Physiology and microbiological quality of fresh-cut mango cubes as affected by high-O-2 controlled atmospheres

摘要

Preliminary study showed that among 40- to 100-kPa O-2 atmospheres, 60-kPa O-2. reduced the respiration of fresh-cut 'Carabao' mango cubes the most when held at 5 degrees C or 13 degrees C for 42 h. Therefore, the effects,of 60-kPa O-2 on the physiology and microbial quality of fresh-cut 'Carabao' and 'Nam Dokmal' mango cubes were determined and compared with those held in air. The high-O-2 atmosphere reduced the respiration rate of 'Carabao' mango cubes stored at 5 degrees C but stimulated the rate after 2 d of storage at 13 degrees C. Browning of 'Carabao' cubes was accelerated by 60-kPa O-2 at 13 degrees C. With 'Nam Dokmai' cubes, the high O-2 had no effect on respiration rate, browning, and incidence of water-soaked appearance at 5 degrees C and 13 degrees C. The high O-2 did not affect texture or ascorbic acid content of 'Carabao' and 'Nam Dokmai' mango cubes at either temperature. Counts of lactic acid bacteria and molds were below the detection level (2.4 log colony-forming units [CFU]/g) during storage at both temperatures. However, 60-kPa O-2 stimulated the growth of mesophille aerobic bacteria on 'Carabao' cubes and yeasts of 'Nam Dokmai' cubes at 13 degrees C. The increased microbial count may have been due to the higher pH of cubes stored in 60-kPa O-2 at 13 degrees C, than at 5 degrees C or in air. Within 'Nam Dokmai' mango cubes, the predominant genera In mesophilic aerobic bacteria were Enterobacter, Klebsiella, and Pantoea and in the yeasts were Candida, Cryptococcus, and,Rhodotorula. These results indicate that 60-kPa O-2 is not desirable for mango cubes when held at 13 degrees C.