Sustained deficit irrigation affects the colour and phytochemical characteristics of pomegranate juice

Abstract

No information exists on the consequences of water stress on the pomegranate (Punica granatum L.) tree in terms of the quality and health/nutritional properties of its juice. In this study the influence of two different sustained deficit irrigation treatments on the colour, antioxidant activity and total phenolic compound, total anthocyanin, punicalagin and ellagic acid contents of pomegranate juice was assessed. Control plants were irrigated at 75% ETo (crop reference evapotranspiration) in order to ensure non-limiting soil water conditions, while others were subjected to sustained deficit irrigation at 43 and 12% ETo throughout the experimental period. Both moderate (43%) and severe (12%) water stress treatments led to pomegranate juices with a more yellowish colour, lower antioxidant activity and lower total phenolic compound, punicalagin and total anthocyanin contents than those from control plants. Pomegranate juice from trees under sustained deficit irrigation was of lower quality and less healthful than that from trees without water stress. From a nutritional point of view, this means that a reduction in irrigation provides a dramatic decrease in bioactive phenolic compounds, especially anthocyanins and punicalagin, and consequently a lower visual attraction of the juice owing to the weak red colour of the fruit.