國內(nèi)外關(guān)于玉米淀粉質(zhì)產(chǎn)品凍融特性變化機制報道較少。本研究以普通玉米淀粉、糯玉米淀粉和高直鏈玉米淀粉為材料，研究凍融處理對玉米淀粉凝膠和玉米淀粉顆粒的結(jié)構(gòu)特性和理化性質(zhì)的影響，主要結(jié)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)普通玉米淀粉凝膠呈網(wǎng)絡結(jié)構(gòu)，其孔洞數(shù)量隨著凍融次數(shù)的增加而增多，而糯玉米淀粉凝膠在凍融2次后開始形成層狀結(jié)構(gòu)，其層距隨凍融次數(shù)增加而減小。凍融處理后，玉米淀粉的結(jié)晶類型由A型轉(zhuǎn)變?yōu)锽型，結(jié)晶度隨凍融次數(shù)增加呈先增加后減小的趨勢。

(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.

與原淀粉相比，玉米淀粉凝膠的-OH和C-O-C吸收峰明顯向左、向右偏移，且峰高減小，說明水與淀粉形成氫鍵，削弱了淀粉分子間氫鍵;隨凍融次數(shù)增加，兩種玉米淀粉凝膠的-OH和C-O-C吸收峰未有顯著偏移，但吸收峰峰高逐漸增大，表明淀粉分子在凍融處理過程中，發(fā)生重結(jié)晶，形成分子間氫鍵。

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.

凍融循環(huán)處理對兩種玉米淀粉凝膠的碘藍值、碘結(jié)合力、大吸收波長和直鏈淀粉含量均無顯著性影響。隨凍融次數(shù)增加，兩種玉米淀粉凝膠的凍融穩(wěn)定性增強，凝膠硬度增大;普通玉米淀粉凝膠的透明度、持水性、RDS與SDS含量逐漸減小，而溶解度、膨脹力、水解率和RS含量逐漸升高，彈性呈先增加后減小的趨勢，所有黏度特性值均呈先減小后增大的趨勢。

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.

糯玉米淀粉凝膠的彈性、膠粘性和糊化溫度增大，內(nèi)聚性呈先下降后上升的趨勢，透明度、持水性、溶解度和膨脹力逐漸減小，黏度值、峰值時間、衰減值和回生值呈先增大后減小的趨勢，RDS、SDS和RS含量及水解率均無顯著變化。

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)隨凍融次數(shù)增加，普通玉米淀粉和糯玉米淀粉顆粒表面的孔洞和凹痕數(shù)量增多，而高直鏈玉米淀粉顆粒表面的凸起減少，表面逐漸變粗糙。不同凍結(jié)溫度對三種玉米淀粉顆粒的形態(tài)特征的影響無明顯差異。普通玉米淀粉和糯玉米淀粉顆粒為A型結(jié)構(gòu)，高直鏈玉米淀粉顆粒為B型，凍融處理后仍保持原有晶型，普通玉米淀粉和高直鏈玉米淀粉顆粒的結(jié)晶度減小，而糯玉米淀粉顆粒的結(jié)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.

隨著凍融次數(shù)的增加，玉米淀粉的持水率和水解率均升高，但凍融次數(shù)和貯藏溫度對碘藍值、碘結(jié)合力、大吸收波長、直鏈淀粉含量、透光率、凍融穩(wěn)定性和熱力學性質(zhì)無顯著影響。隨凍融次數(shù)增加，在-20℃凍結(jié)條件下，普通玉米淀粉的糊化溫度無顯著性變化，黏度值、衰減值和回生值逐漸減小，峰值時間增大，而糯玉米淀粉的峰值黏度增加，終黏度呈先增加后減小的趨勢。

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℃條件下，普通玉米淀粉的黏度值、衰減值和回生值逐漸增大;在-80℃條件下，普通玉米淀粉的終黏度和回生值逐漸增大;在-40℃和-80℃條件下，糯玉米淀粉的黏度值和衰減值逐漸增大，回生值逐漸減小。

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.

凍融循環(huán)處理對玉米淀粉凝膠的結(jié)構(gòu)特性和理化特性的影響大于玉米淀粉顆粒。淀粉凝膠在凍融循環(huán)處理過程中，其淀粉分子重排形成老化淀粉，并隨著凍融次數(shù)的增加，老化度增大，凝膠變硬，導致淀粉質(zhì)產(chǎn)品質(zhì)量劣變;而淀粉顆粒受結(jié)冰膨脹壓力的作用，其內(nèi)外結(jié)構(gòu)破壞，但不足以導致淀粉顆粒的理化特性和酶解特性的大幅度改變。更多相關(guān)內(nèi)容就來我們網(wǎng)站http://www.qylxschool.cn咨詢！

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 http://www.qylxschool.cn consulting service