Volume 3 • Issue 2 • 1000119 126 Madridge J Food Technol. ISSN: 2577-4182 Madridge Journal of Food Technology Research Article Open Access Thermodynamic analysis of Experimental Sorption isotherms of dietetic Chhana Kheer Anuj Kumar Gautam 1 , Tanweer Alam 2 *, Aastha Bhardwaj 3 and Alok Jha 4 1 Scientist (Animal Science), Krishi Vigyan Kendra, Jalaun, UP- 285001, India 2 Joint Director & Regional Head, Indian Institute of Packaging, New Delhi- 110092, India 3 Lecturer, Department of Food Technology, Jamia Hamdard, New Delhi- 110062, India 4 Ex- South Asia Head, International Livestock Research Institute, India Article Info *Corresponding author: Tanweer Alam Joint Director & Regional Head Indian Institute of Packaging New Delhi- 110092 India Tel: +91-9310601300 E-mail: amtanweer@rediffmail.com Received: August 4, 2018 Accepted: August 29, 2018 Published: September 3, 2018 Citation: Gautam AK, Alam T, Bhardwaj A, Jha A. Thermodynamic analysis of Experimental Sorption isotherms of dietetic Chhana Kheer. Madridge J Food Technol. 2018; 3(2): 126-131. doi: 10.18689/mjft-1000119 Copyright: © 2018 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Published by Madridge Publishers Abstract The equilibrium moisture contents of dietetic chhana kheer were determined using the static gravimetric method at 10, 25 and 37°C over a range of water activity from 0.113 to 0.868. Out of the six sorption models fitted to the sorption data, Modified Mizrahi model for 10 and 25°C and Guggenheim-Anderson-de Boer (GAB) model for 37°C, was described as the best to determine water activity relationship of dietetic chhana kheer having the highest coefficient of determination (R 2 ) and the lowest root mean square error (RMSE). The isosteric heat of sorption which was calculated from Clausius-Clapeyron type equation was observed to increase with decrease in the moisture content. Also, it was found to come closer to the heat of vaporization of free water above 25.95 kJ/kg. Keywords: Water activity; Chhana kheer; Thermodynamics; Isosteric heat of sorption; Heat of vaporization. Introduction Kheer is a heat desiccated, cereal-based sweetened and concentrated milk product, commonly used as a dessert. It is usually made by boiling milk along with rice and sugar to get a semi-solid consistency. Its thick consistency is the result of the concentration of milk and simultaneous oozing out of rice starch into milk. Kheer is a product that is prepared on all social rituals and festive occasions and finds mention in ancient vedic and religious texts [1]. In South Asia, Kheer is prepared and eaten on almost every festival. It is also eaten among the Muslim community of North India, and also in Pakistan, Iran and Afghanistan. It is deeply rooted as a traditional dairy delicacy in social lives, cultural festivals and religious ceremonies in Indian sub-continent, which is now being liked and accepted in various other countries also. In chhana kheer, instead of using rice, chhana (a product obtained by heat-acid coagulation of milk) is used. Large scale manufacturing of chhana kheer has been difficult due its very poor shelf life and lack of mechanized production and packaging technologies. High moisture content of chhana kheer results into spoilage of the product within two weeks even at refrigeration temperature. Moisture sorption isotherms show the relationship between water activity and moisture content of a food sample at a specific temperature as well as pressure [2]. These isotherms are an important tool to assess and predict the shelf-life stability, storage conditions and packaging problems encountered by foods during storage [3]. Water activity plays a vital role in spoilage of foods, determining the shelf-stability and deteriorative mechanisms in food systems. Several scientists have reported and ISSN: 2577-4182