Ethanolic Extracts from Agro-Industrial Co-Products Enhance Oxidative Stability of Candelilla Wax or Celluloses Derivatives Oleogels

Abstract

Ethanol oleoresins obtained from orange peel, pea pod, or pomegranate peel were employed to enrich soybean oil before elaborating two types of oleogels, one made with candelilla wax, another made with a mixture of celluloses derivatives, in order to determine their effect on oleogel oxidative stability. Orange peel oleoresin obtained a higher amount of polyphenols as catechol acid equivalent (9.09 meq/g), as compared to pea pod oleoresin or pomegranate peel (8.80 and 8.55, respectively), although pomegranate peel presented the higher TEAC (1.67, twice than the other samples). Oleogels elaborated with celluloses were presented better oxidative stability (oxidative rancidity and peroxide index) as compared to samples elaborated with candelilla wax, since waxes minor constituents employed as oleogelators could promote prooxidant activity. Samples with pomegranate oleoresin presented enhanced oxidative stability. Candelilla wax has a more marked effect on the oleogels thermal properties of due to their influence on fatty acids crystallization, because in celluloses oleogels the mechanism of gelation does not imply the formation of a highly ordered secondary structure. This finding opens the possibility to, on one hand, use oleoresins to enhance the oxidative stability of oleogels; and on the other hand, to select the oleogelator, waxes, or celluloses, based on thermal properties and other aspects, depending on the further application of oleogel thinking in oleogel thermoreversible capacity.

Variations in Microstructural and Physicochemical Properties of Candelilla Wax/Rice Bran Oil–Derived Oleogels Using Sunflower Lecithin and Soya Lecithin

“…The cooling profile in all the samples except Sy5 peaked at ~40 °C (T c ), indicating the major role of n-alkanes in guiding the crystallization. A similar crystallization peak has been observed for oleogels prepared by using CW in soybean oil [ 62 ]. Although few studies have reported the role of vegetable oil in maintaining the melting and crystallization temperature [ 63 ], it is quite possible that the wax has more influence on the thermal properties of the oleogels.…”