Article Influence of sucrose concentration on electric conductivity of banana pulp during ohmic heating P Poojitha and KA Athmaselvi Abstract Ohmic heating is a substitutive rapid heating method for food products. In this study, banana pulp with different concentrations of sugar is ohmically heated and the influence of sucrose concentration on electrical conductivity was investigated. The electrical conductivity, pH, total soluble solids, acidity, ascorbic acid con- tent before and after ohmic heat treatment were also analysed. As the sucrose concentration increased, heating time at various voltage gradients 13.33, 20 and 26.66 V/cm increased, and the electrical conductivity decreased. As the voltage gradient increased, the pH and TSS of treated pulp with different sugar concen- tration increased followed by decrease in colour and acidity. Keywords Ohmic heating, banana pulp, sucrose concentration, voltage gradients, electrical conductivity Date received: 6 July 2017; accepted: 7 June 2018 INTRODUCTION Traditional way of heating fundamentally involves the heat transfer mechanism of conduction, convection and radiation. It leads to non-uniform treatment and known loss of product quality (Ghourchi and Barzegar, 2009). In order to subdue these problems, substitutive technologies utilizing electrical energy directly in the food processing have pulled interest in the food indus- try (Akanbi et al., 2006; Alibas et al., 2007; Contreras et al., 2008; Duan et al., 2011). Ohmic heating is an electro-thermal method of pro- cessing. It is a food processing technique in which the alternating current (AC) passes through the food and leads to internal generation of energy in foods (Skudder, 1988). During ohmic heating, a mild electro- poration occurs, forming holes in the cell membrane leading to permeability of ions through the pores to the electrode with opposite charges thereby generating heat. Ohmic heating is based on the transit of electrical current (AC) through a body such as a liquid particu- late food system which serves as an electrical resistance in which heat is generated. The amount of heat gener- ated is directly linked to the current caused by the volt- age gradient in the field, and the electrical conductivity (Shirsat et al., 2004). Electro-technologies for food pro- cessing are worthier and more environmentally friendly than conventional methods used currently. And also ohmic heating can intensify both heat and mass transfer (Kemp and Fryer, 2007). The most important factors of ohmic heating are electrical conductivity and its tem- perature dependence. In ohmic heating terminology, the electrical conductivity is a measure of the mineral or ionic content. Hence, it is very important to deter- mine the electrical conductivity of the food product in the ohmic heating process because it assesses the suitableness of the product for ohmic heating. The elec- trical conductivity increases with rising temperature, suggesting that ohmic heating becomes more effective as temperature increases (Icier and Ilicali, 2004; Ye et al., 2004). Electrical conductivity of the liquid Department of Food Process Engineering, School of Bioengineering, SRM University, Kattankulathur, India Corresponding author: KA Athmaselvi, Department of food process engineering, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, India. Email: athmaphd@gmail.com Food Science and Technology International 0(0) 1–9 ! The Author(s) 2018 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1082013218787069 journals.sagepub.com/home/fst