Exploring the Effects of Pre-treatments on the Quality and Shelf Life Attributes of Karonda (Carissa carandas L.) Fruit Powder

Background: Karonda (Carissa carandas) is valued for its nutritional and medicinal properties, but has a shorter shelf life. Therefore, this study aimed to enhance the functional qualities and extend the shelf life of Karonda fruits through the application of different pre-treatment methods prior to drying. Methods: Mature green Karonda fruits were subjected to three different pre-treatments lemon immersion (LI), sugar immersion (SI) and honey immersion (HI) before being dehydrated in a cabinet tray dryer at 60°C. The dried fruits were then powdered, packed in polyethylene pouches and stored at -20°C for subsequent processes. Result: The study demonstrated that Karonda fruit powder pre-treated with lemon immersion (LI) exhibited the most favourable results. Different pre-treatment methods significantly influenced the functional, physicochemical, colour, microstructural images (SEM), sensory and storage stability properties of the fruit powder. In terms of functional properties, lemon immersion enhanced the bulk density and foaming capacity of the powder, indicating improved structural and functional behaviour, despite slight reductions in water absorption capacity and swelling index. Among the physicochemical attributes, LI-treated samples showed the highest acidity, reduced water activity and lower sugar content. SI treated samples retained maximum colour values followed by LI, Control and HI samples. Sensory evaluation revealed that LI-treated powder received the highest overall acceptability scores from the panellists. Storage studies further indicated that lemon-immersed Karonda powder-maintained stability for up to six months, comparable to the untreated control. Overall, lemon immersion proved to be the most effective pre-treatment, significantly enhancing the quality, functionality and shelf life of Karonda fruit powder, making it suitable for potential commercial applications.