Browsing by Author "Ofosu-Ansah, Eric"
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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 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.