高温高压蒸汽处理对米糠理化和营养特性的影响

Effects of High-temperature and High-pressure Steam on Physicochemical and Nutritional Properties of Rice Bran

为考察高温高压蒸汽对米糠理化特性和营养品质的影响,该研究评价了121℃高温高压蒸汽处理时间对米糠脂肪酶活性、物理特性(粘度、色度和微观结构)、营养组分(可溶性蛋白质含量、粗脂肪含量及其组成)和植物化学成分(植酸、γ-谷维素、酚类物质及其活性)的影响规律。结果表明,处理1 min脂肪酶活性损失率达81.86%,进一步延长处理时间对脂肪酶活性损失率并无显著提高。随处理时间的延长,米糠的粘度由14.67 cP降低至7.00 cP,颜色则明显加深,结构上表现更加致密。高温高压蒸汽处理1 min后,米糠可溶性蛋白含量降低71.89%,粗脂肪提取率提高5.94%;植酸、γ-谷维素和结合酚不受处理的影响,但米糠游离酚含量由0.51%下降至0.46%,其ORAC(oxygen radical absorbance capacity)抗氧化活性由183.20降低至149.22μmol TE/g DW。上述结果表明,121℃高温高压蒸汽处理1 min为最佳米糠处理时间。研究结果为高温高压蒸汽在米糠加工中的应用提供了理论指导。

In order to investigate the effects of high-temperature and high-pressure steam on the properties of rice bran,different high-temperature(121)and high℃-pressure steaming treatment durations were investigated.Lipase activity,physical properties(viscosity,chromaticity and microstructure),nutritional composition(soluble protein content,crude fat content and composition)and phytochemical composition(contents and activities of phytic acid,γ-oryzanol,phenolics)were determined.The results showed that the loss rate of lipase activity reached 81.86%after 1 min of steaming,and longer treatment did not significantly increase the lipase activity loss rate.The viscosity of the rice bran decreased from 14.67 cP to 7.00 cP,and the color deepened as the treatment time increased.Meanwhile,the micro-structure of rice bran became denser after treatment.The soluble protein content of rice bran decreased by 71.89%,while the extraction rate of crude fat increased by 5.94%after 1 min of steaming.The contents of phytic acid,γ-oryzanol and bound phenolics are not affected by steaming.However,the content of free phenols in rice bran reduces from 0.51%to 0.46%,and its ORAC(oxygen radical absorbance capacity)antioxidant activity decreases from 183.20μmol TE/g DW to 149.22μmol TE/g DW.The results revealed that 1 min high-temperature and high-pressure steaming at 121 is the optimal treatment for rice bran.These findings provide a theoretical guidance for the application of high℃-temperature and high-pressure steam in rice bran processing.