Effects of pressure and temperature on the texture of plant foods

我们研究了压力和温度对蔬菜等植物性食物质地的影响。以日本萝卜为样本。样品经400MPa加压、60℃加热、室温静置、99.5℃蒸煮处理。采用感官评价法和四径法测定了样品的织构性能，结果表明，这些预处理措施抑制了样品的软化。60℃加热条件下的硬化程度比加压条件下的硬化程度更明显。采用预处理后的试样对硬化机理进行了研究。经预处理后，加热加压样品的六偏磷酸酯溶性果胶含量增加，果胶的酯化程度降低。细胞壁中的金属离子和电荷水含量几乎没有变化。结果表明，在盐酸的果胶部分和0.2%氢氧化钠可溶性果胶中，蛋白质的含量有所增加，从而使蛋白质与纤维素结合。在蒸煮前先加热加压再静置会改变蛋白质的溶解度，蛋白质的不溶性与这些预处理的硬化有关。

We have studied the effects of pressure and temperature on the texture of plant foods such as vegetables. Japanese radish was used as samples. The samples were treated by pressunzation at 400MPa and by heating at 60℃ and stood at room temperature and then cooked at 99.5℃. The texture property of the samples was measured by sensory evaluation and tetrameter, The softening of the samples were suppressed by these pretreatments. The degree of the hardening was more marked in the case of 60℃ heating than that in the case of pressurization. The mechanism of the hardening was investigated by using pretreated samples. Hexametaphosphate-soluble pectin of the heated and pressurized samples increased and the degree of esterification of pectin decreased by pretreatments. The metal ions in the cell wall and fee water contents did not almost change. It was suggested that protein was bounded to the cellulose due to the increase of amount of it in the pectin fraction of the hydrochloride and 0.2 % sodium hydroxide-soluble pectin. It was also suggested that the solubility of protein was changed by heating and pressurizing and then standing before cooking, and the insolubilization of protein was related to the hardening by these pretreatment.