4. Discussion
The quality of pitaya fruit deteriorated gradually during
postharvest storage, but fresh-cut processing had little adverse
effect on the contents of VC, TSS and TA, all of which are important
quality properties of pitaya fruit. Flesh color is another important
quality characteristic of fresh-cut pitaya fruit, the increase in b*
value is probably owing to the oxidation of total phenolics to
quinones, which can be spontaneously polymerized to form brown
pigments (Degl’Innocenti et al., 2005). In our experiment,
browning color appeared on the surface of fresh-cut pitaya fruit
and made them unacceptable after 4 d of storage. As shown in the
TABC assay, fresh-cut processing inevitably increased the growth
of microorganism in fresh-cut products. Previous studies have reported that commonly the total aerobic bacterial count in freshcut vegetable products varied from 6 to 9 log CFU kg 1 (Ragaert
et al., 2007). All the results of quality evaluation suggested that
different cutting styles didn’t have much adverse effect on the
quality of pitaya fruit during 4 d of storage at 15 C.