小麦麸膳食纤维对猪肉肌原纤维蛋白凝胶功能特性的影响

Effect of Wheat Dietary Fibers on Functional Properties of Pork Myofibrillar Protein Gels

为开发低脂肪多纤维的健康肉制品,明确膳食纤维添加对肉制品品质的影响,以猪肉肌原纤维蛋白为研究对象,利用单因素分析法研究肌原纤维蛋白热诱导凝胶性质及小麦麸膳食纤维对猪肉肌原纤维蛋白功能特性的影响.结果表明：肌原纤维蛋白变性聚集的温度范围是40～70 ℃;肌原纤维蛋白凝胶硬度和保水性随肌原纤维蛋白质量浓度增加而增大,当质量浓度到达70 mg/mL时,凝胶硬度和保水性趋于稳定;pH值为5.5时肌原纤维蛋白凝胶硬度达到最大,凝胶保水性在pH 7.0时趋于稳定;离子强度为0.6 mol/L时凝胶的硬度和保水性趋于稳定.随着小麦麸膳食纤维添加量的增加,肌原纤维蛋白乳化性有所升高但是不明显,当添加量为5%时,乳化性增加7.4%,肌原纤维蛋白乳化稳定性降低;蛋白的弹性模量增大;凝胶硬度和保水性提高,添加量为4%时变化趋于平缓.随着膳食纤维粒径的减小,肌原纤维蛋白凝胶硬度和保水性逐渐提高;微观结构更加致密;蛋白弹性模量降低.由此可见,膳食纤维能够明显改变肌原纤维蛋白功能特性,通过在肉制品中添加适量的膳食纤维可以明显改良肉制品的风味,并替代脂肪,减少人体热量的摄入.

In order to develop healthy meat products with low fat and high fiber and to clearly define the effect of dietaryfiber on the quality of meat products, we investigate properties of heat-induced gels of pork myofibrillar protein （MP） aswell as examined the influence of adding wheat bran dietary fibers to heat-induced MP gels on their properties using theone-factor-at-a-time method. The results showed that the denaturation temperature of MP ranged from 40 to 70 ℃. Withthe increase in protein concentration, the water-holding capacity （WHC） and gel hardness increased to reach a plateau at70 mg/mL. At pH 5.5, the heat-induced gel showed the maximum hardness, and WHC tended to be stable at pH 7.0. Both gelhardness and WHC showed a stable trend at the ionic strength of 0.6 mol/L. Meanwhile, the emulsifying capacity of MP wasincreased but not significantly with increasing addition of wheat bran dietary fibers, showing an increase of 7.4% at an addedconcentration of 5%, whereas emulsion stability decreased. Moreover, the elastic modulus, hardness and WHC of heatinducedMP gels were enhanced. The gel hardness and WHC reached a plateau with the addition of 4% of wheat bran dietaryfibers. Gel microstructure became more loose with enlarged pore size as observed under scanning electron microscope （SEM）.By adding dietary fibers with smaller particle size, the WHC and hardness of gels became stronger, microscopic structurebecame more compact, a the value of elastic modulus became smaller. In conclusion, dietary fiber can obviously changethe functional properties of myofibrillar proteins. The addition of the right amount of dietary fiber in meat products cansignificantly improve meat flavor as a substitute for fat to reduce energy intake.