芸豆淀粉理化特性研究

淀粉是芸豆中的主要碳水化合物,其性质直接影响芸豆资源的开发与利用.以花芸豆、小红芸豆、红芸豆、小黑芸豆和小白芸豆等菜豆属芸豆为试验材料,采用湿磨法提取淀粉,以马铃薯淀粉和玉米淀粉为对照,分析芸豆淀粉的颗粒特性与糊化特性.结果表明,5种芸豆淀粉颗粒形貌相似,大淀粉颗粒多为卵圆形或肾形,小颗粒多呈圆形,淀粉颗粒长轴粒径介于玉米淀粉和马铃薯淀粉之间.淀粉颗粒偏光十字多为较粗的“X”形或斜“十”形,较明显.芸豆淀粉溶解度和膨胀度均随温度升高而增大,属限制型膨胀淀粉.芸豆淀粉的透光度明显小于马铃薯淀粉,冻融稳定性不及玉米淀粉和马铃薯淀粉.芸豆淀粉起糊温度、峰值黏度、破损值、最终黏度和回生值分别为76.6 ～ 77.8℃、117.3 ～ 150.9 RVU、5.0 ～ 32.0 RVU、205.1 ～225.2 RVU和91.9～104.2 RVU.芸豆淀粉糊表现出好的热稳定性、抗剪切,易回生.

Physicochemical Properties of Kidney Bean Starches

Starch is the main carbohydrate in kidney beans,and its properties have a direct influence on the exploitation and utilization of kidney beans.Colored kidney beans,small red kidney beans,red kidney beans,black beans,and other phaseolus legumes have been selected as materials,and the starch is extracted through wet milling process.Besides,it analyzes particles′ characteristics and pasting properties of kidney bean starch compared with potato starch and corn starch.The results showes that the features of the five kidney bean starch′s particles are similar.Large starch particles are mostly oval or kidney shaped,and small particles are mostly round.Starch particles′ long axis size is between that of corn starch and potato starch.Most of the polarization crosses are apparent and like thick "X" or inclined "十" shape.The solubility and dilation of kidney bean starch will increase when the temperature is increased.It belongs to restrictive swelling starch.Transparency of kidney bean starch is significantly less than potato starch′s.Freeze-thaw stability of kidney bean starch is less than corn starch’s and potato starch′s.Pasting temperature,peak viscosity,breakdown,final viscosity and setback value of kidney bean starch are 76.6~77.8 ℃,117.3~150.9 RVU,5.0~32.0 RVU,205.1~225.2 RVU and 91.9~104.2 RVU 91.9~243.3 RVU.Pastes of kidney bean starch have showed the heat stability,shear capacity and high retrogradation trend.