Pan Yonggui, Guo Yuting, Huang Qun, Zhang Weimin, Zhang Zhengke
College of Food Science and Engineering Hainan University Haikou China.
Hainan Key Laboratory of Food Nutrition and Functional Food Haikou China.
Food Sci Nutr. 2021 May 24;9(7):3768-3776. doi: 10.1002/fsn3.2341. eCollection 2021 Jul.
Previous study indicates that kernel of areca nut is susceptible to enzymatic browning caused by phenolic oxidation, which involves the ingression of oxygen into interior tissue. However, the reason for permeation of oxygen into the interior of areca nut and its possible influencing factors (e.g., temperatures) are little known. In the present study, we set three storage temperatures (25, 10, and 5°C) and investigated the effects on kernel browning and related physic-biochemical and tissue morphological changes. The results showed that the most severe kernel browning was observed in areca nut stored at 25°C, followed by 5°C. Comparatively, a slower browning development was found in areca nut stored at 10°C. More serious kernel browning at 25 and 5°C might be attributed to increased membrane permeability and aggravated tissue damage in view of morphological observations on pericarp, mesocarp, and kernel shell. Higher lignin content and phenylalanine ammonia-lyase activity were observed in mesocarp of areca nuts stored at 25 and 5°C as compared to 10°C, indicating that mesocarp lignification could facilitate the permeability of oxygen. Furthermore, the data showed that storage at 25 and 5°C induced the higher polyphenol oxidase activity while accelerating the decline in total phenolic content in areca nut kernel, which could contribute to higher occurrence of enzymatic browning reaction compared to that at 10°C. These results suggest that natural senescence at 25°C and severe chilling stress at 5°C could be influencing factors triggering the permeation of oxygen, leading to internal kernel browning in areca nut.
先前的研究表明，槟榔核易受酚类氧化引起的酶促褐变影响，这涉及氧气进入内部组织。然而，氧气渗入槟榔核内部的原因及其可能的影响因素（如温度）鲜为人知。在本研究中，我们设置了三个储存温度（25、10和5°C），并研究了其对槟榔核褐变以及相关物理生化和组织形态变化的影响。结果表明，在25°C储存的槟榔中观察到最严重的槟榔核褐变，其次是5°C。相比之下，在10°C储存的槟榔中褐变发展较慢。从果皮、中果皮和核壳的形态观察来看，25°C和5°C时更严重的槟榔核褐变可能归因于膜通透性增加和组织损伤加剧。与10°C相比，在25°C和5°C储存的槟榔中果皮中观察到更高的木质素含量和苯丙氨酸解氨酶活性，表明中果皮木质化可能促进氧气的通透性。此外，数据表明，在25°C和5°C储存会诱导槟榔核中更高的多酚氧化酶活性，同时加速总酚含量的下降，这可能导致与10°C相比更高的酶促褐变反应发生率。这些结果表明，25°C的自然衰老和5°C的严重冷胁迫可能是触发氧气渗透的影响因素，导致槟榔核内部褐变。
