Abstract:
Tomato (Lycopersicon esculentum Mill.) is among the most perishable horticultural products
and, after harvest management of this crop is a crucial task to minimize losses and extend their
shelf life. This work was conducted to determine effect of edible coating material, coated at
different harvesting stage of tomato fruits to prolong their storage life with desired
physicochemical properties. Fruits of a fresh tomato variety Barbados were obtained from
Awassa Jittu farm, Ethiopia. Fruits were harvested at mature-green, turning and light red
stages. Treatments from three maturity stages were coated with two types of edible coating
materials (Pectin and Chitosan) and laid out in factorial arrangement. of completely randomized
design with three replications. Sample fruits were evaluated periodically for different changing
parameters with storage time, including weight loss, color, firmness, pH, total soluble solids
(TSS), titratable acidity (TA), TSS to TA ratio, ascorbic acid, total phenolic content, lycopene
and extent of disease incidence and severity. Results of the study indicated that, coating of
tomato fruits either with chitosan or pectin was found to delay the ripening process and maintain
fruit quality. All combined treatment combinations resulted in a significant delay in the change
of weight loss, TA, TSS, disease incidence, disease severity and ripening index as compared to
that of uncoated control fruits. Accordingly the shelf life was extended during ambient storage at
average temperature 220
C+1 and 74+1 % relative humidity. Maximum shelf life was observed
for tomatoes harvested at turning stage coated by pectin (17days) followed by chitosan coated
fruit at harvested at turning stage (16 days). Minimum shelf life was for uncoated fruits at the
same harvesting stage (10 days). Moreover, in respect of antioxidant properties of certain
compounds, coated tomato fruits revealed higher amount of ascorbic acid, lycopene and
phenolic contents. Fruits coated with either chitosan or pectin at turning maturity stage showed
the best result in almost all quality parameters. Thus, it can be concluded that choosing the
optimum stage of maturity of fruits plays a key role in order to achieve the full objectives of
coating as it has a great influence on the quality attributes of tomato fruits. The shelf life of
uncoated fruits was on average around 10 days as opposed coated fruits stayed sound for about
17 days. This provides an advantage of prolonging the shelf life of tomato fruit by one week with
sole application of edible coating materials. The result can be very promising, if coating
materials combined with low temperature storage.
