Department of Agriculture
Permanent URI for this collectionhttps://ir.mug.edu.gh/handle/123456789/136
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Browsing Department of Agriculture by Subject "Colour"
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Item Effect of Roasting Conditions on the Browning Index and Appearance Properties of Pulp Pre-Conditioned and Fermented Cocoa (Theobroma Cacao) Beans(Journal of Nutritional Health & Food Science, 2014-02-06) Afoakwa, Emmanuel Ohene; Budu, Agnes Simpson; Mensah-Brown, Henry; Takrama, Jemmy Felix; Ofosu-Ansah, EricAppearance is an important quality determinant of cocoa beans and it is used as standard criteria to establish the degree of fermentation and drying of the beans. Changes in browning index and colour (L*a* b*) during roasting of pulp pre-conditioned and fermented cocoa beans were studied using standard analytical methods. Increasing pod storage and roasting time at 120o C led to variable increases in browning index (BI) and b*-values of the beans with decreases in the L* and a* values. Cocoa pod stored for 10 days showed the highest BI (1.144) with the least L* value (24.15) whilst beans from the unstored pods showed the least BI (1.007) with the highest L* value (25.55). The rates of change in BI and colour (L*, a*, b*) were however more pronounced during roasting than pod storage. Brown pigment formation (BI) and the L* value were more pronounced after 30 minutes of roasting in beans from pods stored for 3 to 7 days. The colour changes in beans from 10 days pod storage was significant (p<0.05) after 45 minutes of roasting. The beans from the pods stored for 3 to 7 days showed consistent decrease in L* and a* values with increasing roasting time whiles the beans from the 10 days of pod storage were observed to produce lower L* value (darker beans) after 45 minutes of roasting. Pod storage between 3 to 7 days could be used to improve the brownness and appearance of roasted cocoa nibs. Beans from cocoa pod stored between 3 to 7 days produced the most acceptable BI and L* value after roasting for 30 minutes at 120o C.Item Optimization of Blanching Time, Sodium Metabisulphite (Na 2 S2O5 ) Concentration and Processing Time on Vitamin C Content, Microbial Quality and Sensory Characteristics during Canning of Green Pepper (Capsicum sinensis) Using Response Surface Methodology(Journal of Food Science and Engineering, 2013-06-20) Afoakwa, Emmanuel Ohene; Mensah-Brown, Henry; Hinneh, MichaelResponse surface methodology and central composite rotatable design (CCRD) for K = 3 were used to investigate the combined effect of blanching time (0-1 min), processing time (10-30 min) and sodium metabisulphite (Na 2S2O5) salt concentration (0%-2%) on vitamin C content, hardness (texture), microbial count and color intensity of green pepper (Capsicum sinensis) during canning. Blanching, processing time and sodium metabisulphite (Na 2S2O5) salt concentration all had variable effects on the vitamin C, microbial quality and sensory characteristics of the canned green peppers. Significant (P < 0.05) interactions were noted between all the factors with high regression coefficients (78.7%-97.0%). Increasing processing time caused significant decreases in vitamin C and microbial load of the product. However, salt concentration had only marginal and insignificant effect on the vitamin C content of the canned product. Sensory evaluation on the product showed that both the pre-processing conditions and of blanching and salt concentrations, and the processing time had varied effects on the color and hardness of the products. Hardness of the canned products generally decreased with increasing processing time and blanching time, while only minimal and insignificant effects were noted with blanching time. Increasing blanching time caused significant increasing retention of the dark green color of the peppers with only slight but insignificant increases noted with processing time, while increases in salt concentration consistently reduced the dark green color of the products. The optimum pre-processing and processing conditions that yielded products with high preference and consumer-acceptability were: blanching time of 0 min, processing time of 10 min and sodium metabisulphite concentration of 0.2%.