Pectin fractions in guava (Psidium guajava L.) cultivars ‘Shweta’ and ‘Lalit’

Abstract

Pectin fractions were studied in developing fruits of guava cvs ‘Shweta’ with white mesocarp and ‘Lalit’ with pink mesocarp. Flowers were tagged, fruits were harvested at 10 days intervals and estimated alcohol insoluble solids (AIS) and pectin fractions, (viz. water (WSP), ammonium oxalate (AOP) and alkali soluble (ASP)). Fruits of cultivar ‘Shweta’ contained 3.73 percent, while cultivar ‘Lalit’ had 3.97 percent AIS throughout development period of 132 days. Proportion of AIS in fruits decreased continuously from 62 to 112 days of fruit development and thereafter it remained almost constant in both the varieties. Total pectin (TP) content was significantly higher in cultivar ‘Lalit’ than cultivar ‘Shweta’ throughout the developmental period and attained maximum at 112 days after fruit set. Water soluble pectin was significantly higher in cultivar ‘Shweta’ towards maturity and ripening of fruits. AOP (pectinic acid) content was higher in cultivar ‘Lalit’ with respect to cultivar ‘Shweta’. Pectinic acid increased continuously in cultivar ‘Shweta’ till 122 days (26.02%), thereafter; it decreased up to 132 days coinciding with ripe fruits. As fruit development advancement, ASP (protopectin) of cultivar ‘Shweta’ was found higher than that of cultivar ‘Lalit’.