麦芽三糖酶酶解大米淀粉产物的回生性质研究

Research on the retrogradation properties of rice starch hydrolyzed by α-maltotriohydrolase

中文关键词:  大米淀粉  麦芽三糖酶  回生控制  分子结构

英文关键词:rice starch  α-maltotriohydrolase  retrogradation control  molecular structure

中文摘要:

      目的 研究麦芽三糖酶对大米淀粉回生性质的影响。方法 以不同麦芽三糖酶添加量(0、200、300、400、500、600 U)水解大米淀粉, 利用差示扫描量热仪、X射线衍射仪测定酶解产物的回生性质和重结晶性质, 并利用凝胶色谱分析系统分析酶对淀粉分子结构的影响。结果 麦芽三糖酶酶解大米淀粉, 随着水解程度增加可显著降低其4℃储藏14 d后的回生焓、相对结晶度以及分子尺寸, 显著提高脱支大米淀粉酶解产物中聚合度(degree of polymerization, DP)<9的极短链所占比例; 淀粉水解率≥25.96%后, 实验条件下未能检测到回生焓和重结晶峰。结论 麦芽三糖酶酶解大米淀粉后可有效抑制酶解产物的回生, 当淀粉水解率≥25.96%, 大米淀粉酶解产物的回生被完全抑制, 这主要是因为支链淀粉的外链被水解生成具有大量DP<9极短链的分支糊精。本研究可为麦芽三糖酶应用大米淀粉制品的酶法回生控制提供理论参考和技术依据。

英文摘要:

      Objective To investigate the effects of α-maltotriohydrolase on the retrogradation properties of rice starch. Methods The rice starch were hydrolyzed with different amount of α-maltotriohydrolase (0, 200, 300, 400, 500, 600 U) to perform retro gradation. The retrogradation properties and re-crystallization properties were analyzed by differential scanning calorimeter and X-ray diffractometer, and the molecular structure was analyzed by the gel chromatography system. Results With increasing α-maltotriohydrolase hydrolysis, the retrogradation enthalpy, relative crystallinity and molecular size of rice starch stored at 4℃ for 14 days were significantly decreased, whereas the proportion of short chains with degree of polymerization (DP) less than 9 were significantly increased. When the degree of hydrolysis over 25.96%, the retrogradation enthalpy and recrystallization peak were both disappeared under the experimental conditions. Conclusion The α-maltotriohydrolase can effectively inhibit the retrogradation of rice starch. When the hydrolysis degree over 25.96%, the retrogradation is completely inhibited, which mainly because the amylose and longer chains of amylopectin are hydrolyzed to generate a large proportion of chains with DP less than 9. These results can prove theoretical reference and technical basis for enlarge the use of α-maltotriohydrolase in the field of enzymatical control of retrogradation of rice starch products.