Upcycling mango and pomegranate peel as pectin source: characterization, fat substitute and retarded lipid oxidation in caramel candy

One of the food industries most promising strategies is to upcycle food waste into nutritious components. This work aimed to upcycle the mango and pomegranate peels dried with different methods (oven, solar, microwave) into a functional ingredient and as a fat substitute in caramel candy. Characterization of extracted pectin; physical properties and antioxidant activity, and for substituted caramel candy; texture profile analysis and thiobarbituric acid (TBA) were investigated. Results showed that oven drying method for mango peel gave the highest yield (16.47%). Scanning electron microscope image (SEM) of all extracted pectin structure was a rough and wrinkled surface. The characteristics of mango and pomegranate pectin samples: methoxyl content, degree of esterification, equivalent weight and anhydrouronic acid content revealed that extracted pectin could be categorized as low-methoxyl pectin. Microwave drying method was the most efficient on increasing the total phenol for mango and pomegranate (63.4–64.3 mg GAE/1 g pectin, respectively), while, high antioxidant activity was also for pomegranate microwave pectin (PMP) 57.23% and 56.4% for mango microwave pectin (MMP). Caramel candy substituted with MMP and PMP had a low melting point. MMP and PMP (0.5%) improved the hardness and chewiness parameters and high acceptability was observed. MMP and PMP induced a decrement in the TBA of caramel candy; the lowest TBA was for caramel substituted with 3% PMP (0.59 mg/kg sample). Results demonstrate that, MMP and PMP could be used as retarded rancidity, functionality as fat substitute, and improve the quality characteristics of caramel candy as well as cheap and healthy.