Varietal Effect on Composition and Digestibility of Seedless Table Grapes (Vitis vinifera L.) under In Vitro Conditions

Grapes are one of the richest sources of polyphenols in the Mediterranean diet and, therefore, a very good source of antioxidants in the human diet. For practical reasons, in recent years the market for seedless grape varieties has grown exponentially. These varieties are not well characterized yet, and therefore it is necessary to study the changes in composition that these new varieties bring in. Likewise, the effect of digestion on the bioavailability of polyphenols in foods of plant origin is well known, which, consequently, will also affect antioxidant activity and, in general, bioactivity. In this work, we studied the effect of the grape variety on the initial grape composition and on the absorbable fraction, as it would reach the intestine after in vitro digestion. Our results showed that black and red varieties have great potential for increasing the antioxidant content of the diet. Additionally, we have concluded that all polyphenols, with the exception of flavanols, see their bioavailable fraction diminished under in vitro conditions.