摘要
在叔丁醇体系中,Novozym 435固定化脂肪酶催化L-抗坏血酸和中链脂肪酸正辛酸发生酯化反应合成L-抗坏血酸辛酸酯(L-AO),在底物(L-抗坏血酸)浓度0.2 mol/L、底物摩尔比6:1、脂肪酶用量20%、反应温度55℃、分子筛添加量60 mg/mL条件下反应12 h,L-抗坏血酸酯化转化率可达85.6%。DSC分析结果表明L-AO具有较低的结晶温度和较高的结晶焓,使其在低温时不易结晶析出。油溶性测定结果显示,L-AO在植物油中的溶解度远远大于L-抗坏血酸棕榈酸酯(L-AP),较高的油溶性有利于扩展其在油脂及脂溶性产品中的应用。羟自由基清除能力以及对油脂的抗氧化性能试验结果表明L-AO具有较强的抗氧化能力,是一种很有潜力的油溶性抗氧化剂。
The esterification of n - octanoic acid with L - ascorbic acid and medium - chain fatty acid n - ca- prylic acidin the presence of immobilized lipase（ Novozym 435 ） as the catalyst and tert -butanol as the solvent to ob- tain L- ascorbyl octanoate（L- AO） was studied. The conversion rate ofL- ascorbic acid could reach 85.6% under the conditions of concentration of L - ascorbic acid 0.2 mol/L, substrate molar ratio 6： 1, enzyme dosage 20%, reac- tion temperature 55 ℃, molecular sieve dosage 60 mg/mL and reaction time 12 h. DSC analysis results indicated that L - AO has lower crystallization temperature and higher crystal enthalpy, which make it not easily to crystallize out at low temperatures. And the oil solubility analysis resluts indicated that the solubilities of L -AO in the vegetable oils are far greater than that of L -ascorbic palmitate （L -AP）, the higher oil -solubility of L -AO benefits to extend its application in oils and fat - soluble products. The antioxidant activities of L - AO were studied by hydroxyl radical system and further evaluated by adding into the soybean oil. The hydroxyl radical scavenging activity and oxidation resistence test results of grease indicated that L - AO had strong oxidation resistance and L - AO was demonstrated to be a potential oil -soluble antioxidants.
出处
《中国粮油学报》
EI
CAS
CSCD
北大核心
2016年第7期107-113,共7页
Journal of the Chinese Cereals and Oils Association
基金
"十一五"国家科技支撑计划(2010BAD01B07)
农业科技成果转化资金项目(2013GB2C300217)
