Open Access Original Research Article

Introduction: The porosity of recent data on the chemical compositions of indigenous food might contribute to poor food choices thereby promoting food and nutrition insecurity. This study provides data on the proximate, mineral and antinutrient compositions of raw, Triticum aestivum, Musa paradisiaca, Xanthosoma sagittifolium, Ipomea batata, Zea mays and Sphenostylis stenocarpa.

Methodology: The raw food materials were purchased in Nigerian markets. Corn grains and African yam bean (AYB) seeds were sorted to remove impurities and separately milled into fine flours. Green matured plantain fruits, cocoyam, yellow and orange fleshed sweet potatoes tubers were separately washed to remove adhering soil particles, peeled and sliced into a thin thickness of about 2 cm and then dried in a food dehydrator (40- 50°C) for 24 hr. After drying, they were separately milled into fine flours. Chemical properties were analyzed using standard laboratory methods. Data generated were computed using means and standard deviations.

Results: The ranges of the proximate compositions of the food materials were as follows: Moisture 4.3-11.8%, ash 0.6 -2.8%, dietary fibre 3.2-17.5%, fat 0.8-4.3%, protein 2.8 - 20% and available carbohydrate 48.5 -72.5%. The mineral contents of the samples were in the following ranges; iron 0.8-5.4 mg/100 g, zinc 0.51-2.43 mg/100 g, calcium 8-109 mg/100 g, potassium 135-325 mg/100 g, sodium 3-12 mg/100 g, phosphorus 84- 688 mg/100 g, magnesium trace -119 mg/100 g. The antinutrients were as follows: trypsin inhibitors 1.85 IU/mg, phytate ranged from 5.1-6.57 mg/g, oxalate 0.21-0.29 mg/g, saponins 0.03-0.02 mg/100 g, raffinose 0.88- 2.18%, stachyose 1.93 – 3.16%, lectins 32.5 Hu/100 g and tannins 0.9 mg/g.

Conclusion: Knowing the nutrient contents of raw food materials will help food producers/processors and consumers combine foods leveraging on the comparative advantage of each nutrient to make up for limited nutrient(s). Also, knowledge of the antinutrient compositions of raw food staples will aid decisions on adequate processing methods to be employed in reducing or eliminating them.

Open Access Original Research Article

Physicochemical, Sensory and Microbial Qualities of Ice Cream Stabilized with Hydrocolloids from Achi (Brachystegia eurycoma) and Ofor (Detarium microcarpum)

K. O. Aremu, T. M. Okonkwo, C. M. Eze, C. H. Agwu, J. I. Agbaka, A. N. Ibrahim

Asian Food Science Journal, Volume 16, Issue 1, Page 14-27
DOI: 10.9734/afsj/2020/v16i130162

Aims: To investigate the physicochemical, sensory and microbial qualities of ice cream stabilized with hydrocolloids from Achi (Brachystegia eurycoma) and Ofor (Detarium microcarpum.

Study Design: A 4×5 split-plot in completely randomized design.

Place and Duration of Study: Department of Food Science and Technology, Faculty of Agriculture, University of Nigeria, Nsukka, Enugu State Nigeria between August 2018 and July 2019.

Methodology: Raw seeds of Achi (Brachystegia eurycoma) and Ofor (Detarium microcarpum) were purchased from Ekeonunwa market, Owerri, Imo State, Nigeria and processed into flours. Hydrocolloids from flours of Achi and Ofor were defatted with n-hexane (50 g/250 ml at 26±2°C) dispersed in distilled water (10 g/250 ml), centrifuged (1250 rpm/30 mins and 1500 rpm/30 mins for achi and ofor respectively). The supernatants obtained were dissolved in isopropanol, decanted dried in a hot air oven (60°C, 10 h), pulverised using a blender and stored in air –tight containers. Twenty (20) litres of ice cream samples were produced. Four (4) litres of the mix was measured out as control (i.e. plain ice cream without any stabilizer). Sixteen (16) additional ice cream mixes were produced in the same way by the addition of CMC, achi hydrocolloids, ofor hydrocolloids and a mixture of hydrocolloids from both achi and ofor as stabilizers, each at 0.1%, 0.2%, 0.3%, 0.4% concentrations. The physicochemical, sensory and microbial properties of the ice cream samples formulated were carried out.

Results: The outcome of physicochemical analysis revealed that viscosity (31.65 ± 0.17 cP – 82.50 ± 0.00 cP), overrun (19.30 ± 0.00% - 98.73 ± 0.00%), total solids (24.36 ± 0.33% - 54.00 ± 1.55%) and melting resistance (36.50 ± 0.58% -  92.50 ± 0.58%) were significantly (P < 0.05) affected by the type of stabilizers as well as their concentrations. The total titratable acidity (0.02 ± 0.00% -  0.02 ± 0.00%) and pH (6.74 ± 0.00 - 7.05 ± 0.05) of the ice cream samples showed no appreciable significant (P > 0.05) difference. The overall acceptability (5.80 ± 1.99 - 7.65 ± 1.00), aftertaste (5.45 ± 2.28 – 7.20 ± 0.89), mouthfeel (5.85 ± 1.79 - 7.25 ± 1.37) and homogeneity             (5.20 ± 1.96 - 7.60 ± 1.39) were significantly (P< 0.05) influenced as deduced from the sensory result.

Conclusion: The incorporation of local stabilizers significantly improved the physicochemical, sensory and microbial qualities of ice cream produced. Hydrocolloid extracts of Detarium microcarpum (Ofor), plant-based natural stabilizer is a capable replacer of CMC in ice cream production because of its higher viscosity than other stabilizers and CMC, agreeable consistency, better consumer preference than other stabilizers, enhanced qualities – slow melting rate i.e. high melting resistance, commendable pseudo-plasticity, effectual overrun which will yield more profits for ice cream manufacturers, bring about a new variety of ice creams that are safe for consumption. Hydrocolloid extracts of Detarium microcarpum, at 0.3%, showed more desirable similar effects on the physicochemical, sensory and microbial qualities of ice cream samples formulated compared to CMC and could, therefore be recommended as a replacer of CMC in ice cream production.

Open Access Original Research Article

Influence of Ocimum gratissimum (Scent Leaf) on the Organoleptic Acceptability and Shelf Stability of Yoghurt

A. N. Ibrahim, C. E. Igwe, I. S. Asogwa, J. I. Agbaka, Q. C. Ajibo

Asian Food Science Journal, Volume 16, Issue 1, Page 28-44
DOI: 10.9734/afsj/2020/v16i130163

Aim: To investigate the preservative efficiency of Ocimum gratissimum or its extracts on yoghurt.

Study Design: Ten yoghurt samples were prepared, furthermore, nine (9) samples were treated with scent leaf in different forms at different concentrations.

Place and Duration of Study: Department of Food Science and Technology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria, between September 2015 and June 2016.

Methodology: Yoghurt was prepared from instant filled milk while Direct Vat Inoculum (DVI) was used as the starter culture. Proximate and phytochemical analyses were carried out following standard procedures. Sensory evaluation was carried out using a 15-man panelist with a seven point hedonic scales and results were statistically analyzed using IBM® SPSS 21.0, at 0.05 probability level. pH and microbial analysis were conducted while bacterial characterization involved biochemical tests and isolation of probable microorganisms employed morphological and structural characteristics.

Results: Result for proximate analysis indicated differences in the nutritional composition of the raw milk and yoghurt (control). Moisture content increased considerably from 10.00% to 69.75%, while a reduction in protein content was reported (8.7% - 4.95%). The lipid content classified the produced yoghurt as a low-fat yoghurt, and expectedly, the carbohydrate content reduced from 58.20% - 22.30%. Phytochemical screening of the different forms of scent leaf indicated the presence of alkaloids, flavonoids, saponins, cardiac glycosides, and steroids, in different concentrations. Sensory scores showed that the panelists preferred yoghurt formulated with 3 mL of squeezed scent leaf extract. pH values decreased with storage period, while microbial load ranged between 0.5× 104 – 2.0 × 104, where Klebsiella spp., Streptococcus spp., E. coli, Bacillus, S. aureus, Pseudomonas spp., Enterobacter, and Proteus spp. were isolated.

Conclusion: The yoghurt samples formulated with squeezed scent leaf extracts had the best organoleptic acceptance, while the sample treated with 3 mL had the lowest microbial load, hence, it can be inferred that the squeezed scent leaf extracts had the best preservative effect.

Open Access Original Research Article

Microbiological Evaluation of Ready-to-Drink Tigernut Drinks Sold within Port Harcourt Metropolis, Rivers State, Nigeria

Francis Sopuruchukwu Ire, Goziem Kim Benneth, Ndukwe Maduka

Asian Food Science Journal, Volume 16, Issue 1, Page 45-58
DOI: 10.9734/afsj/2020/v16i130164

Aims: Tigernut drink are made from tigernut tubers (Cyperus esculentus L.) and rich in nutrients. This drink is locally produced and widely consumed in Nigeria irrespective of social status. This study is aimed at evaluating the microbial quality and physicochemical property of tigernut drinks sold within Port Harcourt metropolis.

Methodology: Thirty (30) samples of freshly prepared and packaged tigernut drinks were randomly purchased from different vendors in five locations of Port Harcourt metropolis (Agip Estate, Abuja Campus (Uniport), Choba, Mile 1 and Mile 2 Markets). The samples were analyzed using standard microbiological and physicochemical methods. SPSS (Statistical Package for the Social Sciences) was used to analyze the data.

Results: Results obtained showed that the pH of the samples ranged from 4.2 to 4.6 while the total heterotrophic bacterial count ranged from 6. 54-6.74 log10 CFU/mL. Total fungal count of tigernut drinks ranged from 6.0-6.2 log10 CFU/mL. A total of nine (9) bacterial genera namely Staphylococcus sp. (37.3%), Escherichia sp. (21.3%), Salmonella sp. (12%), Pseudomonas sp. (12%), Klebsiella sp. (4%), Bacillus sp. (4%), Micrococcus sp. (4%), Enterobacter sp. (2.7%) and Corynebacterium sp. (2.7%) were isolated from the samples. Six (6) fungal genera were also encountered in the drink sampled which include Rhizopus sp. (1.4%), Saccharomyces sp. (4.4%), Aspergillus sp. (30.9%), Fusarium sp. (26.5%), Penicillium sp. (30.9%) and Candida sp. (5.9%). The result revealed that Staphylococcus sp. had the highest percentage of occurrence (37.3%) followed by E. coli (21.3%), while Enterobacter sp. (2.7%) and Corynebacterium sp. (2.7%) recorded the least. Among the fungal isolates, Aspergillus sp. and Penicillium sp. had the highest percentage of occurrence (30.9%) whereas Rhizopus sp. had the least (1.4%). The results of this study revealed that all the samples from the five (5) locations were heavily contaminated with pathogenic microorganisms and found not suitable for human consumption based on the standard recommended by National Agency for Food and Drug Administration and Control (NAFDAC). NAFDAC stipulated that mesophilic aerobic count of locally prepared beverages should be < 5.0 log10 CFU/mL.

Conclusion: The huge contamination recorded in all the samples irrespective of the location could be linked to poor hygienic levels during processing. Therefore, good manufacturing practices, public health enlightenment campaign and strict regulations from relevant agencies are recommended to avoid foodborne infections, diseases and possible deaths which could result from consumption of such contaminated tigernut drinks.

Open Access Original Research Article

This study assesses the effect of fermentation process on the nutritional compositions of a corn-based food “Etsew”. Dried corn Zea mays var “Obaatampa” was used for the study. A total of 9 samples were collected and analyzed for a period of one month. These were dried corn, steeped corn, milled corn, three samples of corn dough with 1 day, 3 days and 5 days fermentation periods and three samples of “Etsew” made from the various fermented corn dough. The test was run on each sample three times to ensure the reliability of test results. Proximate analysis was done on the samples using standard methods. Results from the study show an increase in moisture, protein, fat, fibre and carbohydrate contents of the corn dough compared to the raw corn. The study also observed reduction in protein, carbohydrate, fat and energy value when heat was applied to the dough during “Etsew” preparation.