hashim ibrahim

Vegetable consumption has been linked in different studies to reducing non-communicable diseases, particularly diabetes, cancer, respiratory disease, and cardiovascular disease. This study selected five leafy vegetables, and their physicochemical characteristics, fatty acid compositions, and functional quality indices were evaluated.

Foreign particles were removed from the samples (Cochorus olitorius, Celosia argentea, Crassocephalum crepidioides, Solanum macrocarpon, and Launaea taraxacifolia) by way of cleaning and were air-dried, and the extraction of the oil was done using the Soxhlet technique. Standard analytical methods were used to determine the physicochemical parameters of the extracted oils, while the gas chromatography technique was used to determine the fatty acid profiles.

The physicochemical parameters of the extracted oils were in the range of 1.08–1.31 meq O2/Kg for peroxide value, 0.14–0.17 mg KOH/g for acid value, 158.92–180.21 mg KOH/g for saponification value, 80.49–102.21 mg I2/g for iodine value, 0.65–0.88% for unsaponifiable matter, 1.29–1.40 at 40 °C for refractive index, and 0.93–1.10 at 15 °C for specific gravity. The predominant fatty acids in all the studied samples were palmitic (29.32–37.44%), linoleic (19.73–22.54%), γ-Linolenic (13.91–16.29%), and α-Linolenic (16.74–19.64) acids. PUFAs constitute over two-thirds of the total UFAs, with linoleic acid having the highest abundance of UFA in all the samples. The calculated ratios of ω 6/ω 3 (1.98–2.05), hypocholesterolemic to hypercholesterolemic (h/H) (1.10–1.59), atherogenicity index (AI) (0.44–0.64), thrombogenicity index (TI) (0.40–0.58), the phospholipid composition of the vegetables had a range of 4.36 to 67.96 mg/100 g. The phytosterol concentrations were between 35.4 and 40.6 mg/100 g and were within the acceptable limit of ≤ 10 for edible oils. The evaluated parameters indicated the vegetable oil samples to be of high nutritional quality with preventive potential against chronic degenerative diseases.

Garlic (Allium sativum) and ginger (Zingiber officinale), as cooking spices, are popular medicinal plants for treating various ailments and physiological disorders. These plants contain a lot of polyunsaturated fatty acids and other bioactive metabolites. This study aims to evaluate physicochemical properties, fatty acid profile, and quality parameters of the oil extracted from Allium sativum and Zingiber officinale.

Fresh Allium sativum and Zingiber officinale were purchased from a local market in Lafia local government, Nasarawa state, Nigeria. The samples were cleaned to remove foreign particles, sun-dried, and the oil was extracted by steam distillation. Physicochemical parameters of the extracted oil including peroxide value (PV), iodine value (IV), acid value (AV), saponification value (SV), unsaponifiable matter (USM), specific gravity (SG), and refractive index (RI) were determined using standard analytical methods, and fatty acid profile was determined by using gas chromatograph.

Physical properties of the extracted oil from Allium sativum and Zingiber officinale were in the range of 0.90-0.97 at 15 oC for SG, and 1.49-1.50 at 40 oC for RI. The chemical parameters ranged from 2.42 to 2.61 meq/kg for PV, 105.64 to 116.20 mg I2/g for IV, 2.60 to 4.52 mg KOH/g for AV, 182.15 to 191.22 mg KOH/g for SV, and 1.02 to 1.11 mg KOH/g for USM. In gas chromatography, 13 and 16 fatty acids were identified in Allium sativum oil and Zingiber officinale oil, respectively. Linoleic acid (25.81-52.20%), oleic acid (20.77-24.06%), and palmitic acid (19.75-20.52%) were the main fatty acids in both samples. The quality parameters including ratio of polyunsaturated/saturated fatty acids (0.64-2.43), ratio of hypocholesterolemic/hypercholesterolemic fatty acids (2.03-3.87), atherogenicity index (0.27-0.91), and thrombogenicity index (0.50-0.80) were within the acceptable range. The fatty acid profile and the quality parameters of the oil samples imply their medicinal and flavoring strength, and candidate them for extended use in food, drug, and cosmetics industries.