Studies On The Browning Control Of Fresh Noodle

Fresh noodle color was investigated by pre-treatment of raw material includingchanging storage temperature, optimization of noodle process and adding differentmodifier to solve the browning of noodle. Noodle color was set as first indicator,combined with the texture performance and sensory score. Influence of differentstarches, water addition, storage temperature and microwave treatment on color andqualities of fresh noodle was investigated comprehensively. Enzyme inactivation ofpolyphenol oxidase by microwave for the first time in the study was used to inhibitPPO activity. According to the noodle color, optimal parameter of microwave wasdetermined.The results showed that (a) The best water addition to make fresh noodle was35%, less than which a worse performance noodle was gained for insufficient doughmatrix. Noodle made with35%water addition had a better color performance, and thedough sheet had a more moderate decrease of whiteness than the others. Noodle madewith higher than35%water-addition had a faster decrease on whiteness duringstorage. A significant correlation between storage temperature and whiteness of24hwas found(r=-0.982).(b) These five starches had a significant effect on fresh noodle color and qualitieswith hardness lower, sensory score higher and chewiness better. Corn starch and peastarch significantly improved the color of fresh noodle with higher addition (>12%,12%respectively). Potato starch, with a lower addition (4%to8%) shortened thecooking time and improved the elasticity. Separation point of sweet potato starchaddition was12%, higher than which could shorten cooking time, low elasticity whilelower than which had a advise effect. When the addition of wheat starch was higherthan12%, resilience and slickness were improved.Different starches significantlyaffected some one kind of noodle properties of texture or sensory score, which gaveus more choices to improve relevant properties or satisfy customers’ unique demands.(c) A significant positive correlation between pull-off force and toughnesssensory of sensory evaluation of noodle made with addition of corn starch, wheatstarch and potato starch(r=0.921,0.937,0.853respectively) was found. There was asimilar correlation between firmness and palatability of corn starch and potato starch(r=0.916,0.892respectively).(d) The optimal proportion of different modifiers was0.4%citric acid,0.4%ofsodium tripolyphosphate,0.6%sodium pyrophosphate, Vc0.06%.(e) Microwave could effectively inhibit the PPO enzyme activity of the flour.The PPO activity decreased nearly70%by treatment of microwave60s,600W. Therewas a significant correlation between microwave time and whiteness value of24h.While when the time was too long or the power was too high, undesirable blackmaterial was found. The best microwave parameter was microwave power500W,time40s.