Degradation Kinetics of Catechin in Aqueous Solution in the Presence of Ascorbic Acid or Octanoyl Ascorbate

Abstract

The amphilic antioxidant, such as acyl ascorbate, would be expected to be a useful food additive. In this study, the antioxidative action of acyl ascorbate was examined, because knowledge of its behavior in aqueous solution is required for its effective use for food. First, the degradation kinetics of ()-catechin in aqueous solution at various pHs and temperatures were empirically expressed by the Weibull equation. The rate constant, k, was the lower at the lower pH and temperature. The temperature-dependency of the k value was analyzed on the basis of the Arrhenius equation, and it was indicated that the enthalpy-entropy compensation held during the degradation. Second, octanoyl L-ascorbate was synthesized by the condensation of L-ascorbic and octanoic acids in acetone using immobilized lipase from Candida antarctica, and the degradation kinetics of catechin in aqueous solution in the presence of octanoyl ascorbate was examined. The dependency of the k value in the catechin solution with octanoyl ascorbate on the concentration of the ascorbate was obviously dif ferent from that with ascorbic acid. That is, the degradation was suppressed at low octanoyl ascorbate concentrations, while proceeded fast at a high concentration, suggesting the formation of the micelle for octanoyl ascorbate at high concentrations.

Degradation Kinetics of Chlorogenic Acid at Various pH Values and Effects of Ascorbic Acid and Epigallocatechin Gallate on Its Stability under Alkaline Conditions

“…17 It is reported that the degradation kinetics of (+)-catechin in an aqueous solution in the absence and presence of ascorbic acid (AA) or octanoyl ascorbate at various pH values and temperatures can be expressed by the Weibull equation. 18 In addition, it is reported that the hydrolysis of 11 different disaccharides (cellobiose, gentiobiose, isomaltose, maltose, trehalose, lactose, leucrose, melibiose, palatinose, sucrose, and turanose) and 5 different monosaccharides (galactose, glucose, mannose, sorbose, and fructose) in subcritical water at 180− 260 °C could be expressed by the Weibull equation. 19,20 Knowledge about the degradation kinetics of food materials in an aqueous solution is important for processing, using, and storing foods and beverages because it will be able to set the use-by date of foods and to predict the duration of their physiological effects in food.…”

Thermal stability of catechin and epicatechin upon disaccharides addition

“…In the same study, it was observed that some common drink ingredients, sucrose, citric acid and ascorbic acid had different impact on the stability of tea catechins. Sucrose appeared to have no effect, but citric acid accelerated the degradation of tea catechins while ascorbic acid acted as both antioxidant and prooxidant, depending on time, protecting and degrading catechin (Chen et al, 2001;Watanabe et al, 2009). In contrast to these findings, some of our previous studies showed that sugars have a certain positive influence on polyphenols (Loncaric et al, 2014;Kopjar et al, 2016;Lon cari c et al, 2016).…”

“…Catechin epimerisation takes place on two asymmetric carbon atoms in the C ring, and therefore, four epimerisation products are possible in theory. Sucrose appeared to have no effect, but citric acid accelerated the degradation of tea catechins while ascorbic acid acted as both antioxidant and prooxidant, depending on time, protecting and degrading catechin (Chen et al, 2001;Watanabe et al, 2009). Further on, it has been shown that oxidation could induce dimerisation and trimerisation, forming new conjugated compounds (Guyot et al, 2003;Contreras-Dom ınguez et al, 2006;Poupard, 2008).…”

Effect of Ascorbic Acid or Acyl Ascorbate on the Stability of Catechin in Oil‐In‐Water Emulsion

“…The partition coefficient, P, of catechin between methyl dodecanate and distilled water was measured, according to a previous report [17]. One mililiter of each 0.1, 1, or 10 mmol/L catechin solution, V aq , and each 5, 10 or 20 mL of methyl dodecanate, V org , were mixed in an amber vial.…”

“…We have studied the influence of ascorbic acid or octanoyl ascorbate, which is one of the most soluble acyl ascorbates in water, on the degradation of (? )-catechin in an aqueous solution, and that of the coexistence of octanoyl ascorbate and citric acid on the catechin stability [17,18]. However, the effect of acyl ascorbate on the stability of catechins in the emulsion, which is a more complex system, is not clear.…”