Study On The Browning Mechanism And Control In Stanuntonia Chinensis DC Wine

Stanuntonia chinensis DC fruit is rich in nutrients and important medical value.But it is so sour that can’t be directly eaten. Processing the fruit to wine can not only reduce the waste of resources but also increase the dissolved of certain nutrients. However, the browning of fruit wine during storage seriously affect the quality of the wine and shorten its shelf life. How to solve this problem is the primary task of growers and fruit wine manufacturers. In this paper, taking stanuntonia chinensis fruit wine as experimental material, we systematic studied enzymatic browning and non-enzymatic browning mechanism, influencing factors and control of browning. It studied the enzymatic characteristics of stanuntonia chinensis DC PPO, and the relationship between the color and the changes in the content of nonenzymatic browning substrate. In addition, the impact of storage conditions for wine was also studied inorder to determine the best storage condition. Several browning inhibitors was also studied for obtaining the best combination of browning inhibitors. The main results showed:1. With spectrophotometry method and based on substrate of catechol, The results showed that it has the best PPO activity at pH 6.5 and temperaturethe 25℃. By pH6.5 for boundary, with the rise and reduce of the pH, the PPO activity decline; by temperature 25℃for boundary, with the rise and reduce of the temperature, the PPO activity decline. the largest decline of PPO activity was at 80℃. Sodium pyrosulfite significantly inhibited PPO’s activity, when the concentration was 0.2g/L, the PPO activity is almost zero.2. During storage, total polyphenols, ascorbic acid, total sugars, reductive sugars and amino acids are all involved in the reaction. Vc can not be detected at the 18th day. On the 36th day,6% of the total sugars,19% of Amino acid was lossed and 39% of the total polyphenols were lossed. The content of reductive sugars has a little fluctuate.3. From the result of path analysis, only total sugars and free amino acids have a significant positive correlation with the lightness(L*) of the stanuntonia chinensis wine. Their direct path coefficient were 0.5073 and 0.4693, so total sugars have a greater influence than the amino acids on the lightness(L*) of the stanuntonia chinensis wine. The lightness(L*) as the dependent variable, total sugar(X1) and free amino acid(X2) as the independent variable, a regression equation: Y=-495.7748+12.7236X1+22.8026X24. As the temperature and the content of oxygen rising, and the light to be more strenger, the color of stanuntonia chinensis DC wine has a more obviously changing during storage. The effect on chromatism(AE) as follows:temperature＞light＞pH＞oxygen concentration; The effect on lightness(L*) as follows:temperature> oxygen concentration＞light＞pH; The effect on redness(a*) as follows:temperature＞light＞oxygen concentration＞pH; The effect on lightness(L*) as follows:temperature＞light＞oxygen concentration＞pH. The temperature was the most important aspect to the color of stanuntonia chinensis wine. The rate of changes in lightness(L*) under 37℃was 115.5 times higher than under 5℃. Therefore the most suitable storage condition is of pH3.3, cold, dark and vacuum.5. The study of the browning inhibitors showed that L-cysteine hydrochloride has tiny influence on In the single factor experiments, the effect of browning inhibitors’s sequences were phytic acid＞EDTA-2Na＞ascorbic acid＞L-cysteine hydrochloride; the best combinations of browning inhibitors selected were phytic acid 0.08g/L、EDTA-2Na 0.3g/L、ascorbic acid 1g/L.