速冻水饺煮后边缘发白现象原因分析

速冻水饺煮后边缘发白现象是行业普遍存在的质量问题,为了探究其发白原因,提高速冻水饺的食用品质,本文以煮制后边缘发白的速冻水饺为研究对象,与熟制后不发白的速冻水饺比对,采用SEM、色差仪等从水分含量、淀粉糊化度、微观结构、食用品质等方面进行研究。结果表明:边缘发白的速冻水饺皮水分含量和糊化度明显低于边缘不发白的速冻水饺皮(p<0.01)。运用Matlab对SEM图像进行处理后得知,不发白水饺皮电镜图片的孔隙面积最大,淀粉糊化程度最高;其次是发白饺子皮,生水饺皮电镜图片的孔隙面积最小,淀粉处于未糊化状态。在相同的电镜倍数和照片分辨率下,边缘发白的熟制速冻水饺皮的微观结构中有明显的未完全糊化的淀粉颗粒。从品质评价方面可以看出,煮后边缘发白部分的水饺皮的食用品质远远差于煮后边缘不发白部分水饺品质。因此熟制速冻水饺皮的发白现象可能是由于水饺皮边缘水分含量低,煮后淀粉未完全糊化造成。 

Analysis about the reason of the white edge of frozen dumpling after cooking

The phenomenon of the white edge 's frozen dumplings after cooking was the common quality problem of the industry.In order to explore the white reason and improve the edible quality of quick-frozen dumplings, this paper took the white edge 's frozen dumplings as our research target, which compared with the normal frozen dumplings. The content of moisture, the gelatinization of starch, the characteristics of texture, the eating quality and so on were researched by using SEM, colorimeter, etc.The results showed that, the moisture content and gelatinization degree of the white edge's frozen dumplings' skin were lower than the frozen dumplings ' skin which was not white (p < 0.01) . The moisture content and degree of gelatinization of the white edge's frozen dumplings' skin was significantly lower than the edge of the frozen dumplings' skin which was not white.After using Matlab to process the SEM image, the pore area of the white dumplings' skin was the largest and the degree of starch gelatinization was the highest.Followed by white dumpling skin, the pore area of raw dumplings' skin was minimum, starch was in the state of not gelatinized.Under the same electron microscope multiples and photo resolution, the microstructure of the white edge's frozen dumplings' skin had starch particles which obviously not entirely gelatinized. From the aspect of quality evaluation, it was found that the edible quality of the white edge's frozen dumplings was far worse than not white edges of a boiled dumpling quality. The white phenomenon of cooked frozen dumplings' skin may be due to the low moisture content, and not entirely gelatinized starch after cooking.