低温等离子体电流强度对糙米食用品质的影响

针对糙米蒸煮时间长、口感粗糙等问题,应用辉光放电等离子体技术对糙米进行处理,利用质构仪、扫描电镜、傅里叶近红外图谱和X射线衍射仪等分析不同电流强度对米饭蒸煮特性、感官品质、质构特性、微观结构和晶体结构的影响。研究结果表明:低温等离子体技术在一定程度上可以改善糙米的蒸煮性能和食用品质,显著提高了糙米饭的浸泡吸水率、加热吸水率、体积膨胀率和固形物损失率(P<0.05),分别增加了3%、30%、50%和0.5%左右,而显著缩短蒸煮时间到24.8 min(P<0.05);相比于对照组糙米,低温等离子体处理后糙米饭质构特性的硬度、咀嚼性和胶黏性显著减小到1566.60 g、451和709.11(2.0 A),而感官评分、弹性、黏附性和回复性显著增大,当电流强度在1.5 A时糙米饭质构特性和感官品质最佳(P<0.05)。通过扫描电镜观察到低温等离子体处理后糙米表面出现凹陷和裂缝,进一步解释了吸水率增加的原因。利用X射线衍射仪分析发现,辉光放电等离子体处理后的糙米结晶度下降,在1.5 A时达到最小值31.19%,但结晶类型未发生改变,仍为典型的A型;傅里叶近红外仪分析发现糙米亲水基团的峰值含量增加,亲水性能增加。综合来看,当电流强度处于1.5 A时糙米的食用品质最佳。研究结果表明低温等离子体技术在改善糙米食用品质方面具有潜在的应用前景。

Effect of Low-temperature Plasma Current Intensity on the Edible Quality of Brown Rice

For the problem of the long cooking time and rough taste of brown rice,the glow discharge plasma technology was used to treat brown rice.Also the texture analyzer,scanning electron microscope,Fourier near-infrared spectrum,and X-ray diffractometer were used to analyze the influence of characteristics,sensory quality,texture characteristics,microstructure and crystal structure caused by different current intensities of rice cooking.The research results showed that low-temperature plasma technology could improve the cooking performance and eating quality of brown rice to a certain extent,and significantly increase the water absorption rate,heating water absorption rate,volume expansion rate and solids loss rate of brown rice(P<0.05)by 3%,30%,50%,and 0.5%respectively(P<0.05).Besides the cooking time of brown rice was shortened to 24.8 min(P<0.05).Compared to the brown rice in control group:the hardness,chewiness and adhesiveness of low-temperature plasma treated brown rice were significantly reduced to 1566.60 g,451 and 709.11(2.0 A),while the sensory score,elasticity,adhesion and recovery were significantly increased.When the current intensity was 1.5 A,the texture characteristics of brown rice and sensory quality was the best(P<0.05).It was observed by scanning electron microscope that there were pits and cracks on the surface of low-temperature plasma treated brown rice, which further explained the increase of water absorption. X-ray diffractometer analysis showed that the crystallinity of glow discharge plasma treated brown rice had decreased, which reached the minimum value of 31.19% at 1.5 A. However its crystal type of had not changed, which was still typical A type. Fourier near infrared instrument analysis found that the peak content of hydrophilic groups in brown rice increased and the hydrophilic properties increased. Taken together, brown rice had the best edible quality when the current intensity was 1.5 A. The research results showed that low-temperature plasma technology had potential applications in improving the edible quality of brown rice.