properties and application performances.