The answer, according to the study, is no. In a chicken embryo model of early-life intestinal stress, whole Rubired grape pomace, a grape seed extract, and a grape skin and pulp food coloring each protected the gut in distinct and only partially overlapping ways. The finding matters because the food industry has largely moved away from whole pomace, which consumers accept poorly, toward derivative products such as grape seed extracts and natural food colorings. If the original byproduct and its derivatives are not functionally interchangeable, then upcycling strategies that assume equivalence may be leaving nutritional value on the table—or, conversely, may be concentrating specific benefits in ways the whole material cannot match.

To test this, the researchers turned to a well-established in ovo approach. Chicken embryos develop rapidly and independently inside the egg, which makes them a powerful platform for studying early-life intestinal biology without the confounding variables of maternal influence or post-hatch diet. The team induced intestinal stress using dextran sulfate sodium, or DSS, a chemical that damages the intestinal epithelial barrier and is widely used to model inflammatory stress in the gut. DSS injures the single layer of cells lining the intestine, disrupting the delicate architecture of villi and crypts that the gut depends on for absorption and renewal. Into this stressed environment, the researchers introduced three Rubired (Vitis vinifera) preparations: the whole pomace (RGP), the seed extract (RSEED), and the skin and pulp food coloring (RCOLOR), each evaluated for its capacity to blunt the damage.

The clearest and most consistent result concerned the small intestine. DSS exposure depleted the surface area of the duodenal villi—the finger-like projections that dramatically expand the absorptive surface of the gut—and reduced both the density and the size of goblet cells, the specialized epithelial cells that secrete mucus and form a first line of defense against luminal threats. Remarkably, all three grape preparations restored these losses. Whether delivered as whole pomace, concentrated seed extract, or natural coloring, the grape-derived material helped the embryonic duodenum rebuild its villus architecture and replenish its mucus-producing cell population. This suggests that the core protective activity against small-intestinal damage is broadly shared across the grape byproduct family, likely reflecting phenolic compounds that persist in every fraction of the fruit.

The colon told a more selective story. Here, DSS triggered crypt hyperplasia—an abnormal proliferation of the invaginated glands that house the gut’s stem cell niche—yet only two of the three preparations countered it. The grape seed extract and the skin and pulp food coloring attenuated colonic crypt hyperplasia, while the whole pomace did not. This split is scientifically significant because it indicates that the compounds responsible for protecting the colonic crypt compartment are not evenly distributed across the grape. The seed and the skin and pulp fractions appear to concentrate bioactivity that the whole pomace, with its different composition and perhaps lower effective doses of key phenolics, could not deliver in this model.

At the molecular level, the picture shifted again. The researchers examined zonula occludens-2, or ZO2, a tight junction protein that helps seal the gaps between adjacent epithelial cells and maintain the integrity of the intestinal barrier. DSS exposure dysregulated duodenal ZO2, and here it was the whole pomace and the food coloring—not the seed extract—that restored normal regulation. Tight junction proteins are central to barrier function; when they falter, the gut becomes permeable to antigens and microbes, fueling inflammation. The fact that RGP and RCOLOR normalized ZO2 while RSEED did not demonstrates that the seed extract, despite its colonic benefits, left a gap in barrier-level protection in the duodenum.

The microbiome added yet another dimension of divergence. Only the grape seed extract recovered the relative abundance of Clostridium, a bacterial genus with important roles in the gut ecosystem, including the production of short-chain fatty acids that nourish colonocytes and support immune development. Neither the whole pomace nor the food coloring achieved this microbial recovery. In other words, each of the three grape products excelled at a different facet of intestinal resilience: all three repaired small-intestinal structure, two of three protected colonic crypts, two of three restored tight junction regulation, and only one reshaped the microbiota in the measured direction. No single preparation dominated across every endpoint.

These results carry real implications for how the food industry approaches upcycling. If grape seed extracts and natural colorings are marketed as functional equivalents of the pomace they come from, the new data suggest that assumption is too simple. The bioactivity of grape byproducts is fraction-dependent: processing decisions that concentrate certain phenolics inevitably redistribute others. For product developers, this means the choice between whole pomace, seed extract, and skin-derived coloring is not merely a matter of consumer acceptance or cost—it is a choice about which biological targets, from villus architecture to tight junction integrity to microbial balance, a given ingredient can realistically support. Conversely, the study strengthens the case for pomace itself as a reservoir of value, since it matched or exceeded its derivatives on several endpoints despite being the least refined material.

The study also highlights the value of early-life models. The embryonic and neonatal gut undergoes rapid maturation, and insults during this window can have lasting consequences for barrier function, immune programming, and microbial colonization. By showing that grape-derived phenolics can counteract DSS-induced stress at this vulnerable stage, the Cornell team adds to a growing body of evidence that maternal and early-life nutrition can be leveraged to support gut health from the very beginning of development. The chicken embryo model, with its speed and controllability, allowed the researchers to compare three products side by side across structural, molecular, and microbial endpoints within a single experimental framework.

The authors are careful about the limits of their work. The findings were generated in an avian embryonic model, and the study itself notes that future research in mammalian models and across extended early-life periods is needed to establish translational relevance and mechanistic context. Chicken embryo intestines differ from mammalian ones in ways that could alter how phenolic compounds are absorbed, metabolized, and delivered to target tissues, and the DSS challenge in ovo is a proxy for inflammatory stress rather than a specific human disease. Still, the central conclusion stands on firm ground within its model: grape byproducts hold genuine potential to mitigate early-life intestinal stress, but they do so in distinct ways. As the pressure to halve global food waste intensifies, the humble pile of pressed grapes left behind after each harvest may prove to be not a liability but a differentiated portfolio of bioactive ingredients—provided that science, not assumption, guides which fraction goes where.

Subject of Research: Effects of grape pomace, seed extract, and skin/pulp food coloring on DSS-induced early-life intestinal stress in a chicken embryo model

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

Article References: Huang, M. Y., & Tako, E. (2026). Comparing the bioactivity of grape byproducts (pomace, seed extract, and skin/pulp food coloring) on DSS-induced intestinal stress in early life. npj Science of Food. https://doi.org/10.1038/s41538-026-01148-0

Image Credits: AI Generated

DOI: 10.1038/s41538-026-01148-0

Keywords: grape pomace, food waste, upcycling, phenolic compounds, intestinal barrier, dextran sulfate sodium, chicken embryo model, goblet cells, tight junctions, ZO2, gut microbiota, early-life nutrition