Ripening-Induced Changes in the Nutraceutical Compounds of Differently Coloured Pepper (Capsicum annuum L.) Breeding Lines

Abstract

To date, several research studies addressed the topic of phytochemical analysis of the different coloured pepper berries during ripening, but none discussed it in the case of purple peppers. In this study we examine whether the anthocyanin accumulation of the berries in the early stages of ripening could result in a higher antioxidant capacity due to the elevated amount of polyphenolic compounds. Therefore, enzymatic and non-enzymatic antioxidant capacity was measured in four distinct phenophases of fruit maturity. Furthermore, the expression of structural and regulatory genes of the anthocyanin biosynthetic pathway was also investigated. An overall decreasing trend was observed in the polyphenolic and flavonoid content and antioxidant capacity of the samples towards biological ripeness. Significant changes both in between the genotypes and in between the phenophases were scored, with the genotype being the most affecting factor on the phytonutrients. An extreme purple pepper yielded outstanding results compared to the other genotypes, with its polyphenolic and flavonoid content as well as its antioxidant capacity being the highest in every phenophase studied. Based on our results, besides MYBa (Ca10g11650) two other putative MYBs participate in the regulation of the anthocyanin biosynthetic pathway.

Antioxidant potential and factors influencing the content of antioxidant compounds of pepper: A review with current knowledge

“…However, in the later stage, the content of metabolites, such as capsaicinoids (capsaicin and dihydrocapsaicin), amino acids (leucine, isoleucine, proline, and phenylalanine), and kaempferol glycosides, increased significantly. In contrast to the above findings reporting higher antioxidant activity in matured stages, some studies reported higher antioxidant activity in fully developed green stage (Dobón‐Suárez et al., 2021; Kappel et al., 2008; Kovacs et al., 2022; Oney‐Montalvo et al., 2020; Thuphairo et al., 2019), which reflects dynamic changes in antioxidant capacity during pepper fruit development. Thus, these studies indicate the importance of considering the maturity stage of pepper at the time of harvesting for maximum nutritional and functional benefits of pepper, which also ultimately affects consumer preferences.…”

“…For example, pepper fruits show the development of distinct colors during different stages of development, such as green, yellow, red, orange, brown, and violet, and green peppers contained high levels of chlorophyll a, free all‐ trans ‐lutein, and carotenoids along with higher levels of polyphenols, proanthocyanins, and total flavonoids; color breaker stage had a higher content of dehydroascorbic acid; matured red stage had a high content of carotenoids (capsanthin, capsorubin, and capsanthin 5,6‐epoxide carotenoids), oligomeric anthocyanins, vitamin C and provitamin A; yellow and orange peppers contained high levels of flavonoids and oligomeric anthocyanins, zeaxanthin, β‐cryptoxanthin, lutein, and α‐ and β‐carotene, whereas purple or violet peppers had high polyphenolic and flavonoid contents along with the main anthocyanin, delphinidin‐3‐ trans coumaroylrutinoside‐ 5‐glucoside (Cervantes‐Paz et al., 2012; Howard, 2001; Jimenez et al., 2003; Kovacs et al., 2022; Marin et al., 2004; Martinez et al., 2005; Sadilova et al., 2006; Shukla et al., 2016; Sun et al., 2007; Thuphairo et al., 2019). Further, most of the studies assessing the antioxidant activity of pepper at these different stages reported increased antioxidant activity with the maturation of peppers, that is, higher antioxidant activity in the red, purple, or yellow peppers compared to immature green peppers (Castro‐Concha et al., 2014; Cervantes‐Paz et al., 2012; Choi et al., 2022; Howard et al., 2000; Jimenez et al., 2003; Kovacs et al., 2022; Manikharda et al., 2018; Sinisgalli et al., 2020). The high antioxidant activity in matured red peppers was identified to be due to the higher content of capsaicinoids, capsinoids, polyphenols, β‐carotene, lycopene, and ascorbic acid (Iqbal et al., 2013; Manikharda et al., 2018; Shukla et al., 2016; Sinisgalli et al., 2020), whereas the highly antioxidant purple pepper had higher polyphenolic and flavonoid contents (Kovacs et al., 2022).…”

“…Further, most of the studies assessing the antioxidant activity of pepper at these different stages reported increased antioxidant activity with the maturation of peppers, that is, higher antioxidant activity in the red, purple, or yellow peppers compared to immature green peppers (Castro‐Concha et al., 2014; Cervantes‐Paz et al., 2012; Choi et al., 2022; Howard et al., 2000; Jimenez et al., 2003; Kovacs et al., 2022; Manikharda et al., 2018; Sinisgalli et al., 2020). The high antioxidant activity in matured red peppers was identified to be due to the higher content of capsaicinoids, capsinoids, polyphenols, β‐carotene, lycopene, and ascorbic acid (Iqbal et al., 2013; Manikharda et al., 2018; Shukla et al., 2016; Sinisgalli et al., 2020), whereas the highly antioxidant purple pepper had higher polyphenolic and flavonoid contents (Kovacs et al., 2022). A more distinctive pattern of change in the antioxidant activities was also observed when the antioxidant activity at three developmental stages, that is, early stage (16–25‐day post‐anthesis), breaker stage (36–38‐day post‐anthesis), and later stage (43–48‐day post‐anthesis), was studied in hot pepper ( C. annuum ‘CM334’) (Jang et al., 2015).…”

“…Several recent studies have shown the potential of pepper antioxidants to ameliorate the oxidative stress related to aging and the development of diseases, such as cancer, neurodegeneration, hyperglycemia, cardiovascular, and other diseases (Allam, 2021; Jang et al., 2022; Lavorgna et al., 2019; Lekala et al., 2019; Pannangrong et al., 2020; Sahid et al., 2023; Sinisgalli et al., 2021; Thongin et al., 2022; Thuphairo et al., 2019; Zimmer et al., 2012). On the other hand, various pre‐ and postharvest factors have also been found to influence the antioxidant capacity of peppers (Chen et al., 2022; Farhoudi et al., 2019; Kasampalis et al., 2022; Kim et al., 2021; Kovács et al., 2022; Martínez‐Ispizua et al., 2021; Moreno‐Ramírez et al., 2019; Ridzuan et al., 2019; Rybak et al., 2022; Salamatullah et al., 2022; Sinisgalli et al., 2020; Valkova et al., 2021; Yap et al., 2022). Understanding these factors may help in selecting the best genotype, cultivation conditions, and postharvest storage and processing methods for an optimum content of the antioxidant compounds in pepper, which can be used as dietary antioxidant supplements and as antioxidant preservatives or additives in spices industries.…”

The Effects of Temperature and Water on the Seed Germination and Seedling Development of Rapeseed (Brassica napus L.)

“…Therefore, a water shortage inhibits the enzymes responsible for hydrolyzing endosperm starch, which supplies energy for plant development by metabolizing sugar [ 17 ]. Water stress, in general, is followed by oxidative stress in seeds during germination, which is characterized by an increase in the production of reactive oxygen species [ 18 , 19 , 20 , 21 ]. Therefore, a combination of the antioxidant activity defense system and the internal content of these substances are essential for successful germination under limited water conditions [ 22 , 23 , 24 ].…”