Biochemical and physicochemical properties of thermally treated natural actomyosin extracted from normal and PSE pork Longissimus muscle

Biochemical and physicochemical properties of thermally treated natural actomyosin (NAM) from normal and pale, soft and exudative (PSE) pork were studied. About 37% and 25% of available sulphydryl groups formed disulphide bonds or other permanent chemical bonds at 70 °C in NAM from normal and PSE pork, respectively. Surface hydrophobicities of NAM from normal and PSE pork at 70 °C were 3.6 and 2.4 times greater than that at 40 °C. About 90% of the α-helical structure of NAM was lost by heating to 70 °C. The temperature at maximum α-helical content decline of NAM was in accordance with the peak 3 thermal transition obtained by differential scanning calorimetry and the lowest storage modulus (G′) during thermal rheology. NAM from normal pork underwent aggregation with a higher extent of hydrophobic interaction and disulphide bonds, higher temperatures at maximum velocity for conformational change and unfolding than that from PSE pork. As a consequence, NAM from normal pork had superior rheological properties.     

Comparison of electrothermal and hydride generation atomic absorption spectrometry for the determination of total arsenic in broiler chicken

The purpose of this study was to estimate total arsenic concentration in different tissues (leg, breast, liver and heart) of broiler chicken by hydride generation atomic absorption spectrometry (HGAAS) and graphite furnace atomic absorption spectrometry (GFAAS), prior to microwave assisted acid digestion. The accuracy of the techniques was evaluated by using certified reference material DORM-2. The percentage recoveries of total As were observed as 100.6% and 99.4% for HGAAS and GFAAS, respectively. The precision of the techniques, expressed as relative standard deviation, was observed as 1.71% and 4.18% for HGAAS and GFAAS measurements, respectively. The limits of detection for HGAAS and GFAAS were 0.025 μg/g and 0.052 μg/g, respectively. The concentrations of total arsenic in different tissues of broiler chicken were found in the range of 2.19–5.28, 2.15–5.22, 2.97–7.17 and 2.68–6.36 μg/g for leg, breast, liver and heart tissues, respectively. At a mean level of chicken consumption (60 g/person/day), people may ingest in the range of 72.0–85.1 μg arsenic/person/day from chicken alone.     

Sargassum swartzii extracts ameliorate memory functions by neurochemical modulation in a rat model

Food Science and Biotechnology - Recently, considerable attention has been paid to drug exploration from natural sources for treating memory loss, a major manifestation of various neurodegenerative...     

Protective effect of ω-3 polyunsaturated fatty acids (PUFA) on sodium nitrite induced nephrotoxicity and oxidative damage in rat kidney

Sodium nitrite (SNT) widely used as a curative agent in meat processing industry possesses cell-transforming mutagenic and cytogenic properties. Dietary omega-3 polyunsaturated fatty acids (ω-3 PUFA) has been shown to reduce the severity of certain types of cancers, cardiovascular and renal diseases. The present study examined whether feeding of fish oil (FO)/flaxseed oil (FXO) has protective effect against SNT-induced toxicity. SNT significantly altered the activities of serum creatinine (Crt), blood urea nitrogen (BUN), metabolic and brush border membrane (BBM) enzymes. SNT caused significant imbalances in the antioxidant system associated with increased lipid peroxidation (LPO). Feeding of FO and FXO with SNT ameliorated the changes in various parameters caused by SNT. Nephrotoxicity parameters lowered and enzyme activities of carbohydrate metabolism, BBM and radioactively labeled inorganic phosphate (³²Pi) transport were improved to near control values. The results of the present study suggest that ω-3 PUFA-enriched FO and FXO from sea-foods and plant sources respectively are similarly effective in reducing SNT-induced nephrotoxicity and oxidative damage.     

Impact properties of thermoplastic composites

The excellent properties exhibited by thermoplastic composites at much reduced weight have attracted attention in the development of products in different sectors. Thermoplastic (TP) composites, because of their distinctive properties as well as ease of manufacturing, have emerged as a competitor against the conventional thermoset resin-based composites. Depending on the application, these composites may undergo impact events at various velocities and often fail in many complex modes. Hence, the development of TP composites having high energy-dissipation at (the desired) much-reduced weight has become a challenging task, but it is a problem which may be alleviated through the appropriate selection of materials and fabrication processes. Furthermore, fibre surface modification has been shown to increase fibre-matrix interfacial adhesion, which can lead to improved impact resistance. Textile preforms are helpful in acting as a structural backbone in the composites since they offer a relatively free hand to the composite designer to tailor its properties to suit a specific application. Additionally, hybrid textile composite structures may help in achieving the desired properties at much lower weight.

Simulation software can play a significant role in the evaluation of composites without damaging physical samples. Once the simulation result has been validated with actual experimental results, it should be possible to predict the test outcomes for different composites, with different characteristics, at different energy levels without conducting further physical tests. Various numerical models have been developed which have to be incorporated into these software tools for better prediction of the result.

In the current issue of Textile Progress, the effects of various materials and test parameters on impact behaviour are critically analyzed. The effect of incorporating high-performance fibres and natural fibres or their hybrid combination on the impact properties of TP composites are also discussed and the essential properties of TP polymers are briefly explained. The effects of fibre and matrix hybridization, environmental factors, various textile preform structures and fibre surface modification treatments on the impact properties of thermoplastic composites are examined in detail. Various numerical models used for impact analysis are discussed and the potential applications of TP composites in automobile, aerospace and medical sectors are highlighted.     

Effects of high hydrostatic pressure on the physicochemical and emulsifying properties of sweet potato protein

The influence of high hydrostatic pressure (HHP) treatment on the physicochemical and emulsifying properties of sweet potato protein (SPP) at various concentrations, e.g. 2%, 4% and 6% (w/v, SPP‐2, SPP‐4 and SPP‐6), was investigated. Significant differences in hydrophobicity, enthalpy of denaturation and solubility were observed (P < 0.05). Emulsifying activity indexes (EAI) of SPP‐2 and SPP‐6 increased at 400 MPa, whereas EAI of all SPP significantly decreased at 600 MPa (P < 0.05). Emulsion stability (ESI) was significantly decreased for SPP‐2 and SPP‐6, while increase in ESI was observed for SPP‐4 above 200 MPa (P < 0.05). SPP‐2 emulsions showed sharp decrease in apparent viscosity with pressure increase, while pseudo plastic flow behaviour was not changed for all of emulsions. Sporamins A and B were well‐adsorbed in pressurised emulsion without displacement. These results suggest that HHP treatment could be used to modify the physicochemical and emulsifying properties of SPP.