Proximate composition and selected functional properties of African breadfruit and sweet potato flour blends.

Full-fat African breadfruit flour was used to replace 30, 40, 50, 60 and 70% of sweet potato flour. The chemical composition and functional properties of composite flours showed that they contain more protein, fat, and ash and less carbohydrate than sweet potato flour. With increasing level of supplementation of breadfruit, ash, protein and fat contents increased while carbohydrate decreased. The composite flours possessed higher water absorption than sweet potato flour. The water absorption capacity increased from 20% for sweet potato flour to the range of 85-120% for composite flours. The oil absorption capacities for some composite flours were higher than that for sweet potato but less than that of breadfruit. Composite flours had good foaming capacity but lacked foaming stability. The bulk density of the composite flours was found to be low which will be an advantage in the preparation of weaning food formulations.

The suitability of African bush mango juice for wine production.

A good quality wine was produced from African bush mango (Irvingia var.gabonensis). Analysis of the African bush mango juice showed that it contained 3.6% total sugar, 1.09% protein, 4.2 degrees Brix soluble solids (SS) 0.5% ash, 50.24% total solids (TS), 66.7 mg/100 ml ascorbic acid and pH 5.12. The juice ameliorated to 23 degrees Brix was inoculated with 3% (w/v) Baker's yeast (Saccharomyces cerevisiae) and held at 30 +/- 2 degrees C for 28 days. SS and pH decreased while titratable acidity (TA) increased with increasing period of fermentation. Fermentation was 110% efficient. The wine produced had 8.12% (v/v) alcohol, 0.78% protein, 6.5% Brix SS, 0.64 g/100 ml TA, and a pH 3.10. Sensory evaluation results showed that there was no significant difference (p = 0.05) in colour, mouthfeel, sweetness, flavour and general acceptability, between African Bush mango wine and a reference wine. The wine was generally accepted.

Effects of processing methods on the quality and acceptability of melon milk.

Physicochemical and sensory characteristics of melon milk samples prepared from toasted, autoclaved, boiled and germinated melon seeds were determined. The germinated melon milk (GMM) had higher protein and ash contents but lower pH and viscosity than the other treated milk samples. Toasting the melon seeds improved the ash, protein, total solids and soluble solids of melon milk more than the boiling and autoclaving processes. The mean sensory scores showed that the GMM was rated lower than the other types of processed milk samples for all the sensory attributes evaluated. The toasted melon milk (TMM) had higher sensory ratings for color, mouthfeel and flavor and was generally preferred to the other treated melon milk samples.

Proximate composition and selected functional properties of fermented and unfermented African oil bean (Pentaclethra macrophylla) seed flour.

Flour samples were prepared from fermented and unfermented African oil bean (Pentaclethra macrophylla) seeds (AOBS). The flour samples were evaluated for proximate composition and certain functional properties. The influence of defatting on these properties was also determined. Fermentation significantly increased (p < 0.05) the protein and decreased the crude fiber, ash, fat and carbohydrate contents of the AOBS flours. The nitrogen solubility of both fermented and unfermented flours was pH dependent with minimum and maximum solubility at pH 4.0 and pH 8.0, respectively, and with increased nitrogen solubility in the fermented sample. The fermented and unfermented flour samples had least gelation concentrations of 14 and 16% (w/v), respectively. The water absorption capacity and foam capacities of the fermented flour were 36 and 34%, respectively, over the unfermented seed flour. On the other hand, fermentation decreased the fat absorption capacity, emulsion activity and emulsion and foam stabilities. Fermentation decreased (p < 0.05) the bulk density of AOBS flour by 15%. Defatting improved all the functional properties evaluated except emulsion activity. These results indicate potential food uses of fermented and unfermented AOBS flour samples as protein supplements in diets and as functional ingredients in formulated foods.

Influence of pH and sodium chloride on selected functional and physical properties of African breadfruit (Treculia africana Decne) kernel flour.

African breadfruit seeds were cleaned, parboiled (98 degrees C) for 15 min, drained and dehulled. The kernels were sun-dried, then milled and sieved into flour. Nitrogen solubility (NS), water absorption capacity (WAC), emulsion activity (EA), viscosity, foaming and emulsifying properties of the flour were determined as functions of pH and NaCl concentration. The NS was pH dependent with a minimum at pH 4 and maximum at pH 10. The flour also exhibited minimum and maximum foam capacity at pH 4 and 10, respectively. The minimum emulsion activity was at pH 4, a value which increased from 7-16% at pH 12. The addition of NaCl at concentrations of 0.2 to 0.4 M improved WAC, NS, foaming and emulsion properties of the flour. Sodium chloride enhanced NS of the flour at pH 4-6 and EA at pH 2-8. The EA at pH 2, 10 and 12 correlated negatively (r = -0.30) with NaCl concentration levels; however, the correlation was not significant (p > 0.05). The flour dispersions had lower viscosities at acid pH and in the presence of NaCl than at neutral and alkaline pH values. Results indicated the flour could be used in food product supplementation.

Physicochemical, microbiological and sensory changes in stored plantain chips.

Plantain chips were produced from unripe plantain fruits. The chips were packed in polyethylene bags and stored at 30 +/- 2 degrees C for 1, 2 and 3 months, respectively. The storage stability of the chips was evaluated by analyzing periodically for changes in the physicochemical, microbiological and sensory characteristics. Protein and ash contents of the chips did not change (p > 0.05) over time. Fat decreased slightly (p > 0.05) over time. Vitamin C decreased and was negatively correlated with storage time (r = -95; p < 0.05). Peroxide value and microbial count increased with storage (p < 0.05). Sensory scores for chips did not change (p > 0.05) at 2 months storage, but, thereafter, decreased (p < 0.05).

Chemical composition and selected functional properties of sweet orange (Citrus sinensis) seed flour.

Flour samples were prepared from dehulled and undehulled sweet orange (Citrus sinensis) seeds. The flour samples were evaluated for proximate composition, mineral content and selected functional properties. Proximate analysis showed a composition of 54.2% fat, 28.5% carbohydrate, 5.5% crude fiber, 3.1% crude protein and 2.5% ash for the dehulled orange seed flour (dry weight). Mineral analyses showed high levels of calcium and potassium in flour samples. Partially defatted and undefatted flour samples prepared from dehulled orange seeds had least gelation concentrations of 10 and 12% (w/v), respectively. Water absorption capacity for the defatted and undefatted dehulled flour samples were 240 and 220%, respectively. Defatting improved oil absorption capacity of the orange seed flour by 84%. Emulsion activity, emulsion stability and foaming capacity decreased following defatting of flour. Foam prepared from defatted flour was less stable than that from full-fat flour. Incorporation of NaCl up to 0.2 M improved the foaming capacity of orange seed flour.