1,721,016 research outputs found
Cholesterol photosensitized oxidation in food and biological systems
No full textLipid oxidation is one of the main chemical degradations occurring in biological systems and leads to the formation of compounds that are related to aging and various chronic and degenerative diseases. The extent of oxidation will depend on the presence of antioxidants/pro-oxidants, the unsaturation degree of fatty acids, and environmental conditions. Lipid oxidation can also affect other molecules that have double bonds in their chemical structures, such as cholesterol. Cholesterol oxidation products (COPs) have been studied in depth, because of their negative and controversial biological effects. The formation of COPs can be particularly favored in the presence of light and photosensitizers, since they generate excited singlet oxygen that rapidly reacts with the double bond by a non radical mechanism and without any induction period. The present review intends to provide an overall and critical picture of cholesterol photosensitized oxidation in food and biological systems, and its possible impact on human health and well-being
Does fried high-oleic sunflower oil impact plasma lipid profile and liver enzymatic activity in rat?
No full textIntroduction: Deep-fat frying is one of the most important and widely spread cooking methods. The characteristics of the oil bath play a preponderant role on frying performance, as well as on the level of neoformation compounds generated by this cooking treatment. Over the past few years, palm oil and its fractions have been widely used as frying oil, due to its stability, low cost and positive impact on the sensory properties of fried food. However, due to its sustainability, process contaminants and health effects, it has been widely replaced with other vegetable oils (such as high-oleic sunflower oil, HOS) or palm-free frying mixtures in the catering sector, which are more unsaturated and thus more prone to oxidation than palm oil. Considering that vegetable oils that oxidize during frying can exert various toxicological effects, it would be interesting to assess the in vivo impact of fried HOS on rat lipid profile and liver Phase I, II and antioxidant enzymatic activity.
Materials and Methods: Twenty-two male Sprague Dawley rats aged 9 weeks and weighing 170-200 g, were housed under 12h-light/12h-dark cycle, 22°C, 60% humidity, and fed ad libitum. After 10-day adaptation, the rats were randomly split into four experimental units: HOS group daily treated with 2.6 g of fresh oil for 7 days; 2) HOS-7F group daily treated for 7 days with 2.6 g of 5-day fried oil (3 cycles at 180°C/day); 3) HOS-14 group daily treated with 2.6 g of fresh oil for 14 days; 4) HOS-14F group daily treated for 14 days with 2.6 g of 5-day fried oil (as described above). The animals were treated by gavage. Rats were fasted 16 h prior to sacrifice, which occurred 24 h after the last treatment, in accordance with approved Ministerial procedures appropriate to the species. Immediately prior to the sacrifice, a blood sample was collected from each animal. The liver was rapidly removed and processed separately.
Results: Only HSO-14F had a significant impact on the animal body weight (5.5% gain, p<0.01 vs HOS-14). HSO-7F group displayed a considerable inactivation of CYP2B1/2 isoform (40% loss, p<0.05 vs. HSO), while an increase (up to 45%, p<0.05 vs. HSO) of QNO1 activity was registered. Concerning plasma lipids, an increase of free cholesterol in fried-oil groups was denoted. On the other hand, no significant changes were observed in the fatty acid composition of both triacylglycerol and phospholipid fractions. In general, the level of cholesterol oxidation products (COPs) in plasma was higher in the fried-oil groups, while a significant reduction of 24-hydroxycholesterol (24-HC) was found in HSO-7F.
Conclusions: Dietary supplementation of fried HSO by gavage did not significantly affect liver Phase I, II and antioxidant enzymes, and fatty acid composition of plasma in rats regardless of the treatment length, so HSO could be considered a valid alternative to palm oil as frying oil. However, the higher presence of COPs in plasma, and in particular the reduction of 24-HC level, could suggest that fried HSO could exert some effect at brain level. A deeper investigation is thus needed to better clarify this result
Impact of e-cig vaping personalization on antioxidant defense: a multidisciplinary approach
No full textEffects of multiple abiotic stresses on lipids and sterols profile in barley leaves (Hordeum vulgare L.).
Full text linkPlants are usually exposed to several types of abiotic stress in regular field conditions. The lipid profile of barley homozygous lines exposed to drought, heat, salinity, and their combinations, was investigated in the present study. Free fatty acids, free sterols, and diacylglycerols were the most abundant classes (∼8.0% of plant material). The genetic background significantly impacted the lipid composition rather than the treatments, and diacylglycerols were the only lipid class affected by salinity (1.84 mg/100 mg plant tissue; ∼33% reduction). However, the genotype × treatment interaction analysis revealed that the lipid and sterol compositions depended on both genotype and environment. Our results suggest that inborn stress tolerance in barley is manifested by enhanced accumulation of most lipids, mainly sterols, especially in heat/drought-stressed plants. In addition, expression of the LTP2 gene may be indirectly involved in the abiotic stress reaction of barley by mediating intracellular transport of some lipid classe
The effect of electronic-cigarettes aerosol on rat brain lipid profile
No full textThe electronic cigarettes (e-cigarettes, e-cigs) have become the most sought-after alternative to the traditional cigarettes, partly due to the widespread perception of safety. However, the high temperature reached by e-cig solutions can generate toxic compounds, some of which are listed as known human carcinogens. To evaluate the impact of e-cig aerosol on rat brain lipid profile, twenty male Sprague Dawley rats were exposed to 11 cycles/day (E-cig group), to consume 1 mL/day of e-liquid, for 5 days/week up to 8 weeks. Ten rats were sacrificed after 4 weeks (4w) and ten at the end of treatment (8w). The composition of total fatty acids, sterols and oxysterols of the lipid fraction of rat brains, was analyzed. The results of the E-cig group were compared with those of the control group (not exposed). After 8 weeks, the saturated fatty acids significantly raised up to 7.35 mg/g tissue, whereas polyunsaturated fatty acids decreased reaching 3.17 mg/g. The e-cig vaping increased both palmitic (3.43 mg/g) and stearic acids (3.82 mg/g), while a significant decrement of arachidonic (1.32 mg/g) and docosahexaenoic acids (1.00 mg/g) was found. Atherogenic (0.5) and thrombogenic (1.12) indices also increased in 8w treated animals. The e-cig aerosol significantly impacted the cholesterol homeostasis, since the latter at 8w (21.57 mg/g) was significantly lower than control (24.56 mg/mg); moreover, a significant increase of 7-dehydrocholesterol (1.87 mg/g) was also denoted in e-cig group. The e-cig aerosol also reduced the oxysterols (19.55 μg/g) formation, except triol and 24(S)-hydroxycholesterol (24(S)-HC), diminished after 8 weeks of exposure. The principal component analysis (PCA) separated all E-cig from control groups, evidencing that oxysterols (except triol and 24(S)-HC) were inversely correlated to 7-DHC and TI. The present research revealed that e-cigs aerosol affected the lipid and cholesterol homeostasis in rat brain, which could contribute to the new occurrence of some neurodegenerative diseases
Effects of phenols extracted from olive vegetation water on oxysterols, mutagenicity and genotoxicity of cooked beef hamburgers
No full textBy-products of the olive oil mechanical extraction process are sources of high value molecules for the production of new foods and/or ingredients with higher functionality. In particular, replacing chemical additives (i.e. nitrite/nitrate salts) in meat preparations with natural compounds from agro-food by-products (such as biophenols) is of great interest to both food industry and consumers, because it increases the sustainability of the food chain while promoting at the same time the launching of clean label meat products. Due to its high concentration in secoiridoids’ derivatives and verbascoside, the addition of a phenolic extract from olive vegetation water in fresh meat products, is expected to exert an antioxidant action towards lipids and myoglobin, as well as an antimicrobial activity especially versus those Gram-positive bacteria having a significant impact on food safety, such as Listeria monocytogenes and Clostridium botulinum. The aim of this study was to evaluate the effect of an extract rich in phenols obtained from olive vegetation water on the oxidative stability of cooked beef hamburgers prepared without chemical additives during storage, as well as on their mutagenicity and genotoxicity. To prepare the hamburgers, minced beef meat was added with 0.8% salt, 2 starter cultures (SafePro® and Bactoferm®) and different concentrations of phenolic extract: control (C), L1 (0.35% of spray-dried phenolic extract, equivalent to 87.5 mg of phenols/Kg), L2 (0.70% of spray-dried phenolic extract, equivalent to 175 mg of phenols/Kg). Raw hamburgers were packed under modified atmosphere and stored under alternating exposure to fluorescent light (12 h dark/12 h light) at 4±2 °C for 9 days. Hamburgers were sampled at different times (0, 6 and 9 days) and grilled at 70 °C. The oxidative stability of the cooked hamburgers was evaluated by thiobarbituric acid reactive species (TBARs) and oxysterols. To assess the in vitro DNA damage and mutagenicity, the Comet assay and the Ames test were performed on the extract of cooked hamburgers, respectively. The results show that the phenolic extract at both concentrations proved to effectively reduce TBARs and oxysterols during shelf-life. Remarkably, TBARs and oxysterols were up to 5.7- and 4-fold lower in phenol-enriched cooked hamburgers, respectively, as compared to the control samples. Moreover, the extract of cooked hamburgers proved to be genotoxic on PBMCs (Primary Peripheral Blood Mononuclear Cells) humans’ cells, while they were not mutagenic. Nevertheless, the genotoxicity was reduced by presence of the phenolic extract. In conclusion, the phenolic extract from olive oil wastewater proved to be an effective antioxidant and to reduce the production of genotoxic compounds (responsible for carcinogenicity of red meats, according to IARC), thus confirming to be a promising ingredient for clean label fresh meat products
Hempseed oil emulsion as pork back fat replacer in cooked sausages
Full text linkMeat products are important sources of various nutrients that are essential for growth and development, but they are also rich in saturated fatty acids (SFA) and cholesterol, which are considered risk factors of several chronic diseases, mainly cardiovascular disease (CVD), cancer, obesity and type 2 diabetes. Several studies have demonstrated that the substitution of pork back-fat with polyunsaturated fatty acids (PUFA) emulsified oils is a good strategy to achieve healthier lipid profiles in meat products, with improved oxidative stability and sensory traits. Hempseed oil represents an interesting alternative, since it is an exceptionally rich source of PUFA with a n-6/n-3 ratio of 3:1 that matches human optimal nutritional needs according to the European Food Safety Authority recommendations (3-5:1). The aim of this study was to evaluate the influence of partial or total replacement of pork back-fat (60% and 100%) by hempseed oil-in-water emulsion on the chemical composition, oxidative stability, and sensory analysis of reduced fat cooked sausages enriched with n-3 PUFA. Three batches of bologna-type sausages were manufactured: control, 60% and 100% replacement. Hempseed oil emulsion was prepared by mixing nine parts of water with one part of isolated solid soy protein, and then with ten parts of hempseed oil. Diverse emulsion percentages were mixed with pork fat according to the desired replacement. All ingredients were minced in a chilled cutter to obtain the complete emulsification of the mixture, which was then subjected to vacuum before being stuffed in 6-cm diameter, water impermeable plastic casings. Sausages were cooked in a water bath at 80 °C for 1 h, until 72 °C was reached at product’s core. Once heating was completed, the sausages were immediately cooled in a water bath for 2 h and stored frozen (−20 °C) under vacuum till analysis. The experiment was run in triplicate. The addition of hempseed oil caused a significant increase in PUFA, with a consequent decrease of SFA and n-6/n-3 ratio according to the percentage of pork back-fat replacement. Sausages added with hempseed oil showed a significant increase in peroxide value, phytosterols and their oxidation products, but no significant effect on thiobarbituric acid reactive substances, cholesterol, cholesterol oxidation products and thiol content, was noted. Moreover, protein carbonyls significantly decreased with increasing amount of hempseed oil. Cooked sausages with 60% replacement showed good sensory acceptability scores, similar to those of samples formulated with pork back fat (control)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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