Stability of polyphenols as a function of their chemical structure and the effect of common food components

Polyphenol stability in food products affects sensorial and health-promoting properties. Thus, understanding the effects of various food components on polyphenols degradation, as a function of their chemical structure, can contribute to optimal product engineering.
The seminar focuses on non-enzymatic degradation and antioxidant capacity (TAC) of polyphenols as a function of their chemical structure and presence of common food components such as ascorbic acid, fructose and canola protein extract. A strawberry polyphenol extract (SPE) and canola protein extract (CPE) were studied as multicomponent polyphenol and plant-based protein models at pH 3. Among CPE proteins, cruciferin was the most involved in interactions, while among polyphenols,flavonols presented the highest relative binding (45±3%- 68±2%) and anthocyanins presented much lower values (0±0.4%-27±1%). The presence of the proteins enhanced mostly the anthocyanins’ stability, yet the extent of the impact was not correlated with the relative binding and the binding affinity of purified single compounds. Comparing most of the identified polyphenols stabilities, anthocyanins and phenolic acids were most unstable in the presence of ascorbic acid while flavonols stability was enhanced.
While polyphenol stability was strongly affected by presence of canola protein, ascorbic acid, and fructose, the TAC was not affected dramatically by the formulation. The TAC was measured by oxygen radical absorption capacity (ORAC) and ferric reducing anti-oxidant potential (FRAP) assays.