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Marine-Derived Omega-3 Fatty Acids and Cardiovascular Disease
Published in Stephen T. Sinatra, Mark C. Houston, Nutritional and Integrative Strategies in Cardiovascular Medicine, 2022
Thomas G. Guilliams, Jørn Dyerberg
Fish oil oxidation is measured using two methods. The first measures oxidized fatty acids directly as a peroxide value (PV or POV). Since these peroxides are transient and can form secondary oxidized molecules, such as aldehydes, a second test is used to detect these oxidized compounds: the anisidine (or p-anisidine) test. By adding the anisidine value to twice the peroxide value (AV+2PV), we get the TOTOX value, which allows for evaluating an oil’s rancidity.97 To control the oxidation of the oil raw material and finished product, most manufacturers add a variety of antioxidants. The most popular are vitamin E, vitamin A, flavonoids, and rosemary or other spice extracts; synthetic antioxidants are rarely used. Most commercially available products contain one or more of these antioxidants, at very low doses, in the finished product. Manufacturers of liquid-filled bottles or softgel capsules also utilize nitrogen (to purge available oxygen), low light and cold temperatures in the manufacturing process to reduce oxidation and extend shelf life. Products that have passed their expiration date should be thrown away, as oxidized fish oil can act as a pro-oxidant and limit the benefits realized if consumed.98,99
Lipid peroxidation and its measurement
Published in Roger L. McMullen, Antioxidants and the Skin, 2018
The peroxide value (PV) is often used as an indicator of the concentration of peroxides (ROOR) and hydrogen peroxides (ROOH) that are present in a given sample. It is typically determined by performing iodometric titration; however, there are a number of different methods that may be used to measure peroxides.1 In the iodometric titration technique, the peroxides oxidize iodide (I−) to iodine (I2), which can be measured by standard titration techniques. This is an official method of the American Oil Chemists Society (AOCS) and is frequently utilized to monitor lipid peroxidation in food and cosmetic samples.131–133 The iodometric titration is typically carried out by reacting potassium iodide (the source of I−) with the sample to be analyzed, which often is a lipid oil system that is suspected of containing ROOR and/or ROOH. By performing the titration, one may quantify the amount of peroxides present in the sample and also investigate the possible prevention of oxidation by antioxidants.
The Quality Determination of Selected Commercial Online Purchased Edible Pomegranate Seed Oils With New Argentometric Liquid Chromatography Method
Published in Journal of Dietary Supplements, 2021
Agnieszka Białek, PhD, DSc, Małgorzata Białek, PhD, Tomasz Lepionka, PhD, Elżbieta Tober, Marian Czauderna, PhD
As there are no legal regulations dedicated to PSO dietary supplements, standard analytical methods used for quality determination of edible oils have been applied. Refractive index (nD) was determined according to ISO 6320:2017 (ISO 2017). The content of double bonds was determined as iodine value (IV) according to ISO 3961:2018 and expressed as mg I2/100 g oil (ISO 2018). The content of hydroperoxides was determined as peroxide value (PV) according to ISO 3960:2017 (ISO 2017). Results are expressed as mEq O/kg oil. The content of free fatty acids was determined as acidic value (AV) according to ISO 660:2009 (ISO 2009). Results are expressed as mg KOH/g oil. The color of oil was performed in CIE L*a*b* system using a Minolta CR-400 chromatometer with glass cell (10 mm optical path) attachment CA-A98 (Konica Minolta, Inc., Tokyo, Japan), according to Moczkowska et al. (2017). The diameter of the measuring head was 8 mm. The device was calibrated on a white standard plate (L* = 98.45, a* = −0.10, b* = −0.13). Illuminant D65 (color temperature: 6500 K) and a standard observer (2°) were used. Color coordinates: L* (lightness or luminance), a* (greenness/redness), b* (blueness/yellowness) were measured at ten randomly selected places on each sample surface and expresses as mean of ten repetitions.
Solvent Extraction and Gas Chromatography–Mass Spectrometry Analysis of Annona squamosa L. Seeds for Determination of Bioactives, Fatty Acid/Fatty Oil Composition, and Antioxidant Activity
Published in Journal of Dietary Supplements, 2018
Mohammad Zahid, Muhammad Arif, Md. Akhlaquer Rahman, Kuldeep Singh, Mohd Mujahid
DPPH scavenging activity (IC50) was calculated graphically (Table 4, Figure 4). Both ethanolic and n-hexane fractions (at concentrations of 1,000 μg/mL) showed 65.5% and 92.0% activity comparable to that of positive control (α-tocopherol; 94.8%). It was found that radical-scavenging activity of the extracts increased with increasing concentration. Lower IC50 value indicates higher antioxidant activity. The antioxidant activity may be attributed to the presence of phenolic compounds and unsaturated fatty acids. The lipid content may change due to oxidation of the oil, which in turn affects the antioxidant potential of the oil; hence, it is important to determine peroxide value of extracted oil.
Production of rice bran oil (Oryza sativa L.) microparticles by spray drying taking advantage of the technological properties of cereal co-products
Published in Journal of Microencapsulation, 2022
Nathan H. Noguera, Dyana C. Lima, José Claudio Klier Monteiro Filho, Rodney A. F. Rodrigues
The peroxide value determination was carried out according to AOCS Official method Cd 8–53 (titration with sodium thiosulfate). The free oil and the particle samples were placed in glass vials and hermetically closed. For the free oil treatment, the amount of oil stored was 0.50 g. The amount of powder, in turn, was determined from the amount of total oil, so that the different microparticles also had 0.50 g of oil each. Bottles of 10 ml for free oil and 15 ml for powders were used, so that the volume of headspace was comparable among treatments. Then, individual vessels were stored in an oven at 60 °C for 8 weeks. Once a week, they were removed for peroxide quantification and then discarded.