Total Antioxidative Capacity and Total Phenolic Levels in Pomegranate Husks Correlate to Several Postharvest Fruit Quality Parameters

Abstract

The demand to extend the marketing period of pomegranates requires a better understanding of the processes occurring during postharvest storage. Among the important factors that limit the long-term storage of pomegranates are disorders occurring on the fruit husk: fungal decay, chilling injury, shrinkage due to weight loss, and husk scald, all leading to loss of visual quality. The aim of this study was to examine processes that taking place during storage, and to analyze the relationship between the total antioxidant capacity and total phenolics content of the husks and the development of husk disorders in seven accessions. While the level of total phenolics increased during storage, concomitantly with the color index, the level of punicalagin, the main polyphenol in the husks with the highest antioxidant activity, declined during storage. The content of titratable acidity was also reduced. Regression analysis indicates that fruit having a high antioxidant capacity, high total phenolics content, and high levels of punicalin in their husks have a better ability to resist fungal decay and weight loss, in addition to being less sensitive to husk scald. On the other hand, the results suggest that the development of most husk disorders is not correlated to the content of total soluble solids, titratable acidity, punicalagin, anthocyanin, or husk color. Nonetheless, poorly colored accessions were relatively more sensitive to chilling injury expressed as surface pitting, compared with the more colored accessions. The appearance of these chilling injury symptoms was not correlated to total phenolics or the antioxidant capacity.