Year: 2019
Type: article
Abstract: The article presents the results of the study of the kinetics of degradation of ascorbic acid (АA in odel jelly during time storage at temperature 4 °С. Jelly samples based on concentrated apple juice and gelatin with a content of 2% and 3% were enriched with AA in the amount of 25, 50 and 75 mg/100 g of the sample. Determination of AA content carried out by galvanostatic coulometric titration. It was found that the content of AA in samples of fruit jelly decreases with increasing storage time. The loss of AA is observed more pronounced in the initial period of storage and is more characteristic of the sample containing 2% gelatin compared with the sample containing 3% gelatin. The mechanism of ascorbic acid degradation is considered as a reaction of its multi-stage oxidation with the dominant stage of oxidation to dehydroascorbic acid. The simulation of the degradation of ascorbic acid in the jelly during storage using the equations of the kinetics of the reaction of zero and first order. The goodness of model fitting to the experimental data was evaluated by adjusted coefficients of determination and the root mean square error. Compared with the zero order, the kinetics of degradation corresponded better to the first-order reaction model for all the studied samples. The reaction rate constant and half-life calculated for a first-order kinetic model are 0.00027 (1 / hour) and 107 days for samples with gelatin content of 2% and, respectively, 0.00015 and 193 days for jelly with a gelatin content of 3%. The obtained values of the first-order reaction rate constants for samples of model jelly correspond to similar values in other food products (juices, drinks, some solid products). The magnitude of the half reaction times allows the residual content of ascorbic acid to be estimated over time. The results are important for the development of technology for ascorbic acid-rich foods.
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3084512141