Effects of high-pressure treatment on mume fruit (Prunus mume)

Physical and physiological changes in mume (Prunus mume Sieb. et Zucc.) sub jected to a 10-minute hydrostatic high-pressure treatment at 5, 10, 50, 100 , 150, and 200 MPa were investigated. Mume fruit exhibited substantial inju ry at pressures >5 MPa. AU treatments induced color changes, which became m ore apparent at pressures >100 MPa. Fruit subjected to pressures greater th an or equal to 100 MPa deteriorated and mere rendered commercially unaccept able. After transfer to atmospheric pressure all treated fruit exhibited lo wer CO2 evolution rates compared with control fruit. Only fruit subjected t o 5 MPa exhibited an increase (27 %)in titratable acidity. Ethylene product ion rate in mume fruit was very high, but consistently and dramatically dec reased after treatment, regardless of the pressure applied, The decline in ethylene production was associated with a decrease in ACC oxidase activity. Chemical names used: 1-aminocyclopropane-1-carboxylic acid (ACC).