While use of synthetic antioxidants (such as butylated hydroxytoluene and butylated hydroxyanisole) to maintain the quality of ready-to-eat food products has become commonplace, consumer concern regarding their safety has motivated the food industry to seek natural alternatives. Phenolic antioxidants can inhibit free radical formation and/or interrupt propagation of autoxidation. Fat-soluble vitamin E (α-tocopherol) and water-soluble vitamin C (L-ascorbic acid) are both effective in the appropriate matrix. Plant extracts, generally used for their flavoring characteristics, often have strong H-donating activity thus making them extremely effective antioxidants. This antioxidant activity is most often due to phenolic acids (gallic, protocatechuic, caffeic, and rosmarinic acids), phenolic diterpenes (carnosol, carnosic acid, rosmanol, and rosmadial), flavonoids (quercetin, catechin, naringenin, and kaempferol), and volatile oils (eugenol, carvacrol, thymol, and menthol). Some plant pigments (anthocyanin and anthocyanidin) can chelate metals and donate H to oxygen radicals thus slowing oxidation via 2 mechanisms. Tea and extracts of grape seeds and skins contain catechins, epicatechins, phenolic acids, proanthocyanidins, and resveratrol, all of which contribute to their antioxidative activity. The objective of this article is to provide an overview of natural antioxidants, their mechanisms of action, and potential applications.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1541-4337.2011.00156.x

Natural antioxidants: sources, compounds, mechanisms of action, and potential applications

The field of polymers derived from non‐petrochemical feedstocks is gaining a great deal of momentum from both a commercial and academic sense Using annually renewable feedstocks, such as biomass, for the production of new plastics can have both economic and environmental benefits Fundamental research in the production, modification, property enhancement, and new applications of these materials is an important undertaking The new materials, concepts, and utilizations that result from these efforts will shape the future of polymers from renewable resources This issue of Polymer Reviews focuses on the production and properties of renewable resource polymers and highlights current trends and research directions

Polymers from Renewable Resources: A Perspective for a Special Issue of Polymer Reviews

Myoglobin and lipid oxidation interactions: mechanistic bases and control

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.

https://www.mdpi.com/2076-3921/8/10/429/pdf

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

Measurement of antioxidant activity

Lipid peroxidation is a primary cause of quality deterioration in meat and meat products. Free radical chain reaction is the mechanism of lipid peroxidation and reactive oxygen species (ROS) such as hydroxyl radical and hydroperoxyl radical are the major initiators of the chain reaction. Lipid peroxyl radical and alkoxyl radical formed from the initial react ions are also capable of abstracting a hydrogen atom from lipid molecules to initiate the chain reaction and propagating the chain reaction. Much attention has been paid to the role of iron as a primary catalyst of lipid peroxidation. Especially, heme protei ns such as myoglobin and hemoglobin and "free" iron have been regarded as major catalysts for initiation, and iron-oxygen complexes (ferryl and perferryl radical) are even considered as initiators of lipid peroxidation in meat and meat products. Yet , which iron type and how iron is involved in lipid peroxidation in meat are still debatable. This review is focused on the potential roles of ROS and iron as primary initiators and a major catalyst, respectively, on the development of lipid peroxidat ion in meat and meat products. Effects of various other factors such as meat species, muscle type, fat content, oxygen availability, cooking, storage temperature, the presence of salt that affect lipid peroxidation in meat and meat products are also discussed.

https://www.koreascience.or.kr:443/article/JAKO200509905823893.pdf

Mechanism of Lipid Peroxidation in Meat and Meat Products -A Review

Rice bran, a byproduct of the rice milling process, contains most of the phytochemicals. This study aimed at determining the concentrations of lipophilic, solvent-extractable (free), and cell wall-bound (bound) phytochemicals and their antioxidant capacities from brans of white, light brown, brown, purple, and red colors, and broccoli and blueberry for comparison. The concentrations of lipophilic antioxidants of vitamin E (tocopherol and tocotrienols) and γ-oryzanols were 319.67 to 443.73 and 3861.93 to 5911.12 μg/g bran dry weight (DW), respectively, and were not associated with bran color. The total phenolic, total flavonoid, and antioxidant capacities of ORAC (oxygen radical absorbance capacity), DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, and iron-chelating in the free fraction were correlated with the intensity of bran color, while variations of these in the bound fraction were less than those in the free fraction among brans. Compounds in the bound fraction had higher antioxidant capacity of ORAC than DPPH, relative to those in the free fraction. The bound fraction of light-color brans contributed as much to its total ORAC as the free fraction. Total proanthocyanidin concentration was the highest in red rice bran, while total anthocyanin was highest in purple brans. The predominant anthocyanin was cyanidin-3-glucoside. Red and purple brans had several fold higher total phenolics and flavonoids as well as ORAC and DPPH, from both free and bound fractions, than freeze-dried blueberry and broccoli. These results indicate that rice brans are natural sources of hydrophilic and lipophilic phytochemicals for use in quality control of various food systems as well as for nutraceutical and functional food application.

Phytochemicals and antioxidant capacities in rice brans of different color.

Free and bound total phenolic concentrations, antioxidant capacities, and profiles of proanthocyanidins and anthocyanins in whole grain rice (Oryza sativa L.) of different bran colours

The susceptibility of meats from different animal species (chicken breast [CB] and thigh [CT], pork [PL and beef [BL]) to lipid oxidation was studied The amounts of TBARS in raw PL, CB, and CT did not change during a 7-d storage period TBARS values of raw BL, however, significantly increased during 7-d storage because of high heme iron content, high lipoxygenase-like activities, and low 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities Ferric ion reducing capacities (FRC) were detected in all raw meats, but their characteristics were different: storage-unstable in CB and CT and storage-stable in PL and BL Ferric ion reducing capacities in raw CB and CT was higher than those of PL and BL, and could be related to their high oxidative stability The TBARS values of cooked meat increased significantly with storage The rates of TBARS increase in cooked CT and BL were significantly higher than those of cooked CB and PL after a 7-d storage Nonheme iron content in cooked BL was higher than other meats and increased significantly after 7 d Cooked BL had a higher amount of heat-stable FRC, which acted as a prooxidant in the presence of high free ionic irons, than other meats Therefore, high heat-stable FRC and increased nonheme iron content in cooked BL were responsible for its high susceptibility to lipid oxidation Despite relatively low nonheme iron and heat-stable FRC levels, cooked CT showed similar levels of TBARS to cooked BL after a 7-d storage because of its high PUFA content

Endogenous Factors Affecting Oxidative Stability of Beef Loin, Pork Loin, and Chicken Breast and Thigh Meats

http://ssu.ac.ir/cms/fileadmin/user_upload/Mtahghighat/tfood/asil-article/a-f2/Effects-of-hydrothermal-processes-on-antioxidants-in-brown-purple-and-red-bran-whole-grain-rice-Oryza-sativa-L-_2014_Food-Chemistry.pdf

Byungrok Min

Papers

Mechanism of Lipid Peroxidation in Meat and Meat Products -A Review

Phytochemicals and antioxidant capacities in rice brans of different color.

Free and bound total phenolic concentrations, antioxidant capacities, and profiles of proanthocyanidins and anthocyanins in whole grain rice (Oryza sativa L.) of different bran colours

Endogenous Factors Affecting Oxidative Stability of Beef Loin, Pork Loin, and Chicken Breast and Thigh Meats

Effects of hydrothermal processes on antioxidants in brown, purple and red bran whole grain rice (Oryza sativa L.)