Decreasing pH Results in a Reduction of Anthocyanin Coprecipitation during Cold Stabilization of Purple Grape Juice

Molecules

David C. Manns¹  Passaporn Siricururatana¹  Olga I. Padilla-Zakour¹  Gavin L. Sacks¹ 

[1] Department of Food Science, New York State Agricultural Experiment Station, Cornell University, 630 W. North St., Geneva, NY 14456, USA

关键词: cold stabilization;    anthocyanin;    potassium bitartrate;    coprecipitation;   

DOI  :  10.3390/molecules20010556

来源: mdpi

【 摘 要 】

Anthocyanin pigments in grape juice can coprecipitate with potassium bitartrate (KHT) crystals during cold stabilization, but factors that reduce these adsorptive losses are not well understood. We hypothesized that coprecipitation on a % w/w basis should be decreased at lower pH. In initial experiments, model juice solutions containing an anthocyanin monoglucoside extract and varying pH values were subjected to cold-storage to induce KHT crystallization, and anthocyanins in the resulting precipitant were characterized by HPLC. The pH of the model juice was directly correlated with the % w/w concentration of anthocyanins in the KHT crystals, with a maximum observed at pH 3.40 (0.20% w/w) and a minimum at pH 2.35 (0.01% w/w). A pH dependency was also observed for anthocyanin-KHT coprecipitation in purple Concord grape juice, although the effect was smaller. Coprecipitation was significantly greater for anthocyanin monoglucosides and acylated anthocyanins as compared to anthocyanin diglucosides at pH > 3.05, but coprecipitation of mono- and acylated forms declined more sharply at lower pH values.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.