Microencapsulation of Conjugated Linoleic Acid (CLA)‐Rich Oil with Skimmed Milk Components Protects against Polymerization

Abstract

Oils rich in conjugated linoleic acid (CLA) are currently used in functional foods because of the positive health effects of some CLA isomers. In this work, microencapsulation of a CLA-rich oil (containing approx. 80% of a mixture of 9c, 11 t, and 10 t, 12c-linoleic acid) with skimmed milk components is proposed as a means to protect it from oxidation and polymerization. The main physicochemical characteristics, i.e. glass transition temperature, mean oil globule size, and distribution, were evaluated. Microencapsulated samples, both intact and devoid of free oil fraction, along with the bulk oil, were oxidized at 30 C in the dark for 3 months. Throughout storage, free and encapsulated oil fractions were separately extracted from samples and analyses including substrate loss by Gas liquid chromatography-Flame ionization detection, polymer determination by High performance size exclusion chromatography-Refractive index detection, and tocopherol content determination by High performance liquid chromatography-Fluorescence detection were performed. Results showed that free oil oxidized much more rapidly than encapsulated oil. High amounts of polymers accumulated in samples with considerable high levels of tocopherols remain in encapsulated oil fractions. In samples devoid of free oil, a drastic change in the physical properties occurred but the oil polymerized to a similar extent to that found in the encapsulated fractions of intact samples.

Glyceridic and Unsaponifiable Components of Microencapsulated Sacha Inchi (Plukenetia huayllabambana L. and Plukenetia volubilis L.) Edible Oils

“…Several papers have focused on the encapsulation feasibility of a very specific group of polyunsaturated fatty acids, conjugated linoleic acid (CLA). CLA contains a very high proportion of trans-fatty acid isomers with the C10-trans-C12-cis isomer often being the most prevalent [27,39,40] and, no report has highlighted an increase in the amount of the trans-isomers. What is more, it was pointed out that the composition of the trans-CLA isomer proportion was reduced significantly in microencapsulated oil samples with respect to the initial oil samples with the consequent increase in the saturated fatty acids, as each fatty acid methyl ester is expressed as a percentage on the total ones [27].…”

Natural Polymers as Carriers for Encapsulation of Volatile Oils: Applications and Perspectives in Food Products

“…Interest in this topic was continued in 2022 and 2023, investigating the effect of peppermint, fennel, and lavender oil on cow’s milk kefir. Figure 2 shows the process of obtaining and encapsulating the volatile oil used by Tita et al [ 82 , 83 , 84 , 85 ].…”

“…This resulted in an innovative dairy product with high nutritional value and health benefits for the consumer. Figure 3 shows samples of yoghurt and kefir with encapsulated volatile oil obtained by Tita et al [ 82 , 83 , 84 , 85 ].…”

“…Interest in this topic was continued in 2022 and 2023, investigating the effect of peppermint, fennel, and lavender oil on cow's milk kefir. Figure 2 shows the process of obtaining and encapsulating the volatile oil used by Tita et al [82][83][84][85]. Sensory and textural properties [82], antioxidant capacity [83], the antimicrobial capacity of Geotrichum candidum, Penicillium expansum, Aspergillus niger, and Escherichia coli, and chemical composition using enzymatic methods [84] were highlighted.…”

“…This resulted in an innovative dairy product with high nutritional value and health benefits for the consumer. Figure 3 shows samples of yoghurt and kefir with encapsulated volatile oil obtained by Tita et al [82][83][84][85]. To maintain the chemical and physical stability of functional meals, free oil was provided as an alternative, and this resulted in a delayed oxidation process for the encapsulated oil component [85].…”