不同剥皮次数对青稞米品质的影响

Effect of different pearling times on the quality of hull-less barley rice

青稞是一种营养丰富的高原特色作物.为改善青稞口感粗糙,蒸煮困难等问题,目前常采用6次碾削剥皮工艺对青稞进行加工,生产青稞米.为获得低能耗的优质青稞米的加工方式,评价不同剥皮次数下青稞米在营养品质、蒸煮品质、感官品质和储藏品质等方面的差异.结果显示:(1)随着剥皮次数的增加,青稞米中大多数营养组分含量减少,其中维生素B6、维生素E、膳食纤维、铁、锌以及酚类和黄酮类等组分含量显著大幅下降,蛋白质、维生素B3含量小幅下降,而总淀粉和β-葡聚糖含量显著升高,γ-氨基丁酸先升高后下降;(2)同时麸皮中纤维素等大分子物质的去除及淀粉含量增加导致青稞米淀粉糊化和膨胀能力增强,未剥皮青稞糊化峰值黏度、最低黏度和最终黏度分别为1 860.50 cP、914.50 cP和2 150.00 cP,剥皮6次后分别增大至4 219.00 cP、2 628.00 cP和5 074.00 cP,同时剥皮后青稞米蒸煮吸水率和膨胀体积也显著升高;(3)剥皮后青稞米饭的硬度由4 708.50 g下降至2 282.00 g,黏性上升为-7.33,口感更佳,感官品质更好;(4)剥皮后青稞米中α-淀粉酶、多酚氧化酶、脂肪酶和过氧化氢酶活性显著下降,但下降程度不大;(5)麸粉富含多种营养组分,是一种具有高开发价值的潜在资源.本研究表明经3次剥皮后的青稞具有外观完整、营养价值和蒸煮品质高、酶活性低及能耗小等特点,可将3次剥皮工艺用于低耗高品质青稞米生产.该结果可为低碳、高功能组分含量青稞米的生产和麸粉的高值利用提供参考.(图7表5参63)

Hull-less barley is a special food crop rich in various nutrients in Qinghai-Tibet Plateau. Six-pearling is often used to produce commercial hull-less barley rice in order to improve its rough taste and inferior cooking quality. This study evaluated the differences in the nutritional, cooking, sensory, and storage qualities of hullless barley rice with different pearling times to obtain suitable processing conditions for the production of highquality hull-less barley rice. With increasing pearling time, the contents of vitamin B6, vitamin E, dietary fiber,iron, zinc, phenols, and flavonoids significantly decreased to a large extent, protein and vitamin B3 decreased slightly, the contents of total starch and β-glucan increased significantly, and γ-aminobutyric acid(GABA) initially increased and then decreased. The peak, trough, and final viscosity of whole grain barley were 1 860.50 cP,914.50 cP, and 2 150.00 cP, respectively, and increased after six-pearling to 4 219.00 cP, 2 628.00 cP, and 5074.00 cP, respectively. At the same time, the water absorption and volume expansion of the pearled hull-less barley increased significantly. The hardness of pearled hull-less barley reduced from 4 708.50 g to 2 282.00 g,its adhesiveness increased from 0.00 to-7.33, and its taste and sensory quality exhibited better. The activities of α-amylase, polyphenol oxidase, lipase, and catalase in pearled hull-less barley slightly decreased. Hull-less bran flour is rich in a variety of nutritional components and could be a potential resource with great developmental value. In general, hull-less barley rice obtained from three-pearling has high nutritional value, high cooking quality,low enzyme activity, and low energy consumption;therefore, it can be used to produce high-quality barley rice.This study provides important information for high-quality pearled hull-less barley and further utilization of barley bran flour.