绿色环保型可食用果蔬保鲜剂SA-cys的合成

Synthesis of green-edible fresh-keeping agent SA-cys for fruit and vegetable

利用海藻多糖(SA)良好的成膜保水性和L-半胱氨酸(L-cys)良好的抑菌、抗氧化性,通过化学改性法制备了巯基含量高达328.27μmol/g的L-cys改性SA(SA-cys)。采用稀释平板计数法的研究表明:在被测试范围内,L-cys对革兰氏阴性大肠杆菌、蜡样芽孢杆菌、革兰氏阳性金黄色葡萄球菌均有很好的抑菌性;SA-cys对革兰氏阴性大肠杆菌、蜡样芽孢杆菌均有较好的抑菌效果,最大抑菌率分别为100.00%,77.24%,对革兰氏阳性金黄色葡萄球菌的最大抑菌率只有61.26%;而SA对3种菌株的最大抑菌率均在40.75%以下,抑菌效果最差。因此,SA-cys在很大程度上综合了L-cys和SA的优势,拓展了SA在果蔬保鲜领域的应用范围。

L-sodium alginate-cysteine（SA-cys）derivative is synthesized by chemical modification based on the film-forming and water retention of sodium alginate（SA）as well as the antibacterial and antioxidant properties ofL-cysteine（L-cys）,whose sulfhydryl content can reach328.27μmol/g. The results of dilution plate counting method show that： within the testingL-cys performs antibacterial effect on Bacillus Cereus, Escherichia coli（Gram-negative）,and Staphylococcus aureus（Gram-positive）;the maximum inhibition rate of SA-cys for Escherichia coli（Gram-negative）and Bacillus Cereus are100.00% and77.24% respectively, while that of Gram-positive Staphylococcus aureus is only61.26%;the maximum inhibition rate of SA on three strains are below40.75%, indicating worst antibacterial effect. Therefore, SA-sys integrates the superiority ofL-cys and SA to expand the application range of SA in fresh keeping for fruits and vegetables.