Protein Processing in Food and Bioproduct Manufacturing and Techniques for Analysis - Food and Industrial Bioproducts and Bioprocessing - page 106

The second step involves the immobilization of the bands to the surface of the membrane
in the same pattern as in the original PAGE gel. Subsequently, the selected proteins
could be analyzed by immunoassays after the treatment of the membrane with specific
antibodies which bind to the antigens in the membrane and can be detected by a variety
of techniques involving treatments with secondary antibodies and staining (Phillips,
1992 ). Prior to antibody binding and staining the remaining protein binding sites on the
membrane must be blocked (e.g., by bovine serum albumin (BSA) or ovalbumin) to
avoid non-specific interaction with the antibodies. Additionally, the removal of unbound
reagents by a series of washes between each binding step is necessary to avoid non-spe-
cific binding.
The detection of the antigen-antibody complexes on the membrane could be performed
by a variety of techniques. The most common method is the application of a secondary
antibody which binds specifically to the primary antigen-antibody complex. Hence, radio-
chemicals, fluorescent compounds, colloidal gold, enzymes, or biotin labels could be easily
bound to the secondary antibody, and protein detection could be deduced from the intensity
of the colored, fluorescent or chemiluminescent end product. Further details on blotting can
be found elsewhere (Amersham, 1999).
3.6 CONCLUSION
Proteins play a key role in food, feed, and in many health and industrial applications. Due to
their versatility, the market for semi-purified and highly purified proteins is likely to grow.
There has been significant effort to identify novel sources of healthy and functional proteins.
Examples of such new sources of proteins include canola and flax proteins that are currently
in industrial production for the food, feed and pharmaceutical industries.
As consumers and the food and industrial products sectors become more environmentally
conscious, techniques that are more energy efficient, sustainable and have a lower carbon
foot print will be required. In this regard novel non-thermal technologies, such as high
pressure processing, pulse electric field and ultrasonication, will be preferred for protein
extraction and/or improving protein functionality. Since the most expensive unit operation
in protein processing is drying, new innovative drying techniques that are cheaper, easy
to use and do not adversely alter protein functionality need to be developed. Additionally,
optimization of the processing conditions for the current techniques and the development of
new processes that could enhance protein functionality while increasing its health benefits
and nutritional properties would be extremely useful.
REFERENCES
Achouri A , Boye JI , Belanger D , Chiron T , Yaylayan , VA , Yeboah FK 2010 . Functional and molecular
properties of calcium precipitated soy glycinin and the effect of glycation with kappa-carrageenan. Food
Res Int 43 ( 5 ): 1494 - 1504 .
Alli I , Gibbs BF , Okoniewska MK , Konishi Y , Dumas F 1993 . Identification and characterization of phaseolin
polypeptides in a crystalline protein isolated from white kidney beans ( Phaseolus vulgaris ) . J Agric Food
Chem 41 : 1830 - 1834 .
Álvarez PA , Ramaswamy HS , Ismail AA 2008 . High pressure gelation of soy proteins: Effect of concentration,
pH and additives . J Food Eng 88 : 331 - 340 .
Amersham 1999a . Protein Electrophoresis Technical Manual . Amersham Biosciences.