Bioactive edible coatings incorporating extract from unfermented and fermented Tamarindus indica residues for the conservation of grapes of the cultivar ‘Italia’

Abstract

Several studies have used edible packaging for food preservation due to its composition of biodegradable polymers and natural additives. In the present work, bioactive extracts obtained from the fermented and unfermented flour of tamarind residues were incorporated into formulations of edible coatings for the conservation of grapes of the cultivar ‘Italia’. The flours extracts were obtained with 80% aqueous ethanol solution. Edible coating formulations containing 10 g L-1 cassava starch and 5 g L-1 chitosan without extract or containing 10 g L-1 unfermented or fermented flour extract were prepared and applied to grapes stored at 25 °C for 15 days. The physical-chemical characteristics of the coated and uncoated fruits were similar during storage. The addition of fermented and unfermented flour extracts to the edible coatings improved the in vitro antioxidant activity of the grapes, especially that determined by the ferric reducing antioxidant power method, on the last day of storage, with emphasis on grapes coated with a formulation containing fermented residue extract. Extracts of tamarind residues incorporated in edible coatings promoted the acquisition of bioactive coatings with the potential to improve the antioxidant activity of grapes during 15 days of storage at 25 °C.