Microbiological and Physicochemical Quality of Enzymatically Peeled Persimmon Fruit for Fresh-cut Slices

Abstract

Enzymatic peeling of ‘Fuyu’ and ‘Tone-wase’ persimmon fruit was conducted for production of fresh-cut slices, and the microbiological and physicochemical quality of enzyme-peeled fresh-cut slices was compared with that of slices manually peeled with a knife. The enzymatic peeling process involved a porous treatment of the peel, heating at 100 °C for 45 s, infusion with 3% protopectinase at 37 °C for 3 h, and rinsing under running tap water. Initially, the peel of ‘Fuyu’ persimmon fruit had microbial counts ranging from 3.9 to 4.2 log cfu·g−1 and a diverse microflora. The heating treatment before the enzymatic peeling process reduced the microbial counts in both the peel and flesh of all fruits to levels below the lower limit of detection. After the enzyme infusion followed by gentle rinsing with tap water, microbial counts of enzyme-peeled fruit were close to or below the level of detection. When microbial contamination of enzyme-peeled and knife-peeled ‘Fuyu’ and ‘Tone-wase’ persimmon slices was compared, the bacterial counts and diversity of bacterial and fungal flora were less in enzyme-peeled slices than in knife-peeled slices. With ‘Tone-wase’ slices, the color index, pH, and texture were unaffected by enzymatic peeling, except for surface lightness, which was lower in enzyme-peeled slices than in knife-peeled slices. These results indicate that enzymatic peeling could be an alternative to knife-peeling of ‘Tone-wase’ persimmon fruit for fresh-cut production from the point of microbiological and physicochemical quality.