气流粉碎分级米糠对面包加工品质的影响

The Impact of Jet-Milled and Air-Classified Rice Bran on Bread Processing Quality

摘要:

为探究气流粉碎分级米糠级分对面粉加工品质的影响，以脱脂米糠（RB）为原料，通过气流粉碎分级技术制备了米糠粗级分（RBC）和细级分（RBF），分析了其营养组成和粒径变化，并探究了其对面包加工品质的影响。结果表明，气流粉碎分级处理后，不同米糠级分组成发生了变化，RBC组膳食纤维含量提高，蛋白质和植酸含量则有所降低，而RBF组则呈现相反的趋势；RBC和RBF组的平均粒径显著降低，降幅分别为37.06%和97.34%，但粒径分布均一性提高；相比于RB组，添加RBC可延长面粉稳定时间，提高面团弹性模量和粘性模量，改善米糠面包加工品质，表现为面包比容提高46.05%和面包芯硬度降低15.12%；而粒径更小的RBF组则表现出相反的作用，即降低了面粉粉质特性和面团流变特性，弱化了面包加工品质作用。对比RB组，粒径更小的RBF组更易促进面筋蛋白解聚，表现为面筋蛋白大聚集体（GMP）含量的降低（23.94%）以及游离巯基含量的增加（42.13%）；而RBC组未显著改变GMP与游离巯基含量水平。研究发现了气流粉碎分级米糠级分对面包加工品质的差异性结果，确定了RBC组米糠可降低米糠对面包加工品质的负面影响，研究结果有望促进米糠在面包中的应用。

Abstract:

To investigate the effects of jet-milled and air-classified rice bran fractions on bread processing quality, defatted rice bran (RB) was utilized as raw material. Rice bran coarse (RBC) and fine (RBF) fractions were obtained through jet milling and air classification techniques. Their nutritional composition and particle size distribution were analyzed, and their impacts on bread processing quality were systematically examined. It was observed that the compositional profiles of different rice bran fractions were altered by jet milling and air classification treatment. The dietary fiber content in RBC was increased, whereas protein and phytic acid contents were reduced. Conversely, opposite trends were demonstrated in that of RBF. Significant reductions in average particle size were achieved in both RBC and RBF groups, showing 37.06% and 97.34% decreases respectively, while particle size uniformity was improved. Compared with the RB group, RBC addition was found to extend dough stability time, enhance both elastic modulus (G') and viscous modulus (G') of dough, and improve bread processing quality. These improvements were manifested through 46.05% increase in specific loaf volume and 15.12% reduction in crumb hardness. In contrast, finer RBF particles exhibited opposite effects, deteriorating farinograph characteristics and dough rheological properties while weakening bread quality attributes. It was revealed that RBF with smaller particle size promoted gluten protein depolymerization more effectively than RB, as evidenced by 23.94% decrease in glutenin macropolymer (GMP) content and 42.13% increase in free sulfhydryl groups. However, RBC showed no significant influence on these parameters. This study established differential impacts of jet-milled rice bran fractions on bread processing quality. RBC was identified as an effective modification to mitigate the negative effects of rice bran incorporation in bread production. These findings provide technical support for expanding rice bran applications in baked products.