大米糊化特性及回生机理研究(精)

大米糊化特性及回生机理研究

谭薇,李珂,卢晓黎 *

(四川大学食品工程系, 四川成都610065

摘要 :采用显微观察和 DSC 差热分析方法对样品进行颗粒特性分析及大米糊化特性研究。当米粉(质量记为 100% 的水分含量分别为 80%、100%、150%时,其晶体融化的起始温度 T 0、顶点温度 T p 和终点温度 T c 基本相同,米粉的融化热焓逐渐升高;水分含量在 50%时,其晶体融化的起始温度 T 0、顶点温度 T p 和终点温度 T c 基本不变, 相对于其他水分含量的样品明显偏低,水分难以与米粉充分混合并完全糊化;水分含量在 200%时,其晶体融化的起始温度 T 0、顶点温度 T p 和终点温度 T c 有显著降低,米粉的融化热焓亦降低。糊化米粉的结晶熔融起始温度 T 0、顶点温度 T p 及终止温度 T c 基本不随时间而变化;而回生度则在 4℃下冷藏时间越长,其值越大。关键词 :大米;糊化特性;回生;差热分析;显微观察

Gelatinization Properties and Resuscitation Mechanics of Rice Retrogradation

TAN Wei,LI Ke,LU Xiao-li*

(Department of Food Engineering,Sichuan University,Chengdu 610065,China

Abstract :The particle behavior of rice was observed by microscope, and the gelatinization properties of rice were tested and analyzed by DSC.The results showed that the initial temperature(T 0,vertex temperature(T p and final temperature(T c of different samples,which have different ratios of water and rice powder as80%(W/W,100

%(W/W,150%(W/W respectively, were basically identical;and the melting enthalpy of rice-powder increased gradually with the increase of water content;sample whose water content was50%has similar T 0,T

p ,T c ,and the lowest melting enthalpy among the experimented samples,the moisture was difficult to mixed into rice-powder and was completely gelatinized;sample whose water content was200%has the lowest T o ,T p ,T c ,and the melting enthalpy of rice-powder was decreased.From the study of the resuscitation mechanism of rice powder, it was found that,for the gelatinized rice-powder,the crystallization and melt temperature of T 0,T p ,T c had almost similar tendency in different storing time.As the gelatinized rice-powder was stored at4℃for different time,its resuscitation degrees were different,the longer it was stored,the higher the resuscitation degree was.

Key words :rice ; gelatinization properties ; resuscitation ; DSC ; microscope observe

中图分类号 :TS210.1

文献标识码 :A文章编

号 :1002-6630(200803-0167-05

收稿日期:2007-11-30

作者简介:谭薇(1982-,女,硕士研究生,研究方向为食品加工与保藏应用技术。

*******************大米是我国的主要粮食作物之一。大米经熟化制成的食品,冷却后由于淀粉发生老化,而使食品的质构与消化性变差。如米饭放置一段时间后会变硬回生,以

大米为主要原料制成的糕点类食品其品质降低的主要表现也是硬化回生,黏弹性降低,这些都是大米中淀粉老化等因素引起的。因此,防止或延缓淀粉老化课题一直是国内外学者研究的难题和热点,目前在该领域的研究主要是将大米中的淀粉提取纯化后,研究其淀粉的糊化特性及回生机理。本实验以大米全粉为原料,研究其糊

化特性及回生机理,旨在以所得结论对大米食品品质的进行改良,提供理论依据和技术参考。

1材料与方法 1. 1

材料

选取成都互利达实业有限公司生产的“谷之源・

天津小站米(籼米”为实验原料。用粉碎机粉碎后,过 80目筛,经热风干燥,制成米粉。原料大米的主要成分含量见表 1。

成分水分蛋白质脂肪淀粉支链淀粉/(% (% (% (% 直链淀粉含量

14.00

7.05

0.78

78.17

2.89

表 1原料大米主要成分

Table 1 Primary components of testing rice

1. 2主要试剂

0.2mol/L碘液(根据 GB601-2002标准配制; 单蒸蒸馏水(pH5.3。

1. 3主要仪器

德国 N E T Z S C H D S C 200P C 差示扫描量热仪、 OLYMPUS CHB-F3N 显微镜、FW177型粉碎机、101A-