Enzymatic Browning Of Fresh-cut Jipicao Yam And Its Control Methods

The Jipicao yam was used as the material during the experiment. The correlationbetween indicators and enzymatic browning characteristics were studied during the storage.Determined the main correlative browning enzymes and systematically researched thecharacteristis of them. And then selected effective inhibitors, through the single factor andorthogonal test, effects of citric acid, EDTA-2Na, ascorbic acid and L-Cysteine on thebrowning control of Jipicao yam slices were studied. The main contents and results were asfollowed:1. There was significantly positive correlation between BD and PPO, POD, MDAcontent; significantly negative correlation between BD and TP content; there was nosignificant correlation between BD and PAL and SOD. The correlation coefficient of PPO,POD with BD was0.902,0.940separately. It was suggested that both of them promoted thebrowning and POD had a greater contribution.2. The result showed that the PPO from Jipicao yam had its greatest activity at30℃andpH6.8. The optimum substrate for PPO was catechol. Ca2+, Ba2+, K+and Mn2+could inhibitthe activity. VC, L-cysteine and NaHSO3were the most effective inhibitors.3. The result showed that the POD from Jipicao yam had its greatest activity at35℃andpH4.0. The capability of the POD combining with various substrates was in the followingorder: Chlorgenic acid＞Guaiacol＞Pyrogallic acid＞Catechol＞Gallic acid. K+and Mn2+could inhibit the activity. VC, L-cysteine, Phytic acid, Oxalic acid, Citric acid, EDTA-2Na andNaHSO3had different degree of inhibitional effect on the activity of POD, where VCandL-cysteine were the most effective inhibitors.4. Citric acid, EDTA-2Na, ascorbic acid and L-Cysteine had inhibitional effect on thebrowning of Jipicao yam slices. The optimum formulated proportion of browning inhibitorswas Citric acid0.75%+L-Cysteine0.06%+EDTA-2Na0.2%+ascorbic acid0.1%.