Preventing oxidation of canola and sunflower oils by addition of pomegranate seed oil

The study was designed to explore the antioxidative effect of pomegranate seed oil (PSO) at different concentrations (5 and 7%) against oxidation of plant-based oils (canola oil and sunflower oil) during storage (60 days) as compared to artificial antioxidant butylated hydroxyanisole (BHA, 200 ppm). Rancimat and Schaal oven analysis were employed for the assessment of potential consequences of PSO against oxidation in plant based oils. The variation in total phenolic contents (TPC), antioxidant activity, peroxide value (POV), and tocopherol contents during storage were evaluated by Schaal oven test at 62 °C. The substantially (P≤0.05) higher induction period (IP) values were observed for PSO blended oil samples as compared to blank oil samples. The addition of PSO in plant-based oils improved the oxidative stability by enhancing the antioxidant potential and TPC, decreasing POV, and slowing down the degradation of tocopherol contents during storage. The findings of the present study suggest that PSO might be used as an alternative potential antioxidant to synthetic antioxidants

Mixed convection dissipative viscous fluid flow over a rotating cone by way of variable viscosity and thermal conductivity

AbstractThe effects of temperature-dependent viscosity and thermal conductivity on the flow and heat transfer characteristics of a viscous fluid over a rotating vertical cone are premeditated. The properties of the fluid are assumed to be constant except for the density difference with the temperature. Also, the effect of viscous dissipation is considered in the energy equation. The highly nonlinear unsteady equations are converted into a system of nonlinear ordinary differential equations which is solved by using Homotopy analysis method. The interesting findings for different pertinent parameters on momentum, energy, skin friction coefficient and local Nusselt number are demonstrated in the form of graphs and tables. A comparison has been made with literature as a limiting case of the well-chosen unsteady problem

Characterisation of bacteriocins produced by Lactobacillus spp. isolated from the traditional Pakistani yoghurt and their antimicrobial activity against common foodborne pathogens

Lactic acid bacteria (LAB) are widely known for their probiotic activities for centuries. These bacteria synthesise some secretory proteinaceous toxins, bacteriocins, which help destroy similar or interrelated bacterial strains. This study was aimed at characterising bacteriocins extracted from Lactobacillus spp. found in yoghurt and assessing their bactericidal effect on foodborne bacteria. Twelve isolated Lactobacillus spp. were examined to produce bacteriocins by the organic solvent extraction method. Bacteriocins produced by two of these strains, Lactobacillus helveticus (BLh) and Lactobacillus plantarum (BLp), showed the most significant antimicrobial activity, especially against Staphylococcus aureus and Acinetobacter baumannii. Analysis of SDS-PAGE showed that L. plantarum and L. helveticus bacteriocins have a molecular weight of ~10 kDa and ~15 kDa, respectively. L. plantarum (BLp) bacteriocin was heat stable while L. helveticus (BLh) bacteriocin was heat labile. Both bacteriocins have shown activity at acidic pH. Exposure to a UV light enhances the activity of the BLh; however, it had negligible effects on the BLp. Different proteolytic enzymes confirmed the proteinaceous nature of both the bacteriocins. From this study, it was concluded that bacteriocin extracts from L. helveticus (BLh) can be considered a preferable candidate against foodborne pathogens as compared to L. plantarum (BLp). These partially purified bacteriocins should be further processed to attain purified product that could be useful for food spoilage and preservation purposes

Heavy Metal Levels in Vegetables and Soil Cultivated with Industrial Wastewater from Different Sites of Chunian and Jamber, District, Kasur

In human diet, vegetables play important role to maintain the physiological conditions. Due to anthropogenic activities and pollution, the food items become contaminated. The present study was performed to evaluate the level of heavy metals in the vegetables irrigated with wastewater across Chunian and Jamber, district, Kasur. Level of heavy metals from the study area like Zinc, Lead and chromium in the soil, water and vegetables was compared. The four sites of each city and 10 vegetables e.g. potato, radish, carrot, fenugreek, spinach, tomato, Onion, Turnip, Cauliflower, Pangalo were selected to conduct the experiment. The vegetables were irrigated with industrial wastewater and the concentration of heavy metals was measured by the atomic absorption spectrophotometer (AAS). We concluded that the level of heavy metals was beyond the FAO limits in irrigated water due to industrial waste. In Jamber and Chunian, the level of Zn and Pb was high and beyond the FAO safe limits in the all water sample, the level of Cr was much higher only in the water sample of one site from Jamber. The concentration of zinc was higher in soil samples as compared to lead and chromium. Zn and Pb in vegetables of study area were labeled as priority pollutants but this concentration was within the safe limits set by FAO. However, constant inspection of heavy metals is recommended to avoid accumulation in the food chain and thus avoid human health risks. Keywords: Atomic absorption spectrophotometer, Heavy metals, Industrial wastewater, Vegetables

Creep processes in magnesium alloys and their composites

A comparison is made between the creep characteristics of two squeeze-cast magnesium alloys (AZ 91 and QE 22) reinforced with 20 vol pct Al2O3 short fibers and the unreinforced AZ 91 and QE 22 matrix alloys. The results show the creep resistance of the reinforced materials is considerably improved by comparison with the unreinforced matrix alloys. It is suggested that creep strengthening in these short-fiber composites arises primarily from the existence of a threshold stress and the effect of load transfer. By testing samples to failure, it is demonstrated that the unreinforced and reinforced materials exhibit similar times to failure at the higher stress levels. A detailed microstructural investigation by transmission electron microscopy (TEM) reveals no substantial changes in matrix microstructure due to the presence of the reinforcement. This suggests that direct composite strengthening dominates over indirect effects