去皮对山药粉理化性质和生物活性的影响

为了研究去皮工序对于山药粉的理化性质和生物活性的影响,以山药为原料,通过热风干燥法制备山药粉;酶水解法测定总淀粉含量和体外消化率;扫描电子显微镜、X射线衍射和傅里叶变换红外光谱考察不同山药粉的形态与结晶结构;分光光度法测定总黄酮、总可溶性多酚含量、还原力和DPPH自由基清除能力。结果表明,经过去皮工序制备的山药粉总淀粉与抗性淀粉含量较大,分别为45.39%和31.11%;未经去皮工序制备的山药粉的水结合能力(194.53 g/100 g)较大,其在不同温度下的膨胀力与溶解度也较大,最大提高率分别为43%和18%;两种山药粉的形态特征和晶体结构相差不大;不经过去皮工序制备的山药粉的总黄酮和总可溶性多酚含量较大,分别为0.059 mg RE/g和0.028 mg GA/g;其DPPH自由基清除能力(EC₅₀值43.86 mg/mL)和还原力(0.223 mg V_C/g)较高;因此,去皮工序对山药粉的理化性质和生物活性有明显影响。根据两种山药粉的特点,可以选择合适的山药粉应用于不同的食品中。

Effect of Peeling on Physicochemical Properties and Biological Activity of the Yam Powders

In order to study the effect of peeling procedure on the physicochemical properties and biological activity of yam powder,yam powder was prepared by hot air drying method;The total starch content and in vitro digestibility were determined by enzymatic hydrolysis. Scanning electron microscopy,X-ray diffraction and Fourier transform infrared spectroscopy were used to investigate the morphology and crystal structure of different yam powders. The total flavonoids,total soluble polyphenols content,reducing power and DPPH free radical scavenging ability were determined by spectrophotometry. The results showed that the total starch content and resistant starch content of the yam powder prepared with the peeling procedure were higher,and were 45.39% and 31.11% respectively. The yam powder prepared without the peeling procedure had larger water binding capacity(194.53 g/100 g),and its swelling power and solubility at different temperatures were also larger with the maximum increase rates 43% and 18%,respectively. The morphological characteristics and crystal structure of the two kinds of yam powder were similar. The total flavonoids and total soluble polyphenols content of yam powder prepared without peeling process were larger,and were 0.059 mg RE/g and 0.028 mg GA/g,respectively. Also,its DPPH free radical scavenging ability(EC₅₀ value 43.86 mg/mL)and reducing power(0.223 mg V_C/g)were higher. Therefore,the peeling procedure has obvious effect on the physicochemical properties and biological activity of the yam powder. According to the characteristics of the two kinds of yam powder,the appropriate yam powder can be selected for use in different foods.