High hydrostatic pressure valorization of red pepper by-products: a sustainable strategy for enhancing safety, color stability, and bioactive compound preservation

This study evaluates the use of high hydrostatic pressure (HHP) as a sustainable strategy for the stabilization of red pepper (RP) ( Capsicum annuum L.) by-products for use in food applications. RP purée was treated at 400, 500, and 600 MPa for 1 and 5 min, and changes after processing and 30 days of refrigerated storage were assessed. HHP treatment significantly reduced mesophilic, psychrophilic, and yeast/mould counts from initial levels of 6.5 log CFU g⁻¹ in untreated samples to below detection limit (<1 log CFU g -1 ) at day 1, maintaining microbiological stability after 30 days of storage. Color was well preserved, with ΔE values after processing ranging from 0.4 to 0.7 (not noticeable to slightly noticeable), while storage induced greater changes (ΔE up to 3.6, well visible), particularly in untreated samples. Total carotenoid content (TCC) and total phenolic content (TPC) showed slight reductions depending on treatment, whereas antioxidant activity (AA) remained stable. Considering microbiological stability during storage as the primary requirement for food applications, treatments were comparatively evaluated in terms of their ability to preserve color and bioactive compounds without substantial losses. Based on this approach, treatment at 600 MPa for 5 min was identified as the most suitable condition, providing the best balance between microbial inactivation and quality preservation. These results demonstrate that HHP is an effective approach for the stabilization of RP by-products, enabling their potential valorisation as natural ingredients through whole-matrix preservation without extraction processes or thermal treatments.