Abstract:

Totally 14 pear varieties for juicing were characterized and their suitability for juicing were evaluated. Physical and chemical indicators (total sugar, reducing sugar, titratable acid, soluble solid content, juice yield) ,degree of browning (total phenolics, PPO, OD420nm, L) and sensory evaluation (appearance, taste, smell) were determined. Results showed that the soluble solid content of pear juice ranged from 10.94% to 13.00%, and the titration acidity ranged from 0.062% to 0.76%. The total phenolics and activities of PPO exhibited uneven distribution in the pear. Total phenolics of pear skin were highest, and correlated significantly with OD420nm at 0.05 level and negatively with L at 0.01 level. Similarly, the PPO activities of skin were higher than that of flesh and core, and correlated with OD420nm of the juice. Through comprehensive evaluation of the 14 pear varieties, Jinxiang, Huangjin and Annli were the suitable varieties for juicing.

Key words: pear, juice-processing, browning, total phenolics, polyphenol oxidase