Biochemical and physical changes in fruits of four guava cultivars during growth and development

Biochemical and physical changes in fruits of four guava cultivars during growth and development were studied. Investigation showed that protein content decreased markedly with fruit growth and development for all cultivars. The maximum level of reduction varied from 0.25 to 0.27%. Moisture content was significantly increased with fruit growth and development in all cultivars. The maximum level varied from 6.2 to 76.0%. Alcohol-insoluble solids (AIS) declined gradually during the initial growing period followed by rapid decline during later stages of development for all cultivars, which differed in their final value (8.67–13.33%). Water-soluble pectin for all cultivars increased gradually with fruit development. The maximum level varied from 0.34 to 0.64%. For all cultivars texture declined gradually during fruit development. The skin colour of the fruit changed gradually from dark green to yellow for all cultivars. Fruits picked before day 106 after fruit set had a reading of more than 30 psi (1 psi ≈ 7.9kPa) which was outside the range of the pressure tester, and thereafter pressure declined rapidly for all cultivars. Fruit volume increased rapidly with fruit development for all cultivars. Softness and yellowness of fruit were associated with lower protein and AIS contents, higher moisture and appreciable amounts of water-soluble pectin.