Abdalbasit Adam Mariod

Determination of aflatoxin levels in Sudanese edible oils.

Fifty-six samples of groundnut, sesame and cottonseed oils form factories, and traditional mills were collected from several localities in Kordofan, Gezira and Khartoum states, Sudan and assessed for aflatoxin B(1) (AFB(1)), aflatoxin B(2) (AFB(2)), aflatoxin G(1) (AFG(1)) and aflatoxin G(2) (AFG(2)), using high performance liquid chromatography (HPLC). Aflatoxin B(1) (AFB(1)) was detected in eight samples representing 14.3%, the highest incidence of aflatoxin contamination occurred in sesame (7 out of 16 samples, 43.75%) followed by groundnut (1 out of 28 samples, 3.57%) while no aflatoxin contamination was detected in cottonseed oil. Aflatoxin B(1) levels in sesame oil samples ranged from 0.2-0.8 microg/kg and were 0.6 microg/kg in groundnut oil samples. All aflatoxin contaminated samples are unrefined. This paper reports the findings of the first exploratory investigation on presence of aflatoxins in Sudanese edible oils collected from three states.

Chemical composition, antioxidant and antibacterial properties of the essential oils of Etlingera elatior and Cinnamomum pubescens Kochummen.

BACKGROUND Plant essential oils are widely used as fragrances and flavours. Therefore, the essential oils from the leaves of Cinnamomum pubescens Kochummen (CP) and the whole plant of Etlingera elatior (EE) were investigated for their antioxidant, antibacterial and phytochemical properties. RESULTS CP and EE were found to contain appreciable levels of total phenolic contents (50.6 and 33.41 g kg(-1) as gallic acid equivalent) and total flavonoid contents (205.6 and 244.8 g kg(-1) as rutin equivalent), respectively. DPPH free radical scavenging activity of CP is superior to EE (P < 0.05) showing IC(50) of 77.2 and 995.1 µg mL(-1), respectively. Methicillin-resistant Staphylococcus aureus (MRSA), Bacillus subtilis, Pseudomonas aeruginosa and Salmonella choleraesuis were tested against CP and EE. Only MRSA was the most susceptible bacteria to CP. GC/MS studies resulted in the identification of 79 and 73 compounds in CP and EE, respectively. The most abundant components of EE included β-pinene (24.92%) and 1-dodecene (24.31%). While the major compound in CP were 1,6-octadien-3-ol,3,7-dimethyl (11.55%), cinnamaldehyde (56.15%) and 1-phenyl-propane-2,2-diol diethanoate (11.38%). CONCLUSION This study suggests that the essential oils from Cinnamomum pubescens Kochummen and Etlingera elatior could be potentially used as a new source of natural antioxidant and antibacterial in the food and pharmaceutical industries.

Sclerocarya birrea (Marula), An African Tree of Nutritional and Medicinal Uses: A Review

Sclerocarya birrea (Anacardiaceae) is a popular African wild tree distributed in many African countries where the leaves, stem bark, root, and fruits are used in food and traditional medicine; the fruit is rich in ascorbic acid. The fruit juice contains sesquiterpene hydrocarbon, which are terpenes found in plants that are reported to have bacteriostatic properties. The fruit contains a hard brown seed. The seed encloses a soft white kernel rich in oil and protein. The oil contains oleic, palmitic, myristic, and stearic acids; the kernel protein contains amino acids, with a predominance of glutamic acid and arginine. The extracts from different parts showed high total phenolic compounds and radical-scavenging capacities and antioxidant activities. Sclerocarya birrea is widely studied with regard to its antidiabetic, anti-inflammatory, analgesic, antiparasitic, antimicrobial, and antihypertenisve activities.

Proximate amino acid, fatty acid and mineral composition of two Sudanese edible pentatomid insects

The amino acid, fatty acid and mineral composition of Aspongubus viduatus F. (melon bug) and Agonoscelis pubescens (Thunberg) (sorghum bug) were investigated. The approximate analyses of A. viduatus and A. pubescens adults showed 8.3 and 7.6% moisture, 27.0 and 28.2% crude protein, 54.2 and 57.3% fat and 3.5 and 2.5% ash on a dry-matter basis, respectively. The bug protein contained 16 amino acids, including all of the essential ones. Compared with the amino acid profile recommended by FAO/WHO, the protein was of medium quality. The most predominant fatty acids in melon bug oil were oleic, palmitic, linoleic and linolenic acids, viz. 45.5, 31.3, 4.9 and 0.48%, respectively and in sorghum bug 41.15, 11.41, 35.28 and 1.28%, respectively. The mineral analysis indicated high P and K content. Scanning electron microscopy was used to study ground insect structure before and after oil extraction. Micrographs of full-fat ground insects were different from defatted ones.

Physicochemical Properties, Phenolic Contents and Antioxidant Activity of Sudanese Honey

The physicochemical properties, antioxidant activities and phenolic contents of seven types of Sudanese honeys derived from flowers of Acacia nilotica, Acacia seyal, Azadirachta indica, Cucurbita maxima, Balanites aegyptiaca, and two Ziziphus spina christi plant species were evaluated. The moisture content was in the range from 16.2 to 21.3, g/100 g honey, ash content from 0.121 to 1.205 g/100 g honey, nitrogen from 0.032 to 0.046 g/100 g honey while the corresponding protein content was 0.200 to 0.286 g/100 g honey. Total phenolic content varied from 4.44 to 201.08 mg/100 g honey as gallic acid equivalent. The values of the antioxidant activities were in a range from 3177 to 6247 μg for the lC50. No significant correlation was established between antioxidant activity and total phenolic contents.

Rapid prediction of phenolic compounds and antioxidant activity of Sudanese honey using Raman and Fourier transform infrared (FT-IR) spectroscopy

Fourier transform infrared with attenuated total reflectance (FTIR-ATR) and Raman spectroscopy combined with partial least square regression (PLSR) were applied for the prediction of phenolic compounds and antioxidant activity in honey. Standards of catechin, syringic, vanillic, and chlorogenic acids were used for the identification and quantification of the individual phenolic compounds in six honey varieties using HPLC-DAD. Total antioxidant activity (TAC) and ferrous chelating capacity were measured spectrophotometrically. For the establishment of PLSR model, Raman spectra with Savitzky-Golay smoothing in wavenumber region 1500-400cm-1 was used while for FTIR-ATR the wavenumber regions of 1800-700 and 3000-2800cm-1 with multiplicative scattering correction (MSC) and Savitzky-Golay smoothing were used. The determination coefficients (R2) were ranged from 0.9272 to 0.9992 for Raman while from 0.9461 to 0.9988 for FTIT-ART. The FTIR-ATR and Raman demonstrated to be simple, rapid and nondestructive methods to quantify phenolic compounds and antioxidant activities in honey.

Rapid Determination of Antioxidant Compounds and Antioxidant Activity of Sudanese Karkade (Hibiscus sabdariffa L.) Using Near Infrared Spectroscopy

The extraction conditions applied in destructive analysis of Hibiscus sabdariffa L. (Hs) matrices before the measurement of antioxidant compounds may reduce their activities during isolation and purification due to decomposition. Hence, near infrared spectroscopic system was applied to determine these compounds. The calibration models developed by using partial least squares regression (PLSR) with 48 Hs samples and 24 unknown samples were used to confirm the robustness of the developed model. The results of calibration models effectively allowed the determination of the concentrations of total phenol content (TPC), total flavonoid content (TFC), total antioxidant content (TAC), ferric reducing antioxidant power (FRAP), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) with high correlation coefficients (0.85–0.91) and small standard error of cross-validation (RMSECV) ranged from 0.08 to 0.33. The prediction capacity (RPD) for TPC, TFC, TAC, FRAP, and DPPH ranged from 3.30 to 8.25, thus demonstrating that the near infrared spectroscopic (NIRS) equations developed were applicable to unknown samples. This study demonstrates that NIRS can be considered as a fast tool for the nondestructive determination of antioxidant compounds (phenolics and flavonoids) and antioxidant activity of the Hs.

Aflatoxin B1 levels in groundnut and sunflower oils in different Sudanese states

In this article, the level of contamination of aflatoxin B1 (AFB1) in groundnut and sunflower oils was determined. The 241 oil samples were collected from Khartoum, Gezira, Kordofan and Algadarif states of Sudan and assessed for AFB1 using high-performance liquid chromatography (HPLC). AFB1 levels in groundnut oil samples ranged from 0.5 to 70 µg/kg and were 0.7 to 35 µg/kg in sunflower oil samples. High contamination was found in unrefined samples. It was concluded that AFB1 levels in oil samples indicated that growing, harvesting, handling and storage of the crops were not done properly.

Effect of the method of processing on quality and oxidative stability of anhydrous butter fat (samn).

In this study four samn samples prepared from cow milk using two processing methods (traditional T1, T2 and factory processed T3, T4) were investigated for their physico-chemical properties, fatty acids composition, oxidative stability and sensory properties. The traditionally processed samples showed a significance difference (p < 0.05) in peroxide value and acid value in comparison to factory processed ones. The peroxide value was 2.5 meq O 2/kg of samn for both T3 and T4 samples, which was higher than the peroxide value of T1 and T2, which was 1.5 and 2.0, respectively. The acid value of T3, T4, T1 and T2 are 2.58, 2.54, 1.122 and 1.121, respectively. The results showed that the FFA% of T3, T4, T1 and T2 are 1.29, 1.27, 0.6 and 0.6, respectively. The major fatty acids of the four samn samples were palmitic, oleic, stearic, myristic and capric acid. T3 and T4 contain high percentage of palmitc acid 37.29 and 39.23%, respectively. Traditionally processed sample T1 contains high amount of oleic acid (26.1%) in comparison with the other three samples. Method of processing affects samn properties, quality and oxidative stability, where traditionally processed samples were significantly preferred (P ≤ 0.05) by the panelists for their color, odor, taste and overall acceptability to the factory processed samples.

Color of Dehydrated Tomato: Effects of Gum Arabic

The efficacy of gum arabic, as a color preservative and inhibitor of non-enzymatic browning of dehydrated tomato during storage, was studied and compared with sodium metabisulfite. Tomato homogenates were treated with 1, 2.5, 5, 7.5, and 10.0% gum arabic and 1.0% sodium metabisulfite, respectively, dehydrated, and color changes were monitored during four months of storage. Water activity decreased significantly (P ≤ 0.05) and Brix values increased significantly (P ≤ 0.05) in gum arabic-treated samples. pH of metabisulfite treated samples is significantly (P ≤ 0.05) higher than that of control and gum arabic treated samples. Lightness (L*) value increased significantly (P ≤ 0.05) with the addition of 5–10% gum arabic compared to the dehydrated control. Browning index of dehydrated tomato decreased significantly (P ≤ 0.05) with the treatments, 1 and 2.5% Gum Arabic, 1% metabisulfite, 5, 10, and 7.5% gum arabic, respectively. Gum arabic at 5–10% (w/w) was more suppressed to browning than sodium metabisulfite. Gum arabic preserved color of dehydrated tomatoes up to 4 months of storage.