Evaluating carboxymethylcellulose encapsulating moringa leaf extract as edible coatings for controlling rind pitting disorder in 'Marsh' grapefruit (Citrus × paradisi)
Development of rind pitting disorder (RPD) in 'Marsh' grapefruit (Citrus × paradisi) during shipping is a major concern as it reduces the fruit market value. This study investigated the potential of carboxymethylcellulose (CMC) encapsulated with moringa leaf extract (MLE) as edible coatings for reducing RPD of 'Marsh' grapefruit during cold storage and shelf-life. Fruit were treated with CMC 0.5% + MLE 10%, CMC 1% + MLE 10%, CMC 0.5% and CMC 1%. Untreated fruit were used as the control treatment. After treatment, fruit were kept at 3±1°C for 9 weeks and thereafter transferred to room temperature (21±1°C) for 2 weeks. Physicochemical attributes such as fruit mass, citrus colour index (CCI), total soluble solids (TSS), titratable acidity (TA), rind dry matter (RDM) were measured and RPD evaluated. The results showed that edible coatings had a significant effect on RPD. CMC 0.5% + MLE 10% and CMC 1% + MLE 10% had RPD incidence of 5.6 and 5.5%, respectively, while CMC 1% and CMC 0.5% had RPD of 7.6 and 9.8%, respectively, compared to 14.5% of the control treatment. Edible coatings had a significant effect (p<0.001) on fruit mass loss and CCI. Overall, coated fruit had lower mass loss than uncoated fruit, with CMC 1% and CMC 1% + MLE 10% having the lowest mass loss of 2.58 and 2.61%, respectively, followed by CMC 0.5% + MLE 10% (2.81%) and CMC 0.5% (2.83%) while the control experienced a higher fruit mass loss (3.75%). These results confirm that CMC provide a semi-permeable barrier to fruit which significantly reduces water loss in fruit rind. From these results, it was deducted that MLE incorporated with CMC as edible coatings reduced RPD development.
Shinga, M.H., Mditshwa, A., Magwaza, L.S. and Tesfay, S.Z. (2021). Evaluating carboxymethylcellulose encapsulating moringa leaf extract as edible coatings for controlling rind pitting disorder in 'Marsh' grapefruit (Citrus × paradisi). Acta Hortic. 1306, 301-308
environmentally friendly coatings, plant extracts, physiological rind disorders, physical and chemical fruit parameters