The Studies On Browning Of Wet Noodles In Storage

Mainly due to Polyphenol Oxidase (PPO), wet noodles could be browned easily duringits storage. The enzymatic characteristics of PPO in wheat flour was studied. And themethods of single factor test and orthogonal design test of L9(3~4) were applied to study thebrowning inhibition of the wet noodles. The factors of temperature, water, ascorbic acid,citric acid and sodium chloride adding on wet noodles were studied. The main experimentalcontents and results are as follows:1. Investigation of the enzymatic characteristics of PPOThe enzymatic characteristics of PPO in wheat flour, and the effects of various factorssuch as temperature, pH value, ascorbic acid and citric acid adding on PPO activity of wheatflour were studied by Spectrophotometry, catechol as substrate. The results showed that theoptimum temperature and pH were40℃and6.0respectively.0.04mol/L ascorbic acid and0.5mol/L citric acid coudle inhibit PPO activity effectively.2. Investigation of the method of noodle browning inhibitionThe methods of single factor test and orthogonal design test of L9(34) were applied tostudy the browning inhibition of the wet noodles. The results showed that each factor couldinhibit PPO activity respectively. The results of the orthogonal design test showed that theoptimal conditions are established as following:①First clear flour with ascorbic acid:temperature is65℃, water addition is34%, ascorbic addition is0.6%, sodium chlorideaddition is2%.②First clear flour with citric acid: temperature is75℃, water addition is34%, citric acid addition is0.5%, sodium chloride addition is3%.③Refined flour withascorbic acid: temperature is65℃, water addition is32%, ascorbic addition is0.7%,sodium chloride addition is3%.④Refined flour with citric acid: temperature is75℃,water addition is32%, citric acid addition is0.6%, sodium chloride addition is3%.