Influence of an O3-atmosphere storage on microbial growth and antioxidant contents of globe artichoke as affected by genotype and harvest time

We investigated the effects of storage at 4°C under ozone-enriched atmospheres on microbiological quality and antioxidant content of three globe artichoke cultivars (‘Violet de Provence’, ‘Tema 2000’ and ‘Apollo’), harvested at different times (winter, early spring, late spring), immediately treated under real industrial operation conditions and analyzed after 0, 3 and 7days of storage. Response of cultivars to postharvest treatments strictly depended upon harvest time. The reduction of both mesophilic bacteria and yeasts and moulds was significant in heads stored under ozone-enriched atmosphere for 3 or 7days with major reductions for ‘Tema 2000’ and ‘Apollo’ harvested in winter and early spring, respectively. Ozone-treated heads of ‘Violet de Provence’ and ‘Apollo’ reported a major ascorbic acid retention and a higher total polyphenol content in winter and early spring harvests, respectively. Finally, regardless of the harvest time, the exposure of globe artichoke heads to an ozone-enriched atmosphere should not exceed 3days in order to preserve the antioxidant content and maintain the microbiological standards.The fresh heads of globe artichokes, endowed with high nutritional value and therapeutic properties, are characterized by a limited shelf life due to the high respiratory rate, weight loss, microbial spoilage, biochemical and/or physiological damages. So far, few studies have been focused on postharvest treatments for delaying ripening and preserving head quality of globe artichoke heads destined to the fresh market and, among them, ozone has emerged as one of the most antimicrobial promising technologies from the health and environmental points of view for its spontaneous decomposition to non-toxic product. With the aim to improve the current knowledge on the efficacy of this innovative postharvest technology in relation to cultivar and harvest time, we studied, under industrial conditions, the effectiveness of storage in an ozone-enriched atmosphere for 3 or 7days on head weight loss, microbiological quality and antioxidants content of three different globe artichoke cultivars harvested at different times. The extension of quality retention could be important for globe artichoke heads destined to both fresh market and food industry.