Recent studies aimed to investigate five phenolic substrates’ reactivities in terms of PPO activity compared with browning symptom occurrence, as well as the efficiency of sericin extracted from ‘Nam Dok Mai Si-Thong’ mango in vitro on polyphenol oxidase (PPO) activity, and the efficiency of sericin coating on browning inhibition of fresh-cut ‘Nam Dok Mai Si-Thong’ mango during storage. The specificity of PPO activity was determined using various substrates such as caffeic acid, catechol, chlorogenic acid, 4-methylcatechol and pyrogallol. PPO extracted from ‘Nam Dok Mai Si-Thong’ mango was more actively specific to catechol and 4-methylcatechol than other substrates that revealed a darker browning color on mango pieces. In vitro, sericin inhibited the activity of PPO reacted with catechol and 4-methylcatechol substrate in mango extracts. The efficiency of sericin coating on browning inhibition of fresh-cut mangoes was then investigated. Application of a 2% sericin coating maintained the visual appearance including the L* value, browning index, browning score, and inhibited enzymatic browning incidence by lowering the increases in total phenol and PPO activity compared to the control during storage at 10°C for 4 days. However, sericin seemed to have no influence on phenylalanine ammonia-lyase (PAL) activity. Moreover, sericin coating enhanced the antioxidant activity of fresh-cut mango when compared to the control. In conclusion, we found that sericin coating is an effective option to maintain the visual appearance, and inhibit the enzymatic browning incidence, of fresh-cut ‘Nam Dok Mai Si-Thong’ mangoes during registered storage.

最近的研究旨在调查五种酚类底物在PPO活性与褐变症状发生方面的反应性，以及从'Nam Dok Mai Si-Thong'芒果中提取的丝胶在体外对多酚氧化酶（PPO）活性的效率，以及丝胶涂层对鲜切'Nam Dok Mai Si-Thong'芒果在储存过程中褐变的抑制作用。使用各种底物（例如咖啡酸，邻苯二酚，绿原酸，4-甲基邻苯二酚和邻苯三酚）确定PPO活性的特异性。从“ Nam Dok Mai Si-Thong”芒果中提取的PPO比其他底物（在芒果片上显示出较深的棕褐色）更活跃地具有特定于儿茶酚和4-甲基儿茶酚的特异性。体外，丝胶蛋白可抑制芒果提取物中邻苯二酚和4-甲基邻苯二酚底物反应的PPO活性。然后研究了丝胶蛋白涂层对鲜切芒果褐变的抑制作用。使用2％丝胶蛋白涂层可保持包括L在内的视觉外观*值，褐变指数，褐变评分和抑制的酶褐变发生率是通过在10°C下储存4天与对照组相比降低了总酚和PPO活性的增加所致。但是，丝胶蛋白似乎对苯丙氨酸氨解酶（PAL）活性没有影响。此外，与对照相比，丝胶蛋白涂层增强了鲜切芒果的抗氧化活性。总之，我们发现丝胶涂层是在注册存储期间保持鲜切'Nam Dok Mai Si-Thong'芒果的视觉外观并抑制酶促褐变的有效选择。