| dc.description.abstract | The present study was conducted with the aim to determine the effect of cooking temperature
and time on the nutritive value of mangoes, carrots and tomatoes. Fruits and vegetables are
important components of a balanced human diet that provide essential vitamins, minerals and
dietary fiber for our bodies. It is required to use a combination of mangoes, tomatoes and carrot
to enrich ketchup, however the temperature and time required for cooking theses fruits with
minimal loss of nutrients is not defined. Therefore, application of processing methods that will
reduce the water content, as well as inhibit enzyme activities, are crucial to extending shelf life,
avoiding wasting and increasing their availability off season. Thermal treatment or cooking is
one of these processing methods used in this study. The mangoes, tomatoes and carrots were
prepared individually into pulp using a blender. 25ml of the prepared samples was used as
standard weight for the different heat treatments and each sample was labeled according to
related time and temperature that is; 70, 80, and 90°C for 3, 5 and 10 minutes for carotenoids
analysis and 7.0, 75, 80, and 90°C for 5, 10 and 15 minutes for determination of vitamin C. The
water bath was preset to the required temperature and checked with a thermometer to match with
the desired test temperature. The labeled beaker (50 ml) containing 25ml of sample was placed in
the water bath set at the required temperature and time. The samples were then removed, cooked
and analyzed for total carotenoids using the Harvest plus method and vitamin C using the 2,6-
dichlorophenol-indophenol titration method. Statistical evaluation and graphical representation
of the data were done using MS Excel. The results showed that interactions of both factors
(temperature and time) had a significant effect on the vitamin C and total carotenoids, indicating
the significance of their appropriate combination. From the results, cooking mangoes at 90°C for
5 minutes, tomatoes at 80-90°C for 5 minutes and carrots at 70°C for 10 minutes preserves both
the total carotenoids and vitamin and hence can be used to produce ketchup of high quality. The
results show that the interactions of both factors (temperature and time) were very important,
indicating the significance of their appropriate combination. High temperature treatments for
longer holding periods indicate an intensification of degradation of nutrients in the fruits and
vegetables. | en_US |
