Mango is one of the popular fruits in Malaysia and has been used in the jam, puree and drinks production. Production of food products using mango pulp has generated by-products such as peel and kernel. Disposal of these by-products will cause environmental pollution if not properly treated. Mango peel contains high nutritional composition and antioxidant properties and can be utilised as food ingredients. The objectives of this study are to determine the nutritional composition and antioxidant properties of the peels of two selected mango varieties, namely Golden Lily and Chokanan. Analysis of proximate composition, minerals, total phenolic compounds, carotenoids, and antioxidant activity (DPPH and ABTS) were carried out in this study. Results of the proximate analysis showed that the peels of both mango varieties were a good source of fibre, which were 14.45% for Golden Lily and 14.89% for Chokanan. The crude fat, crude protein, and total carbohydrate of Chokanan peel (2.62%, 4.67% and 57.74%, respectively) were higher than the Golden Lily peel (1.13%, 2.90% and 53.16%, respectively). Contrastingly, the moisture content of the Golden Lily peel (24.67%) was higher than the Chokanan peel (16.61%). Potassium was the main mineral found in both Golden Lily and Chokanan mango peels (8802.10 mg/kg and 8443.60 mg/kg, respectively). The total phenolic compounds in the peels of both mango varieties were not significantly different. The Chokanan peel contained a higher carotenoids content (35.26 µg/g) than the Golden Lily peel (15.03 µg/g). The ABTS value for Chokanan peel was higher (1406.00 μmol TE/g) than Golden Lily peel (1314.00 μmol TE/g). This study showed that Chokanan and Golden Lily mango peels have the potential to be utilised as ingredient in food products due to their high fibre content.
Effect of different storage temperatures on physical and physiological changes of Golden Lily mango was investigated. Zinc oxide (ZnO) nanoparticles edible coating was prepared by sol-gel method and Golden Lily mangoes were dipped in the solution and stored at different (32℃, 27℃ and 5℃) temperatures for 7 days. The mangoes were characterized by Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), Fourier-transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) after 7 days of storage. Both the analysis of FESEM and EDX revealed the highest volume ratio of ZnO nanoparticles with a homogeneous dispersion throughout the mango peel surface is at 5℃. FTIR spectra revealed the absence of Zn–O bonding as metal oxides absorption is expected to be in the region below 700 cm-1. The mangoes stored at 5℃ delayed ripening, slowed down weight loss and found to be firmer than mangoes stored at 32℃ and 27℃.