The basic Research and Application of Gelation Mechanism of Food Macromolecules under High Pressure

1.明胶：研究了在3000atm压力范围内明胶凝胶熔化温度(Tm)随压力的变化规律。(DTM/DO)为(3-4)×10^-3；K cm^2/kg，与明胶浓度无关。凝胶的体积变化是负的，尽管由于聚合物链的脱水导致的体积增加通常伴随着螺旋-螺旋转变。这一结果表明，在凝胶的渣链结中存在一些聚合物-水-聚合物氢桥。琼脂糖凝胶：(dTM/dp)为2.3×10~(-3)/gt；K cm~(^2)/gk。凝胶的体积变化仍为负值，但与明胶相比，其值很小。与卡拉胶不同，这种负体积变化也不能用简单的聚合物-聚合物氢键机制来解释。牛奶酪蛋白：在P&lt；1500大气压下，酶处理的酪蛋白胶束被解离，而较高的压力则相反地增强了胶束的结合。这一结果与P&lt；1500以下压力抑制凝乳链的观察结果一致。这些结果表明，高压将为理解凝胶化机理提供有用的信息，也适用于食品工业中食品大分子成胶能力的调节。

1. GELATIN: The pressure dependence of melting temperature (Tm) of gelatin gel was studied under pressure region up to 3000 atm. (dTm/dO) was (3-4) x 10^<-3> K cm^2/kg independent of gelatin concentration. The volume change on gelation was negative although a coil-helix transition generally accompanies the volume increase due to dehydration of polymer chains. This result suggests that there are some polymer-water-polymer hydrogen briges in the dross-link junctions of gel.2. AGAROSE: (dTm/dP) was 2.3 x 10^<-3> K cm^2/gk. The volume change on gelation was still negative but its value was very small as compared with that of gelatin. The negative volume change also can not explained by a simple polymer-polymer hydrogen bond mechanism, different from carrageenan gels.3. MILK CASEIN: Micelle of enzyme-treated caseins was dissociated with under P < 1500 atm, but higher pressure oppositely enhanced the association of micelle. This result consists with the observation that the milk curdlink is depressed by pressure under P < 1500.These results indicate that high pressure would pressent useful informations for understanding the gelation mechanism and also be applicable for regulation of gel-forming ability of food macromolecules in the food industry.