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Chapter 18
Food ingredients and
enzymes of Microbial origin
introduction
Many microbial metabolites can be used as food additives to improve nutritional value, flavor,
color, and texture. Some of these include proteins, essential amino acids, vitamins, aroma
compounds, flavor enhancers, salty peptides, peptide sweeteners, colors, stabilizers, and
organic acids. Because they are used as ingredients, they need not come only from microorganisms used to produce fermented foods but can be produced by many other types of
microorganisms (also algae) with regulatory approval for safety before use in foods. Many
enzymes from bacteria, yeasts, molds, as well as from plant and mammalian sources, are currently used for the processing of foods and food ingredients. Some examples are production
of high-fructose corn syrups, extraction of juice from fruits and vegetables, and enhancement
of flavor in cheese.
Recombinant DNA technology (or biotechnology) has opened up the possibilities of identifying and isolating genes or synthesizing genes encoding a desirable trait from plant and animal
sources or, from microorganisms that are difficult to grow normally, clone it in a suitable vector
(DNA carrier) and incorporate the recombinant DNA in a suitable microbial host that will express
the trait and produce the specific additive or enzyme economically. 1 In addition, metabolic engineering, by which a desirable metabolite can be produced in large amounts by a bacterial strain, is
being used to produce food additives from new sources. The metabolites can then be purified and
used as food additives and in food processing, provided they are a safe-to-use, generally regarded
as safe (GRAS)–listed compound. 2 Some of these aspects involving genetic manipulations are discussed in Chapter 13. The microbiology of the production and uses of some additives and enzymes
are discussed here.
Chapter 18
Food ingredients and
enzymes of Microbial origin
introduction
Many microbial metabolites can be used as food additives to improve nutritional value, flavor,
color, and texture. Some of these include proteins, essential amino acids, vitamins, aroma
compounds, flavor enhancers, salty peptides, peptide sweeteners, colors, stabilizers, and
organic acids. Because they are used as ingredients, they need not come only from microorganisms used to produce fermented foods but can be produced by many other types of
microorganisms (also algae) with regulatory approval for safety before use in foods. Many
enzymes from bacteria, yeasts, molds, as well as from plant and mammalian sources, are currently used for the processing of foods and food ingredients. Some examples are production
of high-fructose corn syrups, extraction of juice from fruits and vegetables, and enhancement
of flavor in cheese.
Recombinant DNA technology (or biotechnology) has opened up the possibilities of identifying and isolating genes or synthesizing genes encoding a desirable trait from plant and animal
sources or, from microorganisms that are difficult to grow normally, clone it in a suitable vector
(DNA carrier) and incorporate the recombinant DNA in a suitable microbial host that will express
the trait and produce the specific additive or enzyme economically. 1 In addition, metabolic engineering, by which a desirable metabolite can be produced in large amounts by a bacterial strain, is
being used to produce food additives from new sources. The metabolites can then be purified and
used as food additives and in food processing, provided they are a safe-to-use, generally regarded
as safe (GRAS)–listed compound. 2 Some of these aspects involving genetic manipulations are discussed in Chapter 13. The microbiology of the production and uses of some additives and enzymes
are discussed here.