Ethylene responses and quality of antioxidant-rich stored barberry fruit (Berberis microphylla)

Abstract

In recent years there has been renewed interest in locally grown and underutilized wild species as sources of bioactive compounds. Barberry (Berberis microphylla G. Forst) is among the southernmost growing fruit bearing species worldwide. The aim of this study was to characterize this species. We evaluated the antioxidant capacity of ripe barberry fruits as compared to pear, orange, apple, strawberry and blueberry. In a second set of experiments ripe barberry fruit was harvested and treated with ethylene and 1-MCP and the changes in ethylene production and respiration rate during storage were assessed. Finally, ripe barberries were harvested and stored at 0, 5 or 10°C for 0, 3, 7, 11 or 15 days. During this period we determined weight loss, respiration rate, the percentage of rotten and physiologically decayed berries, firmness, sugar content, acidity, pH, anthocyanins, phenolics and antiradical capacity. Barberries showed 10-fold higher antioxidant capacity than apple, orange and pear and superseded four times that of antioxidant-rich fruits such as blueberry. 1-MCP treatments increased ethylene production suggesting that the hormone auto inhibits it biosynthesis. The fruit stored best at 0°C and this should be the recommended temperature to minimize deterioration and prevent losses of bio-active compounds. The fruits show a non-climacteric physiology, with ethylene biosynthesis being under negative feedback control. Barberries are an extraordinary high source of antioxidants among fruits.