Nigerian Food Journal最新文献

The objective of this study was to evaluate the effect of fermentation on the phenolic, vitamin C and total flavonoid contents and antioxidant properties of okra seed. The okra seeds were removed from the pod of matured and fibrous okra that cannot be easily cut with kitchen knife, and was allowed to undergo chance fermentation for 120 h. Samples were taken for antioxidant analysis at 24 h, 72 h and 120 h, respectively. The aqueous extracts of fermented and unfermented okra seeds were obtained and subsequently used for the analysis. The phenolic, vitamin C and total flavonoid contents and the antioxidant properties (ferric reducing antioxidant power (FRAP) and 1, 1-diphenyl-2 picrylhydrazyl (DPPH) free radical-scavenging ability) of the extracts were determined. The results revealed that fermented okra seeds had significantly (p < 0.05) higher phenolic content, vitamin C, total flavonoid and non-flavonoid contents and showed greater antioxidant activities than unfermented okra seed. Okra seeds fermented for 24 h exhibited the highest ferric reducing antioxidant power of 980 mgAAE/100 g and the least IC₅₀ of 2.27 mg/ ml for DPPH free radical-scavenging ability than the others. Okra seeds fermented for 24 hours had significantly (p < 0.05) higher antioxidant activities. The product from fermented okra seeds could be used for the production of functional foods.

Persistence of Campylobacter sp and its biofilm forming ability was assessed in two poultry abattoirs at two weeks intervals. Average prevalence (63.75%) of Campylobacter spp. was observed on assessing a total of 160 samples collected from the surfaces of packaging table (80%), dressing table (75%), floor source (70%) and washing table (30%). Biofilm assessment formed by Campylobacter jejuni within 5-days at 37°C were in decreasing order of washing table > packaging table > dressing table > floor. An average rate (19.6%) of isolates to develop biofilm observed in both sites was considered relatively low. Absorbance value (Optical Density-OD_590nm) of formed biofilms ranged from 0.483 – 0.952. Wastewater from the facilities showed higher TDS (643 – 820 mgl⁻¹), TSS (1200 – 1775 mgl⁻¹), COD (152 – 141 mgl⁻¹) and BOD (30.3 – 32.5mgl⁻¹) than the WHO standards of 500 mgl⁻¹, 100 mgl⁻¹, 10 mgl⁻¹ and 6 mgl⁻¹ respectively. This is a clear indication of heavy microbial presence in the wastewater. Total bacterial count (TBC) was slightly higher in site A (4.4 × 10⁵ CFU/ml) than site B (3.5 × 10⁵ CFU/ml). Efficiency index ratio (≈/> 1) observed in all tested drugs suggests their effectiveness in campylobacteriosis management. Decreasing drug sensitivity pedigree was observed with streptomycin > erythromycin & gentamincin > tetracycline & neomycin > penicillin > riphapicin & ampicillin > norflaxicin & cephalexin. These results of frequency and biofilm forming tendencies of Campylobacter spp. observed in this study can be of value in checkmating campybacteriosis outbreak from poultry abattoir facility.

Fresh edible inner tender stem (matrix) and base of domesticated elephant grass shoot were evaluated for water-soluble vitamins B₁, B₂, B₃, B₆ and vitamin C. The B-vitamins were determined using high performance liquid chromatographic (HPLC) technique, while vitamin C was evaluated using 2, 6 dichlorophenolindophenol (DCIP) titration method. The optimum blanching time of the matrix was also determined. Samples were water-blanched from 0 to 16 min at intervals of 2 min. Optimum cooking time was determined to be the time at which vitamin C showed maximum retention after the intervals of blanching. Vitamins B₁, B₂, B₃, B₆ and C concentrations (mg/100 g fresh weight) in the samples were respectively 1.23 mg/100 g, 4.37 mg/100 g, 12.35 mg/100 g, 2.40 mg/100 g and 17.23 mg/100 g in the matrix and 0.86 mg/100 g, 3.72 mg/100 g, 6.40 mg/100 g, 1.59 mg/100 g and 18.30 mg/100 g in the base. The amounts of the B-vitamins in 100 g portion of the samples adequately satisfy the RDAs for the respective B-vitamins for normal healthy adults. The matrix was significantly higher (p < 0.05) than the base in vitamins B₁, B₃ and B₆. The matrix showed an optimum blanching time of 10 min. This was considered the optimum cooking time required to avoid significant loss of vitamin C and other heat-labile nutrients in elephant grass matrix.

False yam (Icacina trichantha) tubers were processed into different flour samples: the raw; steeped-sun-dried; steeped- oven-dried; blanched-sun-dried and blanched-oven-dried samples. The nutrient composition: proximate and mineral elements contents of the flour samples were studied. The lipid, protein and carbohydrate contents of the samples ranged between 1.77 to 5.76%, 3.01 to 60.3% and 85.56 to 93.31% respectively, while the energy values ranged between 394.27 to 412.46 Kcal. Concentration of potassium, sodium, calcium and iron (among others) ranged between 20.835 and 31.51 mg/l, 2.409 and 18.890 mg/l, 90.250 and 112.550 mg/l to 0.777 and 2.840 mg/l respectively. False yam tuber, apart from being a good source of energy for man, is rich in mineral elements (potassium, sodium and calcium).

Processing affected the levels of nutrients, in the flour samples.

The use of cassava starch and soy protein concentrate edible coatings containing 20% glycerol in extending the shelf life of toasted groundnut during ambient (27 ± 1°C) storage for 14 days was studied. Chemical indices of oxidative rancidity and sensory parameters were evaluated using standard procedures. Moisture uptake, peroxide and thiobarbituric acid values of uncoated groundnuts were higher than 100% cassava starch coated groundnuts while toasted groundnuts coated with 50:50 (cassava starch:soy protein concentrate) had the lowest values. Toasted groundnuts coated with 50:50 (Cassava starch:soy protein concentrate) film had higher colour, taste, texture and overall acceptability scores than toasted groundnuts coated with 100% cassava starch film and control. The use of 50:50 (cassava starch:soy protein concentrate) edible coatings on toasted groundnut extended the shelf life of toasted groundnuts for 14 days compared to uncoated toasted groundnuts which developed objectionable taste after second day of storage at ambient (27 ± 1°C) condition.

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.

The proximate composition, functional and antinutritional properties of flour produced from seeds of mangoes grown in Ebonyi State were studied. Two cultivars: India and Indochinese were used for the study. The aim of the study was to determine any possible potential that flour obtained from these seeds might possess. Results revealed that flours from India and Indochinese cultivars had protein contents of 6.00 and 4.95%; moisture, 5.00 and 10.36%; fibre, 11.00 and 15% while the carbohydrate was 74.41 and 64.23% respectively. Results from the functional properties showed that flours from both of the cultivars had water absorption capacities of 2.0 g/g and 1.5 g/g; oil absorption capacity of 2.16 g/g and 1.83 g/g while foaming capacity was 3.79 g/g and 3.75 g/g with India cultivar having higher values for each of the functional properties studied although, there was no significant difference (p > 0.05) in the values except for the water absorption capacity. Levels of hydrogen cyanide, phytic acid and trypsin inhibitors were generally low and within safe levels.

Bread-making potentials of composite flours containing 90% wheat and 10% acha enriched with 0-15% cowpea flour were investigated. Proximate composition and functional properties of the blends were studied using AOAC standard methods. Bread loaves were prepared from the blends using the straight dough method and evaluated for loaf height, loaf volume, loaf weight and sensory characteristics. Crude protein, crude fat, crude fibre and ash contents increased significantly (p < 0.05) with increase in level of cowpea flour addition, but moisture content was not significantly (p > 0.05) different among the blends. Functional properties, with exception of bulk density and swelling capacity, were significantly (p < 0.05) different among the blends. Average loaf height and loaf volume decreased significantly (p < 0.05) with increased cowpea flour but loaf weight showed opposite trend with significant (p < 0.05) differences as cowpea flour increased. However, the addition of cowpea flour significantly (p < 0.05) decreased the loaf specific volume but all enriched samples were not significantly (p > 0.05) different. Bread samples from composited blends were rated lower than bread from all wheat bread. Bread loaves from enriched composite flour with up to 10% cowpea flour were acceptable to the panelists.

The effect of toasting time on the functional properties of Brachystegia eurycoma flour was investigated. The water absorption capacity, swelling power and solubility index of the flour, increased with increase in toasting time, while the oil absorption capacity and amylose content of the flour decreased with increase in toasting time. The peak viscosity, final viscosity, break down and setback viscosity increased from 134.67 to 176.24 RVU, 460.33 to 650.43 RVU, 57.83 to 120.33 RVU and 405.70 to 581.17 RVU respectively, as the toasting time increased. The pasting temperature decreased from 88.25 to 78.32 °C, as the toasting time increased from 0 to 12 min. Regression models that could be used to adequately express the relationships existing between the functional properties of the flour and toasting time were established.

In this paper mathematical models describing thin layer drying of cashew kernels in a batch dryer were presented. The range of drying air temperature was 70 – 110°C. The initial moisture content of the cashew kernels was 9.29% (d.b.) and the final moisture content was in the range of 3.5 to 4.6% dry-basis. Seven different thin layer mathematical drying models were compared according to their coefficients of determination (R²) mean square error (MSE) and mean relative deviation modulus (P) to estimate drying curves. The effects of the drying air temperature and time on the drying model constants and coefficients were predicted by multiple regression analysis using linear and non-linear type models. The results have shown that among the models, the Page model was found to be the best for describing the drying behaviour of cashew kernels with R², MSE and P values of 0.9830, 0.00311 and 5.046 respectively.