Increase in colour stability of pomegranate juice against 5-hydroxymethylfurfural (HMF) through copigmentation with phenolic acids

BACKGROUNDAnthocyanins are responsible for both attractive colour of pomegranate juice (PJ) and its health-promoting effects against cancer and coronary heart disease. However, 5-hydroxymethylfurfural (HMF) at some concentrations causes anthocyanin degradation. The present study aimed to reduce the degradation of PJ anthocyanins as a result of HMF at various concentrations (0-20 mg L-1) through phenolic acid [PA; ferulic (FA), gallic (GA) and caffeic acids (CA)] copigmentation during storage at 20 & DEG;C. RESULTSA strong correlation (r = 0.872) was found between anthocyanin degradation rate and HMF concentration in PJ without PA addition. An increase in HMF concentration during storage caused faster (< 32%) anthocyanin degradation. However, PA addition reduced (< 60 times) the HMF formation rate. The lowest HMF formation rates (0.07-0.28 day(-1)) were determined in PJ with added GA. Although GA caused an important increase in content of cyanidin-3-glucoside (16-42%), which is major PJ anthocyanin, against HMF at all concentrations, CA (15%) and FA (28%) increased cyanidin-3-glucoside content against 10 mg of HMF L-1. FA maintained its protection effect against the highest HMF concentration (20 mg of HMF L-1), but CA lost its protection effect. Generally, FA increased stabilities of hyperchromic effect (HE) (9.6-27.7%) and colour density (CD) (57.1-74.3%) at all HMF concentrations, although CA increased HE stability (19.8-37.7%) in the presence of 10 and 20 mg of HMF L-1. Interactions of 'all individual anthocyanins-FA' and 'delphinidin-based anthocyanins-GA/CA' resulted in copigmentation. CONCLUSIONFA addition was recommended to increase CD and HE for PJ containing HMF between 3.1-5.6 mg L-1, whereas the addition of GA was recommended to increase anthocyanin stability for PJ containing 12.0 mg of HMF L-1. & COPY; 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Automated summary

The study aimed to reduce the degradation of pomegranate juice anthocyanins caused by HMF through phenolic acid copigmentation. Results showed that the addition of FA and GA reduced the degradation rate, while CA had a protective effect only at low concentrations.