Mixtures of Stearoyl-6-O-ascorbic Acid and α-Tocopherol:  A Monolayer Study at the Gas/Water Interface

Abstract

In the recent past the antioxidant properties of vitamin C, vitamin E, and their derivatives have been extensively studied, particularly for their peculiar activity as radical scavengers. Furthermore, the association of vitamin C with vitamin E shows an interesting synergic effect in preventing the oxidation of unsaturated fatty compounds such as linoleic acid, with vitamin C acting as a protective shield for vitamin E in solution against oxidizing agents. Vitamin C derivatives, such as its alkanoyl-6-O-ascorbic acid esters, act even better than ascorbic acid itself, because they possess the amphiphilic structure that allows the molecule to enter the hydrophobic region of a micelle or of a liposome. In order to deepen the understanding of the vitamin C/vitamin E mixed system and of the role played by ascorbic acid in restoring tocopherols, the miscibility properties of ascorbic acid derivatives and of tocopherols need to be studied in all states of aggregation (Langmuir monolayers, micellar dispersions, vesicles). In this paper we report a detailed study of the properties and behavior of monomolecular films of stearoyl-6-O-ascorbic acid (ascorbyl stearate), and α-(±)-tocopherol at different temperatures and pH, and of their mixtures at 20 °C at the gas/water interface. Our results show that ascorbyl stearate produces monolayers with both liquid-expanded and liquid-condensed phases, while α-tocopherol films are in the liquid-expanded phase only. The two pure components are completely miscible at the gas/water interface in all ratios, and indicate the presence of repulsive interactions between the hydrocarbon chains of the surfactants.

Antioxidative Properties of Stearoyl Ascorbate in a Food Matrix System

“…In addition, when a comparison was done between the antioxidative abilities of ascorbic acid and stearoyl ascorbate in the matrix of wheat starch, they were not much different because their k and Y 0 values were close to each other. The result was in accordance with previous reports about the antioxidative ability of the stearoyl ascorbate in prevention of the oxidation of linoleic acid 4,6 .…”

Effect of Surfactants and Solutes (Glucose and NaCl) on Solubility of Kavain—A Technical Note

“…Octanoyl-6-Oascorbic acid (ASC-8) was synthetised according to literature (17). Sodium laurylethere sulphate (SLES) 28% w/v in water was from Galeno (Prato, Italy).…”

Modified Cellulose Nanocrystal for Vitamin C Delivery

“…Hydroxyl groups in position 2 possess a pKa of 11.6. Hydroxyl groups in positions 5 and 6 act as secondary and primary alcoholic residues, respectively (36). CNCS/VC complexes are formed through non-covalent bonds, such as H-bonds and hydrophobic interactions (37).…”