Changes in Textural Properties of Low-Moisture Foods and Its Mechanism

以小麦、玉米、土豆、大米等不同淀粉原料制成的27种商品糖果和土豆、水果、蔬菜制成的天然油炸片为研究对象，研究了吸收水分对糖果质地的影响及其机理。在相对湿度为7.6 ~ 97%的10个水平下静置后，在相对湿度为32%以下时，试样的断裂力和断裂能变化较小，在相对湿度为68 ~ 88%左右时，试样的结构特征可分为两类。一组（如曲奇、饼干等）变软，另一组（如森贝）由糊化淀粉组成，变硬。样品的破碎性能与其糊化程度呈高度正相关。此外，添加改性淀粉的烘焙小麦粉制品（促进型和抑制型淀粉糊化）的结果与糖果相似。说明淀粉凝胶的形成和水分条件是增强低吸湿性样品组织的重要因素。

The effects of absorbed moisture on texture properties and its mechanism were studied with twenty-seven kinds of commercial confections made from different starch ingredients (i.e., wheat, corn, potato and rice) and natural fried chips made of potato, fruits and vegetables. After the confectionary goods were left standing at ten levels of relative humidity (R.H. 7.6 - 97 %), the change of breaking force and breaking energy were small when the moisture was below R.H.32%, and the textural characteristics of test samples were found at around R.H. 68 - 88% to be classified two groups. One group (i.e., cookie, biscuit etc.) became softer, and the other (i.e., senbei) consisting of gelatinized starch became harder. A high positive correlation was obtained between the breaking properties of samples and their gelatinization. Also the results of baked wheat flour products with of modified starches (promotion type and suppressiontype of starch gelatinization) and were obtained similar as the confections. It was suggested that starch-gel formation and water condition were the important factors to strengthen the sample tissue with low moisture absorption.