Comparing the bioactivity of grape byproducts (pomace, seed extract, and skin/pulp food coloring) on DSS-induced intestinal stress in early life

According to the 2024 Progress Report for Sustainable Development Goal (SDG) Target 12.3, the call to halve global food waste is rapidly growing out of reach, and immediate action, no matter the perceived scope, is urgently needed. A major opportunity lies in grape pomace (GP)—the primary byproduct of juice and winemaking. GP is not only a waste management concern, but also a reservoir of 60–70% of grape phenolic compounds. Despite the well-studied anti-inflammatory and prebiotic activity of phenolic compounds, GP is not widely accepted by consumers. Thus, products like grape seed extracts and natural food colorings have been developed. The functionality of these GP-derived products relative to the original, whole GP remains understudied. Understanding whether GP offers similar value compared to its derivative products could enhance upcycling efficacy. We evaluated Rubired (Vitis vinifera) GP (RGP), grape seed extract (RSEED), and grape skin/pulp food coloring (RCOLOR) extract for their capacity to attenuate dextran sulfate sodium (DSS)-induced early-life intestinal stress in a chicken embryo model. All three extracts restored DSS-induced depletions of duodenal villus surface area and goblet cell density and size, while only RSEED and RCOLOR attenuated colonic crypt hyperplasia. RGP and RCOLOR, not RSEED, normalized duodenal zonula occludens-2 (ZO2) dysregulation. However, RSEED, not RGP and RCOLOR, recovered relative Clostridium abundance. These results highlight the potential of GP products to affect early-life intestinal stress, albeit in distinct ways. Future studies in mammalian models and across extended early-life periods are needed to establish translational relevance and mechanistic context.