Studies On Preservation Of Glutinous Rice Products

The shelf-life of glutinous rice cake products is the key factor of food quality andsafety.In order to improve the shelf-life of product the experiment chose the anti-aging agent toretard the aging of glutinous rice cake, and chose the water activity lowering agents to controlmicrobial growth and reproduction. The sensory evaluation was taken as an index todetermine addition of anti-aging agents. Through single-factor experiment by several wateractivity lowering agents, selected which the effect of lowing water activity were significant,then selected the optimal combination. Then some specific water activity were selected bypreservation experiment, the selected products were storage in room temperature.Microorganism indicators of New Year cake was regularly detected, then New Year cake ofdifferent water activity was observed during storage of the total number of changes inbacterial impact, and mildew sensory inspection conducted on a regular basis.According to experiments, the basic ingredients of glutinous rice cakes were: water,glutinous rice flour, sugar, lard. The best additions were as follows: sugar60%, water75%-80%, lard10%.The results of experiment were: guar gum0.4%, sucrose ester0.3%, modifiedstarch(acetyl crosslink com starch)0.2%increase in volume, α-amylase was0.04%, at thistime of the anti-aging effect of New Year cake was the best.The results of water activity lowering agent were: sodium chloride, glycol, citric acid andcompound phosphate. Compound phosphate composition was:3:3:8. In the orthogonalexperiment, the optimum combinations were composed by follows:0.1%compoundphosphate,0.3%glycol,0.4%citric acid,3.5%sodium chloride. The Aw value was0.808.In the preserve experiment, with the reduction of water activity, bacteria and fungi wereinhibited. At the same storage conditions (20℃-25℃),colonies of0.808grew slowest. Whenthe water activity of product was0.926, colony forming units reached759cfu/g at the first21days, which was more than750cfu/g of National Standard of the People’s Republic of China.When the water activity of product was0.808, the colony forming units reached251cfu/g at the first21days. When the water activity was0.808, mould grew on the products at the19thdays, while when the water activity was0.926, there was mould at the3rd days, and themould was very serious at the7th days. The shelf-life of products was from3d to18d, and theshelf-life of products was prolonged obviously.