Variation of carbohydrate composition of two forms of fruit from jack tree ( Artocarpus heterophyllus L.) with maturity and climatic conditions

Abstract

Soft and firm varieties of jackfruit of three stages of maturity (7–8, 10–12, and 14–16 weeks), harvested from the central, western and eastern parts of Bangladesh, were analysed. The dry matter content of perianth and seed of the soft and firm varieties increased from 10.0 to 32.0% and 19.0 to 52.0%, respectively, while the ash content decreased from 5.7 to 2.0% and 4.9 to 1.5%, respectively, on a dry matter basis. The free sugars of jackfruit samples increased with maturity from 1.5 to 10.5% and 1.4 to 5.2% of their dry matter for the soft and firm varieties, respectively. In all cases varying proportions of glucose, fructose and sucrose were the major sugar constituents. The starch content of the perianth samples increased from 7.8 to 47.0% and from 9.0 to 50.5%, on a dry matter basis for the soft and firm varieties, respectively, whereas, that for seed increased up to 65.0 and 59.0%, respectively. Microscopic examination of the samples showed the perianth to contain thin-walled cells packed with starch granules, some organized into distinct clusters. From both the chemical and histological studies, it appeared that the starch content of both perianth and seed of soft and firm varieties of jackfruit samples gradually increased with the increase of maturity. The total dietary fibre varied from 42.0 to 55.0% in the perianth. However, that of seed changed very little. The results show that the starch and total dietary fibre contents of jackfruit are higher than those of other fruits and vegetables of Bangladesh. ©