超高压处理对发芽糙米淀粉凝胶特性的影响

摘要

In this paper,starches from germinated brown rice were treated by high hydrostatic pressure (HHP) processing.The effects of pressure level,pressure holding time and pH on texture and gelation properties of starch gel,as well as the freeze-thawing stability were studied.It was found that the adhesiveness,cohesiveness,resilience and gumminess of starch gel were improved by HHP.RVA results exhibited that after HHP treatment for 20 min,peak viscosity of starch gel rose from 404.83 mPa · s to 595.75 mPa · s,while hot paste viscosity,final viscosity,setback and attenuation values were also increased.However,the peak time and pasting temperature of starch gel decreased after pressure treatment.The effects of pressure level and pH on RVA were insignificant,indicating that pressure-treated starch were more stable to pressure and pH change.Besides,after treating at 200 MPa and pH 5 or 8 for 10 min,the freezing-thawing stability of starch gel also got improved.%糙米发芽过程中,淀粉理化特性发生改变,该研究采用超高压技术处理发芽糙米淀粉,考察处理压力,保压时间及pH值对发芽糙米淀粉凝胶质构特性、糊化特性及冻融稳定性的影响.结果表明,不同压力、保压时间、pH处理对淀粉凝胶的弹性、黏着性、胶黏性、回弹性、咀嚼性有不同程度的改善.RVA结果显示,当保压时间为20 min时,峰值黏度由404.83 mPa·s增至595.75 mPa·s,同时热糊黏度、最终黏度、回生值、衰减值也呈现上升趋势,出峰时间减小,糊化温度降低;超高压处理压力和pH对淀粉的糊化特性的影响较小,说明超高压处理的淀粉对压力和pH有较好的稳定性.超高压处理后淀粉的冻融稳定性显著提高,在200 MPa时达到最大;随保压时间延长,淀粉糊析水率呈先下降后上升趋势,保压时间为10 min时,淀粉糊的析水率达到最小值;当pH为5或8时析水率与对照相比没有显著变化(p＞0.05).