Study On Nata De Coco Drying Methods And Their Effects On Dried Product Quality

Nata is a kind of highly polymerized gelatinous brous membrane formed by glucose molecules linking by P-1,4-glucoside bond which generated by Microorganism Fermentation uses mainly coconut juice. Nata characterized by low calorie, high fiber, smooth, high chewiness, unique flavour e ct, therefore, Nata is a kind of ideal health food material which has the effectiveness of slimming, prevent constipation, enhance bowel movement, detoxification, lowe cholesterol e ct. Nata has good water holding ability.It’s inconvenience to storage, transportation and is largely in thrall of it’s practice range because Nata which applied in food, cosmetic and other industry are formed of a hydrate in market recently. However, increasly crystallization after dry coursed Nata has a lower capability of rehydration. Nata that dried with simple dry method insoluble in boiling water has a poor rehydration and the rehydration do not increased with the increase of time. We should extend Nata’s space application instead of restricted in the application and applied scope recently in food to keep up the vitality and raise the added value of Nata. So it is of great significance for expand the applied scope and develop new product to found a proper dry method and explore a pretreatment technology which makes Nata has a good rehydration after dry.Different dry methods of Nata are studied for the influence of rehydration characters of Nata and each process of dry method are optimized to get the optimum technological conditions in this article.1. Different pretreatment filler are studied and the results indicate that CMC shows the best rehydration ratio high at45.87of Nata.2. AD, FD, AD+FD are studied for rehydration ratio, hardness and elastic of Nata after dry. The result shows that FD and AD+FD have a better rehydration characters than AD. The property of AD, FD, and AD+FD are below respectively:rehydration:49.18,115.57,110.56; hardness:104.98g,25.44g,22.52g; elastic:1.88mm,2.03mm,2.11mm.3. The optimum technological condition of different dry method was determined by the experiment, it is respectively AD:oven temperature60℃, Nata to CMC solution ratio1:2, CMC concentration0.9%, vacuum infusion time4.5h; FD:drying vacuum degree0.52mbr, CMC concentration0.9%, Nata to CMC solution ratio1:2, vacuum infusion time4.5h; AD+FD:oven temperature60℃, drying vacuum degree0.52mbr, moisture conversion point60%, vacuum infusion time4.5h, CMC concentration 0.9%.4. Using conductivity Meter tasted the eutectic point was-5.5℃～-6.3℃by the experiment of FD.5. The optimal selection of rehydration ratio, hardness and elastic after beating at100℃forlOmin through Box-behnken response surface designs, there are AD:49.18,104.98g,1.88mm; FD:115.57,25.44g,2.03mm; AD+FD:110.56,22.52g,2.11mm.6. the result showed that surface appearance and structural of dried Nata are obviously shrinkage and deformation, with a compact constitution and had a bad rehydration characters after AD; FD had a very loosely structured organization, porous structure and good rehydration characters; AD+FD had a porous structure and the rehydration characters are close to FD, but a slightly fluffy lower than FD by scanning electron microscope (SEM).7. Considering comprehensively rehydration ratio, hardness, elastic, chromatic difference and so on, the products after FD and AD+FD are more close to fresh products while AD had a bad rehydration characters.