湿热处理对马铃薯淀粉-大豆肽复合物的理化和消化特性的影响

The Influence of Heat Moisture Treatment on the Physicochemical and Digestive Properties of Potato Starch-Soy Peptide Complex

研究湿热处理(HMT)的水分条件对马铃薯淀粉与大豆肽复合物(PS-SPT)的理化和消化性质的影响。采用扫描电子显微镜和偏光显微镜研究复合物的形貌特征;利用差示扫描量热仪测定复合物的热力学特性;采用布拉班德粘度仪测定复合物的黏度特性;采用Englyst体外消化法测定复合物的体外消化性。结果表明:HMT后淀粉-大豆肽复合物偏光十字减弱,团聚现象增加。淀粉-大豆肽复合物糊化温度(T_(o)、T_(p)和T_(c))显著升高,焓变(ΔH)显著降低,且T_(o)、T_(p)和T_(c)随HMT水分含量的增加呈逐渐升高的趋势。与物理混合样品相比,HMT后淀粉-大豆肽复合物的起糊温度升高,膨胀度、峰值黏度、热糊黏度和冷糊黏度均出现大幅下降。随着HMT水分含量的增加,淀粉的膨胀度和峰值黏度逐步降低。蒸煮后的体外消化性表明,HMT使马铃薯淀粉-大豆肽复合物的快消化淀粉含量(RDS)降低,而抗性淀粉(RS)含量升高。35%的HMT水分条件下,马铃薯淀粉-大豆肽复合物中RDS含量最低(81.53%±1.22%),RS含量最高(11.76%±0.62%)。这说明湿热处理显著改变了马铃薯淀粉-大豆肽复合物的理化和消化特性。HMT过程中直链/支链淀粉发生重组,大豆肽的物理包埋作用,以及马铃薯淀粉带负电荷基团与大豆肽侧链基团之间的相互作用均会降低淀粉的消化性。本研究为优化含慢消化淀粉和抗性淀粉的新型低GI食品的加工方法,提供理论参考。

The purpose of this study was to investigate the effects of heat moisture treatment(HMT)with different moisture levels on the physicochemical and digestive properties of potato starch(PS)and soybean peptide(SPT)complexes.The morphological characteristics of the complexes were studied by scanning electron microscopy and polarized light microscopy;the thermal properties of the complexes were determined by differential scanning calorimetry;the pasting characteristics of the complexes were determined by Brabender viscometer;the in vitro digestibility of the complexes was determined by Englyst in vitro digestion method.Results showed that PS-SPT complex under HMT showed weaker and fuzzier polarized cross,and more agglomerates.Higher gelatinization temperatures(T_(o),T_(p) and T_(c))and lower enthalpy change(ΔH)were observed for PS-SPT complex under HMT.The higher the moisture level is during HMT,the higher gelatinization temperatures are.Compared with physical mixed conterpart,the PS-SPT complex under HMT displayed higher pasting temperature,significant lower swelling power(SP),peak viscosity(PV),hot paste viscosity and cold paste viscosity.The SP and PV reduced gradually with the increase in moisture content of HMT.Lower rapidly digestible starch and higher resistant starch(RS)contents were found for PS-SPT complex under HMT.Thereinto,the PS-SPT complex with 35%moisture level during HMT displayed the lowest RDS(81.53%±1.22%)and highest RS content(11.76%±0.62%).Therefore,HMT significantly changed the physicochemical and digestive properties of PS-SPT complex.These results could be attributed to restructuring of amylose/amylopectin chains,physical barrier of SPT,and interactions between negatively charged groups in PS and side chain groups in SPT.The study will deepen the understanding of food multicomponent interactions and provide important theoretical guidance for low-GI food development containing slowly digestible starch and resistant starch.