Protein Oxidation in Muscle Foods: A Comprehensive Review

Muscle foods and their products are a fundamental part of the human diet. The high protein content found in muscle foods, as well as the high content of essential amino acids, provides an appropriate composition to complete the nutritional requirements of humans. However, due to their special composition, they are susceptible to oxidative degradation. In this sense, proteins are highly susceptible to oxidative reactions. However, in contrast to lipid oxidation, which has been studied in depth for decades, protein oxidation of muscle foods has been investigated much less. Moreover, these reactions have an important influence on the quality of muscle foods, from physico-chemical, techno-functional, and nutritional perspectives. In this regard, the loss of essential nutrients, the impairment of texture, water-holding capacity, color and flavor, and the formation of toxic substances are some of the direct consequences of protein oxidation. The loss of quality for muscle foods results in consumer rejection and substantial levels of economic losses, and thus the control of oxidative processes is of vital importance for the food industry. Nonetheless, the complexity of the reactions involved in protein oxidation and the many different factors that influence these reactions make the mechanisms of protein oxidation difficult to fully understand. Therefore, the present manuscript reviews the fundamental mechanisms of protein oxidation, the most important oxidative reactions, the main factors that influence protein oxidation, and the currently available analytical methods to quantify compounds derived from protein oxidation reactions. Finally, the main effects of protein oxidation on the quality of muscle foods, both from physico-chemical and nutritional points of view, are also discussed.

Ferroptosis: Can Iron be the Last or Cure for a Cell?

Ferroptosis is one of the forms of programmed cell death. Besides being a necessary micronutrient, iron is the key element that initiates ferroptosis in the cell. Intracellular unstable iron accumulation increases the amount of intracellular ROS, especially by the peroxidation of unsaturated membrane phospholipids. Insufficient antioxidant capacity and decreased glutathione levels play an important role in this process. The research reveals that an imbalance between unoxidized polyunsaturated fatty acids (PUFAs) and oxidized PUFAs, particularly oxidized arachidonic acid, accelerates ferroptosis. These oxidative reactions change the permeability of lysosomal and cellular membranes and cell death occurs. Iron chelators, lipophilic antioxidants, and specific inhibitors prevent ferroptosis. In addition to being accepted as a physiological process, it seems to be associated with tissue reperfusion damage, ischemic, neurodegenerative diseases, hematological and nephrological disorders. Ferroptosis is also being explored as a treatment option where it may offer a treatment option for some types of cancer. In this section, the brief history of ferroptosis, its morphological, molecular, and pathophysiological features are mentioned. Ferroptosis seems to be a rich field of research as a treatment option for many diseases in the future.

The Influence of Butter and Oils on Oxidative Reactions during In Vitro Gastrointestinal Digestion of Meat and Fish

Oxidative reactions during cooking and gastrointestinal digestion of meat and fish lead to the formation of various lipid- and protein oxidation products, some of which are toxic. In the present study, it was investigated how the addition of 3% butter or oils affect lipid- and protein oxidation during cooking and in vitro digestion of meat (chicken thigh, chicken breast, beef) and fish (mackerel, cod). These muscle foods were selected based on their differences in heme-Fe and PUFA contents, and n-6/n-3 PUFA ratio, and therefore varying potential to form oxidation products during digestion. Without additional fat, mackerel digests displayed the highest n-3 PUFA oxidation (4-hydroxy-2-hexenal, propanal, thiobarbituric reactive acid substances), and chicken digests the highest n-6 PUFA oxidation (4-hydroxy-2-nonenal, hexanal), whereas both lipid- and protein oxidation (protein carbonyl compounds) were low in cod and beef digests. Lipid oxidative reactions were generally not altered by the addition of butter to any muscle matrix, whereas the addition of fish oil and safflower oil in different ratios (3:0, 2:1, 1:2, 0:3) as n-3 PUFA and n-6 PUFA source respectively, stimulated oxidative reactions, especially during digestion of beef. Since beef was considered the muscle matrix with the highest potential to stimulate oxidation in the added fat substrate, in a second experiment, beef was cooked and digested with 3% butter or seven commercial vegetable oils (sunflower-, maize-, peanut-, rapeseed-, olive-, rice bran- or coconut oil), all labeled ‘suitable for heating’. No relevant oxidative reactions were however observed during digestion of beef with any of these commercial vegetable oils.

Predicted Shelf-Life, Thermodynamic Study and Antioxidant Capacity of Breadsticks Fortified with Grape Pomace Powders

Grape pomace (GP), is the main winemaking by-product and could represent a valuable functional food ingredient being a source of bioactive compounds, like polyphenols. Polyphenols prevent many non-communicable diseases and could contrast the oxidation reaction in foods. However, the high content in polyunsaturated fatty acid, the described pro-oxidant potential action of some polyphenols and the complex interactions with other components of matrices during food processing must be considered. Indeed, all these factors could promote oxidative reactions and require focused and specific assay. The aims of this study were to evaluate the effects of GP powder (GPP) addition (at 0%, 5% and 10% concentrations) in breadsticks formulations both on the antioxidant activity at room temperature during storage and on the shelf-life by the OXITEST predictive approach. GPP fortification increased the total polyphenols content and the antioxidant activities of breadsticks. FRAP reduced during the first two days of storage at room temperature, TPC increased during the 75 days, while ABTS showed a slight progressive decrease. However, GP negatively influenced OXITEST estimated shelf-life of breadsticks, incrementing the oxidation rate. In conclusion, even if GP fortification of breadsticks could improve the nutritional value of the products, the increased commercial perishability represents a drawback that must be considered.

Processes of chemical transformations in heavy aromatic hydrocarbons of the Surakhan oil under the action of UV rays

Photooxidative transformations and mechanisms of oxidative reactions in aromatic groups of hydrocarbons isolated from heavy Surakhan (Azerbaijan) petroleum under atmospheric conditions have been investigated. Polycyclic aromatic hydrocarbons, which are part of the aromatic components of heavy Surakhan petroleum, after irradiation with UV rays for 1÷11 hours in the presence of oxygen undergo chemical transformations: endoperoxides polycyclic aromatic hydrocarbons, quinones, etc. are formed. It was found that oxidation products under atmospheric conditions can be formed as follows: during the oxidation of acenes (naphthalene, anthracene), which are part of the aromatic groups of petroleum components, excited aromatic hydrocarbons (donor) interact with atmospheric oxygen (acceptor) in the triplet state with the transition of the acceptor to excited state with the formation of singlet oxygen 1O2, in this case the donor molecule returns to the ground state. When phenanthrene is photooxidized, quinones are formed (the reaction is irreversible).

Phytochemicals from Indian Ethnomedicines: Promising Prospects for the Management of Oxidative Stress and Cancer

Oxygen is indispensable for most organisms on the earth because of its role in respiration. However, it is also associated with several unwanted effects which may sometimes prove fatal in the long run. Such effects are more evident in cells exposed to strong oxidants containing reactive oxygen species (ROS). The adverse outcomes of oxidative metabolism are referred to as oxidative stress, which is a staple theme in contemporary medical research. Oxidative stress leads to plasma membrane disruption through lipid peroxidation and has several other deleterious effects. A large body of literature suggests the involvement of ROS in cancer, ageing, and several other health hazards of the modern world. Plant-based cures for these conditions are desperately sought after as supposedly safer alternatives to mainstream medicines. Phytochemicals, which constitute a diverse group of plant-based substances with varying roles in oxidative reactions of the body, are implicated in the treatment of cancer, aging, and all other ROS-induced anomalies. This review presents a summary of important phytochemicals extracted from medicinal plants which are a part of Indian ethnomedicine and Ayurveda and describes their possible therapeutic significance.

The Quality of Superior Seedless Bunches during Shelf Life as Determined by Growth on Different Rootstocks

Vineyard rootstocks are an important tool in the local and international market for growing the Superior Seedless grape cultivar, which is highly favored by customers. As a result, it is vital to pay close attention to the quality of clusters during handling. The current study aimed to determine whether Superior Seedless vines can be grown on specific rootstocks, resulting in higher quality during shelf life. Vines of the Superior Seedless vine cultivar that were used were 13 years old and had been grown on sandy soil. These vines were grafted onto four different rootstocks (genotypes), namely Freedom, 1103 Paulsen, SO4, and Own Root. The soluble solids content (SSC%) was selected as 16%. Bunches were subsequently stored in the lab at 27 ± 1 °C with 57 ± 3% air relative humidity for three days. Rootstock 1103 Paulsen’s quality was found to be superior to that of the other rootstocks, according to the results of the study. Rootstock 1103 Paulsen maintained its ascorbic acid (AA) content, which is reflected in its antioxidant capacity, according to the results. In addition, lipid peroxidation accumulation and ion leakage percentages indicated that oxidative reactions were at their lowest levels. The results show that 1103 Paulsen decreases cellular metabolism enzyme activities at the shelf life level and improves the bunch quality of Superior Seedless (scion) grapes within 4 days of application. As a whole, the results show that the 1103 Paulsen rootstock produces Superior Seedless bunches of a high quality that is preserved throughout the shelf life period.

Preservation of meat products with natural antioxidants from rosemary

Oxidative reactions can reduce the quality of meat products. Synthetic antioxidants can delay the formation of oxidation products but their use in muscle foods has been reconsidered among modern consumers willing to purchase clean label products. Rosemary is a relevant source of antioxidants that can be explored as natural additive in muscle foods. This review aims to provide an overview of the protective effect of rosemary active against the oxidative decay in meat products. The use of rosemary essential oil or extract can slow the progression of oxidative reactions and preserve redness, reduce the accumulation of primary and secondary lipid oxidation and protein oxidation products, and slow the increase of perceived rancidity in sensory analysis. These effects were reported during the storage of patties, burgers, meatballs, sausages, and nuggets. In this sense, rosemary extracts and essential oil can be explored as natural antioxidant in meat products.