sustainability Article Food Preservative Capabilities of Grape (Vitis vinifera) and Clementine Mandarin (Citrus reticulata) By-products Extracts in South Africa Trust M. Pfukwa 1, Olaniyi A. Fawole 2,3, Marena Manley 1 , Pieter A. Gouws 1, Umezuruike Linus Opara 2,3 and Cletos Mapiye 4,* 1 Department of Food Science, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa;
[email protected] (T.M.P.);
[email protected] (M.M.);
[email protected] (P.A.G.) 2 Postharvest Technology Research Laboratory, South African Research Chair in Postharvest Technology, Department of Horticultural Sciences, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa;
[email protected] (O.A.F.);
[email protected] (U.L.O.) 3 Postharvest Technology Research Laboratory, South African Research Chair in Postharvest Technology, Department of Food Science, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa 4 Department of Animal Sciences, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa * Correspondence:
[email protected]; Tel.: +27-21-808-2640 Received: 15 February 2019; Accepted: 19 March 2019; Published: 22 March 2019 Abstract: The drive towards sustainable food systems coupled with increased consumer sophistication have prompted innovation in waste valorization. Grape and citrus processing by-products, abundant in the Mediterranean and tropical regions, respectively, are expanding and are sustainable sources of bioactive phytochemicals that can be used as natural preservatives for foods. Phytochemical composition, antioxidant, and antimicrobial properties of extracts from grape pomace (GPE), seeds (GSE), and clementine mandarin peel and pulp (MPE) grown in South Africa were analyzed.