Current trends in bioactive peptides from muscle foods and their potential application

Muscle protein is a valuable source of energy and essential amino acids, which are needed for growth and maintenance of physiological functions. It also provides peptides known as bioactive peptides exerting some health benefits, including antihypertension, antioxidant activity, immunomodulatory activity, and improving brain function, among others. Bioactive peptides can be generated from digestion or enzymatic reaction. Cooking condition is found to critically affect digestibility of chicken breast and release of bioactive peptides. Extreme thermal treatment at 121°C/15 min reduces simulated gastrointestinal digestion (GI) of chicken breast. In addition, release of peptides inhibiting angiotensin converting enzyme (ACE) that regulates blood pressure via renin–angiotensin system decreases. This implies that extreme thermal process of muscle food lower nutritional values and available ACE inhibitor peptides. Enzymatic hydrolysis is also an effective means to produce bioactive peptides, providing appropriate protease(s) is applied under the optimal condition. Hydrolysates or bioactive peptides would likely be modified through GI digestion. Thus, changes of bioactivities upon GI digestion should be taken into consideration for optimization of protein hydrolysate production. Structural changes of bioactive peptides further take place during transepithelial transport. This would definitely affect bioactivities of peptides reaching the target organ in either positive or negative manner. To further develop functional food or nutraceutical products, efficacy of bioactive peptides should be tested in vivo to assure their health benefits.