Potential increasing in the cold‑storage of 'Fukuhara' loquat using heat treatments

Abstract

The objective of this work was to evaluate the efficiency of heat treatments on the potential improvement of the cold-storage of 'Fukuhara' loquat, and the effects of these treatments on the quality and on physicochemical and biochemical properties of fruits. The treatments applied were: storage at 1°C for 60 days (control); storage at 5°C for 60 days (standard); storage at 5°C for 7 days, and at 1°C for 53 days; storage at 10°C for 7 days, and at 1°C for 53 days; intermittent heat, in cycles of 6 days at 1°C + 1 day at 15°C, for 60 days; fruit conditioning at 37°C for 3 hours, and at 1°C for 60 days; and fruit conditioning at 37°C for 6 hours, and at 1°C for 60 days. The fruits were kept at 85–90% relative humidity, over the whole storage. The following parameters were determined: pulp firmness, incidence of internal browning, titrable acidity, pH, content of soluble solids, ascorbic acid and phenolic compounds, activity of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD), in evaluations after 15, 30, 45 and 60 days of storage. There was a correlation between firmness level and POD activity, after 60 days of cold storage. Intermittent heat and at 37°C for 3 hours were efficient in controling internal browning in fruit pulp. Heat treatments did not prevent the increase of pulp firmness. Heat treatments increase cold-storage potential of loquat without changing fruit physicochemical properties.