General Purpose Equipments/ Instruments

These equipments/ instruments are general purpose and are required in any chemical laboratory. A brief description of there instruments is given below:

i. Water Bath: It is used for heating purposes for samples of milk and milk products and certain other heating operations. It should have a digital temperature display, temperature range from 10o C to 100o or higher and stainless steel interior heating with an overheating protection. Operation of the bath must be with distilled water.

ii. Analytical Balance: The analytical balance is the most important instrument in any chemical laboratory and is used to weigh the sample as well as the analytical reagents. The modern instruments are equipped with piece counting and percentage determination devices and formulation memory. Maximum capacity of the balance may be upto 200g weight and the minimum weight which can be determined must be 1/10 h of mg.

iii. Drying/ heating oven: Oven is used for drying glassware and heating the samples, particularly in the determination of moisture and fat percentage in milk and milk products. The temperature range may be from 10o C to 150o C or higher. It should be thermo statistically controlled and equipped with air circulating fan.

iv. Muffle Furnace: Muffle furnace is used for ashing the sample of milk and milk products in the determination of salt constituents like calcium, magnesium, sodium, potassium, chloride, phosphorous etc. Muffle furnace must have maximum temperature up to 1000o C or 1200o C and must be equipped with a pyrometer.

v. Magnetic Stirrer: Magnetic stirrer or laboratory stirrer is used for shaking or mixing the sample. It can also be equipped with a hot plate.

vi. pH Metter: It is used for the determination of pH and oxidation-reduction potential of samples or other substances like buffers and other reagent solutions.It must have the ability for automatic temperature compensation, recorder connection and calibrated data memory. This instrument measure the potential difference between a glass electrodes and a standard calomel electrodes and is calibrated with buffers of known pH. Temperature compensation devices are incorporated to correct for temperature deviations. Liquid and semisolid foods can be examined for their pH but solid food is used only after making slurry with water.

vii. Kjeldahal digestion and distillation apparatus: It is used for the determination of nitrogen content in a food products. The protein content of the product is then calculated by multiplying the nitrogen content with a factor which is derived on the basis of percentage of nitrogen in the proteins of a particular food. For milk and milk product this factor is 6.38 as milk proteins contain about 15.65% nitrogen in them. The original instrument consists of aluminum frame in which digestion cum distillation flask is fitted alongwith a glass tube and metallic (silver) tube and glass condenser which convert the ammonia gas into liquid ammonia to be collected in a conical flask containing standard solution of acid. Now a days more sophisticated and automatic instruments are available for the determination of proteins by kjeldahal method.

viii. Infrared moisture balance: The improved moisture balance is used for determination of moisture content of food products without changing their chemical structure while loosing water under exposure to infrared radiation.The instrument is very handy and portable with sensitive torsion balance calibrated in moisture percentage.

ix. Karl Fisher Titration Apparatus: It is widely used titrimetric method for moisture determination in food products. The equipment is available with a choice of titrators, coulmeters, stand and accessories as well as reagents for titration. The equipment can be connected to a PC equipped with software for an accurate automatic system that meets all needs for moisture determination.