Abstract

Baobab (Adansonia digitata L.) powder has high gelling capacity, but its potential has not been exploited. In the present study, baobab powder was assessed as a potential alternative for commercial pectin in jam making. Its gelling ability and potential use was compared to that of commercial pectin in the production of jam from different indigenous fruits available in Tanzania. Jams were produced fromindigenous fruits obtained from various areas of Tanzania including, Smelly-berry (Vitex mombassae), Wild loquat (Uapaca kirkiana) and Marula plum (Sclerocarya birrea) using lemon extract, commercial pectin and baobab (Adansonia digitata L.)powder as sources of pectin. Total soluble solids (TSS) and total titratable acidity(TTA) for fruit pulps and jams were measured to obtain the required acid to sugar ratio for quality jam. Pectin content of the fruit pulps, baobab and lemon extract were also determined. Shelf life of jams stored at room temperature was monitored for six months by determining moisture content, TSS, TTA, and microbiological changes. Sensory evaluation of the jams was performed to assess consumers’ preference among the produced jams. Findings of this study reveal that, TSS ranged from 11.6% in Adansonia digitata L. to 16.9% in Uapaca kirkiana.TTA was highest in Adansonia digitata L. (2.27%) and lowest in Uapaca kirkiana(0.05%). Pectin content in fruits was highest in Adansonia digitata L. (2.56 %) and lowest in Vitex mombassae (0.12%). Jams formulated without addition of pectin were inferior in quality. Commercial pectin and baobab powder produced jams which did not differ significantly (p<0.05) in moisture content, TSS and TTA. Jams formulated with commercial pectin and baobab powder were of acceptable quality up to six months. Sensory evaluation revealed that jam produced from Sclerocarya birrea was significantly (p<0.05) superior in all sensory attributes compared to other fruits. The use of baobab powder as a source of pectin gave high quality jams, which compared favorably with that of commercial pectin.

Key words: Indigenous fruits, jam, baobab powder, pectin.