关键词: 加工型辣椒, 鲜食型辣椒, 代谢物, 比较代谢组, 果实品质

Abstract:

【Objective】 Chili pepper, the most widely cultivated vegetable crop in China, is classified into processing or fresh-eating types based on their utilizations. This study aimed to thoroughly explore the metabolic differences between these two categories by analyzing and comparing the metabolites in the fruits of processing and fresh-eating chili peppers at both the mature green and mature red stages. The research sought to lay a theoretical groundwork for understanding the metabolic and quality variations between the two types of chili peppers. 【Method】Fruit samples from the processing type chili pepper, P059, and the fresh-eating type, F270, were collected at the mature green and mature red stages. Differential metabolites were identified and analyzed by using liquid chromatography-mass spectrometry (LC-MS) combined with multivariate statistical techniques. 【Result】A comprehensive analysis identified 1 465 metabolites in the fruits of processing type P059 and fresh-eating type F270 at both mature green and mature red stages. These metabolites spanned various categories, including lipids, amino acids, and terpenes. The comparative assessments at identical maturity stages showed that the lipid content in P059 fruits was significantly higher than in F270 at both maturity stages. Notably, metabolites such as linoleic acid and 9, 10-dihydroxy-12-octadecenoic acid from the linoleic acid pathway (map00591) exhibited substantial differences. At the mature green stage, the spermidine level in P059 was over twice that was found in F270, while the homovanillic acid level in F270 was 2.93 times higher than that in P059. At the mature red stage, P059 contained 5.74 times more capsaicin than F270, whereas the proline level in F270 was 2.47 times higher than in P059. Moreover, the comparative analysis of differential metabolites during the maturation process of these two chili peppers revealed distinct metabolic changes. N-Carbamoyl-putrescine, involving in the arginine and proline metabolism pathway (map00330), showed significant variation in P059 but remained unchanged in F270. Conversely, vitamin A levels in F270 increased by 277% throughout maturation. Both varieties exhibited a substantial increase in citric acid and abscisic acid, with concentrations rising approximately 1.7-fold for citric acid and 8.4-fold for abscisic acid in P059; and 1.7-fold and 12-fold, respectively, in F270. In contrast, 13-hydroxy-9, 11-octadecadienoic acid levels diverged, surging by 300% in P059 from the mature green to the red stage, while F270 showed a significant decrease. 【Conclusion】 This study employed metabolomics techniques to explore the metabolic differentials between mature green and mature red fruits in processing type P059 and fresh-eating type F270 chili peppers. The results revealed distinct metabolites, including lipids, amino acids, vitamins, and organic acids, that differentiate the two chili pepper types. Additionally, this study shed light on the changing trends of specific metabolites, such as citric acid, abscisic acid, and 13-hydroxy-9,11- octadecadienoic acid during the maturation process of these chili peppers. These insights contribute to a more detailed understanding of the quality differences between processing and fresh-eating chili peppers.

Key words: processing-type chili pepper, fresh-eating-type chili pepper, metabolite, comparative metabolomics, fruit quality