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 "Acidity"
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Item Changes in Nib Acidity, Proteolysis and Sugar Concentration as Influenced by Pod Storage and Roasting Conditions of Fermented Cocoa (Theobroma cacao) Beans(Journal of Food Science and Engineering, 2013-12-20) Ofosu-Ansah, Eric; Budu, Agnes Simpson; Mensah-Brown, Henry; Takrama, Jemmy Felix; Afoakwa, Emmanuel OheneChanges in nib acidity, protein and sugar concentration during roasting of pulp pre-conditioned and fermented cocoa (Theobroma cacao) beans were investigated. A 4 × 4 full factorial design with the principal experimental factors as pod storage (0, 3, 7 and 10 d) and roasting time (0, 15, 30 and 45 min) were used. The roasted samples were evaluated for pH, titratable acidity, protein content and sugars concentrations using standard methods. Increasing pod storage caused consistent increases in pH with concomitant decreases in titratable acidity, whereas increasing roasting time caused only marginal and insignificant changes in pH but significantly decreased the titratable acidity. The protein content decreased significantly (P < 0.05) with increasing pod storage and roasting time. Reducing sugars increased marginally with increasing pod storage treatments whiles increasing roasting time significantly (P < 0.05) decreased the reducing sugars of the beans for all pod storage. The non-reducing sugar and total sugar content of the beans decreased significantly from 3.493 mg/g to 2.641 mg/g and from 9.284 mg/g to 8.891 mg/g, respectively, for pods stored from 0 to 10 days while roasting time caused slight decreases in non-reducing sugars with a considerable decrease in total sugars. Pod storage up to seven days decreased considerable the nib acidity (non-volatile acids), non-reducing sugars and total sugars while roasting up to 45 min at 120 °C caused dramatic decreases in the nib acidity and reducing sugars with only marginal decreases in non-reducing sugars and total sugars.Item Changes in some biochemical qualities during drying of pulp pre-conditioned and fermented cocoa (Theobroma Cacao) beans(African Journal of Food, Agriculture, Nutrition and Development, 2015-01-01) Afoakwa, E. O; Kongor, J. E; Budu, A. S; Mensah-Brown, H; Takrama, J. FFermentation and drying are critical to the development of flavour precursors that generate into distinctive chocolate flavour notes during industrial manufacture. These processes also lead to reduction in acidity and free fatty acids of nibs, which dictates the levels of bitterness and colour development in chocolates. This study investigated changes in nib acidity, flavour precursors (sugars concentration and proteins) and free fatty acids during drying of pulp pre-conditioned and fermented cocoa beans using a 4 x 3 full factorial experimental design with pod storage (0, 3, 7 and 10 days) and drying time (0, 3 and 6 days) as the principal factors. Non-volatile (titratable) acidity, pH, sugars (reducing, non-reducing and total sugars), changes in protein content and free fatty acids of the beans were studied using standard analytical methods. Increasing pod storage consistently increased pH of the fermented nibs at the end of drying with consequential decrease in titratable acidity. The pH increased from 4.92 for the freshly harvested pods to 6.00 for pods stored for 10 days at the end of the drying process. Similarly, pH of the fermented beans increased with increasing drying time for all pod storage treatment except for pods stored for 10 days. The pH of fermented beans whose pods were stored for 3 and 7 days were 5.26 and 5.56 respectively after drying for 7 days. Protein, reducing sugars, non-reducing sugars and total sugars decreased significantly (p<0.05) with increasing duration of drying at all pod storage periods. Pod storage and drying significantly (p<0.05) increased the free fatty acids content of the fermented nibs. The FFAs of the dried beans increased from 0.47% for the unstored (freshly harvested) pods to 0.55% for pods stored for 3 and 7 days and 0.58% for pods stored for 10 days. However, FFAs content of all the dried fermented beans were below the acceptable limits of 1.75% oleic acid equivalent in cocoa butter at all pod storage periods. Storage of cocoa pod between 3–7 days with 7 days of drying (after 6 days fermentation) led to considerable reductions in nib acidity, reducing sugars, nonreducing, total sugars and proteins and acceptable FFA levels.Item Fermentation Capacity of Yeasts Using Mango (Mangifera indica Linn.) as Substrate(Food Science and Quality Management, 2013) Kamassah, Anthony K.Q.; Saalia, Firibu K.; Osei-Fosu, Paul; Mensah-Brown, Henry; Sinayobye, Emmanuel; Tano-Debrah, KwakuThe goal of this study was to address the problem of large post harvest losses of mangoes by employing yeast fermentation technology to produce a more stable, value-added product in this case fruit wine. The design of the study involved determination of the fermentative capabilities of four commercial yeast types on musts obtained from an improved (Keitt) mango cultivar that is popularly cultivated in some parts of Ghana for export. The characteristics of the mango musts that were monitored included total soluble solids (TSS), pH and total acidity (TA), microbial populations (aerophilic mesophiles, yeasts and Acetic acid Bacteria), alcohol content and colour over the course of the fermentations. Descriptive and hedonic sensory evaluation was carried out on the ferments obtained from all treatments. Results showed that two of the yeast types namely; Red Star Pasteur and Red Star Montrachet displayed superior fermentation characteristics and produced mango wines that were acceptable by both descriptive and affective sensory panels.