谷物膨化机理的研究

本文以被膨化谷物为对象,探讨谷物膨化的机理。 谷物在膨化器中具备了能量条件,当骤释至常态时,就朝着混乱度增大即熵增加的方向进行,就发生膨化。膨化使谷物的结构发生了变化,宏观上谷物的质地疏松,体积增大;微观上挤压式膨化呈片态结构,气流式膨化呈蜂窝状结构。膨化使谷物处于易被酶水解的状态。膨化使淀粉粒解体,蛋白质变性,脂肪分解。膨化使淀粉降解。表现在淀粉含量减少,糊精和还原糖增加,还原能力增强,碘兰值增高,同时淀粉获得较高的α化度;蛋白质也趋向降解,(月示)、胨、缩氨酸和氨基酸有所增加;脂肪由于分解而减少;伴随上述变化,水溶性成分显著增加。 谷物膨化机理的研究,可得出膨化技术在食品特别是发酵工业中应用的理论依据。

Studies on the Mechanisms of Cereals Expansion

The objective of this paper was to study expanding mechanism of cereal products.When cereal in an extruder had higher energy and were then released to the normal state, they were expanded. During the process, the degree of confusion was enhanced and entropy mcreaesd. Cereal structure varied due to expanding. Macroscopically the texture of cereals became loose and the volume larger. Microscopically expanded products had the laminated structure and explosion-puffod products had the honeycomb structure. Expanding made cereal products easier to be enzyme-hydrolysed. After expansion, starches were degraded, proteins denatured and lipids broken. Starch degradation resulted in the reduction of starch contents, the increase of dextrine and reducing sugar, the improvement of reducing ability, the rise of iodine value and higher degree of a-starches. Denatured proteins resulted in increase of proteose. peptone, peptide and amino-acid to some degree, lippid contents were decreased due to breaking. Together with all the above changes, the water-soluble substances were increasd significantly.studies on expanding mechanisms of cereals may obtain the theoretical basis of application of expanding technology to food industry aad especially to fermentation industry.