ABSTRACT
Enzymes are novel biocatalysts employed extensively in various catalytic reactions. The enzyme activities are often inhibited by substances that are present at the site of enzyme action. In fact, enzyme inhibition is the science of enzyme-substrate reaction inuenced by the presence of any organic chemical, inorganic metal, or biosynthetic compound due to their covalent or noncovalent interactions with the enzyme active site. The substances that inhibit enzymes are called enzyme inhibitors. Although enzyme inhibitors are used as drugs in therapeutic applications and as biocontrol agents, their role in food processing is less known. Whereas enzymes are extensively used in food and beverage processing, which has been discussed extensively in other chapters in this book, it is important to appreciate
20.1 Introduction .................................................................................................................................. 465 20.2 Enzyme Inhibitors ........................................................................................................................ 466
20.2.1 Protease Inhibitors ........................................................................................................... 466 20.2.1.1 Types of Proteases ........................................................................................... 466 20.2.1.2 Protease Inhibitors ........................................................................................... 467 20.2.1.3 Sources of Protease Inhibitors ......................................................................... 467 20.2.1.4 Classication of Protease Inhibitors ................................................................ 468
20.2.2 Small Molecule Inhibitors ............................................................................................... 469 20.2.3 Proteinaceous Inhibitors .................................................................................................. 470 20.2.4 Mechanism of Inhibition ................................................................................................. 470
20.3 Applications of Enzyme Inhibitors in Food and Beverage Processing ....................................... 470 20.3.1 Protease Inhibitors ........................................................................................................... 470
20.3.1.1 Milk ...................................................................................................................471 20.3.1.2 Meat Tenderization ...........................................................................................471 20.3.1.3 Seafood-Surumi Processing .............................................................................471 20.3.1.4 Shrimp Preservation ........................................................................................ 472
20.3.2 Polyphenol Oxidase (PPO) Inhibitors ............................................................................. 472 20.3.2.1 Enzymatic Browning of Fruits, Vegetables, and Seafood ............................... 472 20.3.2.2 Antibrowning of Fruits, Vegetables, and Seafood ........................................... 473
20.3.3 Lipase Inhibitors .............................................................................................................. 473 20.3.3.1 Source of Lipase Inhibitors ...............................................................................474 20.3.3.2 Application of Lipase Inhibitors .......................................................................474
20.4 Conclusion .....................................................................................................................................474 References ...............................................................................................................................................474
the fact that, often, enzyme activities need to be regulated toward optimal performance and desired activities. This regulation can be conveniently carried out employing inhibitor substances, which are available as both natural substances from microbe, plant, and animal resources and as synthetically prepared substances. In this context, the concept of application of enzyme inhibitors for regulating enzyme activities during food and beverage processing and extending their shelf life is discussed in this chapter.
