Taofik A. Shittu

Evaluating Some Empirical Models for Predicting Water Absorption in African Breadfruit (Treculia Africana) Seeds

Abstract Water absorption process during soaking of African breadfruit (ABF) seeds was studied at five typical soaking temperatures, ranging between 30 and 70°C. The progress of water absorption by the seeds followed an exponential increase with increase in temperature. The experimental data were fitted to three empirical equations. All the equations were able to explain over 90% of the experimental data. The predicted water absorption capacity (M e ), which ranged between 68 and 92/100 g dry solid were not significantly affected by temperature changes (p > 0.05) while the time to achieve maximum water absorption capacity ranged between 9 and 140 h. The water absorption rate constant in Singh–Kulshresthas model was more sensitive to temperature changes than from the others. By applying Arrhenius equation, it was shown that water absorption at 30–70°C was the predominant process responsible for the changes in mass of ABF seeds. The differences in the experimental and predicted data from the three models were compared to evaluate their goodness of fit. The chi-square and the root mean square deviation (RMSD) showed that Singh–Kulshrestha and Pilosofs models described better the moisture variation in soaked ABF seeds with time. In terms of residual moisture plots, Singh–Kulshresthas model gave a more random distribution at all soaking temperatures, making it a better fitting equation.

Effect of Hydrocolloids and Egg Content on Sensory Quality of Coated Fried Yam Chips

This study investigated the effect of hydrocolloid (xanthan gum, gum tragacanth, and carboxymethyl cellulose) at 0.5–1.5% concentration and egg content (egg white or whole egg) as coating ingredients on the sensory quality of fried yam chips (FYC). The coated chips were evaluated for appearance, texture, taste, flavor, and overall acceptability using a nine-point hedonic scale. Descriptive sensory evaluation of the samples using generic method was also conducted. The studied independent variables had significant (p < 0.05) effects mainly on the appearance and texture of the FYC. Generally, the acceptability scores decreased significantly with increased hydrocolloid concentration (p < 0.05). Appearance had highest significant correlation (p < 0.01, r = 0.764) with overall acceptability. Eight of over fifty descriptors generated by the trained panelists were agreed upon as non-redundant, discriminatory attributes of the coated FYC. Similarity map of the descriptors were defined by two principal components accounting for 53.06% and 40.18% of total variance of rotation sums of squared loadings.

Effect of water yam (Dioscoreaalata) flour fortified with distiller's spent grain on nutritional, chemical, and functional properties

Abstract It was envisaged that the inclusion of treated distillers spent grain (DSG) to yam flour might increase its nutritional value, with the aim of reducing nutritional diseases in communities consuming yam as a staple. Hence, yam flour was fortified with DSG at 5–35%. The effects of this fortification on the nutritional, chemical, and functional properties of yam flour were investigated. The result showed a significant increase (P ≤ 0.001) in fat, ash, protein, total amino acids, total dietary fiber, and insoluble dietary fiber contents of the blends as DSG increased except for starch and soluble dietary fiber contents, which decreased. The functional properties showed a significant (P ≤ 0.001) reduction with DSG inclusion. The inclusion of DSG increased both the tryptophan and methionine contents of the blends. Therefore, the DSG fortified yam flour could contribute to quality protein intake in populations consuming yam as a staple, due to its indispensible amino acid content.

Physicochemical Properties and Phytochemical Components of Spiced Cucumber-Pineapple Fruit Drink

ABSTRACT A blend of equal portions of cucumber (50%) and pineapple (50%) juices was mixed with clove and ginger powder spices at 0.25% (CPCLG1), 0.5 (CPCLG2), 0.75% (CPCLG3) and 1% (CPCLG4) (w/v) respectively to develop a new fruit drink with health benefits. The juice blend without spice extract (CP) was used as reference sample. Samples were analysed for oBrix, pH, acidity, specific gravity, total solids and ascorbic acid (vitamin C). The phytochemicals present in the products were also determined using chemical method and Gas chromatography-mass spectrometry (GC-MS). There was significant reduction in the oBrix from 8.08 to 7.60%, pH (4.41 to 4.36) and total solid (7.96 to 7.71%). Specific gravity was 1.020 while the acidity increased from 0.20 to 0.22% as the levels of spices increased. The phytochemical compounds identified in the products include alkaloids, flavonoids, saponins, steroids, tannins, terpenoids and phlobatannins. The quantitative phytochemical contents showed 0.1 μg/ml Isoquinoline in CP, 0.03271 μg/ml Isoquinoline in CPCLG1; 0.00199 μg/ml Octanoid acid, 0.00224 μg/ml Metroprolol, 0.00231 μg/ml Fumaric acid, 0.00263 μg/ml Benzoquinone, 0.00264 μg/ml Betaxolol, and 0.002471 μg/ml 1-nonene in CPCLG2; 0.00070 μg/ml Limonene and 0.00146 μg/ml Caryophyllene in CPCLG3 and 0.00048 μg/ml P-Benzoquinone, 0.00074 μg/ml 4H-Quinolizine, 0.00017 μg/ml 3-pyridinepropanol, 0.00559 μg/ml Chlorogenic acid, 0.00559 μg/ml Camphene and 0.00089 μg/ml Benzofuranone in CPCLG4. The types and quantities of phytochemicals present in the products were influenced by the formulation of the products.

Production and Quality Evaluation of Noodles From Sweet Potato Starch

The effect of extrusion parameters (feed moisture content, barrel temperature, and screw speed) on the quality of noodles produced from sweet potato starch was investigated. Starch was extracted from the tuber of sweet potato and processed into noodles using single screw cooking extruder. The moisture, protein, and ash contents of the noodles decreased linearly with the feed moisture content and barrel temperature but decreased with increasing screw speed. Increased feed moisture content also led to decrease in water absorption capacity, cooking time, and water solubility index. Lateral expansion increased with increasing barrel temperature. Barrel temperature had significant effect (p < 0.05) on lateral expansion while screw speed and feed moisture content had significant effect (p < 0.05) on cooking time. Significant (p < 0.05) positive correlation was obtained between the overall sensory acceptability, appearance, firmness, and chewiness. The study showed that noodles of desirable functional qualities and sensory acceptability can be obtained from sweet potato starch using barrel temperature of 110°C, screw speed of 100 rpm, and feed moisture content of 47.5%.

Effect of Honey as Partial Sugar Substitute on Pasting Properties, Consumer Preference and Shelf Stability of Cassava-Wheat Composite Bread

The effect of partial substitution of sugar with liquid honey on the pasting properties of cooked dough made from cassava-wheat composite (10:90) flour as well as the sensory preference and shelf stability of its bread was investigated. Sucrose (S) in the bread recipe formulation was substituted with honey (H) at levels 0, 10, 20, 30, 40 and 50%, respectively to give 6 treatments, namely 0H:100S, 10H:90S, 20H:80S, 30H:70S, 40H:60S and 50H:50S. Amylograph pasting properties of the dried crumbs were determined using standard analytical procedures. Fresh bread samples were subjected to sensory evaluation and fungal count during storage (6 days). Peak, final and setback viscosities of bread crumb decreased (32.29 to 25.33, 58.54 to 43.00 and 30.96 to 23.66 RVU), respectively as the level of honey inclusion increased. Honey substitution levels used did not significantly (p > 0.05) affect aroma and texture of the bread samples but composite bread with 20% level of honey substitution was most preferred in terms of colour while composite bread with 30% level of honey substitution was most acceptable in terms of taste and overall acceptability. Fungal count in stored honey-cassava-wheat bread varied significantly (p < 0.05) from 0.6 to 4.0 × 10 2 , 1.0 to 6.9 × 10 2 , 2.2 to 57.0×10 2 , 32.0 to 135.7×10 2 , 34.0 to 140.0×10 2 and 42.0 to 159.3 ×10 2 ) cfu/ml from day 1 to day 6, respectively. From the study, it was concluded that substitution of sugar with honey in dough formulations significantly (p < 0.05) affects dough pasting properties, improves acceptability of the composite bread and reduces staling rate.

Changes induced by soaking period on the physical properties of maize in the production of Ogi

Abstract This study was aimed at investigating the effect of soaking method and period on some selected physical properties on maize varieties. Five varieties of maize (A4W, C3Y, D8W, B2Y and E9W) were soaked for 12–96 h at ambient temperature of 28 and average hot temperature of 65°C as generally praciticed in the production of Ogi from cereals. Some selected physical properties were evaluated based on a 5 × 2 × 9 factorial design (varieties × soaking methods × soaking periods). The reseult revealed that the linear dimensions of the five varieties of soaked maize increased with increase in linear dimensions up to about 36th hour of soaking. The percentage increase in width was in the range of 5.482–9.67%, 4.064–8.25%, 3.76–6.81% and 0.88–1.81%, for C3Y, B2Y, D8W, A4W and E9W for both soaking conditions, respectively. Significant difference (p < 0.05) existed between the maize varieties for surface area and the volume. These increased with increase in moisture content and soaking period with the highest surface area recorded for maize variety E9W at 36th hours of 65°C. There were significant differences (p < 0.05) between unsoaked and soaked maize varieties for all the samples. Values obtained for sphericity increased with increase in soaking period. There was no significant difference (p > 0.05) in the values obtained for sphericity at soaking condition of 65°C compared with soaking at 28°C. This study showed that the period of soaking had significant effect (p < 0.05) in increasing the overall dimensions of maize grains up to 36th hour and thereafter witnessed an irregular pattern.

Flour, dough and bread properties of wheat flour substituted with orange-fleshed sweetpotato flour

ABSTRACT This study investigated some quality attributes of composite flours, dough and bread from wheat flour substituted with orange-fleshed sweetpotato (OFSP) flour at 0–30% levels. Chemical, functional and pasting properties of flours, rheological properties of dough, as well as chemical composition and physical properties of bread were determined. Protein content of composite flours decreased by 25.51–37.37% at 10–30% OFSP flour substitution. Flour composites were higher in ash (2.12–2.33%), crude fibre (3.28–4.34%), water (1.45–2.08 ml/g) and oil (1.45–1.67 ml/g) absorption capacities. Wheat flour (100%) had maximum peak viscosity of 117.71 Rapid Visco Units (RVU) which decreased by 0.71–30.80% with OFSP flour substitution. Dough from composites had higher hydration (82.15–112.10%) and breakdown torque (0.38–0.42 Nm) but lower stability (1.16–2.38 min), protein weakening (0.06–0.37 Nm), starch gelatinization (0.46–0.81 Nm), stability of hot gel (0.04–0.43 Nm) and starch retrogradation (0.46–0.81 Nm). Bread substituted with OFSP flour had higher total carotenoids (1565.50–5179.27 µg/100 g), weight (193.74–198.50 g) and crumb moisture (27.81–27.91%).

Modelling of mechanical properties of five maize varieties at critical processing conditions in the production of fermented slurry-ogi

ABSTRACT This research work was conducted to investigate the impact of critical processing conditions on the selected mechanical properties of maize in the production of fermented ogi slurry. Five varieties of maize (A4W, C3Y, D8W, B2Y, and E9W) were soaked at 28 ºC and average hot soaking at 65ºC, respectively, for 96 h at 12-h interval. Selected mechanical properties were evaluated based on a 5 × 2 × 9 factorial design (varieties× soaking methods× soaking periods). Force (FB) and energy required to break (EB) maize grains decreased significantly (p < 0.05) up to the 12th hour. The EB reduced from 873.3 to 70.0 N mm and from 873.3 to 77.8 N mm for variety E9W at soaking conditions of 28ºC and 65ºC, respectively. Similar trends were observed for other maize varieties. Modulus of elasticity and resilience decreased significantly (p < 0.05) with increase in soaking period and moisture content. The EB to break maize grains was directly proportional to the product of Young’s modulus and area (Em A1.5), the FB and area (Fm A°.5) and force required to break and geometric mean diameter (F Dg2) of maize grains with a high R2 (0.9610.999). This study suggested that the duration of soaking between 12 and 24 h should be enough to significantly (p > 0.05) reduce the hardness, force, and energy required to break whole maize grains in the production of this fermented product and relevant for predicting minimum required energy for a large-scale operation.

Screening for gum-producing Lactic acid bacteria in Oil palm (Elaeis guineensis) and raphia palm (Raphia regalis) sap from South-West Nigeria

Abstract Lactic acid bacteria have wide applications in food processing. Lactic acid bacteria produced exopolysaccharides (EPS) which could be used as possible replacer for commercial stabilizer and thickeners produced by nonfood grade bacteria. Seventy‐two samples of Oil and Raphia palm sap were collected in eighteen locations across South‐Western Nigeria and screened for exopolysaccharide production in 6% sucrose agar using streaked plate method. Four hundred EPS‐producing bacteria (EPB) isolated were clustered based on morphological characteristics into two broad groups and preliminary screened for EPS‐producing capacity. Twenty representative of EPB were selected from the broad groups for tentative identification by API 50CHL and 10 high yielding EPB were selected for large‐scale EPS production. Each strain was inoculated into 6% sucrose broth with 3% (v/v) preculture grown overnight in a 1.5 ml flask and incubated at 37°C for 72 hr. The EPSs were purified and freeze‐dried prior to quantification of yields. EPS‐producing bacteria were identified as Leuconostoc lactis, Lactobacillus fermentum, Lactobacillus delbrueckii ssp. lactis, L. delbrueckii ssp. delbrueckii, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus crispatus, and Leuconostoc mesenteroides ssp. mesenteroides/dextranicum. EPS yield ranged from 132–810.75 mg/L and EPS‐producing potential of lactic acid bacteria (LAB) strains ranged; 36% (132–245 mg/L), 36% (250–460 mg/L), and 28% (461–820 mg/L). L. plantarum had the highest EPS yield of 810.75 mg/L whereas L. crispatus had the least yield 242.5 mg/L. These results suggest that majority of LAB in palm wine saps are gum‐producing bacteria. Leuconostoc and Lactobacillus were the most abundant LAB found in this study while L. plantarum could have applications as potential starter cultures for the production of exopolysaccharides (EPS) at industrial level.