Biochemical Changes Associated with Growth and Development of Grape Var. Bangalore Blue

Pre-harvest Biochemical changes in grape var. Bangalore blue was studied for fixing the maturity standard of this fruit. The physico-chemical constituents viz., length, volume, weight, acidity, carbohydrate, vitamin C, minerals, anthocyanin and tannin content were studied at certain intervals from seven days after flowering to mature stage. During the growth and development the average length, diameter, volume and weight of berry increased. The berries were green at early stages and developed a deep blue colour at the mature stage. The extraction of this pigment with acidic methanol revealed its absorption maxima at 540 μ and the optical density was highest at the mature stage. Acidity of the developing fruits increased upto 48 days of berry growth and then started decreasing. The concentration of vitamin C was in trace amount at early stages and it was 1 mg per 100 gm fruit at mature stage. T. S. S. increased with berry development. The concentration of tannin was also in the increasing order with maturity. At mature stage the concentration of total, reducing and non-reducing sugars were found to be 6.2, 3.6 and 2.5 per cent respectively, whereas the concentration of sucrose, glucose and fructose were 2.3, 3.0 and 0.5 per cent respectively. The concentration of calcium, magnesium and potassium decreased with maturity and the content of iron and phosphorus remained more or less constant throughout development. The grape var. Bangalore blue should be harvested after 90 days of flowering to obtain optimum mature and quality fruits under Bangalore conditions.