Edible Composite Coating of Methyl Cellulose for Post-Harvest Extension of Shelf-Life of Finger Hot Indian Pepper (Pusa jwala)

Abstract

Chillies of Pusa jwala variety were coated with composite coating formulation made up of methyl cellulose (MC) and oleic acid (OA) to evaluate the effectiveness of edible coating in extending the shelf‐life of chillies. Edible coating showed good stability, transparency and glossiness when applied on chilli fruit. The coatings when applied on green chillies resulted in restriction in metabolic activities and delayed senescence. MC‐based coating was found to reduce physiological weight loss, textural softening and development of red pigment in the fruit peel. Coated fruit synthesized phenolic compound slower than uncoated fruit bringing about slow changes in capsaicin content as well. MC‐OA based coating could extend the shelf‐life of green chillies to 8 days under ambient storage conditions (24 ± 1C, RH 70 ± 5%) against the 5‐day shelf‐life of uncoated ones. Practical Applications Chilli is considered as one of the most important commercial spice crops and is a widely used universal spice. Preserving fresh chillies with simple, edible coating formulation would reduce the cost of preservation using other expensive and energy consuming techniques such as cold storage and CAP/MAP. As the coating gives each fruit its own micro‐packaging, coated fruits can be well handled as those of uncoated chillies. Being edible and water soluble the coating would not be harmful to consumers compared to use of chemical preservatives.

Gum arabic based composite edible coating on green chillies

“…The change in the chlorophyll content on the coated chilli was not significant until the 8th day of storage due to the restricted activity of chlorophyll degrading enzymes. The possible cause for the reduction in chlorophyll content is an acceleration in the activities of chlorophyll digesting enzymes such as chlorophyllase, chlorophyll oxidase and peroxidase during maturation (Chaple et al, 2016). Comparable results were seen in the case of chillies coated with shellac-based coatings (Chitravathi et al, 2014).…”

“…In uncoated samples, gain in T.S.S. can also result due to moisture loss by the fruit and transformation of organic acids to sugars (Chaple et al, 2016). Further reduction in T.S.S.…”

“…The above procedure was performed again and again until the residue was colourless. The supernatant collected was made up to 100 ml using 80% acetone and absorbance was recorded at 645 and 663 nm (Chaple et al, 2016 ).…”

“…For the estimation of total phenolic content, approximately 2 g of ground chilli sample was extracted in 20 ml of 90% methanol for 2 h. It was then filtered and total phenolic content was estimated with gallic acid as a standard (Chaple et al, 2016).…”

“…The firmness of both control and the coated chillies were analysed throughout the storage period by using the TA-XT Plus digital texture analyser (Chaple et al, 2016). The penetration test was used to find out the firmness of chillies.…”