Unlock Exclusive Discounts & Flash Sales! Click Here to Join the Deals on Every Wednesday!

Study of the forms of bound water in bread and bakery products by Differential thermal analysis (DTA) (CAT#: STEM-ACT-0025-WXH)

Introduction

In bread and bakery products, water is present in free and bound forms. The amount of easily removable water in these products cannot be high because of the predominance of biopolymers - proteins and starch, and non-starch polysaccharides. Part of the water can easily penetrate into micro pores in the protein and be retained by a macromolecular matrix; some authors refer to this form of water as physic-mechanically bound. Low energy binding is characteristic of osmotically retained water. Adsorbed water (water of polymolecular and monomolecular layer) and organically bound water is considered as bound water.
Adsorption is accompanied by a thermal effect, and removal of this water requires a large amount of energy. The stronger the bond, the greater the energy required to break it.




Principle

Differential thermal analysis (DTA) is a thermoanalytic technique that is similar to differential scanning calorimetry. In DTA, the material under study and an inert reference are made to undergo identical thermal cycles, (i.e., same cooling or heating programme) while recording any temperature difference between sample and reference. This differential temperature is then plotted against time, or against temperature (DTA curve, or thermogram). Changes in the sample, either exothermic or endothermic, can be detected relative to the inert reference. Thus, a DTA curve provides data on the transformations that have occurred, such as glass transitions, crystallization, melting and sublimation. The area under a DTA peak is the enthalpy change and is not affected by the heat capacity of the sample.

Applications

A DTA curve can be used only as a finger print for identification purposes but usually the applications of this method are the determination of phase diagrams, heat change measurements and decomposition in various atmospheres.
DTA is widely used in the pharmaceutical and food industries.
DTA may be used in cement chemistry, mineralogical research and in environmental studies.

Procedure

In DTA, the material under study and an inert reference are made to undergo identical thermal cycles, (i.e., same cooling or heating programme) while recording any temperature difference between sample and reference.

Materials

Differential Thermal Analyzer / DTA Analyzer
Advertisement