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Chemical and Enzymatic Modification of Protein

This document discusses chemical and enzymatic modification of proteins. It introduces how proteins are widely used in foods for their nutritional and functional properties, like emulsification and gelation. Both chemical and enzymatic methods can be used to modify these functional properties. Specifically, it discusses how acylation and glycosylation are examples of chemical modifications that can impact functionality. Enzymatic modifications using proteases and transglutaminase are also discussed. The effects of these modifications on protein solubility, gelation, emulsification, and foaming properties are described. Finally, some applications of these modifications in cereal, milk, and meat products are provided.

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402 views14 pages

Chemical and Enzymatic Modification of Protein

This document discusses chemical and enzymatic modification of proteins. It introduces how proteins are widely used in foods for their nutritional and functional properties, like emulsification and gelation. Both chemical and enzymatic methods can be used to modify these functional properties. Specifically, it discusses how acylation and glycosylation are examples of chemical modifications that can impact functionality. Enzymatic modifications using proteases and transglutaminase are also discussed. The effects of these modifications on protein solubility, gelation, emulsification, and foaming properties are described. Finally, some applications of these modifications in cereal, milk, and meat products are provided.

Uploaded by

my kanigiri
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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CHEMICAL AND

ENZYMATIC
MODIFICATION OF
PROTEIN
INTRODUCTION
• Protiens are used abundantly in the food industries because of their
nutritional value and techno funtional properties such as
emulsification,foaming,gelation,hydration and textural properties.

• These funtional properties of proteins are related to their molecular


structures.

• There have been number of ways to enhance functionalities of maney


food proteins including physical chemicals and enzymatic methods.

• Modifications of functionality of food proteins increases their


applications as food ingredient.
• Chemical modifications describes the modification addition or removal
through chemical reaction of any of variety of macro molecules including
proteins and nucleic acids.

• The various funtional groups of proteins including


amino,carboxyl,disulfide,imitate,phenolic,sulahydrle,thioether and
guanidine.

• Consequently, reaction such as


actuation,phosphorylation,estarification,glycation.
Chemical modifications of food protien

1.Acylation of food protien


protien s-acylation is the reversible addition of fatty acids to the cysteine
residues of target protien
2. Glycosylation of food protien

• Glycosylation is an interesting tool for improving food protien


functionality .
• Prevents the progression of mailard reaction ,resulting in a glycosylatio
the end product.
Enzymatic modification of food protein

• Protease and transglutaminase are the most frequently used enzymes for
modifying the polypeptide back bone of food protien.
• Functional properties of proteins like solubility,gelation, emusification
and foaming.
1.Solubility

• Prototypical modification has special important for the


improvement of solubility of protein.

• Zeina, the maize protein that is highly insoluble at ph 2-


5,exhibited good solubility (30%-50%).

• At this ph range when only 1.9%of the peptide bond were split
by treatment with trypsin.
2.Gelation

• Hydrolysis was presumed to be detrimental to the gelling properties


of protein because of the reduced hydrophobicity of hydrolysis.

• The increased net changes on the protien result in increased charge


repulsion between peptide, decreasing their gelling ability .
3. Emulsification

• Emulsifying properties of protein are sensitive to proteolytic


modification.

• Limited hydrolysis of casein decreased the Emulsifying activity at all


ph.
4. Foaming

• The excellent foaming properties of soybean protien from mucor miehel.

• Due to narrow molecules weight distribution of peptide produced by this


enzymes.
Applications
• a) Cereal products:
• Cross linking of cereal proteins has major potential in modification of technological and sensory
properties of cereal products. TG mediated protein crosslink results in alluring of rheological
properties of gluten by decreasing dough extensibility, increased water absorption and hinder the
growth of air bubbles in the dough, thereby decreasing volume of bread. In the preparation of
pasta and noodles, cross linking of gluten causes an increase in resistance for thermal processing.
• b) Milk products:
• Creation of inter-/ or intra molecular covalent bonds by TG cross-linking of milk proteins results
in modification of textural and water binding properties of milk products especially, in low fat or
protein products with acceptable texture.. In the production of fermented milk product such as
yogurt, the introduction of covalent bond by enzymatic cross linking into gel network results in
increase in gel firmness and sensory properties.
• c) Meat products:
• Enzymatic cross linking of the myofibrillar protein myosin
improves the texture and water holding properties of meat or fish
products and add value to meat and fish of poorer quality. In
addition to restructuring, TG is successfully exploited in
improving textural properties of heated meat products such as
hams and sausages and enhancing surimi (fish paste) gelation and
textural properties.
THANK YOU

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