Effect of thermal shock cycling on storage stability and quality of fresh-cut potato

Abstract

To enhance the storage stability and quality of fresh-cut potato, potato cubes with dimensions of 1 x 1 x 1 cm(3), 2 x 2 x 2 cm(3), and 3 x 3 x 3 cm(3) were blanched at 90 degrees C for 15, 30, or 45 s, followed by soaking in ice-water for 1 min; the treatment was repeated for up to six cycles. The 2 x 2 x 2 cm(3) and 3 x 3 x 3 cm(3) potato cubes subjected to six thermal shock cycles for cycling times of 30 s and 45 s showed significant lowering of the browning index during storage at ambient temperature. The 1 x 1 x 1 cm(3) potato cube was most highly susceptible to browning, although repeated thermal shock cycling reduced the development of browning. A higher number of thermal shock cycles effectively decreased the polyphenol oxidase (PPO) activity of the potato cubes. The reduction of the PPO activity was more pronounced as the sample size decreased. The hardness of the raw and fried samples decreased, along with reduction of the melting enthalpy, as the treatment time and number of cycles increased. The browning index of the fried potato declined as the number of cycles increased.