Chemistry and reactions of reactive oxygen species in foods

Selenized non-Saccharomyces yeasts and their potential use in fish feed

Selenium (Se) is a vital trace element, essential for growth and other biological functions in fish. Its significance lies in its role as a fundamental component of selenoproteins, which are crucial for optimal functioning of the organism. The inclusion of Se in the diets of farmed animals, including fish, has proved invaluable in mitigating the challenges arising from elemental deficiencies experienced in captivity conditions due to limitations in the content of fishmeal. Supplementing diets with Se enhances physiological responses, particularly mitigates the effects of the continuous presence of environmental stress factors. Organic Se has been shown to have higher absorption rates and a greater impact on bioavailability and overall health than inorganic forms. A characteristic feature of yeasts is their rapid proliferation and growth, marked by efficient mineral assimilation. Most of the selenized yeasts currently available in the market, and used predominantly in animal production and aquaculture, are based on Saccharomyces cerevisiae, which contains selenomethionine (Se-Met). The object of this review is to highlight the importance of selenized yeasts. In addition, it presents metabolic and productive aspects of other yeast genera that are important potential sources of organic selenium. Some yeast strains discussed produce metabolites of interest such as lipids, pigments, and amino acids, which could have applications in aquaculture and further enrich their usefulness.

Lipid Peroxidation in Muscle Foods: Impact on Quality, Safety and Human Health

The issue of lipid changes in muscle foods under the action of atmospheric oxygen has captured the attention of researchers for over a century. Lipid oxidative processes initiate during the slaughtering of animals and persist throughout subsequent technological processing and storage of the finished product. The oxidation of lipids in muscle foods is a phenomenon extensively deliberated in the scientific community, acknowledged as one of the pivotal factors affecting their quality, safety, and human health. This review delves into the nature of lipid oxidation in muscle foods, highlighting mechanisms of free radical initiation and the propagation of oxidative processes. Special attention is given to the natural antioxidant protective system and dietary factors influencing the stability of muscle lipids. The review traces mechanisms inhibiting oxidative processes, exploring how changes in lipid oxidative substrates, prooxidant activity, and the antioxidant protective system play a role. A critical review of the oxidative stability and safety of meat products is provided. The impact of oxidative processes on the quality of muscle foods, including flavour, aroma, taste, colour, and texture, is scrutinised. Additionally, the review monitors the effect of oxidised muscle foods on human health, particularly in relation to the autooxidation of cholesterol. Associations with coronary cardiovascular disease, brain stroke, and carcinogenesis linked to oxidative stress, and various infections are discussed. Further studies are also needed to formulate appropriate technological solutions to reduce the risk of chemical hazards caused by the initiation and development of lipid peroxidation processes in muscle foods.

Changing Despicable Me: Potential replacement of azo dye yellow tartrazine for pequi carotenoids employing ionic liquids as high-performance extractors

Color is a crucial sensory attribute that guides consumer expectations. A high-performance pequi carotenoid extraction process was developed using ionic liquid-based ethanolic solutions and a factorial design strategy to search for a potential substitute for the artificial azo dye yellow tartrazine. All-trans-antheraxanthin was identified with HPLC-PAD-MSn for the first time in pequi samples. [BMIM][BF4] was the most efficient ionic liquid, and the maximization process condition was the solid-liquid ratio R(S/L) of 1:3, the co-solvent ratio R(IL/E) of 1:1 ([BMIM][BF4]: ethanol), and three cycles of extraction with 300 s each and yielded 107.90 μg carotenoids/g of dry matter. The ionic liquid-ethanolic solution recyclability was accomplished by freezing and precipitating with an average recovery of 79 %. In CIELAB parameters, pequi carotenoid extracted with [BMIM][BF4] was brighter and yellower than the artificial azo dye yellow tartrazine. A color change of 11.08 and a hue* difference of 1.26° were obtained. Furthermore, carotenoids extracted with [BMIM][BF4] showed antioxidant activity of 35.84 μmol of α-tocopherol. These findings suggest the potential of employing the pequi carotenoids to replace the artificial azo dye yellow tartrazine in foods for improved functional properties.

The Peptide Fractions of Cheddar Cheese Made with Lactobacillus helveticus 1.0612 Play Protective Effects in H2O2-Induced Oxidative-Damaged Caco-2 Cells Models

In this study, water-soluble peptide (WSP) fractions of cheddar cheese made with Lactobacillus helveticus 1.0612 were purified into WSP-Ⅰ (<3 kDa), WSP-Ⅱ (3-10 kDa), and WSP-Ⅲ (>10 kDa). The protective effects of WSP, WSP-Ⅰ, WSP-Ⅱ, and WSP-Ⅲ fractions against oxidative stress in Caco-2 cells were assayed, and the cytoprotective mechanism of WSP-Ⅰ on cells oxidative damage was elucidated via metabolomics. The results showed that all four peptide fractions were able to attenuate the decrease in cell viability caused by oxidative stress and also could reduce the production of reactive oxygen species and malondialdehyde caused by oxidative stress, and increased cellular catalase and superoxide dismutase activities, thereby enhancing cellular antioxidant capacity. The WSP-Ⅰ fraction with the highest protective effect was used for metabolomics analysis, and 15 significantly different metabolites were screened. Functional pathway analysis revealed that the protective effect of the WSP-I fraction was related with nine metabolic pathways and weakened the metabolic disorders caused by H₂O₂ via regulating energy metabolism and amino acid metabolism. All in all, peptide fractions of cheddar cheese showed a cytoprotective effect through improved cellular metabolism.

Investigation of oxidative characteristics, fatty acid composition and bioactive compounds content in cold pressed oils of sunflower grown in Serbia and Argentina

Background

In this work, the chemical composition analysis was performed for cold pressed oils obtained from the 15 sunflower hybrids grown in Serbia and Argentina, as well as the determination of their oxidative quality. The fatty acid composition and bioactive compounds including total tocopherols, phenols, carotenoids, and chlorophyll contents were investigated. The oxidation products were monitored through the peroxide value (PV), anisidine value (AnV), conjugated dienes (CD) and conjugated trienes (CT) content, and total oxidation index (TOTOX) under accelerated oxidation conditions by the oven method.

Results

Linoleic acid was the most abundant fatty acid in investigated oil samples, followed by oleic and palmitic acids. The mean contents of total tocopherols, phenols, carotenoids, and chlorophyll were 518.24, 9.42, 7.54 and 0.99 mg/kg, respectively. In order to obtain an overview of sample variations according to the tested parameters Principal Component Analysis (PCA) was applied.

Conclusion

PCA indicated that phenols, chlorophyll, linoleic and oleic acid were the most effective variables for the differentiation of sunflower hybrids grown in Serbia and Argentina. Furthermore, based on the fatty acid composition and bioactive compounds content in the oils, a new Artificial Neural Network (ANN) model was developed to predict the oxidative stability parameters of cold pressed sunflower oil.

Association of the Oxidative Balance Score and Cognitive Function and the Mediating Role of Oxidative Stress: Evidence from the National Health and Nutrition Examination Survey (NHANES) 2011-2014

BACKGROUND

Oxidative stress is possibly related to cognitive function decline. The oxidative balance score (OBS) that combines pro- and antioxidant components from diet and lifestyle has been reported to be associated with age-related diseases.

OBJECTIVES

We aimed to investigate the association between OBS and cognitive function in older adults and explore whether oxidative stress mediated this relationship.

METHODS

A total of 1745 adults aged ≥60 y were included in the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Cognitive function was measured using 4 tests: the immediate recall test, delayed recall test, animal fluency test (AFT), and digital symbol substitution test (DSST). Weighted multivariate linear regression and restricted cubic splines (RCS) analyses were used to evaluate the association between OBS and cognitive function, and mediation analysis was used to test the indirect effect of oxidative stress indicators on the association.

RESULTS

The OBS was positively associated with AFT, DSST, and global cognitive function in older adults, and the beta estimates (95% CI) were 0.015 (0.008, 0.034), 0.009 (0.002, 0.025), and 0.030 (0.024, 0.074), moreover, RCS results suggested an approximately linear dose-response relationship between the OBS and these 3 tests. The highest quartiles of these 3 tests were also significantly correlated with OBS. Albumin, uric acid, and serum 25(OH)D concentrations were significant mediators of the relationship between OBS and cognitive function, and the overall mediation effect proportion was 36% when included in 1 model.

CONCLUSIONS

OBS was positively correlated with cognitive function in older adults, and albumin, uric acid, and serum 25(OH)D concentrations could be the driving mediators of the association. The findings emphasize the importance of a healthy, antioxidant diet and lifestyle that contribute to cognitive function. J Nutr 20xx;x:xx.

Chemical decontamination of foods using non-thermal plasma-activated water

The presence of chemical contaminants in foods and agricultural products is one of the major safety issues worldwide, posing a serious concern to human health. Nonthermal plasma (NTP) containing richly reactive oxygen and nitrogen species (RONS) has been trialed as a potential decontamination method. Yet, this technology comes with multiple downsides, including adverse effects on the quality of treated foods and limited exposure to entire surfaces on samples with hard-to-reach spots, further hindering real-life applications. Therefore, plasma-activated water (PAW) has been recently developed to facilitate the interactions between RONS and contaminant molecules in the liquid phase, allowing a whole surface treatment with efficient chemical degradation. Here, we review the recent advances in PAW utilized as a chemical decontamination agent in foods. The reaction mechanisms and the main RONS contributors involved in the PAW-assisted removal of chemical contaminants are briefly outlined. Also, the comprehensive effects of these treatments on food qualities (chemical and physical characteristics) and toxicological evaluation of PAW (in vitro and in vivo) are thoroughly discussed. Ultimately, we identified some current challenges and provided relevant suggestions, which can further promote PAW research for real-life applications in the future.

Extracts of Eryngium foetidum Leaves from the Amazonia Were Efficient Scavengers of ROS and RNS

Eryngium foetidum L. is an edible plant widespread in Amazonian cuisine and its leaves have high levels of promising phenolic compounds for the production of extracts to be used as natural antioxidant additives. In this study, the in vitro scavenging capacity of three freeze-dried extracts of E. foetidum leaves, obtained by ultrasound-assisted extraction using green solvents [water (H₂O), ethanol (EtOH), and ethanol/water (EtOH/H₂O)], was investigated against the most common reactive oxygen species (ROS) and reactive nitrogen species (RNS) generated in both physiological and food systems. Six phenolic compounds were identified, chlorogenic acid (2198, 1816 and 506 μg/g) being the major compound for EtOH/H₂O, H₂O, and EtOH extracts, respectively. All E. foetidum extracts were efficient in scavenging all the ROS and RNS (IC₅₀ = 45-1000 µg/mL), especially ROS. The EtOH/H₂O extract showed the highest contents of phenolic compounds (5781 μg/g) and showed the highest efficiency in scavenging all the reactive species, with high efficiency for O₂^•- (IC₅₀ = 45 μg/mL), except for ROO^•, for which EtOH extract was the most efficient. Therefore, E. foetidum leaf extracts, especially EtOH/H₂O, showed high antioxidant potential to be used as natural antioxidants in food formulations and are promising for nutraceuticals products.

Application of Polysaccharide-Based Edible Coatings on Fruits and Vegetables: Improvement of Food Quality and Bioactivities

Most foods derived from plant origin are very nutritious but highly perishable products. Nowadays, the food industry is focusing on the development of efficient preservation strategies as viable alternatives to traditional packaging and chemical treatments. Hence, polysaccharide-based edible coatings have been proposed because of their properties of controlled release of food additives and the protection of sensitive compounds in coated foods. Thus, this technology has allowed for improving the quality parameters and extends the shelf life of fruits and vegetables through positive effects on enzyme activities, physicochemical characteristics (e.g., color, pH, firmness, weight, soluble solids), microbial load, and nutritional and sensory properties of coated foods. Additionally, some bioactive compounds have been incorporated into polysaccharide-based edible coatings, showing remarkable antioxidant and antimicrobial properties. Thus, polysaccharide-based edible coatings incorporated with bioactive compounds can be used not only as an efficient preservation strategy but also may play a vital role in human health when consumed with the food. The main objective of this review is to provide a comprehensive overview of materials commonly used in the preparation of polysaccharide-based edible coatings, including the main bioactive compounds that can be incorporated into edible coatings, which have shown specific bioactivities.

An Impedimetric Biosensor for Detection of Volatile Organic Compounds in Food

The demand for a wide choice of food that is safe and palatable increases every day. Consumers do not accept off-flavors that have atypical odors resulting from internal deterioration or contamination by substances alien to the food. Odor response depends on the volatile organic compounds (VOCs), and their detection can provide information about food quality. Gas chromatography/mass spectrometry is the most powerful method available for the detection of VOC. However, it is laborious, costly, and requires the presence of a trained operator. To develop a faster analytic tool, we designed a non-Faradaic impedimetric biosensor for monitoring the presence of VOCs involved in food spoilage. The biosensor is based on the use of the pig odorant-binding protein (pOBP) as the molecular recognition element. We evaluated the affinity of pOBP for three different volatile organic compounds (1-octen-3-ol, trans-2-hexen-1-ol, and hexanal) related to food spoilage. We developed an electrochemical biosensor conducting impedimetric measurements in liquid and air samples. The impedance changes allowed us to detect each VOC sample at a minimum concentration of 0.1 μM.

Formation pathways of aldehydes from heated cooking oils

Cooking emissions account for a major fraction of urban volatile organic compounds and organic aerosol. Aldehyde species, in particular, are important exposure hazards in indoor residential and occupational environments, and precursors to particulate matter and ozone formation in outdoor air. Formation pathways of aldehydes from oils that lead to their emissions are not well understood. In this work, we investigate the underlying mechanisms involved in the formation of aldehydes from heated cooking oil emissions, through studying how antioxidants and oil composition modulate oxidation chemistry. Our results demonstrate that gaseous emissions are driven by radical-mediated autoxidation reactions in cooking oil, and the composition of cooking oils strongly influences the reaction mechanisms. Antioxidants have a dual effect on aldehyde emissions depending on the rates of radical propagation reactions. We propose a mechanistic framework that can be used to understand and predict cooking emissions under different cooking conditions. Our results highlight the need to understand the rates and mechanisms of autoxidation and other reactions in cooking oils in order to accurately predict the gas- and particle-phase emissions from food cooking in urban atmospheres.

The physiochemical and photodynamic inactivation properties of corn starch/erythrosine B composite film and its application on pork preservation

This study explored the effect of erythrosine B (EB) as a photosensitizer in corn starch (CS) film and its physicochemical properties and photodynamic bacteriostatic ability against Staphylococcus aureus, Escherichia coli, and Salmonella both in vitro and inoculated on pork under the irradiation of D65 light-emitting diode (LED) (400-800 nm). The study revealed that the physiochemical properties of CS films: moisture content, water solubility, and water vapor transmission were improved with the addition of EB. In addition, the elasticity and the thermal stability of the film were enhanced. The results showed that the CS-EB films stimulated a maximum of 26.36 μg/mL hydrogen peroxide and 74.5 μg/g hydroxyl radical under irradiation. The CS composite films with a 5 % concentration of EB inhibited the bacterial growth by 4.7 Log CFU/mL in vitro after 30 min of illumination, and 2.4 Log CFU/mL on the pork samples under the same experimental condition. Moreover, the antibacterial ability was enhanced with the increase in EB concentration. Overall, the CS-EB composite films can inhibit the growth of bacteria through photodynamic inactivation and has the potential to become a new type of environmentally friendly packaging material.

Dityrosine in food: A review of its occurrence, health effects, detection methods, and mitigation strategies

Protein and amino acid oxidation in food products produce many new compounds, of which the reactive and toxic compound dityrosine, derived from oxidized tyrosine, is the most widely studied. The high reactivity of dityrosine enables this compound to induce oxidative stress and disrupt thyroid hormone function, contributing to the pathological processes of several diseases, such as obesity, diabetes, cognitive dysfunction, aging, and age-related diseases. From the perspective of food safety and human health, protein-oxidation products in food are the main concern of consumers, health management departments, and the food industry. This review highlights the latest research on the formation pathways, toxicity, detection methods, occurrence in food, and mitigation strategies for dityrosine. Furthermore, the control of dityrosine in family cooking and food-processing industry has been discussed. Food-derived dityrosine primarily originates from high-protein foods, such as meat and dairy products. Considering its toxicity, combining rapid high sensitivity dityrosine detection techniques with feasible control methods could be an effective strategy to ensure food safety and maintain human health. However, the current dityrosine detection and mitigation strategies exhibit some inherent characteristics and limitations. Therefore, developing technologies for rapid and effective dityrosine detection and control at the industrial level is necessary.

An Efficient Processing Strategy to Improve the Flavor Profile of Egg Yolk: Ozone-Mediated Oxidation

This study investigated the effect of ozone treatment on egg yolk volatiles and fatty acids. The composition and content of volatile substances and the fatty acid content of the egg yolk were changed significantly after ozonation. With proper ozone treatment (30 min), the aldehyde content in the egg yolk increased from 78.08% to 94.63%, and the relative content of dibutyl amine decreased from 1.50% to 0.00%. There were no significant differences among the types of fatty acids in the egg yolks after being treated with ozone, but there were differences in their relative contents. The results of SDS-PAGE showed no significant difference in yolk protein composition and contents among the groups. SEM results showed that moderate ozone treatment (20 min and 30 min) led to a regular and dense network structure of egg yolk. These results provided a theoretical basis for expanding the application of ozone technology in the egg yolk processing industry.

Scavenging Capacity of Extracts of Arrabidaea chica Leaves from the Amazonia against ROS and RNS of Physiological and Food Relevance

Arrabidaea chica, a medicinal plant found in the Amazon rainforest, is a promising source of bioactive compounds which can be used to inhibit oxidative damage in both food and biological systems. In this study, the in vitro scavenging capacity of characterized extracts of A. chica leaves, obtained with green solvents of different polarities [water, ethanol, and ethanol/water (1:1, v/v)] through ultrasound-assisted extraction, was investigated against reactive oxygen (ROS) and nitrogen (RNS) species, namely superoxide anion radicals (O₂^•−), hydrogen peroxide (H₂O₂), hypochlorous acid (HOCl), and peroxynitrite anion (ONOO⁻). The extract obtained with ethanol–water presented about three times more phenolic compound contents (11.8 mg/g) than ethanol and water extracts (3.8 and 3.6 mg/g, respectively), with scutellarein being the major compound (6.76 mg/g). All extracts showed high scavenging efficiency against the tested ROS and RNS, in a concentration-dependent manner with low IC₅₀ values, and the ethanol–water extract was the most effective one. In addition, all the extracts were five times more efficient against ROO^• than Trolox. Therefore, the extracts from A. chica leaves exhibited high promising antioxidant potential to be used against oxidative damage in food and physiological systems.

Advances on nanoformulation approaches for delivering plant-derived antioxidants: A case of quercetin

Oxidative stress has been implicated in tumorigenic, cardiovascular, neuro-, and age-related degenerative changes. Antioxidants minimize the oxidative damage through neutralization of reactive oxygen species (ROS) and other causative agents. Ever since the emergence of COVID-19, plant-derived antioxidants have received enormous attention, particularly in the Indian subcontinent. Quercetin (QCT), a bio-flavonoid, exists in the glycosylated form in fruits, berries and vegetables. The antioxidant potential of QCT analogs relates to the number of free hydroxyl groups in their structure. Despite presence of these groups, QCT exhibits substantial hydrophobicity. Formulation scientists have tested nanotechnology-based approaches for its improved solubilization and delivery to the intended site of action. By the virtue of its hydrophobicity, QCT gets encapsulated in nanocarriers carrying hydrophobic domains. Apart from passive accumulation, active uptake of such formulations into the target cells can be facilitated through well-studied functionalization strategies. In this review, we have discussed the approaches of improving solubilization and bioavailability of QCT with the use of nanoformulations.

Chronic acrylamide exposure resulted in dopaminergic neuron loss, neuroinflammation and motor impairment in rats

Acrylamide (ACR) as a by-product of Maillard reaction is widely present in food. Although ACR is known to exhibit neurotoxicity, most studies about ACR neurotoxicity are currently short-term high-dose providing limited reference value for human exposure. The present study aims to determine the effects of chronic ACR exposure on dopaminergic neurons in rat nigra and the potential mechanism from the perspective of NLRP3 inflammasome-mediated neuroinflammation. The SD rats were maintained on treated drinking water providing dosages of 0, 0.5, or 5 mg/kg/day ACR for 12 months. ACR exposure caused motor dysfunction in rats, which was associated with dopaminergic neuron loss, α-Synuclein (α-Syn) accumulation and decreased brain-derived neurotrophic factor (BDNF) in nigra. ACR activated microglia by increasing Iba-1⁺, Iba-1⁺CD68⁺ positive cells and the percentage of ameboid-shaped ones in rat nigra. ACR markedly upregulated the protein levels of NLRP3 inflammasome constituents NLRP3 and caspase-1 and inflammatory cytokine IL-1β. ACR chronic exposure increased the risk of Parkinson's disease (PD) like dopaminergic neuron depletion in nigra potentially through NLRP3 inflammasome-mediated neuroinflammtion.

Physicochemical properties and volatile formation mechanism of medium-chain triacylglycerols during heating

Medium-chain triacylglycerols (MCTs), including caprylic acid (C8), a mixture of caprylic acid and capric acid (C8+C10), and high-MCT coconut oil (HMCO), were heated at 180°C. Their volatile profiles were analyzed to determine the MCT degradation mechanisms. As heating time increased to 10 h, secondary oxidation products and acid value of all samples increased continuously. Ketones, alkanes, fatty acid anions, fatty acid esters, and lactones were found in all heated MCTs. 2-Hexanone and heptane were detected in C8 after 2 h of heating, and 2-heptanone, heptanal, methyl octanoate, γ-octalactone, and δ-octalactone were detected after 4 h. For the C8+C10, ketones, alkanes, and aldehydes were first observed. Hydrolysis and decarboxylation seem to occur first for ketone and alkane formation. Cracking and cyclization may occur later for fatty acid esters and lactones in heated MCTs. This result can help to understand thermal decomposition mechanisms of saturated fatty acids like MCTs. PRACTICAL APPLICATION: Medium-chain triacylglycerols (MCTs) have been used in cosmetic and fragrance industries due to their high oxidative stability, relatively high polarity, and smooth textures. In addition, MCTs have gained popularity among consumers for their health beneficial effects. MCTs could be used as major continuous phases for many food ingredients receiving high thermal energy for cooking. The results of this study can provide basic and useful information on the physicochemical properties and thermally decomposed volatile profiles from MCTs, which can help to produce stable processed products with lengthy shelf-lives in the food industry.

Photo-Oxidative Stability of Aqueous Model Systems Enriched with Omega-3 Long-Chain Polyunsaturated Fatty Acid-Rich Microalgae as Compared to Autoxidative Stability

Several species of microalgae are promising as an alternative source of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). Photoautotrophic species show the greatest potential, since incorporating them into food products leads to oxidatively stable products; however, the presence of photosensitizers could reduce the shelf-life due to the appearance of photo-oxidation on exposure to light. This study investigated the oxidative impact of illumination for aqueous model suspensions enriched with Phaeodactylum (phototrophic microalgae─containing potential photosensitizers) and Schizochytrium (heterotrophic microalgae─lacking photosensitizers) during storage for 28 days at 37 °C. Primary (peroxide value) and secondary (volatiles with gas chromatography (GC)-mass spectrometry) oxidation products, n-3 LC-PUFA content (GC), and pigments (high-pressure liquid chromatography) were assessed. The results showed that photo-oxidation did not cause oxidative instability for Phaeodactylum samples compared with strong autoxidation in Schizochytrium samples. For the Phaeodactylum-enriched suspensions, only minimal photo-oxidation could be detected and the n-3 LC-PUFA content remained stable throughout storage regardless of illumination.

Oxidation of Whey Proteins during Thermal Treatment Characterized by a Site-Specific LC-MS/MS-Based Proteomic Approach

Thermal treatment is often employed in food processing to tailor product properties by manipulating the ingredient functionality, but these elevated temperatures may accelerate oxidation and nutrient loss. Here, oxidation of different whey protein systems [α-lactalbumin (α-LA), β-lactoglobulin (β-LG), a mix of α-LA and β-LG (whey model), and a commercial whey protein isolate (WPI)] was investigated during heat treatment at 60-90 °C and a UHT-like treatment by LC-MS-based proteomic analysis. The relative modification levels of each oxidation site were calculated and compared among different heat treatments and sample systems. Oxidation increased significantly in protein systems after heating at ≥90 °C but decreased in systems with higher complexity [pure protein (α-LA > β-LG) > whey model > WPI]. In α-LA, Cys, Met, and Trp residues were found to be most prone to oxidation. In β-LG-containing protein systems, Cys residues were suggested to scavenge most of the reactive oxidants and undergo an oxidation-mediated disulfide rearrangement. The rearranged disulfide bonds contributed to protein aggregation, which was suggested to provide physical protection against oxidation. Overall, limited loss of amino acid residues was detected after acidic hydrolysis followed by UHPLC analysis, which showed only a minor effect of heat treatment on protein oxidation in these protein systems.

A Photosensitized Singlet Oxygen (1O2) Toolbox for Bio-Organic Applications: Tailoring 1O2 Generation for DNA and Protein Labelling, Targeting and Biosensing

Singlet oxygen (¹O₂) is the excited state of ground, triplet state, molecular oxygen (O₂). Photosensitized ¹O₂ has been extensively studied as one of the reactive oxygen species (ROS), responsible for damage of cellular components (protein, DNA, lipids). On the other hand, its generation has been exploited in organic synthesis, as well as in photodynamic therapy for the treatment of various forms of cancer. The aim of this review is to highlight the versatility of ¹O_2, discussing the main bioorganic applications reported over the past decades, which rely on its production. After a brief introduction on the photosensitized production of ¹O₂, we will describe the main aspects involving the biologically relevant damage that can accompany an uncontrolled, aspecific generation of this ROS. We then discuss in more detail a series of biological applications featuring ¹O₂ generation, including protein and DNA labelling, cross-linking and biosensing. Finally, we will highlight the methodologies available to tailor ¹O₂ generation, in order to accomplish the proposed bioorganic transformations while avoiding, at the same time, collateral damage related to an untamed production of this reactive species.

Sauropus androgynus (L.) Merr.: a multipurpose plant with multiple uses in traditional ethnic culinary and ethnomedicinal preparations

Various plants form the basis of multiple traditional ethnic cuisines and ethnomedicinal practices across the globe. The ethnic cuisines cater to the nutritional, dietary and medicinal requirements of the tribal and rural communities even today. Using literature from various scholarly databases, this study was conducted to consolidate a comprehensive review on the use of Sauropus androgynus (L.) Merr. in various traditional ethnic cuisines and ethnomedicinal preparations across the globe. The survey shows that it is used in multiple ethnic cuisines and is variously known in different countries and among the communities. Further, it possesses multiple nutritional and ethnomedicinal properties. Considering its importance in ethnic foods and ethnomedicinal preparations, it is important to investigate the nutritional composition, phytochemical constitution and pharmacological basis of ethnomedicinal uses. Therefore, we further compiled this information and found that it is a rich source of both micro- and macronutrients and packed with several bioactive compounds. Survey of pharmacological studies on its traditional medicinal uses supports its ethnomedicinal properties. Despite its importance in traditional food and ethnomedicinal systems, it remains underexplored. Limited information on the toxicity of its various extracts shows that further studies should be conducted to understand its safety aspects. Further clinical studies to prospect possible drug candidates from it should be attempted.

Insights on the role of chemometrics and vibrational spectroscopy in fruit metabolite analysis

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The use of vibrational spectroscopy combined with data analytics is discussed.

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The measure of bioactive compounds metabolites in fruit samples is presented.

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Advantages and limitations of these techniques are discussed.

The last three decades have demonstrated the ability of combining data analytics (e.g. big data, machine learning) with modern analytical instrumental techniques such as vibrational spectroscopy (VIBSPEC) (e.g. NIR, Raman, MIR) and sensing technologies (e.g. electronic noses and tongues, colorimetric sensors) to analyse, measure and monitor a wide range of properties and samples. Developments in instrumentation, hardware and software have placed VIBSPEC as a useful tool to quantify several bioactive compounds and metabolites in a wide range of fruit and plant samples. With the incorporation of hand-held and portable instrumentation, these techniques have been valuable for the development of in-field and high throughput applications, opened new frontiers of analysis in fruits and plants. This review will present and discuss some of the current applications on the use of VIBSPEC techniques combined with data analytics on the measurement bioactive compounds and plant metabolites in different fruit samples.

Dietary cholesterol oxidation products: Perspectives linking food processing and storage with health implications

Dietary cholesterol oxidation products (COPs) are heterogeneous compounds formed during the processing and storage of cholesterol-rich foods, such as seafood, meat, eggs, and dairy products. With the increased intake of COPs-rich foods, the concern about health implications of dietary COPs is rising. Dietary COPs may exert deleterious effects on human health to induce several inflammatory diseases including atherosclerosis, neurodegenerative diseases, and inflammatory bowel diseases. Thus, knowledge regarding the effects of processing and storage conditions leading to formation of COPs is needed to reduce the levels of COPs in foods. Efficient methodologies to determine COPs in foods are also essential. More importantly, the biological roles of dietary COPs in human health and effects of phytochemicals on dietary COPs-induced diseases need to be established. This review summarizes the recent information on dietary COPs including their formation in foods during their processing and storage, analytical methods of determination of COPs, metabolic fate, implications for human health, and beneficial interventions by phytochemicals. The formation of COPs is largely dependent on the heating temperature, storage time, and food matrices. Alteration of food processing and storage conditions is one of the potent strategies to restrict hazardous dietary COPs from forming, including maintaining relatively low temperatures, shorter processing or storage time, and the appropriate addition of antioxidants. Once absorbed into the circulation, dietary COPs can contribute to the progression of several inflammatory diseases, where the absorbed dietary COPs may induce inflammation, apoptosis, and autophagy in cells in the target organs or tissues. Improved intake of phytochemicals may be an effective strategy to reduce the hazardous effects of dietary COPs.

Polyphenols as Antioxidants for Extending Food Shelf-Life and in the Prevention of Health Diseases: Encapsulation and Interfacial Phenomena

Toxicity caused by the exposure to human-made chemicals and environmental conditions has become a major health concern because they may significantly increase the formation of reactive oxygen species (ROS), negatively affecting the endogenous antioxidant defense. Living systems have evolved complex antioxidant mechanisms to protect cells from oxidative conditions. Although oxidative stress contributes to various pathologies, the intake of molecules such as polyphenols, obtained from natural sources, may limit their effects because of their antioxidant and antimicrobial properties against lipid peroxidation and against a broad range of foodborne pathogens. Ingestion of polyphenol-rich foods, such as fruits and vegetables, help to reduce the harmful effects of ROS, but the use of supramolecular and nanomaterials as delivery systems has emerged as an efficient method to improve their pharmacological and therapeutic effects. Suitable exogenous polyphenolic antioxidants should be readily absorbed and delivered to sites where pathological oxidative damage may take place, for instance, intracellular locations. Many potential antioxidants have a poor bioavailability, but they can be encapsulated to improve their ideal solubility and permeability profile. Development of effective antioxidant strategies requires the creation of new nanoscale drug delivery systems to significantly reduce oxidative stress. In this review we provide an overview of the oxidative stress process, highlight some properties of ROS, and discuss the role of natural polyphenols as bioactives in controlling the overproduction of ROS and bacterial and fungal growth, paying special attention to their encapsulation in suitable delivery systems and to their location in colloidal systems where interfaces play a crucial role.

A metabolomics approach to evaluate the effect of lyophilization versus oven drying on the chemical composition of plant extracts

Lyophilization is the “gold standard” for drying plant extracts, which is important in preserving their quality and extending their shelf-life. Compared to other methods of drying plant extracts, lyophilization is costlier due to equipment, material and operational expenses. An alternative method is post-extraction oven-drying, but the effects of this process on extract quality are unknown. In this study, crude extracts from Arthrocnemum macrostachyum shoots were compared using three post-extraction drying methods (lyophilization and oven drying at 40 and 60 °C) and two extraction solvents (water and aqueous 50% ethanol). Untargeted metabolomics coupled with chemometrics analysis revealed that post extraction oven-drying resulted in the loss of up to 27% of molecular features when compared to lyophilization in water extracts only. In contrast, only 3% of molecular features were lost in aqueous 50% ethanol extracts when subjected to oven drying. That is to say, ethanol used as a solvent has a stabilizing effect on metabolites and enhances their resistance to thermal transformation in the oven. Collectively, oven-drying of extracts was as effective as lyophilization in preserving metabolites in extracts only when 50% ethanol was used as a solvent. The results presented in this paper demonstrate the value of selecting solvent-appropriate post-extraction drying methods.

Antrocaryon amazonicum: An unexploited Amazonian fruit with high potential of scavenging reactive oxygen and nitrogen species

Antrocaryon amazonicum fruits are unexploited sources of bioactive compounds found in the Amazonia region of Brazil. In this study, for the first time, the carotenoid and phenolic compound profiles of the pulp and peel of A. amazonicum fruits, from two varieties at two harvest periods, were determined by LC-MS. Additionally, the potential of the peel and pulp extracts to scavenge physiologically relevant reactive oxygen species (ROS) and reactive nitrogen species (RNS) was assessed. The major carotenoids in both parts of the fruits were lutein, accounting for ≈42% of the identified carotenoids in the peel and ≈25% in the pulp, whereas catechin and hydroxybenzoic acid derivatives were the major phenolics in both parts. The peel extract, which presented the highest bioactive compound contents, was more efficient to scavenge ROS than the pulp. The peel extract showed high scavenging efficiency (IC₅₀ ) for singlet oxygen (¹ O₂ ; 16 µg/ml), hypochlorous acid (HOCl; 20 µg/ml), peroxynitrite (ONOO^- ; 38 µg/ml), and superoxide radical (O₂ ^•- ; 47 µg/ml), whereas the pulp extract exhibited high efficiency for ONOO^- (13 µg/ml), followed by HOCl (30 µg/ml), ¹O₂ (76 µg/ml), and less efficient for O₂ ^•- (44 µg/ml). Therefore, A. amazonicum fruits can be seen as an expressive source of bioactive compounds with high antioxidant potential to be further investigated to inhibit or delay oxidative processes both in food and physiological systems triggered by ROS and RNS. PRACTICAL APPLICATION: Bioactive compound extracts of Antrocaryon amazonicum fruits have high potential to be exploited for inhibiting or delaying oxidative processes and increase food stability.

Wearable and Mobile Sensors for Personalized Nutrition

While wearable and mobile chemical sensors have experienced tremendous growth over the past decade, their potential for tracking and guiding nutrition has emerged only over the past three years. Currently, guidelines from doctors and dietitians represent the most common approach for maintaining optimal nutrition status. However, such recommendations rely on population averages and do not take into account individual variability in responding to nutrients. Precision nutrition has recently emerged to address the large heterogeneity in individuals' responses to diet, by tailoring nutrition based on the specific requirements of each person. It aims at preventing and managing diseases by formulating personalized dietary interventions to individuals on the basis of their metabolic profile, background, and environmental exposure. Recent advances in digital nutrition technology, including calories-counting mobile apps and wearable motion tracking devices, lack the ability of monitoring nutrition at the molecular level. The realization of effective precision nutrition requires synergy from different sensor modalities in order to make timely reliable predictions and efficient feedback. This work reviews key opportunities and challenges toward the successful realization of effective wearable and mobile nutrition monitoring platforms. Non-invasive wearable and mobile electrochemical sensors, capable of monitoring temporal chemical variations upon the intake of food and supplements, are excellent candidates to bridge the gap between digital and biochemical analyses for a successful personalized nutrition approach. By providing timely (previously unavailable) dietary information, such wearable and mobile sensors offer the guidance necessary for supporting dietary behavior change toward a managed nutritional balance. Coupling of the rapidly emerging wearable chemical sensing devices-generating enormous dynamic analytical data-with efficient data-fusion and data-mining methods that identify patterns and make predictions is expected to revolutionize dietary decision-making toward effective precision nutrition.

Superoxide dismutase: an updated review on its health benefits and industrial applications

Many short-lived and highly reactive oxygen species, such as superoxide anion (O₂^-) and hydrogen peroxide (H₂O₂), are toxic or can create oxidative stress in cells, a response involved in the pathogenesis of numerous diseases depending on their concentration, location, and cellular conditions. Superoxide dismutase (SOD) activities as an endogenous and exogenous cell defense mechanism include the potential use in treating various diseases, improving the potential use in treating various diseases, and improving food-stuffs preparation dietary supplements human nutrition. Published work indicates that SOD regulates oxidative stress, lipid metabolism, inflammation, and oxidation in cells. It can prevent lipid peroxidation, the oxidation of low-density lipoprotein in macrophages, lipid droplets' formation, and the adhesion of inflammatory cells into endothelial monolayers. It also expresses antioxidant effects in numerous cancer-related processes. Additionally, different forms of SOD may also augment food processing and pharmaceutical applications, exhibit anticancer, antioxidant, and anti-inflammatory effects, and prevent arterial problems by protecting the proliferation of vascular smooth muscle cells. Many investigations in this review have reported the therapeutic ability and physiological importance of SOD. Because of their antioxidative effects, SODs are of great potential in the medicinal, cosmetic, food, farming and chemical industries. This review discusses the findings of human and animal studies that support the advantages of SOD enzyme regulations to reduce the formation of oxidative stress in various ways.

Riboflavin-Sensitized Photooxidation of Low-Density-Lipoprotein (LDL) Cholesterol: A Culprit in the Development of Cardiovascular Diseases (CVDs)

The oxidation of human low-density-lipoprotein (LDL) particles is responsible for the development of cardiovascular diseases (CVDs). In the present study, the occurrence of riboflavin-sensitized photooxidation of LDL particles was examined in an in vitro system. The presence of light, oxygen, and photosensitizer (50 μM riboflavin) caused the riboflavin-sensitized photooxidation of human LDL particles thereby increasing in the conjugated dienes (CDs) by 32.5 ± 4.8% (p < 0.05), indicating that this could serve as a major culprit in the development of CVDs. A 1 h radiation caused a 63.6 ± 0.3% degradation of the riboflavin content, and this indicates the extremely fast reaction of the riboflavin-sensitized photooxidation. The singlet oxygen quenching capacity of β-carotene was determined at three different concentrations (10, 50, and 100 μM), exhibiting both antioxidant and prooxidant effects, depending on the concentrations used. In addition, ascorbic acid displayed a high incorporation rate into the LDL particles, implying its potential in preventing riboflavin photosensitization of LDL particles. To the best of our knowledge, this is the first report on the riboflavin-sensitized photooxidation of LDL particles in an in vitro system, proposing a new possible mechanism in the development of CVDs.

Role of milk and honey in the tolerance of lactobacilli to oxidative stress

In the development of functional probiotic food, the carrier matrices should be carefully selected and optimized to ensure the highest levels of probiotic survival in the symbiotic food along storage. Because milk and honey food matrices are rich in antioxidant substances, the aim of the research was to evaluate their effect in protecting lactobacilli from reactive oxygen species (ROS) generated by the addition of hydrogen peroxide. Viability assays were performed with and without the addition of H₂O₂, in three different matrices: 0.9% peptone saline, 5% honey, or 12% reconstituted skim milk. The milk matrix provided protection for the Lacticaseibacillus paracasei DTA83 and Lacticaseibacillus rhamnosus DTA76. However, this protective effect was not observed in the survival of Lactobacillus acidophilus La 5. Honey solution did not maintain the viability of probiotic microorganisms exposed to hydrogen peroxide and, on the contrary, caused a significant reduction in the population of L. rhamnosus DTA76 (p < 0.001). Lower membrane lipid peroxidation due to H₂O₂ exposure was observed in L. acidophilus La 5 and L. rhamnosus DTA76, but this marker showed no relation with viability. It was concluded: (i) lactobacilli from the Lacticaseibacillus genus were the ones that benefited most from the lactic environment; (ii) the absence of the protective effect of honey was possibly due to the presence of Fe²⁺ which reacts with H₂O₂ to produce hydroxyl radicals; and (iii) cell viability did not correlate with membrane lipid peroxidation, and it is not a good marker to evaluate this type of damage in cells of different microorganisms.

Mechanisms for Tuning Engineered Nanomaterials to Enhance Radiation Therapy of Cancer

Engineered nanomaterials that produce reactive oxygen species on exposure to X- and gamma-rays used in radiation therapy offer promise of novel cancer treatment strategies. Similar to photodynamic therapy but suitable for large and deep tumors, this new approach where nanomaterials acting as sensitizing agents are combined with clinical radiation can be effective at well-tolerated low radiation doses. Suitably engineered nanomaterials can enhance cancer radiotherapy by increasing the tumor selectivity and decreasing side effects. Additionally, the nanomaterial platform offers therapeutically valuable functionalities, including molecular targeting, drug/gene delivery, and adaptive responses to trigger drug release. The potential of such nanomaterials to be combined with radiotherapy is widely recognized. In order for further breakthroughs to be made, and to facilitate clinical translation, the applicable principles and fundamentals should be articulated. This review focuses on mechanisms underpinning rational nanomaterial design to enhance radiation therapy, the understanding of which will enable novel ways to optimize its therapeutic efficacy. A roadmap for designing nanomaterials with optimized anticancer performance is also shown and the potential clinical significance and future translation are discussed.

Analysis of Protein Oxidation in Food and Feed Products

Food and feed proteins are subject to oxidation reactions during production, processing, and storage. Several individual oxidized amino acids have been described in model systems and food; however, protein oxidation in food is still mostly assessed by the analysis of protein carbonylation. In the present review, the chemistry of protein oxidation and its implications for protein functionality, food flavor, and nutritional physiology are briefly summarized. Limitations of generic methods targeting redox-relevant functional groups and properties of typical reaction products, such as the determination of protein carbonyls and fluorescence spectroscopy, are presented. Methods for the quantitation of individual oxidation products of susceptible amino acids, such as cysteine, methionine, phenylalanine, tyrosine, and tryptophan, are reported. Special regard is paid to limitations resulting from the required hydrolysis procedures and unintended formation of the analytes during sample pretreatment. If available, results from food analysis obtained by different methods are compared. Suggestions and requirements for future works on protein oxidation in food and nutrition are given.

Dietary Antioxidants and the Mitochondrial Quality Control: Their Potential Roles in Parkinson's Disease Treatment

Advances in medicine and dietary standards over recent decades have remarkably increased human life expectancy. Unfortunately, the chance of developing age-related diseases, including neurodegenerative diseases (NDDs), increases with increased life expectancy. High metabolic demands of neurons are met by mitochondria, damage of which is thought to contribute to the development of many NDDs including Parkinson’s disease (PD). Mitochondrial damage is closely associated with the abnormal production of reactive oxygen species (ROS), which are widely known to be toxic in various cellular environments, including NDD contexts. Thus, ways to prevent or slow mitochondrial dysfunction are needed for the treatment of these NDDs. In this review, we first detail how ROS are associated with mitochondrial dysfunction and review the cellular mechanisms, such as the mitochondrial quality control (MQC) system, by which neurons defend against both abnormal production of ROS and the subsequent accumulation of damaged mitochondria. We next highlight previous studies that link mitochondrial dysfunction with PD and how dietary antioxidants might provide reinforcement of the MQC system. Finally, we discuss how aging plays a role in mitochondrial dysfunction and PD before considering how healthy aging through proper diet and exercise may be salutary.

Quantification of Cooking Method Effect on COP Content in Meat Types Using Triple Quadrupole GC-MS/MS

A diet containing cholesterol is an essential component of biological function; however, cholesterol oxidation products (COPs) remain a major public health concern. This study investigated the effects of cooking methods (boiling and frying) on the production levels of COPs in processed foods. Samples, as represented by minced beef, chicken sausages, and fish fillets, were subjected to different cooking methods followed by COP extraction using a saponification method. Then, six common COPs, 5α-cholest, α-epoxy, β-epoxy, 25-HC, triol, and 7-keto, were quantified by triple quadrupole gas chromatography-mass spectrometry (GS-MS/MS). A significantly high number of COPs were detected in minced meat, of which 7-keto and triol were detected as major oxidation products, followed by chicken sausages and fish fillets (p ≤ 0.05). Compared to boiling, frying generated significantly more COPs, specifically triol (0.001-0.004 mg/kg) and 7-keto (0.001-0.200 mg/kg), in all samples. Interestingly, cholesterol level was found to be slightly (but not significantly) decreased in heat-treated samples due to oxidation during cooking, producing a higher number of COPs. Notably, the fish fillets were found to produce the fewest COPs due to the presence of a low amount of cholesterol and unsaturated fatty acids. In conclusion, adapting boiling as a way of cooking and choosing the right type of meat could serve to reduce COPs in processed foods.

Inactivation of foodborne pathogens by the synergistic combinations of food processing technologies and food-grade compounds

There is a need to develop food processing technologies with enhanced antimicrobial capacity against foodborne pathogens. While considering the challenges of adequate inactivation of pathogenic microorganisms in different food matrices, the emerging technologies are also expected to be sustainable and have a minimum impact on food quality and nutrients. Synergistic combinations of food processing technologies and food-grade compounds have a great potential to address these needs. During these combined treatments, food processes directly or indirectly interact with added chemicals, intensifying the overall antimicrobial effect. This review provides an overview of the combinations of different thermal or nonthermal processes with a variety of food-grade compounds that show synergistic antimicrobial effect against pathogenic microorganisms in foods and model systems. Further, we summarize the underlying mechanisms for representative combined treatments that are responsible for the enhanced microbial inactivation. Finally, regulatory issues and challenges for further development and technical transfer of these new approaches at the industrial level are also discussed.

Purification and identification of novel antioxidant peptides from watermelon seed protein hydrolysates and their cytoprotective effects on H2O2-induced oxidative stress

The aim of this study was to purify and identify antioxidant peptides from watermelon seed protein hydrolysates (WSPHs-I: Mw < 1 kDa) and further evaluate their cytoprotective effects against H₂O₂-induced oxidative stress in HepG2 cells. After purification by Sephadex G-15 and semi-preparative reversed-phase high performance liquid chromatography (RP-HPLC), five peptides, RDPEER (P1), KELEEK (P2), DAAGRLQE (P3), LDDDGRL (P4), and GFAGDDAPRA (P5) were sequenced by LC-MS/MS and synthesized with solid-phase synthesis method. These peptides showed desirable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity (IC₅₀: 0.216 ± 0.01-0.435 ± 0.03), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity (IC₅₀: 0.54 ± 0.02-1.23 ± 0.03), and oxygen radical absorbance capacity (ORAC) (82.36 ± 1.2-130.67 ± 2.2 μM TE/mg). Among them, peptide P1 exhibited the strongest antioxidant capacity. Moreover, the results suggested that peptide P1 may protect HepG2 cells from H₂O₂-induced oxidative damage by significantly inhibiting reactive oxygen species (ROS), [Ca²⁺]i, malondialdehyde (MDA) levels and increasing antioxidative enzyme activities.

Profiling of amino acids and their interactions with proteinaceous compounds for sewage sludge dewatering by Fenton oxidation treatment

During advanced oxidation treatment for enhancing sludge dewaterability, the peptide chains of protein can be decomposed into amino acids. Protein exhibits a great impact on sewage sludge dewaterability. However, the role of amino acids in sludge dewatering remains unclear. In this study, among the 23 types of amino acids investigated, tryptophane (Trp) and lysine (Lys) were identified as the key amino acids affecting sludge dewaterability during Fenton oxidation treatment. The content of lysine showed positive correlations with capillary suction time (CST), specific resistance to filtration (SRF), and bound water content, and the concentrations of total protein, low molecular weight protein, amines and amides, and 3-turn helix of proteinaceous compounds in bound extracellular polymeric substances (EPS), while the content of tryptophane showed negative correlations with the above parameters. The amino acids may be sourced from damage of the membrane and ribosomal proteins by hydroxyl radicals, and the peptide bonds connected with tryptophane were more inclined to be decomposed than other amino acids. Particularly, more amino acids of tryptophane can result in more hydrophobic interaction, and less necessary energy barrier for aggregation of particles. As such, regulating protein degradation towards production of tryptophane may be related with enhanced sludge dewaterability by Fenton oxidation treatment.

Evaluating the In Vitro Potential of Natural Extracts to Protect Lipids from Oxidative Damage

Lipid peroxidation is a chemical reaction known to have negative impacts on living organisms' health and on consumer products' quality and safety. Therefore, it has been the subject of extensive scientific research concerning the possibilities to reduce it, both in vivo and in nonliving organic matrices. It can be started by a variety of oxidants, by both ROS-dependent and -independent pathways, all of them reviewed in this document. Another feature of this reaction is the capacity of lipid peroxyl radicals to react with the non-oxidized lipids, propagating the reaction even in the absence of an external trigger. Due to these specificities of lipid peroxidation, regular antioxidant strategies-although being helpful in controlling oxidative triggers-are not tailored to tackle this challenge. Thus, more suited antioxidant compounds or technologies are required and sought after by researchers, either in the fields of medicine and physiology, or in product development and biotechnology. Despite the existence of several laboratory procedures associated with the study of lipid peroxidation, a methodology to perform bioprospecting of natural products to prevent lipid peroxidation (a Lipid Peroxidation Inhibitory Potential assay, LPIP) is not yet well established. In this review, a critical look into the possibility of testing the capacity of natural products to inhibit lipid peroxidation is presented. In vitro systems used to peroxidize a lipid sample are also reviewed on the basis of lipid substrate origin, and, for each of them, procedural insights, oxidation initiation strategies, and lipid peroxidation extent monitoring are discussed.

Lutein reverses hyperglycemia-mediated blockage of Nrf2 translocation by modulating the activation of intracellular protein kinases in retinal pigment epithelial (ARPE-19) cells

Diabetic retinopathy (DR) is a major cause of acquired blindness among working adults. The retinal pigment epithelium (RPE), constitutes an outer blood-retinal barrier, is vastly affected in diabetic humans and animals. Lower levels of lutein in the serum and retina of diabetic population, and beneficial effects of carotenoids supplementation in diabetic retinopathy patients created an interest to examine the protective effect of lutein on hyperglycemia-mediated changes in oxidative stress and antioxidant defense system in ARPE-19 cells. The WST-1 assay was performed to analyze the impact of glucose, and lutein on the viability of ARPE-19. The intracellular oxidative stress was measured by a DCF (dichlorofluorescein) assay, mitochondrial membrane potential (MMP) was monitored using a JC-10 MMP assay kit and GSH level was examined using GSH/GSSG ratio detection kit. The oxidative stress markers, protein carbonyl and malondialdehyde were spectrophotometrically measured using 2,4-dinitrophenylhydrazine and 2-thiobarbituric acid, respectively. The expression of endogenous antioxidant enzymes and regulatory proteins in ARPE-19 was quantified by western blotting. The localization of Nrf2 protein was examined by immunofluorescent staining. The results show that lutein (up to 1.0 μM) did not affect the viability of ARPE-19 grown in both normal and high-glucose conditions. Lutein treatment blocked high glucose-mediated elevation of intracellular ROS, protein carbonyl and malondialdehyde content in ARPE-19 cells. The decreased MMP and GSH levels observed in ARPE-19 grown under high-glucose condition were rescued by lutein treatment. Further, lutein protected high glucose-mediated down-regulation of a redox-sensitive transcription factor, Nrf2, and antioxidant enzymes, SOD2, HO-1, and catalase. This protective effect of lutein was linked with activated nuclear translocation of Nrf2, which was associated with increased activation of regulatory proteins such as Erk and AKT. Our study indicates that improving the concentration of lutein in the retina could protect RPE from diabetes-associated damage.

Optimization of carotenoids production by Rhodotorula mucilaginosa (MTCC-1403) using agro-industrial waste in bioreactor: A statistical approach

Bio-colorants are preferred over synthetic colors as bio-colorants not only impart characteristic color to the food also contain harmless bio-active antioxidant nutrients. The present study was undertaken to investigate the potential of agro-industrial waste (Onion peels, potato skin, mung bean husk and pea pods) for carotenoid production from Rhodotorula mucilaginosa. After screening of appropriate carbon, nitrogen sources from agro-industrial waste, the fermentation conditions (pH, temperature, agitation) were optimized using Response Surface Methodology and optimum conditions were pH 6.1, temperature 25.8 ᴼC and agitation 119.6 rpm. Further, to evaluate the effect of aeration on carotenoids synthesis, fermentation was carried out in 3 L bio-reactor under optimum conditions with an air input of 1.0 vvm. Aeration causes elevation of more than 100 μg carotenoids per g of dry biomass. LC-MS of extracted pigment confirmed the presence of some other carotenoids along with β-carotene. The major carotenoid compounds were found from the investigation were torularhodin, β-carotene, and torulene.