Year: 2020

Aug 17

Fundamental Principle of ELISA

Enzyme linked immunosorbent essay (ELISA) is a biochemical technique used mainly in immunology to detect the presence of antibody or antigen in a sample. The Elisa has been used as diagnostic tool in medicine and plant pathology as well as quality control check in various industries.

Principle: Unknown amount of antigen (protein) is affixed to the surface and then specific antibody is washed over the surface, so that it can bind to specific antigen. The antibody-antigen complex is flooded with enzyme that can convert the complex to some detectable signal. For example, in case of fluorescence ELISA, when light is shown upon the sample, antigen/antibody complexes will fluoresce so that amount of antigen in the sample can be measured. Read more

Aug 12

Mixing Index and Power Required for Mixing Newtonian and Non-Newtonian Fluid

Newtonian and Non-Newtonian Fluid

Newtonian fluid: For such fluids, viscosity is dependent only on temperature. There is linear increase in shear stress with increasing shear rate. For such fluid, viscosity remain constant no matter how fast they are forced to flow through pipe or channel. Example; water, organic solvent, honey

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Aug 09

Mixing and Homogenization

Mixing is a unit operation in which uniform mixture is obtained from two or more compounds by dispersing one within another. When two or more materials are mixed, the goal of mixing is to obtain homogeneous final mixture. Homogeneity is the quality of being homogeneous. A perfect homogeneous sample indicates the state of complete mixing. Mixing has no preservative effect on food. It is a processing aid to alter eating quality of food and to achieve different functional and sensory quality of food. In some food adequate mixing is necessary to ensure that the proportion of each component in the sample complies with legislative standards. Read more

Aug 07

SPS and International Standard Setting Bodies

Sanitary and Phytosanitary (SPS) Agreement:

SPS agreement regulates the conditions under which national regulatory authorities may set and enforce health and safety standards that directly or indirectly affect international trade. In particular, it applies to any measure applied
1. to protect consumers and animals from food and feed borne risks
2. to protect consumers, animals and plants from pest or disease related risks Read more

Aug 06

Extraction Equipment in Food Industries

Design of extraction equipment may vary depending on nature of raw material used and intended product characteristics. Equipment design and working principle also largely dependent on scale of production or processing (large scale / small scale) and economic feasibility. Some popular extraction equipment used in food industries are described below.

Bollman extractor: Bollman extractor consists of perforated bucket elevator in series into which the fresh solid are fed at one end while fresh solvent is added at another end. Solids are fed into each bucket which will be moving downward until half the way and later on, bucket will be moving upward. Read more

Aug 05

Extraction Techniques

Depending upon need and quantities of material to be handled, different extraction techniques are used in food industries. Some popular extraction techniques are
1. Single stage batch extraction
2. Multi stage cross flow extraction
3. Multi stage counter current extraction

1. Single stage batch extraction:
It is a batch extractor in which the solids are brought in contact with adequate quantity of solvent so as to leach out the solute from solid into the solvent. The process can be accompanied with heating or stirring as the process demands. When the extraction process reaches equilibrium, the solution is decanted and excess solvent from the solution is removed to obtain pure solute. Example; brewing tea or coffee, extraction of oleoresins. Read more

Aug 04

Preservation and Maintenance of Industrially Important Cultures

Microorganism for the production of industrially important products are useful only if they can be maintained indefinitely in healthy, pure and genetically stable form. Industrial culture collection consists of stock culture. Stock culture may be simply defined as a culture which serves as source of inoculum. Stock cultures are of two types.
1. Working stock culture: Working stock culture: This culture is maintained at vigorous and uncontaminated condition. Since this culture is used frequently, it must be routinely checked for characteristic feature and contamination.
2. Primary stock culture: This culture is kept for long term storage and are maintained at low physiological activity condition. The cultures are used to produce new working stock culture as per need. Read more