Analysis of physicochemical factors related to the automatic pellicle removal in Korean chestnut (Castanea crenata).

Analyses were carried out for condensed tannin content, soluble sugar content, color, firmness, and peeling ratio of the pellicle of 14 varieties of Korean chestnut. The correlation between these physicochemical components and the peeling ratio was measured. The total soluble sugar content ranged from 4.20 to 11.83%. Condensed tannin contents in the inner and outer chestnut shells were 7.83-71.42% and 0.31-2.04%, respectively. In the outer shell of chestnut, CIE L* value was 26.98-33.34, CIE a value was 7.56-14.90, and CIE b value was 7.36-15.67. Firmness of chestnut was 4.41-9.20 kg. Peeling ratio of the pellicle by the peeling machine was significantly different with variety. The average peeling ratio was 63.79%, and that of the Okkwang variety was the highest at 85.29%. A negative correlation was found between tannin content of inner shell and peeling ratio (r = -0.57), but the correlation coefficients between other components and the peeling ratio were not significant.