Effect of heating oxyhemoglobin and methemoglobin on microsomes oxidation

Dry food affects the oxidative/antioxidant profile of dogs

BACKGROUND

Including adequate concentrations of antioxidants in dog diets has been recommended to reduce their vulnerability to the action of free radicals and reactive oxygen species (ROS). Oxidative stress in dogs has been associated with a wide range of diseases and disorders, as well as with ageing. There are few reports about the influence of diet on dog's antioxidant profile and oxidative stress.

OBJECTIVE

The objective of this study was to evaluate the effect of four types of dry dog food on the oxidative/antioxidant profile of dogs.

METHODS

Six Beagle dog males were used. The study included four experimental diets (dry foods A-D). Each dry food was supplied for 5 weeks to all dogs, for a total of 24 weeks, including an adaptation week between one food and another. For each dry dog food, the total phenolic content (TPC), total antioxidant capacity (TAC) and cytotoxicity were evaluated. Each week, a blood sample was collected to measure ROS and TAC of plasma. A crossover repeated measures design was used. Mixed models were adjusted, and means were compared using the Tukey test.

RESULTS

Food A had the highest values for TPC and TAC. Food C had the lowest levels of ROS, whereas food B had the highest TAC in the blood plasma. The dog had a significant influence on the redox state of its blood plasma, even when the same dog was fed the different dry foods.

CONCLUSION

Dry dog food influences the oxidative/antioxidant profile of dog's blood plasma; however, this seems to be unrelated to the antioxidant profile of the food.

Impact of dielectric barrier discharge cold plasma on the lipid oxidation, color stability, and protein structures of myoglobin-added washed pork muscle

Cold plasma has been considered a novel non-thermal processing technique and attracted a high attention by the food industry. In this study, the influences of dielectric barrier discharge cold plasma (DBD-CP) on the myoglobin (Mb)-added washed pork muscle (WPM) were evaluated. The electrophoresis pattern, autoxidation, and secondary structure of Mb were analyzed. The results found that DBD-CP caused the decrease of the redness and total sulfhydryl (T-SH) in WPM, while the increase of non-heme, peroxide value (PV), and thiobarbituric acid reactive substances (TBARS), suggested that treatment triggered protein oxidation and heme degradation. Additionally, DBD-CP treatment enhanced the autoxidation of Mb, induced the release of intact heme from the globin, rearranged the charged groups, and promoted Mb aggregation. The transformation of α-helix into the random coil of Mb demonstrated that DBD-CP weakened the tensile strength. Overall, data indicated that DBD-CP promoted autoxidation and changed the secondary structure of Mb, accelerating Mb-mediated lipid oxidation in WPM. Thus, further studies about the optimization of processing conditions by DBD-CP need to be performed.

Human risk of diseases associated with red meat intake: Analysis of current theories and proposed role for metabolic incorporation of a non-human sialic acid

One of the most consistent epidemiological associations between diet and human disease risk is the impact of red meat consumption (beef, pork, and lamb, particularly in processed forms). While risk estimates vary, associations are reported with all-cause mortality, colorectal and other carcinomas, atherosclerotic cardiovascular disease, type II diabetes, and possibly other inflammatory processes. There are many proposed explanations for these associations, some long discussed in the literature. Attempts to explain the effects of red meat consumption have invoked various red meat-associated agents, including saturated fat, high salt intake, Trimethylamine-N-oxide (TMAO) generation by microbiota, and environmental pollutants contaminating red meat, none of which are specific for red meat. Even the frequently mentioned polycyclic aromatic carcinogens arising from high temperature cooking methods are not red meat specific, as these are also generated by grilling poultry or fish, as well as by other forms of cooking. The traditional explanations that appear to be more red meat specific invoke the impact of N-nitroso compounds, heme iron, and the potential of heme to catalyze endogenous nitrosation. However, heme can be denatured by cooking, high levels of plasma hemopexin will block its tissue delivery, and much higher amounts of heme likely originate from red blood cell breakdown in vivo. Therefore, red meat-derived heme could only contribute to colorectal carcinoma risk, via direct local effects. Also, none of these mechanisms explain the apparent human propensity i.e., other carnivores have not been reported at high risk for all these diseases. A more recently proposed hypothesis involves infectious agents in beef from specific dairy cattle as agents of colorectal cancer. We have also described another mechanistic explanation for the human propensity for risk of red-meat associated diseases that is consistent with most observations: metabolic incorporation of a non-human sialic acid N-glycolylneuraminic acid (Neu5Gc) into the tissues of red meat consumers and the subsequent interaction with inflammation-provoking antibodies against this "xenoautoantigen". Overall, we conclude that while multiple mechanisms are likely operative, many proposed theories to date are not specific for red meat, and that the viral and xenoautoantigen theories deserve further consideration. Importantly, there are potential non-toxic dietary antidotes, if the xenoautoantigen theory is indeed correct.

Effect of fermentation time and vegetable concentrate addition on quality parameters of organic Botifarra Catalana, a cured-cooked sausage

The effects of the addition of two different sources of nitrite (pure NaNO2 or a nitrate-rich vegetable concentrate) and three different fermentation times with nitrate-reducing cultures (6, 12, or 24 h at 16 °C) on microbial counts, pH, residual nitrate and nitrite amounts, and susceptibility to oxidation of botifarra catalana sausage were studied. Moreover, curing efficiency, color, tocopherol and tocotrienol contents, oxidative status, and consumer acceptability of these sausages were assessed after vacuum packaging and storage at 4 °C for up to 180 days. Residual nitrate and nitrite amounts were lower than the limits established by the European Union for organic meat products. Longer periods of fermentation produced higher meat curing efficiency ratios, whereas consumer acceptability scores were highest for sausages with added vegetable concentrate. Storage of the sausages caused small quality changes. Therefore, these results indicate that vegetable concentrate is a useful alternative for organic cured-cooked meat products.