冻融处理对玉米淀粉凝胶和颗粒的影响

国内外关于玉米淀粉质产品冻融特性变化机制报道较少。本研究以普通玉米淀粉、糯玉米淀粉和高直链玉米淀粉为材料，研究冻融处理对玉米淀粉凝胶和玉米淀粉颗粒的结构特性和理化性质的影响，主要结果如下:

There are few reports at home and abroad on the mechanism of freeze-thaw characteristics of corn starch products. In this study, ordinary corn starch, waxy corn starch and high amylose corn starch were used as materials to study the effects of freeze-thaw treatment on the structural characteristics and physicochemical properties of corn starch gel and corn starch granules. The main results are as follows:

(1)普通玉米淀粉凝胶呈网络结构，其孔洞数量随着冻融次数的增加而增多，而糯玉米淀粉凝胶在冻融2次后开始形成层状结构，其层距随冻融次数增加而减小。冻融处理后，玉米淀粉的结晶类型由A型转变为B型，结晶度随冻融次数增加呈先增加后减小的趋势。

(1) Ordinary corn starch gel has a network structure, and the number of holes increases with the increase of freezing and thawing times, while waxy corn starch gel begins to form a layered structure after twice freezing and thawing, and its layer spacing decreases with the increase of freezing and thawing times. After freeze-thaw treatment, the crystalline type of corn starch changed from A type to B type, and the crystallinity increased first and then decreased with the increase of freeze-thaw times.

与原淀粉相比，玉米淀粉凝胶的-OH和C-O-C吸收峰明显向左、向右偏移，且峰高减小，说明水与淀粉形成氢键，削弱了淀粉分子间氢键;随冻融次数增加，两种玉米淀粉凝胶的-OH和C-O-C吸收峰未有显著偏移，但吸收峰峰高逐渐增大，表明淀粉分子在冻融处理过程中，发生重结晶，形成分子间氢键。

Compared with the original starch, the - OH and C-O-C absorption peaks of corn starch gel shifted significantly to the left and right, and the peak height decreased, indicating that water formed hydrogen bonds with starch, weakening the hydrogen bonds between starch molecules; With the increase of freeze-thaw times, the - OH and C-O-C absorption peaks of the two corn starch gel did not shift significantly, but the peak height of the absorption peaks gradually increased, indicating that starch molecules recrystallized and formed intermolecular hydrogen bonds during freeze-thaw treatment.

冻融循环处理对两种玉米淀粉凝胶的碘蓝值、碘结合力、大吸收波长和直链淀粉含量均无显著性影响。随冻融次数增加，两种玉米淀粉凝胶的冻融稳定性增强，凝胶硬度增大;普通玉米淀粉凝胶的透明度、持水性、RDS与SDS含量逐渐减小，而溶解度、膨胀力、水解率和RS含量逐渐升高，弹性呈先增加后减小的趋势，所有黏度特性值均呈先减小后增大的趋势。

Freeze thaw cycle treatment had no significant effect on the iodine blue value, iodine binding force, large absorption wavelength and amylose content of the two corn starch gel. With the increase of freeze-thaw times, the freeze-thaw stability of the two corn starch gel increased, and the hardness of the gel increased; The transparency, water holding capacity, RDS and SDS content of ordinary corn starch gel gradually decreased, while the solubility, swelling power, hydrolysis rate and RS content gradually increased. The elasticity first increased and then decreased, and all viscosity characteristic values first decreased and then increased.

糯玉米淀粉凝胶的弹性、胶粘性和糊化温度增大，内聚性呈先下降后上升的趋势，透明度、持水性、溶解度和膨胀力逐渐减小，黏度值、峰值时间、衰减值和回生值呈先增大后减小的趋势，RDS、SDS和RS含量及水解率均无显著变化。

The elasticity, stickiness and gelatinization temperature of waxy corn starch gel increased, the cohesion first decreased and then increased, the transparency, water retention, solubility and swelling power gradually decreased, the viscosity value, peak time, decay value and retrogradation value first increased and then decreased, and the content of RDS, SDS, RS and hydrolysis rate did not change significantly.

(2)随冻融次数增加，普通玉米淀粉和糯玉米淀粉颗粒表面的孔洞和凹痕数量增多，而高直链玉米淀粉颗粒表面的凸起减少，表面逐渐变粗糙。不同冻结温度对三种玉米淀粉颗粒的形态特征的影响无明显差异。普通玉米淀粉和糯玉米淀粉颗粒为A型结构，高直链玉米淀粉颗粒为B型，冻融处理后仍保持原有晶型，普通玉米淀粉和高直链玉米淀粉颗粒的结晶度减小，而糯玉米淀粉颗粒的结晶度增大。

(2) With the increase of freezing and thawing times, the number of holes and dents on the surface of common corn starch and waxy corn starch particles increased, while the bulges on the surface of high amylose corn starch particles decreased, and the surface became rough gradually. The effects of different freezing temperatures on the morphological characteristics of the three corn starch granules were not significantly different. The common corn starch and waxy corn starch granules are of type A structure, and the high amylose corn starch granules are of type B structure. After freeze-thaw treatment, they still maintain the original crystal form. The crystallinity of common corn starch and high amylose corn starch granules decreases, while the crystallinity of waxy corn starch granules increases.

随着冻融次数的增加，玉米淀粉的持水率和水解率均升高，但冻融次数和贮藏温度对碘蓝值、碘结合力、大吸收波长、直链淀粉含量、透光率、冻融稳定性和热力学性质无显著影响。随冻融次数增加，在-20℃冻结条件下，普通玉米淀粉的糊化温度无显著性变化，黏度值、衰减值和回生值逐渐减小，峰值时间增大，而糯玉米淀粉的峰值黏度增加，终黏度呈先增加后减小的趋势。

With the increase of freeze-thaw times, the water retention and hydrolysis rate of corn starch increased, but the freeze-thaw times and storage temperature had no significant effect on iodine blue value, iodine binding force, large absorption wavelength, amylose content, light transmittance, freeze-thaw stability and thermodynamic properties. With the increase of freezing and thawing times, under the freezing condition of - 20 ℃, the gelatinization temperature of common corn starch has no significant change, the viscosity value, decay value and retrogradation value gradually decrease, and the peak time increases, while the peak viscosity of waxy corn starch increases, and the final viscosity first increases and then decreases.

在-40℃条件下，普通玉米淀粉的黏度值、衰减值和回生值逐渐增大;在-80℃条件下，普通玉米淀粉的终黏度和回生值逐渐增大;在-40℃和-80℃条件下，糯玉米淀粉的黏度值和衰减值逐渐增大，回生值逐渐减小。

At - 40 ℃, the viscosity value, decay value and retrogradation value of common corn starch gradually increased; At - 80 ℃, the final viscosity and retrogradation value of common corn starch gradually increased; At - 40 ℃ and - 80 ℃, the viscosity and decay value of waxy corn starch gradually increased, and the retrogradation value gradually decreased.

冻融循环处理对玉米淀粉凝胶的结构特性和理化特性的影响大于玉米淀粉颗粒。淀粉凝胶在冻融循环处理过程中，其淀粉分子重排形成老化淀粉，并随着冻融次数的增加，老化度增大，凝胶变硬，导致淀粉质产品质量劣变;而淀粉颗粒受结冰膨胀压力的作用，其内外结构破坏，但不足以导致淀粉颗粒的理化特性和酶解特性的大幅度改变。更多相关内容就来我们网站https://www.qiluxinke.com咨询！

The effect of freeze-thaw cycle treatment on the structure and physicochemical properties of corn starch gel was greater than that of corn starch granules. During the freeze-thaw cycle treatment of starch gel, its starch molecules rearrange to form aging starch, and with the increase of freeze-thaw times, the aging degree increases, and the gel hardens, leading to the deterioration of the quality of starchy products; However, the internal and external structures of starch granules are damaged by the ice swelling pressure, but it is not enough to cause a significant change in the physicochemical properties and enzymatic hydrolysis properties of starch granules. Come to our website for more relevant content https://www.qiluxinke.com consulting service