Mark P. Richards

Bio: Mark P. Richards is an academic researcher from University of Wisconsin-Madison. The author has contributed to research in topics: Lipid oxidation & TBARS. The author has an hindex of 26, co-authored 83 publications receiving 2790 citations. Previous affiliations of Mark P. Richards include University of Massachusetts Amherst.

Measuring antioxidant effectiveness in food

Abstract: Many new in vitro methods have been developed to evaluate antioxidant activity. Unfortunately, these in vitro methods often correlate poorly with the ability of compounds to inhibit oxidative deterioration of foods because the in vitro assays do not account for factors such as the physical location of the antioxidant, its interaction with other food components, and environmental conditions. To accurately evaluate the potential of antioxidants in foods, models must be developed that have the chemical, physical, and environmental conditions expected in food products. This paper outlines model systems of the evaluation of antioxidants in three types of foods: bulk oil, oil-in-water emulsions, and muscle foods. These model systems are not intended to be inclusive of all possible methods to measure lipid oxidation and antioxidant activity. However, use of these models would allow researchers to more easily compare research results from one paper to another.

Contributions of blood and blood components to lipid oxidation in fish muscle

Abstract: There was a wide variation in the amounts of hemoglobin extracted from the muscle tissue of bled and unbled fish Averaged values suggested that the residual blood level in the muscle of bled fish was substantial Myoglobin content was minimal as compared to hemoglobin content in mackerel light muscle and trout whole muscle Hemoglobin made up 65 and 56% of the total heme protein by weight in dark muscle from unbled and bled mackerel, respectively Bleeding significantly reduced rancidity in minced trout whole muscle, minced mackerel light muscle, and intact mackerel dark muscle but not minced mackerel dark muscle stored at 2 degrees C The reduction was in the number of fish that had a longer shelf life; muscle from certain bled fish had rancidity that was comparable to the rancidity in unbled controls The soluble contents of erythrocytes accounted for all of the lipid oxidation capacity of whole blood added to washed cod muscle Limiting lysis of erythrocytes delayed lipid oxidation, which was likely due to keeping hemoglobin inside the erythrocyte Apparent breakdown of lipid hydroperoxides occurred only when a critical level of hemoglobin was present Blood plasma was slightly inhibitory to oxidation of washed cod lipids These studies suggest that blood-mediated lipid oxidation in fish muscle depends on various factors that include hemoglobin concentration, types of hemoglobin, plasma volume, and erythrocyte integrity

Effect of pH on lipid oxidation using trout hemolysate as a catalyst: a possible role for deoxyhemoglobin.

Abstract: Hemoglobin-mediated lipid oxidation was studied by adding hemolysate to washed cod muscle. Three pH values were examined (pH 7.6, 7.2, and 6.0). The lag time prior to rancidity and thiobarbituric acid reactive substance development decreased greatly as the pH was reduced (p < 0.01). Formation of methemoglobin due to autoxidation of the heme pigment was found to occur more rapidly at reduced pH. Also, the level of deoxyhemoglobin was found to sharply increase with pH reduction in the range of pH 7.6-6.0. This suggested a potential role for deoxyhemoglobin as a catalyst. ATP lowered hemoglobin oxygenation at pH 7.2. Peroxidation of linoleic acid by oxy/deoxyhemoglobin and methemoglobin was investigated at two levels of preformed lipid hydroperoxides. At a reduced level of preformed lipid hydroperoxides, oxy/deoxyhemoglobin stimulated peroxidation of linoleic acid, whereas methemoglobin did not. At the higher level of preformed lipid hydroperoxides, both oxy/deoxyhemoglobin and methemoglobin were active. This investigation suggests that reduced hemoglobins played an important role in lipid oxidation processes.

Effect of Washing with or without Antioxidants on Quality Retention of Mackerel Fillets during Refrigerated and Frozen Storage

Abstract: Unwashed fillets from stage I rigor mackerel deteriorated extensively compared to unwashed fillets from stage III mackerel; this was likely related to the greater amount of blood contaminating the fillet surface of the fresher fish. Washing improved the quality of fillets from rigor fish but not stage III fish, which was attributed to the greater amount of blood removal from the fresher fish by washing. Having antioxidants in the washing solution doubled the shelf life of fillets compared to water-washed fillets. Filleting in an antioxidant solution slightly but significantly improved quality compared to cutting in air and rinsing with antioxidant solution 1 min after filleting with frozen but not refrigerated samples. Improvements with antioxidants were seen with fillets from stage I but not stage III mackerel. The pro-oxidative activity in extracts prepared from fillet surface tissue using linoleic acid as substrate was stimulated by lipid hydroperoxides. The heme proteins present in tissue extracts had...

A Comprehensive Review on Lipid Oxidation in Meat and Meat Products.

Abstract: Meat and meat products are a fundamental part of the human diet. The protein and vitamin content, as well as essential fatty acids, gives them an appropriate composition to complete the nutritional requirements. However, meat constituents are susceptible to degradation processes. Among them, the most important, after microbial deterioration, are oxidative processes, which affect lipids, pigments, proteins and vitamins. During these reactions a sensory degradation of the product occurs, causing consumer rejection. In addition, there is a nutritional loss that leads to the formation of toxic substances, so the control of oxidative processes is of vital importance for the meat industry. Nonetheless, despite lipid oxidation being widely investigated for decades, the complex reactions involved in the process, as well as the different pathways and factors that influenced them, make that lipid oxidation mechanisms have not yet been completely understood. Thus, this article reviews the fundamental mechanisms of lipid oxidation, the most important oxidative reactions, the main factors that influence lipid oxidation, and the routine methods to measure compounds derived from lipid oxidation in meat.

Antioxidant and anti-inflammatory activities of essential oils: a short review.

Abstract: Essential oils are complex mixtures isolated from aromatic plants which may possess antioxidant and anti-inflammatory activities of interest in thye food and cosmetic industries as well as in the human health field. In this work, a review was done on the most recent publications concerning their antioxidant and anti-inflammatory activities. At the same time a survey of the methods generally used for the evaluation of antioxidant activity and some of the mechanisms involved in the anti-inflammatory activities of essential oils are also reported.