Effects of thermal treatment on the characteristics quality of some Ghanaian vegetable oils (palm, coconut and groundnut)

Introduction: Vegetable oils contain natural antioxidants and other properties reported to impart anti-diabetic properties when consumed, in animal study. In humans however, these oils are subjected to high temperatures during cooking before consumption. High temperature tends to affect the characteristic quality and potential to impart on health benefits such as antidiabetic properties. The objective of this work was to determine the characteristics quality of vegetable oils after thermal treatment that equates to temperatures oils are subjected to during food processing/cooking.Methodology: Three portions of 200g of each fresh unrefined red palm oil, coconut oil and groundnut oils in three conical flasks T1, T2 and T3 were heated to room temperature 28oC (T1) to 100o C in boiling water (T2) and to 200o C in electric cooker oven (T3) for 10 minutes. Acid, iodine, peroxide, saponification, unsaponification values of the oils, Phytoconstituents (Flavanoids, polyphenols saponins etc) and antioxidant (Vitamin A&C) and DPPH (1,1-Diphenyl-2-Picrylhydrazyl) Radical Scavenging Activity were then determined after cooling to room temperature. Results: Coconut oil heated to 200˚C had the least Acid value of 2.89±0.135 whiles Palm oil heated to 100 ˚C had the highest value of 19.57±0.165. There were no peroxides formed in Coconut and Palm oils at 28 ˚C as well as Palm oil at 100 ˚C. However, peroxides were highest in Coconut oil at 200˚C with value of 15.28±2.315. Saponification value of groundnut oil at 28 ˚C was the least at 89.52 ± 2.18 and 296.57±1.045 the highest in coconut oil at 200 ˚C. Heating however increased the unsaponifiable matter in all the vegetable oils used. Total antioxidant capacity was not significantly changed across the temperature treatment. Total phenolic content was not significantly changed for palm oil but was significantly increased at 100C for coconut and groundnut oilsConclusion: The quality of the oils in terms of acid value, iodine vale, peroxide value and saponification value, total antioxidant and phenolic content were retained after one heat treatment. This implies the quality of the oils are maintained after a single heating. The oils may still retain antidiabetic property when consumed after processing.

Effect of Graphene Nanoparticles Addition on Superconductivity of YBa2Cu3O7~δ Synthesized via the Thermal Treatment Method

The development of high-temperature superconductor (HTS) YBa2Cu3O7~δ (Y123) bulks in industrial applications were established years ago. It is one of the developments that currently attracts great attention especially in transportation, superconductor cables and wires. This study is focused on the preparation of the Y123 bulk superconductors by the thermal treatment method due to the promising ways to develop high-quality Y123 superconductors with its simplicity, low cost, and relatively low reaction temperature used during the process. Y123 were added with graphene nanoparticles (x = (0.0–1.0) wt.%). Samples were then characterized by X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), and alternating current susceptibility (ACS). It was found that Y123 confirmed that the majority of phases in all the XRD patterns was the orthorhombic crystal structure and the Pmmm space group with secondary phases belonged to Y2Ba1Cu1O5 (Y211). The highest Tc obtained when graphene nanoparticles were added in the Y123 sample was x = 1.0 wt.%, followed by x = 0.5 wt.% with 92.64 and 92.59 K, respectively. From the microstructure analysis, the average grain size significantly decreased to 4.754 µm at x = 0.5 wt.%. The addition of graphene nanoparticles had disturbed the grain growth of Y123, affecting the superconducting properties of the samples. On the other hand, the intergranular critical current density, Jcm, was found to increase with graphene nanoparticle addition and had the highest value at x = 1.0 wt.%, indicating that graphene nanoparticles acted as pinning centers in the Y123 matrix.

High Pressure Processing Impact on Emerging Mycotoxins (ENNA, ENNA1, ENNB, ENNB1) Mitigation in Different Juice and Juice-Milk Matrices

The aim of the present study was to investigate the potential of high-pressure processing (HPP) (600 MPa during 5 min) on emerging mycotoxins, enniatin A (ENNA), enniatin A1 (ENNA1), enniatin B (ENNB), enniatin B1 (ENNB1) reduction in different juice/milk models, and to compare it with the effect of a traditional thermal treatment (HT) (90 °C during 21 s). For this purpose, different juice models (orange juice, orange juice/milk beverage, strawberry juice, strawberry juice/milk beverage, grape juice and grape juice/milk beverage) were prepared and spiked individually with ENNA, ENNA1, ENNB and ENNB1 at a concentration of 100 µg/L. After HPP and HT treatments, ENNs were extracted from treated samples and controls employing dispersive liquid-liquid microextraction methodology (DLLME) and determined by liquid chromatography coupled to ion-trap tandem mass spectrometry (HPLC-MS/MS-IT). The results obtained revealed higher reduction percentages (11% to 75.4%) when the samples were treated under HPP technology. Thermal treatment allowed reduction percentages varying from 2.6% to 24.3%, at best, being ENNA1 the only enniatin that was reduced in all juice models. In general, no significant differences (p > 0.05) were observed when the reductions obtained for each enniatin were evaluated according to the kind of juice model, so no matrix effects were observed for most cases. HPP technology can constitute an effective tool in mycotoxins removal from juices.