Food Technology

  RHEOLOGY Rheology is the science that concerns with the flow of liquids and the deformation of solids and describes the interrelation between force, deformation and time. The term comes from Greek “Rheos” meaning to flow. TYPES OF FLOW Rheology has developed two classes of liquids: Newtonian and Non-Newtonian fluids. Newtonian Fluids Newtonian fluids are those which follow Newton's hypothesis, and they are considered to be perfectly viscous. This is because the ratio between the shear rate and shear stress are constant, or in other words, the viscosity of the liquid remains constant at all possible shear rates for a given temperature. Examples: Pure water, oils, and organic solvents. Non Newtonian fluids Most liquids are non-Newtonian fluids, meaning they do not have a constant ratio between their shear rate and shear stress. As a result, the viscosity of the material is highly variable.  Examples: mayonnaise, paints and emulsions. IMPORTANCE OF RHEOLOGY Study of rheol...

  ENZYMES Enzymes are protein that act as “biological catalyst”. Catalyst accelerates chemical reaction. The molecules upon which enzymes may act are called substrates , and the enzymes convert the substrates into different molecules known as products . LOCK AND KEY MODEL The mechanism of enzymatic reactions in which it proposed that the enzymes and substrates bind temporarily to form an enzyme substrate complex. The binding site on the enzyme is known as the “active site” and is structurally complementary to the substrate. Thus the enzyme and substrate are said to fit together as do a lock and key. COMMON ENZYMES USED IN FOOD INDUSTRY Following are the enzymes used in food processing industry. AMYLASE: Amylase is a hydrolytic enzyme that breakdown starch into dextrin and sugar. Amylase extends the shelf life of bread and working as fermentation improvers. Amylase intensify flavors and crust color by enhancing “ millard browning” and caramelization reaction. Amylase act as c...