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.
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
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
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
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
Crude fat containing non glyceride components like mucilages, gums, hydrocarbons, free fatty acids, pigments, sterols along with oil are prone to rancidity. Therefore, impurities should be removed prior to storage and distribution of fats and oil. Purification steps normally involves
Vitamin refer to essential dietary factor which is required by an organism in small amounts and whose absence results in deficiency diseases. Vitamins are important for their regularity and protective functions. Unlike most other nutrients, they are required in very small amounts. But it is necessary to provide these in diet because many of them cannot be synthesized in our body. Excess intake of any vitamin however is harmful. Vitamins are generally classified on the basis of their solubility.
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.
