Using convective hot air drying to stabilize mango peel (Cv-Chausa): evaluating effect on bioactive compounds, physicochemical attributes, mineral profile, recovery of fermentable sugar, and microbial safety

The presence of carbon and nitrogenous compounds in mango processing by-products makes them excellent substrates for the biosynthesis of many microbial metabolites using the fermentation process. Pre-treatment of the substrate with retention of crucial microbial growth supporting compounds is vital for designing and optimizing fermentation media for enhanced production of desired metabolites. Keeping this in mind, we analyzed the effect of convective hot air drying (50, 60, 70, and 80 °C) conditions on the bioactive compounds (especially carbohydrates and nitrogen), physico-chemical attributes, mineral elements, fermentable sugar, and microbial safety of mango peels (Cv-chausa) powder. Results indicated that different drying temperatures insignificantly (P > 0.05) affected the carbohydrates and reducing sugar (except at 80 °C) along with nitrogen and protein contents. The pH, ascorbic acid, total phenolic, and antioxidant activity decreased with an increase in drying temperatures. Inductively coupled plasma-optical emission spectrometry analysis revealed increased concentrations of majority nutrients with incremental temperature, possibly due to excessive desiccation and substantial dry matter increase. After 30 days at room temperature storage, the microbial load was within safe limits, as samples were devoid of food pathogens. Briefly, the study suggests the effectiveness of convective hot air drying (at 70–80 °C) for efficient drying and prolonged storage of stable powdered form mango peels (MP). The obtained MP powder can be used as a feedstock (with safe storability, preserved bioactive, primarily carbon and nitrogen compounds) for the year-round use in the microbial fermentation process and potential development of functional food.