POSTPROCESSING DIP MAINTAINS QUALITY AND EXTENDS THE SHELF LIFE OF FRESH-CUT APPLE

摘要

An aqueous solution with hypochlorite as a sanitizer, sodium erythorbate (isoascorbate), n-acetylcysteine and 4-hexylre-sorcinol as reducing and anti-browning agents, and Ca propionate as a firming agent was developed for postprocessing dip of fresh-cut 'Gala' apple. The additional effect of edible coating materials to the aqueous solution of additives was also investigated. The edible coating film-forming agents were soybean oil emulsion, chitosan and carboxymethyl cellulose (CMC), which were expected to form a protective layer on the cut surface of the apple wedges, decreasing water loss and other deteriorating factors due to cutting. Apple slices were dipped in aqueous solutions of sanitizer, with or without anti-browning and firming agents (additives), and with or without film-formers. Treated slices were then allowed to drain for 1 h at 5.5 °C before placement in perforated polyethylene bags (20 x 18 cm, thickness 30 m, with ten 1.5 mm holes) and storage at 5.5 °C for up to 14 days. Slices dipped in water (control, containing hypochlorite only) lost marketable quality within a day, because of severe browning accompanied by a sharp decrease of hue angle (h°_(ab)), and lightness (L*), and an increase in a* and b* values. Slices dipped in theaqueous solution plus additives maintained cut surface color, inhibited ethylene production, maintained firmness, and maintained the major aroma of apple. However, these slices exhibited green mold after 8 days of storage. Addition of soybean oil emulsion reduced water loss, whereas chitosan and CMC did not, although water loss was not a problem for polyethylene packaged products. The wedges dipped in coatings lost several major volatiles of apple compared to those dipped in the aqueous solutions. These results suggest that a dip with a sanitizer, firming agent, and reducing/anti-browning agents is beneficial of fresh-cut apple quality. Addition of film-formers led to loss of important aroma compounds while chitosan did not reduce decay as has been reported for whole fruits.