Industrial scale microwave processing of tomato juice using a novel continuous microwave system

Abstract

This study evaluated the effect of an industrial scale continuous flow microwave volumetric heating system in comparison to conventional commercial scale pasteurisation for the processing of tomato juice in terms of physicochemical properties, microbial characteristics and antioxidant capacity. The effect against oxidative stress in Caco-2 cells, after in vitro digestion was also investigated. Physicochemical and colour characteristics of juices were very similar between technologies and during storage. Both conventional and microwave pasteurisation inactivated microorganisms and kept them in low levels throughout storage. ABTS[Symbol: see text](+) values, but not ORAC, were higher for the microwave pasteurised juice at day 0 however no significant differences between juices were observed during storage. Juice processed with the microwave system showed an increased cytoprotective effect against H2O2 induced oxidation in Caco-2 cells. Organoleptic analysis revealed that the two tomato juices were very similar. The continuous microwave volumetric heating system appears to be a viable alternative to conventional pasteurisation.

Microwave flow and conventional heating effects on the physicochemical properties, bioactive compounds and enzymatic activity of tomato puree

“…These results showed that at a similar temperature (96 ± 2 °C) MWP maintained a better TAC than CP. In the same way, Stratakos et al reported that TAC in heated tomato juice was higher for MWP compared to CP at 85 °C. TAC depends on the extract and the intensity of heating applied to tomato samples .…”

Phenolic Antioxidant Capacity: A Review of the State of the Art

“…Currently, this method is widely used in many laboratories around the world due to its simplicity of use [28][29][30]. Thus, the antioxidant activity of a vast range of compounds has been reported using this method.…”

Thermal and non‐thermal processing technologies on intrinsic and extrinsic quality factors of tomato products: A review

“…Quality of tomato and tomato products is affected by the use of heating during the industrial processing; color, viscosity and flavor are somewhat altered. Regarding the color, pigment degradation, and Maillard reactions can occur as well as ascorbic acid degradation (Stratakos, Delgado‐Pando, Linton, Patterson, & Koidis, ). Shi, Dai, Kakuda, Mittal, and Xue () reported significant loss in redness and color intensity of tomato puree after heating at 60–120°C for 1–6 hr.…”