Quality of Fresh-cut Pineapple Cubes Treated by Either High Pressure or Thermally Blanching

The quality of fresh-cut pineapple cubes was assessed following treatments of either high pressure of 400 MPa for 5 min or thermal blanching in 97 °C water for 3 min and subsequent storage. Both treatments reduced the microbial counts from 4.5 log cfu/g for bacteria and 4.9 log cfu/g for fungi to non-detectable levels on pineapple cubes. Pressure treated cubes presented a similar color index (L* and b* values), rate of electrolyte leakage from tissue slices, and texture as untreated cubes. Thermally blanched cubes showed lower b* values and a higher electrolyte leakage rate compared to the untreated cubes. A microstructural study revealed that cell wall disruption by the high pressure treatment was caused on only one cut side of the cubes but not on the other cut sides. During storage of pineapple cubes in modified atmosphere packages at 1 °C for 6 days, bacterial and fungal counts increased to approximately 5 log cfu/g on untreated samples but remained at non-detectable levels on either pressurized or blanched samples. The high pressure treatment induced color deterioration with the decrease in L* and b* values, increased the rate of electrolyte leakage, and changed the texture of pineapple cubes relative to untreated samples during storage, but these quality changes were less when compared with blanched samples. These results suggest that the high pressure application for fresh-cut pineapple may be commercially feasible as an alternative to thermal blanching.