Bioprocessing of Grape Pomace for Value Added Ingredients with Utilization in Baked Products

Bioprocessing grape pomace (GP) presents a sustainable solution aligned with circular economic principles and transforms it into valuable functional ingredients for baked products. This review (2020-2025) synthesizes enzymatic and microbial strategies that modify the fiber-phenolic matrix and improve dough performance. Enzyme-assisted extraction, alone or combined with ultrasound or pressurized liquids, increases extractable polyphenols and antioxidant capacity in GP fractions used as flour substitutions or pre-ferments. Fungal solid-state and lactic fermentations liberate bound phenolic compounds and generate acids and exopolysaccharides. Among these routes, enzyme-assisted extraction and lactic sourdough-type fermentations currently appear the most compatible with bakery-scale implementation, offering substantial phenolic enrichment while relying on relatively simple, food-grade equipment. In current bakery applications, GP is mainly used as crude grape pomace powder, which typically shows higher total phenolics and antioxidant capacity. Moreover, in several models it lowers starch hydrolysis and predicted glycemic index. The practical substitution rate is between 5 and 10% of flour, which balances nutritional gains with processing disadvantages. These can be mitigated by fractionation toward soluble dietary fiber or co-fortification with flours rich in protein and fiber. An additional benefit of these methods includes reduced mycotoxin bioaccessibility in vitro. A key evidence gap is the absence of standardized comparisons between raw and bioprocessed GP in identical formulations. Overall, GP emerges as a promising ingredient for bakery products, while the added technological and nutritional value of bioprocessing remains to be quantified.