Kinetic modeling of ascorbic acid degradation of pineapple juice subjected to combined pressure-thermal treatment. (May 2018)

• Record Type: Journal Article
• Authors: Dhakal, Santosh; Balasubramaniam, V.M.; Ayvaz, Huseyin; Rodriguez-Saona, Luis E.
• Is Part Of: Journal of food engineering. Volume 224(2018)
• Page Start: 62
• Page End: 70
• Publication Date: 2018-05
• Subjects: Ascorbic acid -- High-pressure processing -- Kinetics -- Thermal processing -- Pressure-thermal treatment -- Pineapple juice; Food industry and trade -- Periodicals; Food -- Analysis -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Analyse -- Périodiques; Aliments -- Recherche -- Périodiques; 664.005
• DOI: 10.1016/j.jfoodeng.2017.12.016
• Languages: English
• ISSNs: 0260-8774

Abstract

Abstract: A study was conducted to investigate and model kinetic degradation of ascorbic acid in freshly prepared pineapple juice subjected to various pressure (0.1, 300, 450 and 600 MPa)-thermal (30, 75, 85 and 95 °C) treatment combinations. Experiments were conducted using a semi-custom made high pressure kinetic tester as well as an aluminum thermal kinetic tester. Thermal degradation of ascorbic acid was described with simple first order kinetics. The thermal rate constants ( k 75 -95 ◦C, 0.1 MPa ) and activation energy ( E a ) for ascorbic acid degradation reaction varied in the range of 0.004–0.006 per min and 14.22–29.78 kJ/mol, respectively. Within the experimental conditions of the study (300–600 MPa at 30 °C for holding times up to 15 min) high pressure processing did not alter ascorbic acid content (535.5–564.5 mg/kg). Combined pressure-thermal treatment (300–600 MPa at 75–95 °C) degraded ascorbic acid with increasing thermal intensity and was modeled using first order fractional conversion kinetics model. The lower asymptote value ( [ A ] ∞ [ A ] 0 ), rate constants ( k 75 -95 ◦C, 600 MPa ) and E a were in the range of 77–85%, 0.108 to 0.138 per min and 17.4–43.8 kJ/mol, respectively. Similarly, pressure sensitivity ( Δ V ≠ ) was ∼0 and −2.99 cm 3 /mol at 30 and 95 °C, respectively. Knowledge gained from the study can be useful for food processors to optimize high pressure treatment conditions for pineapple juice products. Highlights: High pressure processing preserved ascorbic acid in pineapple juice. Increasing thermal intensity under pressure increased ascorbic acid degradation. First order fractional conversion model described ascorbic acid degradation during combined pressure-thermal treatment. Ea of ascorbic acid degradation during combined pressure-thermal treatment was estimated at 17.4–43.8 kJ/mol.