A THEORETICAL STUDY OF COOLING OF VEGETABLES

Abstract

Food products of plant origin have a tendency to deteriorate due to biological processes and microbiological processes after harvest. Deterioration includes change in appearance, taste and odour. Hence cooling and/or precooling is done shortly after harvest. Precooling is the process of cooling fruits and vegetables after harvest and prior to transportation and storage. For an efficient cooling system for fruits & vegetables a knowledge of their heat transfer characteristics is essential. The present investigation aims to obtain heat transfer characteristics of approximately cylindrical shaped vegetables of finite length (viz, cucumber) and approximately conical shaped vegetables of finite length (viz. Carrot) during precooling analytically. The governing equation for transient heat transfer with associated initial and boundary conditions have been solved using finite difference numerical method. An excellent agreement of these solutions with the available experimental results for both the cases has validated the numerical model used. The time temperatare variations are presented graphically and the half cooling time is determined. The temperature profiles within the product have also been given. These reveal the heat transfer characteristics for the cylindrical as well as conical shaped food products.