Activated carbon derived from Mahachanok mango seeds as a potential material to delay the ripening of mangoes

Abstract

The mango processing industry in Thailand generates significant waste, with over 60 % consisting of mango seed. Mahachanok mango seeds, a by-product of mango processing, can be processed into highly porous activated carbon with potential application in agricultural and food preservation. This study investigated the potential of activated carbon derived from Mahachanok mango seeds on delaying the ripening of Nam Dok Mai mangoes. The activated carbon was prepared through a two steps process: biochar preparation followed by activation using KMnO4. The morphology of activated carbon was characterized by Fourier transform infrared (FT-IR) spectroscopy, Brunauer-Emmett-Teller (BET) surface area, and Scanning electron microscopy (SEM). The optimal carbonization temperature was determined, and the activated carbon was applied to mango storage. The mango ripening was assessed by measuring weight loss, total color difference (ΔE), firmness, total soluble solids (TSS), titratable acidity (TA), and TSS/TA ratio as a ripening level indicator. The optimal carbonization temperature was found to be 500 °C, yielding 25.47 % activated carbon with iodine number of 361.77 mg I2/g AC. The activated surface carbon contained hydroxyl and manganyl groups, with a BET-surface area of 0.649 m2/g. Mangoes stored with 10 g of synthesized activated carbon exhibited the best delay in ripening, extending the ripening process by five days compared to the control. On the 8th day of storage, mangoes became early ripe with firmness and TSS/TA values for 10 g of synthesized activated carbon were 0.467 N/mm and 22.35, respectively (p < 0.05). The TSS/TA ratio indicated that this treatment effectively maintained mango quality for up to 14 days of storage. Activated carbon derived from Mahachanok mango seed shows promising results in delaying mango ripening, especially when used at 10 g dosage. This approach utilized food processing waste to create a valuable product for post-harvest handling, potentially improving the freshness of exported fruit.