Phytochemicals preservation in strawberry as affected by pH modulation.

Ana Oliveira, Maria Helena Gomes, Elisabete M C Alexandre, Fátima Poças, Domingos P F Almeida, Manuela Pintado

Index: Food Chem. 170 , 74-83, (2014)

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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.Copyright © 2014 Elsevier Ltd. All rights reserved.