大米蛋白与阿魏酸酶法交联物的乳化特性和抗氧化稳定性

摘要

研究漆酶(laccase,LAC)催化大米蛋白(rice protein,RP)与阿魏酸(ferulic acid,FA)交联产物的乳化特性和抗氧化稳定性.发现RP乳液在pH 5和pH 3条件下出现了明显的相分离,RP乳液在pH 7和pH 9条件下有部分聚集状态,说明RP在酸性范围的乳化稳定性远远小于碱性范围的乳化稳定性;RP/FA/LAC酶法交联物乳液在pH 5、7、9条件下的乳液粒径和乳析层指数都小于RP乳液;在pH 3条件下乳液粒径和乳析层指数大于RP乳液;RP乳液中的氢过氧化物含量(11.12 mmol/kg)、硫代巴比妥酸反应产物(thiobarbituric acid reactive substances,TBARS)含量(0.73 mmol/kg)和己醛含量(0.986 mg/L)明显高于RP/FA/LAC酶法交联物乳液中氢过氧化物含量(3.59 mmol/kg)、TBARS含量(0.23 mmol/kg)和己醛含量(0.191 mg/L),表明RP/FA/LAC酶法交联物具有更好的抗氧化稳定性.研究结果显示LAC催化FA与RP形成的交联物在含有乳化体系等食品加工中具有潜在应用价值.%The aim of this study was to investigate the emulsifying properties and antioxidant stability of laccase (LAC)-mediated cross-linked products of rice protein (RP) and ferulic acid (FA).RP emulsion showed marked phase separation at pH 5 and 3,while only partial aggregation was observed at pH 7 and 9,suggesting even lower stability in the acidic pH range than in the basic pH range.The particle size and creaming index of cross-linked RP/FA/LAC emulsion were less than those of RP emulsion at pH 5,7 and 9,but higher at pH 3,suggesting that emulsion stability of crossed RP/FA/LAC emulsion was improved at pH 5,7 and 9,but was unstable at pH 3.Moreover,the contents of hydroperoxide (11.12 mmol/kg),TBARS (0.73 mmol/kg) and hexanal (0.986 mg/L) in RP emulsion were significantly higher than those in cross-linked RP/FA/LAC emulsion (3.59 mmol/kg,0.23 mmol/kg and 0.191 mg/L,respectively),suggesting that RP/FA/LAC cross-linking had better oxidative stability at the emulsion interface.Enzymatic cross-linking between RP and FA will have potential application in emulsion system for food processing.