Influence of CO2 and C2H4 Adsorbents to the Symptoms of Internal Browning on the Packaged ‘Silver Bell’ Pear (Pyrus communis L.)

Abstract

After harvesting, pears undergo numerous biochemical processes and frequently fail to reach acceptable quality. The uses of packaging and ethylene (C 2 H 4 ) absorber are regarded as well-known ways to solve that problem. However, accumulated CO 2 in the package can promote the symptoms of internal browning on pear flesh also exacerbated by too low O 2 concentrations. To inhibit the symptoms in ‘Silver Bell’ pear for a long period, we utilized CO 2 adsorbent, CO 2 adsorbent plus C 2 H 4 adsorbent, and without both adsorbents in a bag to investigate their effects on internal browning development for 7 months in cold-storage. We found both adsorbents successfully reduced CO 2 and C 2 H 4 levels even though the incidences were visually found at 3 months of storage. Most severe internal browning was observed on CO2 adsorbent-untreated pears under high CO 2 levels (7-9%) increasing since the beginning of storage. Therefore, there were no significant differences on the color and flesh firmness among the treatments, except controls, during cold-storage. Internal browning-affected pears showed harder flesh, greener and darker color compared with unaffected pears. Interestingly, control samples also suffered internal browning under low CO 2 (̴ 0.1%) and high O 2 (̴ 20.5%) concentrations after 5 months in storage with medium damage levels. We conclude that the uses of CO 2 and C 2 H 4 adsorbents successfully lowered CO 2 and C 2 H 4 levels in the bags during cold storage, but the both failed to prevent an internal browning development because too long storage period eventually caused internal browning.