Evaluation of gamma irradiation on the microbiological, phytochemicals, and aromatic profiles of sun-bleached preserved pepper (Capsicum annuum L.)

Sun-bleached preserved pepper (SPP) is a low-salt fermented product whose commercial application is often limited by microbial spoilage. This study evaluated the efficacy of gamma irradiation (2–10 kGy) as a preservation method for SPP, focusing on its impact on microbial safety, key phytochemicals (including phenolics and capsaicinoids), and volatile compounds. Irradiation at doses of 2–8 kGy effectively reduced or eliminated total viable counts, yeasts, moulds, coliforms, and Staphylococcus aureus . Total phenolic content was well retained (83–85%), and irradiation promoted the conversion of insoluble phenolics into soluble forms. Capsaicinoid levels increased markedly, with a 221% rise observed at 10 kGy. GC-IMS combined with multivariate analysis revealed a dose-dependent modulation of the volatile profile. Irradiation enhanced the formation of aldehydes and ketones (associated with fatty, green, spicy notes), while leading to the degradation of alcohols, acids, and esters (linked to floral and fruity nuances). A multi-criteria evaluation identified 6 kGy as the optimal dose, ensuring microbial control while preserving desirable quality attributes. These findings support the application of gamma irradiation to improve the safety and stability of low-salt fermented vegetables, thereby facilitating their commercial production.