Journal of Food Science and Engineering 1 (2011) 77-84 Thermal Degradation and Decomposition Kinetics of Freeze Dried Cow and Camel Milk as well as Their Constituents K. V. Sunooj 1,2 , J. George 2 , V. A. Sajeev Kumar 2 , K. Radhakrishna 2 and A. S. Bawa 2 1. Department of Food Science and Technology, Pondicherry University, R. Venkataraman Nagar, Pondicherry 605014, India 2. Defence Food Research Laboratory, Siddarthanagar, Mysore 570011, India Received: March 17, 2011 / Published: July 20, 2011. Abstract: A study was conducted to evaluate thermal properties and degradation kinetic parameters of FD cow milk and camel milk powder. FT-IR was used to confirm the fat removal from the whole milk powder. Differential Scanning Calorimetry (DSC) was used to study the thermal transitions. DSC thermograms of WMP showed a two-step endotherm, the former at lower temperatures (cow milk 16-35 °C, camel milk 25-60 °C) and the later at higher temperatures (cow milk 75-125 °C, camel milk 90-160 °C). The main difference observed between cow and camel milk was peak maximum temperature for fat melting, ΔH and other decomposition temperatures. The enthalpy of fat melting was 2.314 J/g and 3.397 J/g for cow and camel milk respectively. Thermogravimetric Analysis (TGA)/derivative thermogravimetric analysis (DTG) also showed two steps degradation. The first step involves lactose degradation and second step corresponds to combined degradation of protein and fat. Hence logβ vs 1000/T was plotted separately for individual components to determine cumulative value of activation energy using Flynn-Wall-Osawa method. Key words: Thermal degradation, differential scanning calorimetry, thermogravimetric analysis, FT-IR, Flynn-Wall-Osawa method. 1. Introduction Milk and milk products are widely accepted by consumers throughout the world, because of their nutritive value and easy availability. Since milk is a highly perishable commodity, it is generally converted into more shelf stable powder form. Milk powder itself is available in various forms like whole milk powder, skim milk powder etc. It is manufactured using various drying processes such as spray drying, freeze drying etc. The main advantage of milk in powder form is that it can be easily transported from areas of surplus to those of deficit and can be reconstituted later at the user end. Milk powder is a common ingredient in several bakery products, soup powders, snacks, chocolates and confectionaries. More recently milk powder has been Corresponding author: K. V. Sunooj, assistant professor, research field: food science and technology. E-mail: sunooj4u@gmail.com. used as a major component in extruded food products for specialty applications like therapeutic foods [1], appetite suppression [2] etc. Maintaining the natural taste, flavour and nutritional attributes of milk powder based products like chocolate, cookies etc. even after processing is always a challenging task [3]. Deterioration in nutritional quality owing to high temperature exposure during baking and extrusion processes is very common [4, 5]. Processing techniques involving elevated temperatures lead to denaturation [6] and reduction in water binding capacity [7] of proteins. Such conditions may also lead to loss of other constituents like sugar [8] and even cause undesirable chemical reactions [9]. Thermal stability of each component in food systems is different. Hence a detailed knowledge with respect to thermal stability and decomposition temperatures is essential for rigorous process and strict quality control during