Biochemical changes in guava (Psidium guajava) fruits during different stages of ripening

The present study was undertaken at Experimental Orchard of the Division of Fruit Science, Faculty ofAgriculture, Udheywalla, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, J & K, India. The study was undertaken in seven guava (Psidium guajava L.) cultivars at three different developmental stages, viz. green mature stage (GMS), half ripe stage (HRS) and full ripe stage (FRS). The results of the present study revealed that with the advancement of fruit maturity at different stages, the total soluble solids (TSS), sugar (total sugars, reducing and non-reducing sugar), ascorbic acid contents increased significantly while, during fruit ripening acidity and pectin decreased. Of all the cultivars studied, L-49 showed highest TSS (12.25 degrees B) followed by Allahabad Safeda (10.75 degrees B). However, total sugar (8.50%) and ascorbic acid (265.09%) were also maximum in L-49 followed by Allahabad Safeda at FRS, L-49 showed minimum acidity (0.26%) and maximum pectin content (0.77%) followed by (0.23 and 0.73%, respectively) in Allahabad Safeda. Pectin methyl esterase (PME) activity increased progressively in all the cultivars up to HRS and subsequently decreased at FRS. Maximum PME activity was found in L-49 (56.25 units/g.fwt) at HRS whereas, it showed a decrease at FRS (52.25 units/g fresh weight (FW) followed by Allahabad Safeda and Lalit. It is thus concluded that L-49 was superior among all the commercial cultivars of guava grown under sub-tropic condition followed by Allahabad Safeda and Lalit.