Product Development: Nutritional Value, Processing and Utilization of Indigenous Fruits from the Miombo Ecosystem - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 303

significantly during the production of jam ( P < 0.001). The vitamin C contents
of fresh pulp and final jam of Strychnos cocculoides were 82.5 and
7.05 mg/100 g, respectively. The huge loss was caused by pressing and heating
during jam preparation (Krige et al. , 2006). Klopotek et al . (2005) observed
that major food nutrients, such as ascorbic acid, total anthocyanins and
hydrophilic antioxidant capacity declined during the processing of strawberries
to different products. The greater reducing sugar content in Strychnos jam was
due to the sucrose added during production of the jam. The added sugar
undergoes hydrolysis to fructose and glucose during heating, in effect
increasing the level of reducing sugar in the final product. Zafrilla et al . (2001)
also found a decrease in flavonol after processing raspberry jam.

16.5 Consumer Evaluation of Indigenous Fruit Products

The involvement of consumers is critical in determining and identifying products
which have a greater chance of being accepted by rural, peri-urban and urban
communities. Consumer assessment of some of the fruit products has been
undertaken in southern Africa. In Malawi, eight juices sweetened with different
amounts of sugar were tested organoleptically by a 16-member panel, who
largely preferred juices with a sugar content of 10% (weight/volume) (Saka et al .,
2001); individual preferences were not significantly different from the overall
preference ( P > 0.05). Consumer evaluations of two different fruit jams indicated
that Strychnos cocculoides jam was significantly superior to Uapaca kirkiana jam
(Saka et al ., 2001). S. cocculoides jam was most preferred by the majority of
consumers, who evaluated the product because the jam had better taste, flavour
and texture. These quality attributes, including greater ease of spreading on
bread, accounted for greater variation in consumer preference for S. cocculoides
products. Pulp squeezed from Uapaca kirkiana fruits make as good a jam as S.
cocculoides (Saka et al. , 2007). However, when left at room temperature or
under refrigeration, the S. cocculoides jam remained unspoiled for over 3 months
while the U. kirkiana jam exhibited fungal growth within a week at room
temperature and after 4 weeks of refrigeration. The longer shelf life of the
Strychnos jam was attributed to its higher acid content (Saka et al ., 1992).
Ndabikunze et al . (2000) reported that all fruit jams tested in a Tanzanian
study were acceptable to consumers. The jams from Adansonia digitata and U.
kirkiana were more strongly preferred (score 8) in all sensory attributes than
that from Tamarindus indica (score 6-7). Mixing A. digitata pulp with Hibiscus
sabdariffa produced a mixed jam with a pleasant sweet-sour taste. The
banana-baobab mixed jam (mixing ratio 2:1) was most preferred ( P

0.05)
for colour, while banana-baobab (3:1) jam was ranked first for spreadability.
Interestingly, A. digitata juice was more preferred than the tamarind juice. To
expand the utilization of A. digitata in juice and jam-making, its pulp could be
used in small proportions, since it forms a very thick gel. Better methods of
extracting baobab powder should be identified in order to minimize the
amounts of foreign substances such as sand particles, which affect the quality
of the final product (Ndabikunze et al ., 2000).