African Journal of Agriculture and Food Security

African Journal of Agriculture and Food Security ISSN 2375-1177 Vol. 8 (5), pp. 001-008, May, 2020. © International Scholars Journals

Full Length Research Paper

Effects of two processing methods on some nutrients and anti-nutritional factors in yellow yam (Dioscorea cayenensis)

P. E. Akin-Idowu^1,2, R. Asiedu^1*, B. Maziya-Dixon², A. Odunola¹ and A. Uwaifo¹

¹Cancer Research and Molecular Biology Laboratories, Department of Biochemistry, University of Ibadan, Ibadan, Nigeria.

²International Institute of Tropical Agriculture, Oyo Road, P. M. B. 5320, Ibadan, Oyo State, Nigeria.

Accepted 22 March, 2020

Abstract

Raw and processed tubers from eight genotypes of yellow yam (Dioscorea cayenensis) were evaluated for their contents of iron, zinc, calcium, phosphorus, total carotenoids, vitamin C, phytic acid and tannin. The mean values obtained (in mg/kg on dry weight basis) were 7.2 for iron, 9.2 for zinc, 169.3 for calcium, 1331.3 for phosphorus, 181.8 for phytate and 353.6 for tannin. Similarly, 6.31 µg/g of total carotenoids and 37.3 mg/kg of ascorbic acid were obtained on fresh weight basis. The genotypes differed significantly (P < 0.05) in tuber contents of zinc, calcium, phosphorus, total carotenoids and vitamin C but they were similar with respect to iron, phytate and tannin contents. Genotype TDc 95-65 had the highest levels of zinc, calcium, total carotenoids and phytate while TDc 95-294 had the highest levels of iron and phytate. Tubers of TDc 95-65, TDc, 95-294, TDc 04-168 and TDc 98-136 are good sources of iron, zinc and phosphorus. The two cooking methods had little effect on the minerals but significantly reduced the levels of total carotenoid, vitamin C, phytate and tannin contents.

Key words: Antinutrients, boiling, Dioscorea cayenensis, phytic acid, pounding and tannin.

African Journal of Agriculture and Food Security ISSN 2375-1177 Vol. 8 (4), pp. 001-004, April, 2020. © International Scholars Journals

Full Length Research Paper

Stability studies and mineral concentration of some Nigerian packed fruit juices, concentrate and local beverages

Dosumu O. O., Oluwaniyi O. O.*, Awolola G. V. and Okunola M. O.

Department of Chemistry, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria.

Accepted 13 February, 2020

Abstract

Time stability and mineral content of some Nigerian packet fruit juices, concentrate and local beverages (sobo drink, kunnu drink, pito and burukutu ) were determined. The pH of the beverages was fairly stable throughout the 15 days the experiment lasted. The acid contents were within suitable range for human consumption and ranged from 0.041 M – 0.205 M. The concentrate has the highest titratable acidity ranging from 0.098 M on day 1 to 0.205 M on day 15. Elemental analysis of the minerals showed that the beverages were rich in macronutrients. Potassium was found to be the most abundant with content ranging from 4.35 – 5.85 mg/mL while manganese and copper were not detectable. Sodium content was between 1.300 – 1.335 mg/mL; calcium 0.560 – 0.925 mg/mL; magnesium 0.005 – 0.06 mg/mL; iron 0.005 – 0.025 mg/mL and zinc 0.005 – 0.010 mg/mL. The results showed that the drinks contain safe levels of mineral elements for human consumption and are sufficiently stable and safe.

Key words: Stability, fruit juices, beverages, concentrate, mineral content.

African Journal of Agriculture and Food Security ISSN 2375-1177 Vol. 8 (4), pp. 001-005, April, 2020. © International Scholars Journals

Full Length Research Paper

Antibacterial effects of extracts of Ocimum gratissimum and piper guineense on Escherichia coli and Staphylococcus aureus

Nwinyi, Obinna C.¹*, Chinedu, Nwodo S. ¹, Ajani, Olayinka O. ², Ikpo Chinwe.O² and Ogunniran, Kehinde O.²

¹Department of Biological Sciences, College of Science and Technology, Covenant University. KM 10 Idioroko Road, Canaanland, PMB 1023 Ota, Ogun State, Nigeria.

²Department of Chemistry, College of Science and Technology, Covenant University, Km 10 Idiroko Road, PMB 1023, Ota, Ogun State, Nigeria.

Accepted 14 February, 2020

Abstract

The upsurge in the prevalence of side effects of many synthetic antimicrobial agents and incidence of multidrug resistant bacteria has spurred scientists on the research for plant based antimicrobial of therapeutic potentials. Ocimum gratissimum and Piper guineense present such potential of high medicinal value. These plants are used in Nigeria traditionally as condiments and for treatment of various ailments such as pyorrhea, dysentery and bronchitis. Aqueous and ethanol extracts of O. gratissimum and P. guineense leaves were screened for antibacterial activity against Escherichia coli and Staphylococcus aureus. Both extracts were found to exhibit selective inhibition against the isolates. The diameter zones of inhibition exhibited by the extracts were between 2 + 0.01 – 10 + 0.10 The minimum inhibitory concentration (MIC) determined by the agar diffusion method was between 10.00 and 2.50 mg/ml^-1. Ethanol extracts showed more inhibitory effect compared to the aqueous extracts. Results obtained show that the extracts of O. gratissimum and P. guineense possess some level of antibacterial activities against E. coli and S. aureus.

Key words: Ocimum gratissimum, Piper guineense, antibacterial activity, minimum inhibitory concentration (MIC), Escherichia coli, Staphylococcus aureus.

African Journal of Agriculture and Food Security ISSN 2375-1177 Vol. 8 (4), pp. 001-009, April, 2020. © International Scholars Journals

Full Length Research Paper

Trials towards reduction of fungal growth and aflatoxin G1 production in Arabic coffee using different additives

Fardos Bokhari* and Magda Mohammad Aly

Faculty of Science, Biology Department, King Abd El-Aziz University, P. O. Box 12161, Jeddah 21473, Saudi Arabia.

Accepted 09 February 2020

Abstract

Thirty samples of coffee beans were collected from different places of Jeddah, Saudi Arabia to determine and identify fungal population. Twenty six species belonging to 7 genera were isolated using potato dextrose agar (PDA) and malt extract agar (MEA) media at 28°C. The most prevalent genera were Aspergillus and Penicillium. Aspergillus was present in 73 and 100% of the samples but Penicillium was present in 86.6 and 100% on the two mentioned media, respectively. Also, Fusarium, Mucor, Rhizopus and Alterneria were recovered in moderate incidences on the two media. Out of the thirty samples of coffee beans collected, thirteen were contaminated with mycotoxin (43.3%). Mycotoxin profiles were also determined in these samples. It was found that aflatoxin G1 (Afl G1) showed the highest incidence rates of occurrence. It occurred in about 23.3% of all samples analyzed and in 54% of the mycotoxin contaminated samples. The other toxins detected were aflatoxins B1 (16.6%), B2 (10%), G2 (6.6%), ochratoxin (10%), patulin (16.6%) and sterigmatocystin (6.6%). The factors affecting the Afl G1 production by Aspergillus flavus were studied. The results clarified that addition of caffeine up to 1 g/l reduced the toxin synthesis (Afl G1) . The effect of some medicinal plants and spices added singly or in combination to the malt extract, on fungal growth and AflG1 production by A. flavus was also studied. Cinnamon and cloves affected fungal growth and mycotoxin production. No growth or toxins were detected in the presence of the two plants. Saffron and ginger did not affect fungal growth or prevented toxin production by A. flavus. In conclusion, coffee beans in Saudi Arabia are highly contaminated with toxigenic fungi, specially, A. flavus, which was found in this study to be the main producer of Afl G1. Medium, temperature, vitamin C, caffeine and some medicinal plants or spices which are used as a traditional additive in Saudi Arabia may affect fungal growth or/and toxin production.

Key words: Aflatoxins, mycotoxin, Aspergillus, coffee beans, secondary metabolites, medicinal plant, spices, additives.

African Journal of Agriculture and Food Security ISSN 2375-1177 Vol. 8 (3), pp. 001-007, March, 2020. © International Scholars Journals

Full Length Research Paper

Quality of fufu processed from cassava mosaic disease (CMD) resistant varieties

Etudaiye, H.A.¹, Nwabueze, T.U.² and Sanni, L.O.³

¹National Root Crops Research Institute (NRCRI), Umudike, P. M. B 7006, Umuahia, Abia State, Nigeria.

²Michael Okpara University of Agriculture, Umudike, P. M. B 7267, Umuahia, Abia State, Nigeria.

³International Institute of Tropical Agriculture, Ibadan, P. M. B 5320, Ibadan, Oyo State, Nigeria.

Accepted 14 October 2019

Abstract

Cassava fufu flours were produced from 43 Cassava Mosaic Disease resistant varieties. The cassava roots were washed, peeled and steeped in water in a 1:2 (v/v) for 48 h to ferment. The fermented pulp was sieved and mechanically milled into flour of 3.0 mm particle size. Proximate composition, functional properties and pasting characteristics of the ‘fufu’ flours were assessed. Moisture content ranged from 5.52 to 12.25%, protein 0.35 to 2.80% and dry matter 87.75 to 94.48%. Water absorption capacity ranged from 0.70 to 2.20 g/ml. The CMD varieties 92B/00068 and M98/0068 had the highest water absorption capacity values. Bulk density ranged from 0.61 in the variety 98/2226 to 0.70 g/ml in varieties 98/0505, 98/0510, 95/0379 and 95/0289 while final viscosity of the fufu flours ranged from 76.00 in 96/1569 to 295.00 RVU in the 99/6012 and pasting temperature from 77.55 to 81.60^oC. Given the economic and nutritional importance of cassava, the development and subsequently processing the CMD resistant varieties into fufu flour will help to improve food security and diversity not only in Nigeria but also beyond.

Key words: Cassava mosaic disease (CMD), fufu, functional properties, pasting characteristics.