Functional properties of feijoa fruit cultivated in southern Brazil

Fruit of four advanced selections of feijoa were harvested at commercial maturity in southern Brazil and assessed for vitamin C (ascorbic acid) content, total phenolic content (TPC) and total antioxidant activity (TAA, by DPPH method) in the peel (epidermis and parenchymatous region) and pulp (inner region) tissues. There was differences between genotypes for all functional attributes. In all genotypes, peel tissue had higher vitamin C content, TPC and TAA than pulp tissue. On average of all genotypes, peel and pulp tissues had, respectively, vitamin C content of 77.64 and 57.21 mg 100 g^-1 FW; TPC of 114.04 and 85.02 mg gallic acid equivalent (GAE) 100 g^-1 FW; and TAA with EC₅₀ (substrate concentration to produce 50% reduction of the DPPH) of 9.03 and 38.79 mg FW g^-1 DPPH. There was a linear relationship between TPC and TAA in peel and pulp tissues. The results show that Brazilian genotypes of feijoa have high vitamin C content, TPC and TAA in the fruit, especially in the peel tissue. Since peel is a portion of the fruit normally discarded, there is ample scope for the development of technologies to include this tissue in food and nutraceutical products.