茶多酚对甘薯淀粉的抗老化研究
Effect of tea polyphenols on the retrogradation of sweet potato starch
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摘要: 淀粉老化会导致淀粉基食品变硬、弹性减小,严重缩短这些产品的货架期。本文通过X-射线衍射、质构分析、色泽分析和傅立叶变换红外光谱等方法检测甘薯淀粉样品在长期储存过程中(80d)的结构和特性变化,研究茶多酚对甘薯淀粉的抗老化效果。纯甘薯淀粉在放置80d之后,硬度接近初始硬度的30倍,而加入9wt.%茶多酚之后,硬度增大趋势得到明显的抑制,80d之后淀粉胶体硬度不足初始硬度的4倍。实验结果显示,茶多酚可抑制甘薯淀粉形成结晶结构,延缓其结晶过程,从而降低甘薯淀粉胶体的硬度,减小胶体的硬度和色泽变化。这说明茶多酚可有效抑制甘薯淀粉的老化。Abstract: Retrogradation in cooked starch based products significantly shortens the shelf life of these products as they become firm and less elastic during storage. In this work, the effect of tea polyphenols ( TPs) on the retrogradation of sweet potato starch during long- term storage ( 80d) was evaluated by characterizing sweet potato starch sample using X- ray diffraction ( XRD) , texture profile analysis ( TPA) , color analysis, and Fourier transform infrared spectroscopy ( FT- IR) .After storage for 80 d, the hardness of pure sweet potato starch increased to about30 times of initial hardness.While for sweet potato starch with 9wt.% TPs, the normalized hardness was less than 4.The experimental results showed that TPs retard the recrystallization of starch, resulting in decrease in the hardness of sweet potato starch gel.The variations of hardness and color of the sweet potato starch gel were also limited by the addition of TPs.The results suggested that the retrogradation of sweet potato starch was inhibited by TPs.