Papers by Tilahun Workneh
Journal of Food Science and Technology-mysore
The major objective of this study was to explore the significance of an integrated agro technolog... more The major objective of this study was to explore the significance of an integrated agro technology in maintenance of postharvest quality of tomato. Preharvest ComCat® treated tomatoes and untreated controls were evaluated for changes in physiological, chemical, and microbiological quality during storage at 13 °C and room temperature (16.9–25.2 °C) and a relative humidity of 34–76%. Effects of disinfection coupled with packaging were evaluated. Physiological weight loss, total soluble solids, peroxidase activity and marketability were maintained better in anolyte disinfected tomatoes. At harvest, ComCat® treated tomatoes had lower pH, glucose and microbial populations, and higher total soluble solids, total titratable acids, sucrose, peroxidase activity than controls. The total soluble solids were better retained in ComCat® treated tomatoes than in control, while the sucrose and glucose contents remained lower after ripening. Peroxidase activities were lower in ripening ComCat® treated tomatoes, and difference in polygalactronase activity was only visible after 30 days. The microbial populations were lower in ComCat® treated fruit. Marketability of ComCat® treated tomatoes was better than that of the control. Integrated technology covering preharvest ComCat® application, disinfection with anolyte water and packaging combined with cold storage at 13 °C maintained the superior quality of tomato.
Journal of Food Quality, 2003
Abstract Carrots (Daucus carota L.) were dipped in anolyte water for 5, 10 and 20 min or in 100 μ... more Abstract Carrots (Daucus carota L.) were dipped in anolyte water for 5, 10 and 20 min or in 100 μg/mL chlorine supplemented water for 20 min to study the effect of anolyte water as an environmentally friendly alternative disinfecting measure for carrots prior to packaging and storage. Packages of carrots were stored at 1 ± 0.5C and ambient temperature (17.5–31.4C). The anolyte water dipping treatment was found to be as effective as chlorinated solutions in controlling growth of aerobic bacteria, molds, yeasts and coliform bacteria during storage. There were no significant differences (P < 0.05) in microbiological changes on carrots dipped in anolyte water for 5, 10, and 20 min. Exposure of carrots to anolyte water for as short as 5 min can be used effectively to reduce and limit growth of aerobic bacteria, molds, yeasts and coliform bacteria. Losses in firmness and physiological weight were higher in carrots dipped in chlorinated water. Anolyte water treatments had no effect on total soluble solid content, pH value, firmness and the overall visual appearance of carrots.
Journal of Food Science and Technology-mysore
Three processing and six fresh market tomato varieties harvested at “mature green” stage were eva... more Three processing and six fresh market tomato varieties harvested at “mature green” stage were evaluated for changes in quality. The total soluble solid, titratable acidity, sugar-acid ratio, pH, ascorbic acid content, colour and firmness were assessed. The storage room air temperature and relative humidity varied from 15.4○C to 16.2○C and 34.8% to 52.4%, respectively. At harvest, Marglobe Improved had better chemical quality characteristics compared with the other five fresh market varieties while towards the end of the storage period, chemical quality characteristics were maintained better in Fetane. The highest pH and sugar/acid ratio were obtained in Metadel compared with all other varieties throughout the storage period. Among the processing tomato variety, Roma VF had better chemical quality than other two processing varieties. Melkashola had the highest total soluble solid content in the group. Although the processing varieties ripened earlier than fresh market ones, they were notably firmer with better quality. The processing types were better in their chemical quality than fresh market genotypes. The fresh table tomato varieties had higher sugar-acid ratio and vitamin C. Marglobe Improved and Metadel could be selected in favor of higher nutritional quality whereas Fetane could be considered for maintenance of better overall quality characteristics.
Journal of Food Science and Technology-mysore
Five hot pepper varieties were grown at Haramaya University Research Farm, Dire Dawa, Ethiopia. T... more Five hot pepper varieties were grown at Haramaya University Research Farm, Dire Dawa, Ethiopia. The experiment was undertaken using completely randomized block design (RCBD) with three replications. Green peppers were stored under ambient and evaporatively cooled conditions. Significant (P ≤ 0.05) differences were observed among cultivars and storage conditions in changes in quality of pepper. Storage at ambient conditions resulted in high weight loss and rapid deterioration in chemical composition. The highest and lowest moisture contents were recorded in Melka Eshet and PBC 600, respectively. Evaporative cooler reduced weight loss and maintained higher levels of pH, ascorbic acid and marketability. The highest weight loss was recorded in Melka Dima stored at ambient condition. The lowest weight loss and highest ascorbic acid content was obtained in Mareko Fana stored in evaporative cooler. After 16 days of storage, all pepper fruits stored at ambient condition were unmarketable while those stored in evaporative cooler were kept up to 28 days. The highest pungency level was observed in ambient storage environment than in evaporative cooler. Evaporative cooling was shown to improve shelf life by four-fold compared to the ambient condition. The shelf life of pepper was improved in all varieties tested while the quality characteristics were maintained better in Mareko Fana than in the other varieties when harvested at mature-green stage and stored under evaporatively cooled storage.
Uploads
Papers by Tilahun Workneh