Interaction of hot water treatments and controlled atmosphere storage on quality of 'Fuyu' persimmons

A matrix of 80 hot water treatment (HWT) temperatures/durations and controlled atmosphere (CA) storage regimes were tested for effects on respiratory activity, ethanol (EtOH) and acetaldehyde accumulation (AA), and storage quality of 'Fuyu' persimmon. Fruit were hot water treated at 47 degrees C for 45, 60, 90, or 120; min, 50 degrees C for 30, 45, 55, or 60 min; 52 degrees C for 20, 30, 40, or 50 min; 54 degrees C for 15, 20, 25, or 30 min; and as a control treatment, 20 degrees C in air. After treatment, fruit were stored in air, 5% CO2: 2% O-2: 10% CO2: 2%, or 100% N-2 for 6 weeks at 0 degrees C. Fruit quality was assessed after a 5 day shelf-life at 20 degrees C. Respiration (CO2 production) was measured on fruit held at 20 degrees C following HWT. After storage, C2H4, CO2, EtOH and AA production were measured on selected treatments at 0, 1, 3, and 5 days at 20 degrees C. Hot water treatment alone, or in combination with CA, ameliorated chilling injury (CI). External browning symptoms developed on fruit in some treatments upon removal from storage, severity of symptoms being positively correlated with increasing HWT duration, and most severe in the CA treatments, especially the 100% N-2 CA. CO2 production increased after HWT and then decreased (within 24 h), but remained at a higher level than the non-heated control. Following storage, CO2 production rates of fruit from all treatments were relatively similar by the end of the 5 days at 20 degrees C. EtOH and AA production were the greatest in the 100% N-2 treatment. Fruit under the longer HWT durations had lower CO2 and C2H4 production after storage and accumulated more EtOH and AA during the 5 day shelf life. These were also the treatments resulting in the lowest levels of CI. Possible mechanisms of HWT and CA alleviation of CI in 'Fuyu' persimmon are discussed. (C) 1997 Elsevier Science B.V.