Ability of Sodium Dodecyl Sulfate (SDS) Micelles to Increase the Antioxidant Activity of α-Tocopherol.

As emulsifiers become saturated on the surface of an emulsion droplet, any additional emulsifier migrates to the aqueous phase. Continuous phase surfactants have been shown to increase α-tocopherol efficacy, but it is unclear if this is the result of chemical or physical effects. The addition of α-tocopherol to an oil-in-water emulsion after homogenization resulted in a 70% increase of α-tocopherol in the continuous phase when sodium dodecyl sulfate (SDS) was at levels that were greater than the SDS critical micelle concentration. Conversely, when α-tocopherol was dissolved in the lipid before emulsification, continuous phase SDS concentrations did not increase. When SDS concentration led to an increase in the aqueous phase α-tocopherol, the oxidative stability of oil-in-water emulsions increased. Data indicated that the increased antioxidant activity was the result of surfactant micelles being able to decrease the prooxidant activity of α-tocopherol. Considering these results, surfactant micelles could be an important tool to increase the effectiveness of α-tocopherol.

Impact of Polyunsaturated Fatty Acid Dilution and Antioxidant Addition on Lipid Oxidation Kinetics in Oil/Water Emulsions.

As consumers increasingly demand "cleaner" labels, one available strategy is diluting oils high in unsaturated fatty acids into more stable, more saturated oils, thus delaying lipid oxidation by decreasing free-radical propagation reactions between oxidized fatty acids and unsaturated lipids. The effect of diluting fish oil into medium-chain triglycerides (MCTs) on oxidative stability was investigated using lipid hydroperoxides and gas chromatography headspace analysis. Dilutions up to 1 in 20 of fish oil in MCT extended propanal formation from 1 to 6 days in Tween-80-stabilized oil-in-water emulsions. This protective effect was not observed in emulsions wherein the two oils were in separate droplets. Fish oil blended with high oleic sunflower oil (HOSO) also demonstrated a protective effect when the oils were in the same emulsion droplets but not in separate emulsion droplets. The present study indicates that dilution can be used to increase the oxidative stability of polyunsaturated fatty acids in oil-in-water emulsions.

Simultaneous determination of terpenes and cannabidiol in hemp (Cannabis sativa L.) by fast gas chromatography with flame ionization detection.

Hemp (Cannabis sativa L.) has become widely used in several sectors due to the presence of various bioactive compounds such as terpenes and cannabidiol. In general, terpenes and cannabidiol content is determined separately, which is time consuming. Thus, a fast gas chromatography with flame ionization detection method was validated for simultaneous determination of both terpenes and cannabidiol in hemp. The method enabled a rapid detection of 29 different terpenes and cannabidiol within a total analysis time of 16 min, with satisfactory sensitivity (limit of detection = 0.03-0.27 µg/mL, limit of quantitation = 0.10-0.89 µg/mL). The inter- and intraday precision (RSD) was <7.82 and <3.59%, respectively. Recoveries at two spiked concentration levels (low, 3.15 µg/mL; high, 20.0 µg/mL) were determined on both apical leaves (78.55-101.52%) and inflorescences (77.52-107.10%). The reproducibility (RSD) was <5.94 and <5.51% in apical leaves and inflorescences, respectively. The proposed and validated method is highly sensitive, robust, fast, and accurate for determination of the main terpenes and cannabidiol in hemp and could be routinely used for quality control.

Effect of Microwave Heating on Phytosterol Oxidation.

The oxidative stability of phytosterols during microwave heating was evaluated. Two different model systems (a solid film made with a phytosterol mixture (PSF) and a liquid mixture of phytosterols and triolein (1:100, PS + TAG (triacylglycerol))) were heated for 1.5, 3, 6, 12, 20, and 30 min at 1000 W. PS degraded faster when they were microwaved alone than in the presence of TAG, following a first-order kinetic model. Up to 6 min, no phytosterol oxidation products (POPs) were generated in both systems. At 12 min of heating, the POP content reached a higher level in PSF (90.96 µg/mg of phytosterols) than in PS + TAG (22.66 µg/mg of phytosterols), but after 30 min of treatment, the opposite trend was observed. 7-Keto derivates were the most abundant POPs in both systems. The extent of phytosterol degradation depends on both the heating time and the surrounding medium, which can impact the quality and safety of the food product destined to microwave heating/cooking.

Antioxidant activity of phenolic compounds added to a functional emulsion containing omega-3 fatty acids and plant sterol esters.

The effect of eleven compounds extracted from red propolis on the oxidative stability of a functional emulsion was evaluated. Emulsions prepared with Echium oil as omega 3 (ω-3 FA) source, containing 1.63 g/100mL of α-linolenic acid (ALA), 0.73 g/100 mL of stearidonic acid (SDA) and 0.65 g/100mL of plant sterol esters (PSE) were prepared without or with phenolic compounds (vanillic acid, caffeic acid, trans-cinnamic acid, 2,4-dihydroxycinnamic acid, p-coumaric acid, quercetin, trans-ferulic acid, trans,trans-farnesol, rutin, gallic acid or sinapic acid). tert-Butylhydroquinone and a mixture containing ascorbic acid and FeSO4 were applied as negative and positive controls of the oxidation. Hydroperoxide, thiobarbituric acid reactive substances (TBARS), malondialdehyde and phytosterol oxidation products (POPs) were evaluated as oxidative markers. Based on hydroperoxide and TBARS analysis, sinapic acid and rutin (200 ppm) showed the same antioxidant activity than TBHQ, representing a potential alternative as natural antioxidant to be applied in a functional emulsion containing ω-3 FA and PSE.

Analysis of phytosterols and phytostanols in enriched dairy products by Fast gas chromatography with mass spectrometry.

A Fast gas chromatography and mass spectrometry method for plant sterols/stanols analysis was developed, using a short capillary gas chromatography column (10 m × 0.1 mm internal diameter × 0.1 µm film thickness) coated with 5% diphenyl-polysiloxane. A silylated mixture of the main plant sterols/stanols standards (ß-sitosterol, campesterol, stigmasterol, campestanol, sitostanol) was well separated in 1.5 min, with a good peak resolution (>1.4, determined on a critical chromatographic peak pair (ß-sitosterol and sitostanol)), repeatability (<13%), and sensitivity (<0.017 ng/mL). The suitability of this Fast chromatography method was tested on plant sterols/stanols-enriched dairy products (yogurt and milk), which were subjected to lipid extraction, cold saponification, and silylation prior to injection. The analytical performance (sensitivity < 0.256 ng/mL and repeatability < 10.36%) and significant reduction of the analysis time and consumables demonstrate that Fast gas chromatography-mass spectrometry method could be also employed for the plant sterols/stanols analysis in functional dairy products.