BIOACTIVE SUBSTANCES IN FOOD - IDENTIFICATION AND POTENTIAL USES

Bioactive substances in foods can represent ''extranutritional'' const ituents naturally present in small quantities in the food matrix, prod uced upon either in vivo or industrial enzymatic digestion, the latter being a result of food-processing activities. Bioactive constituents of food evoke physiological, behavioral, and immunological effects. Ev idence from both epidemiological and animal studies has suggested chem opreventative roles for phytochemicals in certain forms of cancers and in the control of hyperlipidemia. Secondary products of plant metabol ism can modulate xenobiotic metabolizing and cholesterol synthetic enz ymes. Unique physicochemical properties of food-derived peptides with characteristic amino acid composition and sequences have been reported to influence intestinal transit, modify nutrient absorption and excre tion, and exhibit immunostimulating and antihypertensive activity. Bio logically active peptides derived from casein, fish muscle, and plant protein hydrolysates have been isolated, purified, and identified in p eptide sequence studies. Therapeutic proteins (e.g., specific antibodi es) derived from animal products such as milk may offer the potential for developing specialized food products with prophylactic as well as nutritive quality. This paper discusses the physicochemical mechanism of action of specific bioactive substances naturally present in or der ived from foods. The biotechnologies employed to develop these product s and the issues concerning acceptance by consumer and regulatory bodi es are also addressed.