丙二醛氧化对大米蛋白功能性质的影响

Effect of oxidative modification by malondialdehyde on functional properties of rice protein

以新收获籼米为原料制备大米蛋白,采用不同浓度丙二醛氧化大米蛋白,研究丙二醛氧化对大米蛋白功能性质的影响。结果表明:随着丙二醛浓度的增加,氧化大米蛋白的羰基和二硫键含量增加,游离巯基含量下降,表明大米蛋白发生了氧化。当丙二醛浓度从0增加到100 mmol/L时,氧化大米蛋白溶解性从28.88%降低至12.20%,持水性从353.67%降低至132.33%,持油性从89.40%上升至189.40%,起泡能力和泡沫稳定性分别从74.27%和54.06%降低至57.56%和38.01%,乳化性和乳化稳定性分别从55.32 m2/g和97.59 min降低至45.13 m2/g和75.29 min,表明丙二醛氧化对大米蛋白功能性质有负面影响。这一结果为进一步改善大米蛋白功能性质提供了有效基础。

Fresh indica rice which oxidatively modified by different concentration of malondialdehyde were used as material to investigate effects of oxidative modification by malondialdehyde on functional properties of indica rice protein. The results indicated that as concentration of malondialdehyde increased,content of rice protein carbonyl and disulfide increased,and content of free sulphydryl decreased,which indicated that incubation of malondialdehyde with rice protein resulted in oxidation of rice protein. As concentration of malondialdehyde increased from 0 to 100 mmol/L,solubility of rice protein decreased from 28.88% to 12.20%,water holding capacity of rice protein decreased from 353.67% to 132.33%,oil-absorbing capacity of rice protein decreased from 89.40% to 189.40%,foaming capacity and foam stability of rice protein decreased from 74.27% and54.06% to 57.56% and 38.01%,respectively,emulsification and emulsion stability of rice protein decreased from55.32 m2/g and 97.59 min to 45.13 m2/g and 75.29 min,respectively. The results indicated that oxidative modification by malondialdehyde had a negative effect on function properties of rice protein. The results provided effective basis for further improve the functional properties of rice protein.