Methodologies for bioactivity assay: Biochemical study

This chapter describes a range of antioxidant and enzyme inhibitory assays commonly used in assessing the in vitro bioactivity properties of food protein-derived bioactive peptides (BAPs). Antioxidant BAPs can prevent or delay oxidation in foods and may contribute to the management of various diseases and disorders related to oxidative stress. The antioxidant activity assays described herein include the ferric-reducing antioxidant power, the oxygen radical absorbance capacity (ORAC), and the Trolox-equivalent antioxidant capacity assays. Inhibition of the activity of enzymes such as angiotensin-I-converting enzyme (ACE), renin, dipeptidyl peptidase IV, α-amylase, α-glucosidase, lipase, tyrosinase, trypsin, chymotrypsin, and acetylcholinesterase is targeted during the design and development of functional foods and drugs for the prevention and management of noncommunicable diseases such as hypertension and diabetes. Therefore details of the protocols used to determine the inhibition of the above enzymes are described herein. The assay details are provided under the following headings: principle of the assay, protocol, analysis, and expression of results together with assay pros and cons along with reference to alternative methods of analysis. The information provided should be useful to those employing in vitro assays for screening, identification, and mechanism of action studies associated with BAPs.