Exogenous application of cysteine in bell peppers: physiological and biochemical responses to stress induced by minimal processing

• Grant number: 24/20968-4
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: May 01, 2025
• End date: February 29, 2028
• Field of knowledge: Agronomical Sciences - Agronomy
• Principal Investigator: Ricardo Alfredo Kluge
• Grantee: Ellen Rayssa Oliveira
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Bell peppers are fruits of high nutritional value, rich in bioactive compounds such as carotenoids and polyphenols, which exhibit antioxidant activity and provide health benefits. These attributes attract consumers in the minimally processed fruits and vegetables market due to their convenience, safety, and nutritional quality. However, minimally processed products (MPP) are more perishable than whole fruits due to cutting, which induces stress in plant tissues. This type of processing leads to an increase in the production of reactive oxygen species (ROS), which act as stress signalers, triggering other biochemical and physiological responses such as increased ethylene production, higher respiratory rates, and activation of oxidases that accelerate senescence.To extend shelf life and preserve the quality of MPP, it is necessary to develop new technologies that minimize physicochemical alterations, reduce postharvest losses, and optimize the postharvest life of these products. In this context, treatment with exogenous application of cysteine emerges as an alternative for maintaining postharvest quality, as cysteine is a natural additive with antioxidant properties that can reduce polyphenol oxidase activity, prevent the oxidation of phenolic compounds, and preserve the visual and nutritional quality of the fruit. The project hypothesis suggests that exogenous application of cysteine can alter the content of bioactive compounds, provide greater protection against oxidative stress induced by minimal processing, and maintain the postharvest quality of minimally processed bell peppers, thus reducing postharvest losses in MPP. Therefore, this research aims to investigate the effect of exogenous cysteine application on the preservation of minimally processed bell peppers and to analyze how cutting-induced stress influences the physiological and biochemical responses of fruits at different maturity stages.