Ohmic heating of strawberry products: electrical conductivity measurements and ascorbic acid degradation kinetics
نویسنده
چکیده
The effects of field strength and multiple thermal treatments on electrical conductivity of strawberry products were investigated. Electrical conductivity increased with temperature for all the products and conditions tested following linear relations. Electrical conductivity was found to depend on the strawberry-based product. An increase of electrical conductivity with field strength was obvious for two strawberry pulps and strawberry filling but not for strawberry topping or strawberry-apple sauce. Thermal treatments caused visible changes (a decrease) in electrical conductivity values of both strawberry pulps tested, but the use of a conventional or ohmic pre-treatment induces a different behavior of the pulps’ conductivity values. Ascorbic acid degradation followed first order kinetics for both conventional and ohmic heating treatments and the kinetic constants obtained were in the range of the values reported in the literature for other food systems. The presence of an electric field does not affect ascorbic acid degradation. 2003 Elsevier Ltd. All rights reserved.
منابع مشابه
Ohmic Heating of Aloe vera Gel: Electrical Conductivity and Energy Efficiency
Ohmic heating is defined as a process which alternating electric current is passed through food with the primary purpose of heating it due to the electrical resistance and can be specially applied as an alternative heating method. In this research, Aloe vera gel concentrates having 0.5-2% soluble solids were ohmically heated up to 60°C by using four different voltage gradi...
متن کاملExperimental Study and CFD Modeling of the Ohmic Heating Process in a Static Two-Phase Biosolid – Liquid System
The effective parameters on Ohmic heating in static system containing biosolid-water were studied. The effects of distribution of particles, salinity and electric field strength on electrical conductivity,</e...
متن کاملStability and sensory shelf life of orange juice pasteurized by continuous ohmic heating.
Electrical heating of food products provides rapid and uniform heating, resulting in less thermal damage to the product. The objective of this research was to examine the effects of ohmic heating on the stability of orange juice with comparison to conventional pasteurization. During storage at 4 degrees C, degradation curves of ascorbic acid followed a linear decrease pattern in both ohmic-heat...
متن کاملOhmic processing of liquid whole egg, white egg and yolk
The Ohmic heating rate of a food is highly influenced by its electrical conductivity. In this study, electrical conductivities, colour changes and system performance of liquid whole egg, white egg and yolk were determined on a laboratory scale static Ohmic heater by applying 30 V/cm voltage gradient. The samples were heated from room temperature through to pasteurization temperature (19 – 60°C)...
متن کاملOhmic Heating is an Alternative Preservation Technique-A Review
Ohmic heating offers an alternating to conventional heating because it simultaneously heats both phases by internal energy generated through electrical energy. In this process heating rate depends upon the electrical conductivity and field strength. By this method a product undergoes a minimum structural damage, retain its nutritional value. This technique gives excellent processed quality prod...
متن کامل