Physico-chemical changes in velvet tamarind (<i>Dialium guineense</i> Wild) during fruit development and ripening

Abstract

Some physical and chemical changes in velvet tamarind (Dialium guineense wild) fruits during development (5th to 11th week), maturation (11th to 13th week) and ripening (13th to 17th week) were studied. The properties investigated during these periods included pod weight, pod diameter, percent fruit portions, sugar and acid composition of the velvet tamarind pulp. Steady changes were recorded in both physical and chemical properties at different stages of fruit development. The single pod weight and diameter increased from mean values of 0.35g and 0.57cm at the 5th week to values of 0.61g and 1.39cm respectively at ripening. The fruit portions maintained steady proportions of about 40%, 37% and 21% for shell, pulp and seed respectively. The values for percent carbohydrate, ethanol soluble sugars and total soluble solids increased significantly (p>0.05) throughout the period of the study, from the 5th week values of 5.80%, 5.30% and 6.25°Brix to values of 35.92%, 29.21%, and 40.01°Brix respectively at ripening (17th week). The sugars identified were glucose, fructose, maltose and sucrose. The titratable acidity increased gradually at first from a value of 1.09% at the 5th week to 3.85% at the 11th week. It then decreased to a value of 3.67% at the 13th week before it rose to a final value to 4.50% at ripening (17th week). The acids identified were tartaric, citric, malic and ascorbic acids. It was observed that the peak period for most acids, sugars and other soluble solids (which are important for the desired flavour of the fruit) is the 17th week.

Keywords: velvet tamarind, fruit, development, Rrpening, acids, sugars, maturity

Nigerian Food Journal Vol. 23 2005: 133-138