Quality attributes, chemical properties, and selected bioactive compounds of pomegranate juice (Punica granatum L.) processed from arils after freezing storage

Abstract

Pomegranate juice quality depends essentially on its chemical and nutritional components stability. The valuable nutritional components may be reduced during its processing or storage. This study examined the effect of pomegranate arils’ frozen storage on juice quality, in terms of physicochemical properties and bioactive compounds stability. The physicochemical criteria (pH, TSS, TA, color attributes) and biochemical criteria (Total Phenolic content, Total anthocyanin content and antioxidant activity) were assessed on pomegranate juice extracted from frozen arils stored at (-18°C) for 6 months. Two cultivars ‘Sefri’ and ‘Wonderful’ were subject to this study. Results showed that the pH, TSS, and TA were generally stable in frozen arils juice. However, arils freezing had a significant effect on pomegranate juice color parameters. In fact, a significant decrease of a* values were revealed in juice samples for both cultivars. Therefore, the color intensity (chroma) has decreased significantly and total color differences (ΔE∗ab) also showed a significant difference (p < 0.05) between fresh juice and frozen arils juice. Arils freezing conditions (−18 °C) for 6 months didn’t affect pomegranate juice physiochemical criteria. However, bioactive compounds of pomegranate juice were reduced significantly. In fact, total phenolic content decreased by about 27% and 31% for ‘Sefri’ and ‘Wonderful’ cultivars, respectively. Total anthocyanins content decreased by 20% and 30% for ‘Sefri’ and ‘Wonderful’ cultivars, respectively. Antioxidant activity, measured based on the juice’s radical scavenging properties using the 2,2-diphenyl-1-picrylhydrazyl method, decreased by about 50% for ‘Sefri’ cultivar and 60% for ‘Wonderful’ cultivar.

Keywords

• grenadier (punica granatum l)
• congélation
• jus de grenade
• propriétés physico-chimiques
• composés bioactifs
• maroc