Quality Mapping of Tigernut Oil and the Extraction Efficiency Between n-Hexane and Petroleum Ether Solvents

Edible Tigernut (Cyperus esculentus) oil samples were separately extracted using n-hexane and petroleum ether solvents. This study aimed at comparing the extraction efficiencies of both solvents and the quality and colour of oil produced with a view for large scale industrial application.  The quality parameters tested included moisture content, saponification value (SV), iodine value (IV), peroxy value (PV), free fatty acid content (FFA), unsaponifiable matter, total fatty matter (TFM), titre (oC), impurity, and colour.. Results showed that n-hexane extraction efficiency was 86% and significantly higher (p<0.05) than that of petroleum ether which gave 75%. n-Hexane produced 17.10g or 19.01±0.11cm³ of oil yield from 20g of powdered tigernut seed, while petroleum ether produced 15.05g or 16.72±0.12 cm³ of oil from 20g of powdered tigernut seed. The mean SG of oil samples was 0.8917±0.011 at 40oC. The appearance of oil extracted with n-hexane was brighter and golden yellow, when compared to that of pet ether which gave a brownish-yellow tint. The colour on Lovibond Scale (R*Y*B*N) using 51/4” cell, showed n-hexane extracted oil to be 0.9R, 10Y, 0B, 0N, while the pet ether extracted oil gave 1.2R 12Y, 0.5B, 0N. There was no significant difference in moisture content of both oil samples. The mean values of chemical quality parameters for both oil samples gave saponification value 209.33±0.58, iodine value 91.33± 0.58 , peroxide value 1.06±0.01, ester value 208.33±1.16, moisture content 0.23± 0.021%, free fatty acid content 0.24±0.0058%, impurity content 0.013±0.0058%, unsaponifiable matter 0.11±0.01% and total fatty matter 95.03±0.027%. GC-MS analysis gave seven major fatty acids of the oil samples after conversion to fatty acid methyl esters (FAMEs). Five of these fatty acids were saturated (SFA) and include  lauric acid (1.32±0.08%); myristic acid (31±1.0%); palmitic acid (14.6±0.1%); stearic acid (3.37±0.15%); crotonic acid (0.53±0.068%), giving a total SFA content of 44.77 ±0.29%. The other two were unsaturated fatty acids (UFA), and included oleic acid (45.9±1.83%) and linoleic acid (9.37±0.15%), giving a total of (55.17±0.76%) UFA content. Therefore, the ratio of UFA:SFA gave 1.18±0.0058, suggesting that the oil may be categorized as an ω-6 edible oil. The quality parameters tested, established the quality mapping for quality control, standardization and regulatory activities of future tigernut oil industry in Nigeria. Keywords: Tigernut,  Oil quality, extraction efficiency, fatty acid, ω-6 edible oil

Anti-nutrient Content, and in vitro Protein Digestibility (IVPD) of Infant Food Produced from African Yam Bean (Sphenostylis sternnocarpa), and Bambara Groundnuts (Voandezela subterranean)

Abstract. African yam bean (AYB) (Sphenostylis stenocarpa) and bambara groundnut (BG) (Voadzeia subterranean) are some of the pulses with unutilized high nutritional value. The aim of this study was to assess the anti-nutrient content of raw and processed AYB and BG, and infant weaning diets formulated from flour processed from both crops, using a Nestle Infant formula (Nutrend) as standard. Reduction of anti-nutrient content was carried out using soaking and germination procedures, followed by oven drying at 105 o C. After germination there was 92.13% tannin, 82.01% phytate, 60.14% cyanate and 80.36% oxalate reductions in AYB. There was 84.34% tannin, 82.34% phytate, 50.04% cyanate and 82.14% oxalate decreases in BG. Anti-nutrient contents of diets ranged from 14.31±0.75 -15.20± 0.61 mg/g for tannin, 17.02±0.81 -24.82±1.65 mg/g for phytate, 1.34±0.01 -1.43±0.01 mg/g for cyanate and 0.14±0.02 -0.55±0.05 mg/g for oxalate. These values compared well with those of the standard formula which gave 15.20±0.52 mg/g, 26.01±1.64 mg/g, 1.56±0.03 mg/g and 0.82±0.05 mg/g anti-nutrient contents of tannin, phytate, cyanate and oxalate. There was a significant (p<0.05) increase in digestibility values of diet 1 (87.60%), diet 2 (85.65%), and diet 3 (84.35%), while the standard diet 4 gave 85.31% digestibility value. Protein concentration (Pe%) of diets were 25.97%, 24.27% and 22.96%, for diets 1, 2 and 3, compared to 18.03% obtained for standard diet 4. The PE% profile and low antinutritional contents in test diets suggest that the diet formulas may serve as alternative infant weaning formulations. Thus, AYB and BG may serve as alternative infant weaning food and bridge in food security gap for weaning formulas

Poly-Electrophilic Sesquiterpene Lactones from Vernonia amygdalina: New Members and Differences in Their Mechanism of Thiol Trapping and in Bioactivity

In addition to known compounds, the leaves of Vernonia amygdalina afforded the new sesquiterpene lactones 14-O-methylvernolide (2), 3'-deoxyvernodalol (6), and vernomygdalin (8). These and related compounds were evaluated for modulation of a series of thiol trapping-sensitive transcription factors (NF-κB, STAT3, and Nrf2), involved in the maintenance of the chronic inflammatory condition typical of human degenerative diseases. Vernolide (1) emerged as a potent inhibitor of STAT3 and NF-κB and showed cytostatic activity toward the prostate cancer cell line DU45, arresting the cell cycle at the S phase. The exomethylene lactones are characterized by multiple Michael acceptor sites, as exemplified by vernolide (1) and vernodalol (5). By using the nuclear magnetic resonance-based cysteamine assay, the most reactive thiophilic site could be identified in both compounds, and competitive experiments qualified vernolide (1) as being more thiophilic than vernodalol (5), in agreement with the results of the pharmacological assays