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Social and Behavioral Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

2002

Selected Works

Post-harvest Technology and Management

Articles 1 - 5 of 5

Full-Text Articles in Social and Behavioral Sciences

Viscoelastic Properties And Changes In Pasting Characteristics Of Trifoliate Yam (Dioscorea Dumetorum) Starch After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh Sep 2002

Viscoelastic Properties And Changes In Pasting Characteristics Of Trifoliate Yam (Dioscorea Dumetorum) Starch After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh

Professor Emmanuel Ohene Afoakwa

Studies were conducted on the viscoelastic properties, as well as the changes in pasting characteristics, of trifoliate yam, Dioscorea dumetorum, starch during post-harvest hardening of the tubers. A 3x4 factorial experiment with blanching treatment time (0, 15 and 30 s) and storage time (0, 12, 24 and 36 h) as the respective variables was performed. The samples were evaluated for pasting temperature, viscosity at 95 _C, viscosity at 95 _C-Hold, viscosity at 50 _C and viscosity at 50 _C-Hold, as well as their changes during storage of the tubers, to determine the starch behaviour of the D. dumetorum tubers during …


Textural And Microstructural Changes Associated With Post-Harvest Hardening Of Trifoliate Yam (Dioscorea Dumetorum) Pax Tubers, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh Aug 2002

Textural And Microstructural Changes Associated With Post-Harvest Hardening Of Trifoliate Yam (Dioscorea Dumetorum) Pax Tubers, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh

Professor Emmanuel Ohene Afoakwa

The textural and microstructural changes associated with the post-harvest hardening phenomenon of Dioscorea dumetorum tubers were studied to determine how texture relates to microstructure during the hardening process. A 2x2x4 factorial experiment with sample treatment,storage conditions and storage time as variables was performed. The tubers were harvested,matured and stored under prevailing tropical ambient conditions (28 _C) and cold room conditions (4 _C) for the study. All the samples were evaluated for their hardness (peak force) and adhesiveness (curve areas). Starch microscopy was done on the freshly harvested tubers,hardened tubers and tubers stored under low temperature conditions (4 _C) during the …


Changes In Cell Wall Constituents And Mechanical Properties During Post-Harvest Hardening Of Trifoliate Yam Dioscorea Dumetorum (Kunth) Pax Tubers, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh Jul 2002

Changes In Cell Wall Constituents And Mechanical Properties During Post-Harvest Hardening Of Trifoliate Yam Dioscorea Dumetorum (Kunth) Pax Tubers, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh

Professor Emmanuel Ohene Afoakwa

In an attempt to investigate the changes leading to the rapid post-harvest hardening of the white cultivars of Dioscorea dumetorum tubers, alterations in the plant cell wall constituents and mechanical properties of the tubers were monitored. A 4x2 factorial experiment with storage time (0, 24, 48 and 72 h) and storage conditions [cold room (4 _C, 85–100% RH) and tropical ambient (28 _C, 62–100% RH)] as variables were performed. Harvested tubers were stored for 24, 48 and 72 h under 4 and 28 _C. Changes in mechanical properties, acid and neutral detergent fibres, lignin, cellulose and hemicellulose contents were monitored. …


Changes In Rheological Properties And Amylase Activities Of Trifoliate Yam, Dioscorea Dumetorum, Starch After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh May 2002

Changes In Rheological Properties And Amylase Activities Of Trifoliate Yam, Dioscorea Dumetorum, Starch After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh

Professor Emmanuel Ohene Afoakwa

Changes in rheological properties and amylase activities occurring in trifoliate yam, Dioscorea dumetorum, starch after harvest were investigated. Trifoliate yam tubers were harvested and stored under tropical ambient (28 _C) and cold room conditions (4 _C) for 12, 24 and 36 h. The D. dumetorum starches were extracted from the tubers under study and samples were evaluated for changes in their rheological properties (paste characteristics) during storage and to study the action of amylases on D. dumetorum starch after harvesting. The post-harvest activities of a and b-amylases were also studied to evaluate their rate of action on D. dumetorum starch. …


Biochemical And Textural Changes In Trifoliate Yam Dioscorea Dumetorum Tubers After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh May 2002

Biochemical And Textural Changes In Trifoliate Yam Dioscorea Dumetorum Tubers After Harvest, Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh

Professor Emmanuel Ohene Afoakwa

Biochemical and textural changes were investigated in trifoliate yam Dioscorea dumetorum tubers, after harvest, in an attempt to study the chemical and physical changes associated with the raw and cooked tubers and how these relate to the hardening phenomenon of the tubers after harvest. A 2x2x3x4 factorial experiment, with cultivar, storage condition, treatment and storage time as their respective variables, was done. Samples were analysed for moisture, starch, reducing sugars, alcohol-soluble sugars, acid and neutral detergent fibre, cellulose, hemicellulose and lignin. The Warner–Bratzler test cell was used in a TA.XT2 Texture Analyser to measure the hardness of cooked tubers. The …