Abstract:

In recent years, plant polyphenols have become a hotspot in food science and nutrition because of the universal
presence and importance for food quality and biological activities. Polyphenols in foods can fall into two categories, i.e.,
free and bound polyphenols. Many studies have shown that the contribution of plant polyphenols to food quality and health
function depends not only on their categories and amounts, but also on forms existing in food matrixes. The existing forms,
analytic methods, free and bound polyphenol contents in various foods (cereals, fruits, vegetables, edible flowers and others)
and the effects of processing on the existing forms of food polyphenols are summarized. Moreover, the existing problems
and future prospects of research on free and bound polyphenols in foods are elaborated.

Key words: free polyphenols, bound polyphenols, form, analysis, processing