Kinetics of Ascorbic Acid Degradation in Green Asparagus during Heat Processing

Abstract

The effect of heating on ascorbic acid in green asparagus during a simulated retort operation was investigated. The asparagus was heated in trays of ethylene-vinyl alcohol copolymer for selected time intervals at four temperatures ranging from 110 to 125 degrees C. It was found that the rate of degradation followed first-order kinetics. Kinetic parameters were obtained by using two least squares methods. The activation energy and z value were 35 kcal/mol and 20 degrees C, respectively.

Determination of reaction orders for ascorbic acid degradation during sterilization using a new experimental device: The thermoresistometer Mastia®

“…The k H -values obtained are lower than those obtained by Van den Broeck et al (1998), Blasco et al (2004), Esteve et al (1998) and Oey et al (2006), probably due to the fact that in our case the anaerobic conditions were strict (the heating media was deaerated before each experiment and nitrogen was used as headspace gas), while in their cases, no deareation is mentioned before heating treatment and therefore a certain amount of oxygen was present in the treated media.…”

“…The activation energy determined had a value of 96 kJ/mol. This value is of the same order of magnitude though slightly lower than those reported for ascorbic acid degradation in plant foods at canning temperature: under anaerobic conditions, Van den Broeck et al (1998) have determined activation energies of 117 kJ/mol and 105 kJ/mol respectively for ascorbic degradation in orange juice and tomato juice between 120 C and 150 C, Esteve et al (1998) have determined an activation energy of 140 kJ/mol for ascorbic acid degradation in green asparagus.…”

“…It is generally assumed that the degradation of ascorbic acid follows first-order kinetics in food systems (Jiang, Zheng, & Lu, 2014), but it can follow second-order kinetics if oxygen is present in a limited amount in the media (Lin & Agalloco, 1979). Ascorbic acid degradation at sterilization temperatures is poorly known, probably because of the difficulty to work at above 100 C (Blasco et al, 2004;Esteve et al, 1998;Oey et al, 2006;Van den Broeck et al, 1998). First order kinetics were reported by Van den Broeck et al (1998) in orange and tomato juices in anaerobic conditions between 120 and 150 C, by Esteve et al (1998) in green asparagus extracts both in aerobic and anaerobic conditions between 110 and 140 C, and by Blasco et al (2004) in mushroom extracts both in aerobic and anaerobic conditions between 110 and 140 C. In the last two cases, degradation was faster under aerobic condition than under anaerobic conditions.…”

“…Ascorbic acid degradation at sterilization temperatures is poorly known, probably because of the difficulty to work at above 100 C (Blasco et al, 2004;Esteve et al, 1998;Oey et al, 2006;Van den Broeck et al, 1998). First order kinetics were reported by Van den Broeck et al (1998) in orange and tomato juices in anaerobic conditions between 120 and 150 C, by Esteve et al (1998) in green asparagus extracts both in aerobic and anaerobic conditions between 110 and 140 C, and by Blasco et al (2004) in mushroom extracts both in aerobic and anaerobic conditions between 110 and 140 C. In the last two cases, degradation was faster under aerobic condition than under anaerobic conditions. Oey et al (2006) state that ascorbic acid degradation follows first order kinetics in a case where oxygen is limited between 110 and 120 C. However they report ascorbic acid degradation profiles which display two steps: a first, very rapid step, corresponding to the aerobic pathway where dissolved oxygen is involved, and a second, slower step when oxygen has been consumed and the anaerobic pathway occurs.…”

“…Nevertheless, thermal treatments can generate undesirable chemical reactions like vitamin degradation, which can lead to products having less nutritive interest. In the literature, only few studies are focussed on the degradation of ascorbic acid at sterilization temperature (Blasco et al, 2004;Esteve, Frígola, Martorell, & Rodrigo, 1998;Oey, Verlinde, Hendrickx, & Van Loey, 2006;Van den Broeck, Ludikhuyze, Weemaes, Van Loey, & Hendrickx, 1998). It is generally assumed that the degradation of ascorbic acid follows first-order kinetics in food systems (Jiang, Zheng, & Lu, 2014), but it can follow second-order kinetics if oxygen is present in a limited amount in the media (Lin & Agalloco, 1979).…”