What is Viscosity?

Viscosity is defined as the resistance of a fluid to flow. Dynamic viscosity’s unit is Pa.s in the SI system and poise (g/cm.s) in the CGS system. Viscosity varies with temperature. Because of the difference in their molecular structure, viscosity of liquids and gases changes by temperature. Viscosity of most of the liquids decreases when temperature increases. In the liquids the cohesive forces between the molecules predominates the molecular momentum transfer between the molecules, mainly because the molecules are closely packed. When the liquid is heated the cohesive forces between the molecules reduce thus the forces of attraction between them reduce, which eventually reduces the viscosity of the liquids. While the viscosity of gases increases with increasing temperature. The reason behind this is again the movement of the molecules and the forces between them. In the gases the cohesive forces between the molecules is lesser, while molecular momentum transfer is high. As the temperature of the gas is increased, the molecular momentum transfer rate increases further which increases the viscosity of the gas (Rheology). 

A Suspension: Skim Milk

In the basic steps in milk processing, second step is separation. The purpose of the separation step is separate raw milk into cream and skim milk. Raw milk is transferred to separator, which is a high-speed centrifuge machine. Lighter part of raw milk is separated from heavier skim milk fraction and stored as cream. Skim milk and cream are stored separately for further processing. At the next step, standardization, these two fractions of raw milk may be mixed by blending to produce products that require milk fat content [1]. 

Laboratory Report Sheet-3

Laboratory Report Sheet of "Protein Determination" experiment.

Document

Protein Determination

Proteins are amino acid polymers. In proteins twenty different types of amino acids occur naturally. Proteins are important constituents of foods for a number of different reasons. They are a major source of energy, it contains essential amino-acids which are essential to human health, but which the body cannot synthesize. Proteins are also the major structural components of many natural foods, often determining their overall texture. Typically, proteins are used as gelling agents, emulsifiers, foaming agents and thickeners. Many food proteins are enzymes which are capable of enhancing the rate of certain biochemical reactions. Therefore food analysts are interested in knowing the total concentration, type, molecular structure and functional properties of the proteins in foods (people.umass.edu, n.d., para. 1 ).

Complex Formation Titrations

PURPOSE

The aims of this experiment are determining magnesium by direct titration and determining calcium by displacement titration and back titration.

THEORY

A complexation reaction involves a reaction between a metal ion (M) and another molecular or ionic entity (D), containing at least one atom with an unshared pair of electrons. Solvent or electron pair donors occupy that all the coordination positions on metal ion.