title: Phytochemicals preservation in strawberry as affected by pH modulation.
abstract: Strawberries purées are incorporated in foods and subjected to pH modulation according to the expected final food matrix. The effect of pH on strawberry polyphenols stored at 4 and 23 °C for 90 days was evaluated. Total antioxidant activity and total phenolics content were only affected by time according to a first order model. The pH 4.5 induced higher decrease in (-)-epigallocatechin gallate (71% and 79%) and quercetin-3-glucoside (29% and 36%), for both storage temperatures. For pH 2.5 and 3.0, ellagic acid increased 84% for 4 °C and 185% for 23 °C. Anthocyanins concentration changes along storage were well described by first order model. The pH value of 2.5 presented the lower kinetic constant rate where cyanidin-3-glucoside, pelargonidin-3-glucoside and pelargonidin-3-rutinoside had a k=0.04, 0.05 and 0.03 day(-1). Lower storage temperature (4 °C) and lower pH (2.5) were the best condition for the preservation of polyphenols in pasteurized strawberry during a 90-day storage period.
authors.affiliation: Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Oliveira
authors.affiliation: Frulact, S.A. Rua do Outeiro 589, 4475-150 Gemunde, Maia, Portugal.
authors.forename: Maria Helena
authors.initials: MH
authors.lastname: Gomes
authors.affiliation: Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal.
authors.forename: Elisabete M C
authors.initials: EM
authors.lastname: Alexandre
authors.affiliation: Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal.
authors.forename: Fátima
authors.initials: F
authors.lastname: Poças
authors.affiliation: Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal.
authors.forename: Domingos P F
authors.initials: DP
authors.lastname: Almeida
authors.affiliation: Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal. Electronic address: mpintado@porto.ucp.pt.
authors.forename: Manuela
authors.initials: M
authors.lastname: Pintado
mesh_terms: D000975:Antioxidants / Q000032:analysis; D031985:Fragaria / Q000737:chemistry*; D005638:Fruit / Q000737:chemistry; D010636:Phenols / Q000032:analysis; D064209:Phytochemicals / Q000032:analysis*; D059808:Polyphenols / Q000032:analysis
chemical_list: D000975:Antioxidants; D010636:Phenols; D064209:Phytochemicals; D059808:Polyphenols
keywords: Anthocyanins; Fragaria×ananassa; Kinetic; Purée processing; pH modulation