湿热和韧化处理对莜麦淀粉结构及消化特性的影响

Effects of heat-moisture and annealing treatment on the structure and digestive properties of naked oat starch

中文关键词:  湿热处理  韧化处理  莜麦淀粉  消化特性

英文关键词:heat-moisture treatment  annealing treatment  naked oat starch  digestive properties

中文摘要:

      目的 研究湿热和韧化改性对莜麦淀粉理化性质和消化特性的影响, 扩大莜麦淀粉在慢消化主食食品中的应用。方法 分别在体系水分含量为15%、20%、25%、30%, 温度为100℃的条件下和料液比为1:5 (m:m), 体系温度为30、40、50、60℃条件下对莜麦淀粉进行湿热和韧化处理, 并采用傅里叶红外光谱、X-射线衍射、扫描电镜、差示扫描量热仪和酶解实验等分析湿热和韧化处理前后莜麦淀粉的理化性质和消化特性变化。结果 湿热和韧化处理均未改变莜麦淀粉原有的A型结晶结构, 但淀粉结晶度表现为下降趋势。且淀粉的糊化焓从1.49 J/g分别降低至0.92 和0.80 J/g。此外, 微观结构表明莜麦淀粉颗粒出现聚集行为。在酶解实验中, 经过湿热、韧化处理的莜麦淀粉中慢消化淀粉(slowly digestible starch, SDS)和抗性淀粉(resistant starch, RS)含量均出现不同程度的改变, 表现为湿热处理后RS含量无显著差异(HTM-20, HTM-25)或降低(HTM-20, HTM-30), 韧化处理后RS含量降低, 但湿热和韧化处理整体上提高了SDS的含量(HTM-20、ANN-30除外)。结论 湿热和韧化处理可以通过改变淀粉理化结构特性, 进而改变莜麦淀粉的消化速率。

英文摘要:

      Objective To investigate the physicochemical property and in vitro digestibility of heat-moisture treatment and annealing modified naked oat starch and expand the application of naked oat starch in slow-digesting foodstuffs. Methods Heat-moisture treatment and annealing processing were carried out at the system moisture content of 15%, 20%, 25%, 30% and the temperature of 100℃ or the material-liquid ratio of 1:5 (m:m) and the system temperature of 30, 40, 50 and 60℃, respectively. The physicochemical properties and digestive characteristics of naked oat starch were analyzed by Fourier infrared spectroscopy, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and enzymatic digestion experiments. Results The heat-moisture treatment and annealing did not change the original A type crystalline structure of naked oat starch, while the crystallinity showed a decreasing trend, and the pasting enthalpy of starch decreased significantly from 1.49 J/g to 0.92 and 0.80 J/g after heat-moisture and annealing, respectively. In addition, the microstructure showed that the naked oat starch granules showed aggregation behavior. In the enzymatic digestion experiments, both slowly digestible starch (SDS) and resistant starch (RS) content in naked oat starch treated with heat-moisture treatment and annealing showed different degrees of alteration, showing no significant difference (HTM-20, HTM-25) or decrease (HTM-20, HTM-30) in RS content after heat-moisture treatment and decrease in RS content after annealing, but heat-moisture treatment and annealing significantly increased SDS content (except HTM-20, ANN-30). Conclusion Heat-moisture treatment and annealing can alter the digestibility of oat starch by changing the physicochemical structural properties of the starch and thus the rate of digestion.