Browsing by Author "Abesekara, C.P."

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    Effect of Potassium (KCI) Application on Postharvest Disease Condition and Fruit Quality of Ripe Papaya (carica papaya L.)
    (Uva Wellassa University of Sri Lanka, 2010) Rathnayake, R.P.S.H.; Sarananda, K.H.; Abesekara, C.P.
    Fusarium is one of the most destructive postharvest diseases of the papaya variety red lady. Fusarium species are a weak pathogen and there are several species causing diseases, where Fusarium moniliform is the most common species causing fruit rot in tropical countries. Initially disease symptoms appear as circular water-soaked lesions on ripening fruit which later becomes depressed. At the advanced stage of disease development, the soft rotted area is covered with a white mycelial mat of the fungus. Fungus also penetrates into the tissues of the fruit, causing it to become darker and softer than the surrounding tissues. Nutritional conditions under which the plants are grown have shown significant impact on the disease severity and disease occurrence. In this study four treatments (0%, 2%, 4% and 6% of KCI) were applied as spray solutions in to the papaya fruits three weeks before harvesting. Treatments were arranged in a Randomized Complete Block Design (RCBD). After fruits were harvested they were inoculated with the fungi and kept under the ambient conditions. Then disease severity, disease lesion development and time taken to disease occurrence were observed. Fruit quality parameters were also measured such as TSS (Total Soluble Solids), pH, peel color, flesh color and fruit firmness. Application of 4% KCI significantly reduced the Fusarium rot than other treatments and it also resulted in fruits having the highest pH and TSS values. Treatments with 4% and 6% KCI gave the best flesh color (dark red / red) and highest fruit firmness at the table ripe stage. There was no significant impact of the 4% and 6% KCI on decreasing the percentage of weight loss during ripening and increasing the peel color development. In this study it was found that the continuous increase of KCI levels, beyond an optimum level caused negative impact on fruit quality. Key words: Fusarium fruit rot, Red Lady papaya, Potassium, Fruit quality, Disease severity
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    Incorporation of Durian (Durio zibethinus) Seed Gum to Fruit Nectar as a Substitute for Xanthan Gum
    (Uva Wellassa University of Sri Lanka, 2010) Nawarathne, N.H.N.T.; Navarathne, S.B.; Abesekara, C.P.
    Xanthan gum is a widely used thickening agent which enhances the customer acceptability in ready to serve fruit nectar industry. This study determines the possibility of using durian seed gum as a substitute for xanthan gum to prevent layer separation. Blanched and raw durian seed slices were pulverized and dried in 3 methods; sun drying, oven drying and cooling in dehumidifier (CDH process). Six quantity levels (1, 2, 3, 4, 5 and 6 g) of those seed particles were mixed with 100 ml of hot (80 °C) and normal water to get the gum. Treatment with the least quantity of seed particles, having a viscosity similar to the 0.5% xanthan gum solution (6 centipoise) was selected as the best preservation method. Gum formed by mixing 5 g of raw CDH processed seed particles in normal water had a viscosity of 6 centipoise. This was used in experiment 2, where durian seed gum was incorporated at 8 dosage levels (5 - 40% in 5% increments) and compared with the fruit nectar added with fresh seed gum and without any added thickening agents. Visual observations were taken for layer separation for 7 days at 24 hrs intervals. No layer separation was observed in both fresh and CDH processed gum added nectar at 20 % level and they were similar to xanthan gum incorporated nectar soon after the preparation (a=0.05). To evaluate the keeping quality, fresh seed gum, CDH processed seed gum and xanthan gum added fruit nectar samples were stored in ambient and refrigerated conditions for three months. In sensory analysis, layer separation and overall acceptability of fresh and CDH processed gum added non-cooled nectars and xanthan gum added cooled and non-cooled nectars changed with time. But sensory properties of fresh seed gum and processed seed gum added cooled nectars did not changed significantly with time. Key words: Durian seed gum, Xanthan gum, Thickening, Dry, Dehumidifier, Viscosity, Layer separation
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    Value Addition to Bitter Gourd (Momoedica charantia)by Preparing a Low Bitterness Spread
    (Uva Wellassa University of Sri Lanka, 2010) Wijekoon, W.M.S.U.K.; Ekanayaka, S.; Abesekara, C.P.
    This study was conducted to find a suitable processing method to make a low bitterness spread to increase the year round availability and consumer preference of bitter gourd (Momordica Charantia). The variety Thinnaweli white was selected to prepare the spread due to its lower blanching time (2 minutes), higher edible portion and ascorbic acid content, less acidity, higher market availability and consumer preference. Blanched bitter gourds slices were prepared into a paste and mixed with 0%, 20%, 40%, and 60% tomato paste. In the sensory evaluation, spread having 60% bitter gourd paste and 40% tomato paste was highly accepted except for color. This product had a pH of 4.47, 6.3 of TSS, moisture content of 90.7% and orange color. Thus this ratio was selected to determine the best pre treatment method. Five pre treatment methods were tested to reduce the bitterness in bitter gourd spread. Each method consists of washing for 10 minutes and blanching for 2 minutes. Washings were done by using tap water, 2% brine solution, coconut water and 2% brine with coconut water. Hot water and 2% brine solutions were used for blanching. All products were tested for physicochemical, microbiological and sensory qualities. Results revealed that within the treatments pH and ascorbic acid content declined during storage while TSS and TA content increased. There was no color changes observed after one month. Least number of microbial colonies after three months were present on 2% brine washed and 2% brine blanched and 2% brine with coconut water washed and 2% brine blanched bitter gourd spreads. In the sensory evaluation 2% brine washed and 2 % brine blanched spread was highly accepted. Thus, 2% brine washing and 2% brine blanching can be recommended as the best pretreatment to get the lowest bitterness spread by mixing with tomato paste at 60 : 40 ratio. Key words: Bitter gourd, Thinnaweli White, Tomato, Blanching, Brine solution, physicochemical attributes