EFFECT OF ARGON-ENRICHED ATMOSPHERES ON SHELF LIFE OF FRESH-CUT 'ICEBERG' LETTUCE
The objective of this study was to evaluate the effect of Ar-enriched atmospheres, on the maintenance of quality characteristics of fresh-cut lettuce during refrigerated storage. Iceberg lettuce was processed according to industry procedures and stored in a humidified flow of air (as a control) and of the following atmosphere: 97% Ar + 3% O2, 50% Ar + 3 % O2, (balanced with 47% of N2), and 97% N2 + 3% O2. Samples were stored at 5°C and evaluated before and after 2 and 9 days of storage. All atmospheres were effective in slowing down respiration rate at 9 days, whereas no significant difference in color, texture, flavor, phenols, antioxidant activity, acetaldehyde and ethanol content were observed. After 9 days of storage, lettuce stored in 50% Ar and in N2 atmosphere showed lower PPO activity than control, whereas samples stored under 97% Ar-enriched atmosphere exhibited an intermediate value. On the other hand, samples stored in 50% Ar-enriched atmospheres and control samples showed a higher cut edge discoloration, compared to samples stored in N2 atmosphere, whereas sample stored in 97% Ar showed intermediate value. Moreover, lettuce stored in 97% Ar best retained ascorbic acid content up to 2 days of storage, but no differences among treatments were detected at the end of storage. At this time samples stored in N2 atmosphere showed the lowest mesophilic load, whereas both 97% Ar and 97% N2 were effective in slowing down yeast and mould. Our results suggest that the effects of argon-enriched atmosphere are quite similar to that of nitrogen, with a lower control of mesophilic bacteria and a better retention of vitamin C. Further investigations are needed to propose argon as an alternative gas in modified atmosphere packaging of fresh-cut lettuce.
Baldassarre, V., Amodio, M.L., De Chiara , M.L. and Colelli, G. (2015). EFFECT OF ARGON-ENRICHED ATMOSPHERES ON SHELF LIFE OF FRESH-CUT 'ICEBERG' LETTUCE. Acta Hortic. 1071, 755-761
'Iceberg' lettuce, controlled atmosphere, non-conventional gas composition, PPO activity, microbial growth, quality