Henry Fok College of Biology and Agriculture, Shaoguan Aromatic Plant Engineering Research Center, Shaoguan University, Shaoguan, China.
Guangdong Province Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou, China.
J Food Biochem. 2021 Sep;45(9):e13798. doi: 10.1111/jfbc.13798. Epub 2021 May 26.
Enzymatic browning is the main quality issue of fresh-cut foods. This study investigated the effects of different concentrations (0.05, 0.1, and 0.2 mM) of melatonin (MT) treatment on the enzymatic browning of four fresh-cut foods, including apples (Malus domestica), pears (Pyrus spp.), potatoes (Solanum tuberosum), and taros (Colocasia esculenta), and found that only 0.05 mM MT was most significant at enhancing the L* values and reducing the browning index (BI) in all four foods. This suggests that 0.05 mM MT might be a universal concentration for the browning alleviation of fresh-cut foods. MT treatment increased the total phenolic contents and PAL activities but reduced the activities of POD, PPO, and LOX in fresh-cut taros. Furthermore, MT significantly affected the expression of sixteen browning-related genes in fresh-cut taros during storage. These results suggest that MT reduced fresh-cut food browning by regulating the activities of browning-related enzymes. However, MT did not significantly influence the browning degree or PPO activity of the taro mash in vitro, suggesting that MT might regulate enzyme activity in an indirect manner. Overall, these results indicate that MT might be a promising anti-browning agent to alleviate the browning of fresh-cut foods. PRACTICAL APPLICATIONS: Melatonin (MT) is an endogenously produced indoleamine. Previous studies have reported that MT displays protective activities in many agricultural products. However, the reported protective MT concentrations vary between different products. To extend this agent to the fresh-cut industry, it is necessary to determine the universal dosage of MT needed for application efficiency. In this study, the effects of three concentrations (0.05, 0.1, and 0.2 mM) of MT on four fresh-cut foods, including apples, pears, potatoes, and taros, were investigated. The results showed that MT treatment alleviated browning development in the slices of these four foods and that 0.05 mM MT was the most effective treatment. Moreover, 0.05 mM MT significantly affected the activities of browning-related enzymes. These results suggest that 0.05 mM MT is a universal dosage for reducing surface browning in fresh-cut foods. This study provides a foundation for the application of MT in the processing of fresh-cut foods, especially fresh-cut taros.
酶促褐变是鲜切食品的主要质量问题。本研究探讨了不同浓度（0.05、0.1 和 0.2mM）褪黑素（MT）处理对四种鲜切食品（包括苹果、梨、土豆和芋头等）酶促褐变的影响，发现只有 0.05mM MT 对所有四种食品的 L*值提高和褐变指数（BI）降低最显著。这表明 0.05mM MT 可能是减轻鲜切食品褐变的通用浓度。MT 处理增加了总酚含量和 PAL 活性，但降低了鲜切芋头等食品中 POD、PPO 和 LOX 的活性。此外，MT 显著影响了鲜切芋头等食品在贮藏过程中 16 个褐变相关基因的表达。这些结果表明，MT 通过调节褐变相关酶的活性来减轻鲜切食品的褐变。然而，MT 对体外芋泥的褐变程度或 PPO 活性没有显著影响，表明 MT 可能以间接方式调节酶活性。总的来说，这些结果表明 MT 可能是一种有前途的抗褐变剂，可减轻鲜切食品的褐变。
褪黑素（MT）是一种内源性产生的吲哚胺。先前的研究报道 MT 在许多农产品中具有保护活性。然而，报道的保护 MT 浓度在不同的产品之间有所不同。为了将该制剂扩展到鲜切工业，有必要确定应用效率所需的 MT 通用剂量。在这项研究中，研究了三种浓度（0.05、0.1 和 0.2mM）的 MT 对包括苹果、梨、土豆和芋头等四种鲜切食品的影响。结果表明，MT 处理减轻了这四种食品切片的褐变发展，0.05mM MT 是最有效的处理。此外，0.05mM MT 显著影响了褐变相关酶的活性。这些结果表明，0.05mM MT 是减少鲜切食品表面褐变的通用剂量。本研究为 MT 在鲜切食品加工中的应用提供了基础，特别是鲜切芋头等。
