Application of citronella and rose hydrosols reduced enzymatic browning of fresh-cut taro.

Hydrosols are byproducts produced by steam distillation of aromatic plant materials. Previous studies reported hydrosols owned effectively inhibitory effects on microbials, but few focused on the effects in reducing enzymatic browning of fresh-cut products. Here, application of citronella hydrosol (CH) and rose hydrosol (RH) obviously reduced values of L*, a* and b* in surfaces of fresh-cut taros, suggesting these hydrosols could reduce browning severity. About 500 ml/L of RH and CH reduced total phenol contents, and activities of phenylalanine ammonia lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO), suggesting hydrosols suppressed browning development by reducing PAL, POD and PPO activities. Studies reported terpenoids had potential inhibition on PPO activity. Chemical composition analysis showed that RH and CH extracts contained abundant terpenoids. These imply that terpenoids contained in two hydrosols might have contributed to the reduction of enzyme activity. This study indicates that hydrosols might be promising natural anti-browning agents for fresh-cut foods. PRACTICAL APPLICATIONS: Hydrosols are the byproducts of essential oil from steam distillation. The work described here shows that application of citronella and rose hydrosols significantly reduced the browning of fresh-cut taros. Moreover, aromatic hydrosols also present inhibitory activity against microorganisms and are generally considered safe for human health. These suggested that aromatic hydrosols are the natural and useful anti-browning agents to preserve the quality of fresh cut foods, and can be well integrated into industrial procedures.