Year: 2020

Jul 13

Conveying and Handling: Application in Food Industries

Conveying is the method of transferring materials from one place to another generally by mechanical means. The use of conveying process are generally in all stages of manufacturing process including harvest and transportation of raw materials to store, preparation of food, movement of food or produce within the factory and movement of finished product to warehouse. It can also be used for presentation of products for selling. Efficient handling is the organized movement of materials in correct quantities to and from correct place accomplished with minimum time, labor, waste, expenditure and with maximum safety. Read more

Jul 11

Size Reduction Equipment

There are various size reduction equipment and have different principle. The common working principles in food industries are slicing (as in preparing potato chips), dicing (cutting into cubes), shredding (shear force as in wheat milling), grinding (impact force as in making spice powder), crushing and pulping (as in fruit juice extraction). However, size reduction equipment are not only used in food processing industries. It is also widely used in construction industries. Common examples are; Jaw crusher and Gyratory crusher.

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Jul 08

Malting of Barley

It is controlled germination process that activates enzyme of resting grain resulting in the conversion of cereal starch to fermentable sugar and partial hydrolysis of protein and other macromolecule. During malting, large molecular weight components of endosperm cell walls, the storage protein and starch granules are hydrolyzed by enzymes rendering them more soluble in water. All cereals grains are capable of undergoing malting barley is the best. Barley is best for malting because, the husk tightly protect the endosperm and developing germ. Also husk aids as filtration aids dring brewing and making extraction easy. The most suitable type of barley for malting are Read more

Jul 07

Microscopy and Types of Microscopes

Microscope is an optical instrument consisting of lens for making enlarged or magnified images of minute objects. Robert Hook (1635 – 1703) made and used a first compound microscope. The basic difference between simple and compound microscope is that simple microscope uses only one lens whereas, compound microscope uses more than one lenses to further magnify the object.

Fig: compound microscope

The ability of microscope to distinguish two adjacent object as separate and distinct images rather than single blurred image is called resolving power of microscope. Theoretically, size of image can be increased by adding lenses. Magnification of object is only useful if the enlarged image is clearly visible. So, effective magnification depends on resolving power of microscope.

A microscope’s resolving power is dependent on wavelength of beam for illumination and optical quality of lenses. Shorter wavelength gives better resolution. Resolution or shortest distance (d) can be calculated by using the formula, d = λ/2nsinϴ  where, d = resolution, λ = wavelength of light, n = refractive index and ϴ = angle subtended.

Note: Oil is used with oil immersion lenses because it has higher numerical aperture than air and also higher refractive index and this greatly improves resolution. Read more

Jul 06

General Laboratory equipment

Fig: Autoclave

Autoclave: Autoclave is a sealed devise that allows the entrance of steam under pressure. The use of moist heat facilitates killing of all microorganisms including heat resistance endospores. The underlying principle is, with increase in steam pressure, the temperature also rises. The water boils at 100°C upon the vapor pressure of atmosphere. Temperature will increase if vapor pressure is increased. The autoclave is operated at 15lb/inch2 for 30 minutes. This temperature for a period of 30 minutes is sufficient to kill all the vegetative and spore cells of microorganism. Pressure temperature relationship is given as Read more

Jul 05

Introduction and Scope of Microbiology

Microbiology is the study of microorganism; a large diverse group of microscopic organism that exist as a single cell or cell clusters. It also includes virus which are microscopic but not cellular. Microbial cells are thus distinct from cells of animals and plants which are unable to live alone in nature and exist as only part of multicellular organism. A single microbial cell is generally able to carry out its life process of growth, energy generation and reproduction independently of other cells, either of same kind.

The existence of microbes was not established until Antony Von Leeuwenhoek (1678) could see them in simple microscope. Lewis Pasteur (1822 – 1895) investigated that boiled medium could remain clear in swan necked flask. Pasteur developed the procedure of gentle heating (pasteurization) to prevent the spoilage of beer and wine by undesirable microbes. This process was later used to prevent milk borne diseases in human beings. Read more