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

Emulsifying Properties and Antioxidant Stability of Enzymatically Cross-Linked Products between Rice Protein and Ferulic Acid

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 atpH5and3,while only partial aggregation was observed at pH7and9,suggesting even lower stability in the acidic pH rangethan in the basic pH range.The particle size and creaming index of cross-linked RP/FA/LAC emulsion were less than thoseof RP emulsion at pH5,7and9,but higher at pH3,suggesting that emulsion stability of crossed RP/FA/LAC emulsion wasimproved at pH5,7and9,but was unstable at pH3.Moreover,the contents of hydroperoxide(11.12mmol/kg),TBARS(0.73mmol/kg)and hexanal(0.986mg/L)in RP emulsion were significantly higher than those in cross-linked RP/FA/LACemulsion(3.59mmol/kg,0.23mmol/kg and0.191mg/L,respectively),suggesting that RP/FA/LAC cross-linking had betteroxidative stability at the emulsion interface.Enzymatic cross-linking between RP and FA will have potential application inemulsion system for food processing.