Cocoa Beverage And The Research On Its Stability

Cocoa beverage was one of three major beverages, and it had a long history. But the cocoa powders were easy to precipitate, which made the shelf life of the beverage too short. Specicial enzymes could be used to destroy the cell structure, especialy the cellulose, hemicellulose, pectin and so on which were insoluble in the cell wall. And protein and starch, which were major in the cell and hard to soluble, would also be hydrolyzed. After the enzymatic treatment, the particle size would decrease, the soluble material would increase, which would inhance the stability of the cocoa powder beverage.In this research, amylase and cellulase were found to have an efficient reaction on the cocoa powder whereas several proteases had no reaction on it. Moreover, the pentosanase could have better effect if used together with the amylase and the cellulase. In this research, the optimal conditions were found as follows: amylase [E]/[S] = 0.5%(w/w), cellulosase [E]/[S] = 2%(w/w) and pentosanase [E]/[S] = 0.2%(w/w) with hydrolysis temperature kept at 50℃during 4h at the natural pH of the cocoa powder.After the treatment of the amylase, cellulase and pentosanase, the composition, microstructure and the charges in the cocoa particles occurred. The soluble composition content increased; and the starch, protein and the cell wall material (CWM) content decreased. At the same time, the particle size decreased, but part of them aggregated. Moreover the pectin was exposed after the enzymatic process, which made the Zeta potential of the particles increase from -20.7mv to -28.08mv.The enzymatic treatment could improve the stability of the cocoa powder beverage, but could not solve it completely. Microcrystalline cellulose (MCC) was found to be the best stabilizer, where the Carboxymethyl Cellulose (CMC), xanthan gum and sodium alginate could cooperate with it. And the optimal dosage of it was 0.3%MCC, 0.03%CMC and 0.01% xanthan gum.It was found that the single emulsifier was not as efficient as the mixed emulsifier, and the most suitable emulsifier was the mixture of PV-1 and sucrose fatty acid esters (SFAE) with HLB 5; the dosage of it was 0.06%. The homogenization before the enzymatic treatment was important, it would improve the efficiency of the enzymatic treatment and the stability of the beverage, the optimal condition was 60 Mpa for three times. And the final homogenzation condition was choosed at 25Mpa/20Mpa with the temperature 70℃.During the storage period, it was found that the control sample was not as stable as the final products; while the content of the soluble material and the reducing sugar increased fist and then decreased, the content of the phenol decreased mostly. High temperature and room-temperature changed the turbidness and the soluble material dramaticly, but little influence on the rate of deposition, stability of the suspended material, the phenol and the reducing sugar.For the huge yield of the gingko and lily in China, it could be used to mixed with the cocoa powder separately to produce one kind of nutritional, healthy beverage.Fuzzy mathematics was used to evaluate their sensory qualities, and best condition of the cocoa-lily beverage was: 1%milk powder+8%sugar+60%lily juice, and the cocoa-gingko beverage was: 2%milk...