青稞全麦馒头的营养、质构及体外淀粉水解特性

Nutritional components, textural properties, and in vitro starch hydrolysis of steamed hulless barley bread

青稞是我国藏区的主要农作物，富含β-葡聚糖、黄酮、生育酚等多种生理活性成分．通过比较分析青稞全麦粉和小麦粉的粉质和糊化特性差异，研制青稞全麦粉占面粉含量60％的高青稞含量的青稞全麦馒头粉，并对青稞全麦馒头的营养、感官、质构以及体外淀粉水解等方面的特性进行评价．结果显示：（1）青稞全麦粉吸水率、弱化度显著高于小麦粉，面团形成时间、稳定时间以及粉质质量指数显著低于小麦粉，通过添加谷朊粉，青稞全麦馒头粉的粉质特性得到了改善，其面团形成时间和稳定时间延长，弱化度降低，粉质质量指数增加；青稞全麦粉比小麦粉更易糊化，峰值粘度、崩解值和回生值增加，混粉后青稞全麦馒头粉的低谷粘度与小麦粉差异显著，其他参数无显著差异；（2）青稞全麦馒头的蛋白质和β-葡聚糖含量都显著高于小麦馒头，其中β-葡聚糖含量为2．33％-2．78％，是小麦馒头的10倍；（3）青稞全麦馒头感官品质显著低于小麦馒头，但仍具有较好的整体接受度；（4）与小麦馒头比较，青稞全麦馒头的硬度、胶着性、咀嚼度等指标显著增加，而粘附性、回复性等指标则显著降低；（5）青稞全麦馒头的抗性淀粉（RS）含量显著高于小麦馒头，而极易消化淀粉（VRDS）、易消化淀粉（RDS）、血糖生成指数（GI）均显著低于小麦馒头．本研究表明，青稞全麦馒头不仅具有独特的口感和香味，而且比小麦馒头具有更高的营养价值，尤其是低GI值，可缓解餐后血糖指数的升高，更利于人们对血糖的控制，因而青稞可以作为一种优质的主要原料用于馒头加工．（图2表7参54）

Hulless barley is the staple food crop in the Tibetan region of China. It has high/%glucan, tocopherol, and tocotrienol content in its grains, which has positive effects on human health. In this study, the farinograph parameters and pasting properties of hulless barley wholegrain flour and steamed hulless barley bread flour were evaluated. Steamed hulless barley bread was prepared that contained 60% hulless barley wholegrain flour, and then its nutritional value, textural properties, and in vitro starch hydrolysis were evaluated. The results showed that hulless barley wholegrain flour had a higher water absorption ratio and degree of softening, but a lower development and stability time and farinograph quality number, than wheat flour did. The farinograph parameters of steamed hulless barley wholegrain bread flour were improved when it contained gluten. Further, hulless barley wholegrain flour was pasted more easily, had a higher peak and trough viscosity, and a lower breakdown and setback value. The steamed hulless barley bread had a higher protein and fl-glucan content （17.48%-17.58% and 2.33%-2.78%, respectively） than those of steamed wheat bread （11.93% and 0.23%, respectively）. Steamed hulless barley bread had fair acceptability, although its general sensory quality was inferior to that of steamed wheat bread. Steamed hulless barley bread tended to be more crispy, hard, and chewy than steamed wheat bread. Steamed hulless barley bread also exhibited a lower equilibrium concentration of hydrolyzed starch, a higher resistant starch （RS） content, and lower very rapidly digestible starch （VRDS）, rapidly digestible starch （RDS）, and glycemic index （GI） content. This study indicates that compared with steamed wheat bread, steamed hulless barley bread has a higher nutritional value and is more beneficial to human health. These results may stimulate further interest in using hulless barley as a premium cereal grain for food processing.