Effect of ultrahigh temperature treatment on qualities of watermelon juice.

Yubin Wang,Yue Ma,Xiaoyan Zhao,Chao Zhang,Xiaofei Guo

doi:10.1002/fsn3.593

Abstract

The watermelon juice was pasteurized by the ultrahigh temperature (UHT) treatment, and the qualities of the pasteurized juice were compared to screen the optimal UHT. The UHT of 120 and 135°C inactivated the microbial colonies and maintained the original color of the watermelon juice. The temperature of 120 and 135°C was also maintained the phenolic content by reducing the polyphenoloxidase activity. Moreover, the C9 aldehydes, especially the (E,Z)‐2,6‐nonadienal, presented the main aroma of the watermelon juice. The C9 aldehydes were formed as the results of the heat reduction and enzymatic metabolism. The temperature of 120 and 135°C reduced the alcohol dehydrogenase activity and well maintained the C9 aldehyde content of the watermelon juice. Hence, the temperature of 120°C of the UHT treatment was the optimal temperature for the production of the watermelon juice.

Highlights

Ultrahigh temperature (UHT) technique heats the feed at a high temperature in a short time, keeping the safety, and the nutrition of the feed (Charles-Rodríguez, Nevárez-Moorillón, Zhang, & Ortega-R ivas, 2007)
Our results proved that the UHT treatment was effective to inactivate the microbial colonies of the watermelon juice (Zhang et al, 2015)
The microbial survival rate of the UHT135 was lower than 0.01%, while that of the UHT110 and UHT 120 was lower than 0.1% and higher than 0.01%

Summary

| INTRODUCTION

Ultrahigh temperature (UHT) technique heats the feed at a high temperature in a short time, keeping the safety, and the nutrition of the feed (Charles-Rodríguez, Nevárez-Moorillón, Zhang, & Ortega-R ivas, 2007). The UHT technique inactivates the microbial colonies of the watermelon juice (Zhang, Wang, Ma, Zhao, & Li, 2015), orange juice (Walkling-R ibeiro, Noci, Cronin, Lyng, & Morgan, 2009), cucumber juice (Liu, Zhang, Zhao, Wang, & Liao, 2016), and sugarcane juice (Jittanit, Wiriyaputtipong, Charoenpornworanam, & Songsermpong, 2011). A higher temperature of the UHT treatment guarantees the safety of the juice (Charles-Rodríguez et al, 2007). The higher temperature of the UHT treatment leads to the degradation of the color, aroma, and nutritional quality of the juice (Tiwari, O’Donnell, Muthukumarappan, & Cullen, 2009). Our results proved that the UHT treatment was effective to inactivate the microbial colonies of the watermelon juice (Zhang et al, 2015). The temperature of the UHT treatment was further explored to find the balance of the safety and qualities of the watermelon juice. The key enzymes related to the formation of the aroma were discussed to give a deeper insight into the qualities of the watermelon juice

| MATERIAL AND METHODS

| RESULTS AND DISCUSSION

| CONCLUSION