Formulation of sub‐micron emulsions containing docosahexaenoic acid esterified in triacylglycerols or phospholipids

Abstract

In food applications, long-chain PUFA can be carried by different lipid molecules, which can affect their end-use properties. The objective of this study was to formulate emulsions containing DHA located exclusively in phospholipids (PL-DHA) or in triacylglycerols (TAG-DHA) and with similar fatty acid profiles and organization. Food grade oils and lecithins were blended on the basis of their fatty acid (FA) contents and submitted to high-pressure homogenization with mineral water. The lecithin containing PL-DHA allowed to stabilize oil-in-water emulsion with droplet average diameter around 240 nm thank to the interfacial molecular packing of the PL species comprising lyso and anionic phospholipids. Small particles around 40 nm were also highlighted by transmission electron microscopy (TEM). To stabilize TAG-DHA emulsion with mainly soybean phosphatidylcholine, Tween-80 was selected among other co-emulsifiers. This TAG-DHA emulsion presented an average droplet diameter of 203 nm and contained small particles (20 nm) viewed by TEM. It had less negative droplet charge and lower supramolecular diffusion coefficient than PL-DHA emulsion. It was less physically stable than PL-DHA emulsion whose droplet size distribution remained unchanged during at least 19 days at 37°C concomitantly with an increase of 1 H NMR FA molecular diffusion coefficient.Practical applications: The sub-micron emulsions designed in this study were physically stable during storage. They were prepared with food-grade oils and characterized by similar FA compositions and structures. They can be used as delivery systems with FA compositions responding to nutritional recommendations.

Amounts of the reactive aldehydes, malonaldehyde, 4‐hydroxy‐2‐hexenal, and 4‐hydroxy‐2‐nonenal in fresh and oxidized edible oils do not necessary reflect their peroxide and anisidine values

“…Kiwiseed oil (unsaturation index = 146.5; n‐6/n‐3: 0.24) and tuna oil (unsaturation index = 284; n‐6/n‐3: 0.21) were characterized by very high unsaturation levels and contents in n‐3 fatty chains, the presence of long‐chain polyunsaturated fatty acids being typical of the fish oil. Tuna oil contained tocopherols mainly as α and γ isomers, counting for about 1000 mg kg −1 as determined by HPLC‐fluorimetry . Originally the vegetable oils also contained tocopherols, but to reduce the time needed for their oxidation, they were stripped from their endogenous antioxidant with alumina as described previously .…”

Lipid Oxidation in Oil‐in‐Water Emulsions: Involvement of the Interfacial Layer

“…Similarly, 1 H NMR diffusion coefficients of the acyl chains of triacylglycerols in marine oil and in a blend of vegetable and marine oils varied between 1×10 −8 and 1.4×10 −7 cm 2 /s. They decreased to 0.45×10 −7 cm 2 /s in the core of the oil droplets of freshly prepared submicron emulsions stabilized by LMWEs (phospholipids and Tween 80) (Kabri and others ). Even if the apparent reaction rates deduced from global measures of oxidation are, by far, slower than such diffusion rates, the effects of the decreased mobility of the triacylglycerol molecules inside the oil droplets should be appreciated with regard to the most rapid and/or limiting steps of oxidation.…”

Prediction of critical times for water-extracted avocado oil heated at high temperatures

“…The method was conducted according to Buttris and Diplock (1984) with the procedure described in Kabri et al (2013). The avocado oil dissolved in n-hexane was analyzed using a HPLC (Ultimate@RS300, Dionex, France) coupled to a fluorescence detector (RF2000, Dionex, France).…”