processing byproducts pose environmental and economic issues. A recent study explored using orange/watermelon/melon peels (10% or 15%) in croissants to develop anti-hyperlipidemic functional foods. Testing on rats showed orange peels had the highest antioxidant activity (DPPH, phenols, flavonoids), with no significant sensory differences in croissants. Byproduct-enriched croissants reduced weight gain, organ weights, improved lipid profiles (lower TG, TC, LDL, VLDL; higher HDL), lowered liver enzymes, regulated blood proteins, renal function and blood glucose, and alleviated liver/heart tissue damage. Thus, such additions effectively ease hyperlipidemia without harming taste, offering new paths for functional foods and sustainable byproduct use.
Picture this: You’re strolling through a bustling Parisian café, the aroma of buttery croissants wafting through the air. You pick one up, its layers crisp and flaky, and take a bite—delicious, as always. But what if this everyday indulgence was doing more than just pleasing your taste buds? What if, hidden in those layers, were ingredients once tossed aside as trash—orange peels, watermelon rinds, melon skins—and what if they held the key to fighting one of the most pressing health crises of our time? It’s a bold idea, but new research published in NPJ Science of Food suggests that this unlikely combination of pastry and produce waste could be a game-changer for heart health and sustainability, especially in regions like Europe and North America, where processed foods and rising obesity rates make lipid disorders a growing concern.
In modern society, our love for convenience foods, coupled with sedentary lifestyles, has led to a sharp rise in lipid metabolism disorders. These disruptions—think high cholesterol or triglycerides—are major drivers of atherosclerosis, a condition where fatty deposits clog arteries, paving the way for heart attacks, strokes, and other life-threatening cardiovascular diseases (CVDs). The numbers are staggering: according to the World Health Organization, CVDs claim 17.9 million lives globally each year, accounting for 31% of all deaths. In low- and middle-income countries, this toll exceeds 75%, but even in high-income nations like those in Europe and North America, CVDs remain a top killer, straining healthcare systems and families alike. In Egypt, for instance, 40% of all deaths are linked to CVDs, a statistic that mirrors broader global trends and underscores the urgent need for innovative solutions.
Meanwhile, the food industry is grappling with another crisis: waste. Every year, tons of fruit byproducts—peels, rinds, and skins from processing—end up in landfills, contributing to environmental pollution and economic losses. In Europe alone, fruit and vegetable waste from processing is estimated to reach millions of tons annually, making sustainability a critical goal for both policymakers and food producers. The question then becomes: Can we turn this waste into something valuable? Could these discarded peels and rinds, rich in nutrients and antioxidants, be transformed into functional foods that support health while cutting down on waste?
From Trash to Treat: The Study’s Design
A recent study titled Investigating the anti-hypolipidemic effects of croissants enriched with fruit byproducts in a rat model set out to answer these questions. The researchers focused on three common fruit byproducts: orange peels (OP), watermelon rinds (WR), and melon peels (MP)—all abundant in global food processing, including in European and American markets. Their goal was to see if adding these byproducts to croissants—a beloved pastry in Western diets—could create a functional food that helps fight high cholesterol, without sacrificing taste.
The team modified croissants by replacing 10% or 15% of the wheat flour with each of the three byproducts. They then put these modified pastries to the test, evaluating three key areas:
- Sensory properties: Would consumers notice a difference in taste, texture, or appearance?
- Antioxidant activity: Do the byproducts boost the croissants’ ability to fight harmful free radicals, which contribute to inflammation and disease?
- Anti-hyperlipidemic effects: In a rat model of high cholesterol, would the modified croissants lower unhealthy lipids and protect organs like the liver and heart?
Figure 1: Effects of Different Treatments on Rat Liver Tissue
Figure 2: Pathological Characteristics of Heart Tissue in Control, Hyperlipidemia, and Treatment Groups
To measure the health effects, the researchers divided rats into nine groups:
- G1: Healthy control (no high cholesterol, no croissants)
- G2: High cholesterol control (no croissants)
- G3: High cholesterol + 40% regular croissants (to test if plain croissants have any effect)
- G4–G5: High cholesterol + croissants with 10% or 15% orange peels
- G6–G7: High cholesterol + croissants with 10% or 15% watermelon rinds
- G8–G9: High cholesterol + croissants with 10% or 15% melon peels
Promising Results: Taste, Antioxidants, and Health Benefits
The findings were encouraging, with positive outcomes across all three areas of evaluation.
Antioxidant Power and Sensory Appeal
First, the byproducts proved to be nutritional powerhouses. Orange peels stood out with the highest ability to scavenge free radicals (measured via DPPH assay), followed by melon peels and watermelon rinds. They also had significantly more phenols and flavonoids—antioxidant compounds linked to reduced inflammation—than the other byproducts. This suggests that adding these peels could boost the croissants’ disease-fighting potential.
When it came to taste, the modified croissants held their own. Sensory tests showed no significant differences between the byproduct-enriched croissants and regular ones, meaning they’re likely to be accepted by consumers. Watermelon rind croissants trended slightly lower in scores, and the 15% melon peel group scored poorest in texture, but these differences weren’t strong enough to make the pastries unappealing—a key win for real-world use.
Health Improvements in Rats
The most striking results came from the rat experiments, which mirrored the metabolic challenges faced by humans with high cholesterol.
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Weight and organ health: Rats fed 15% melon peels (G9) or 15% watermelon rinds (G7) gained significantly less weight than the high cholesterol control group (G2). G9 also had much lighter organs: liver weight dropped by 36.5%, heart by 21.4%, and spleen by 29.1%—signs that the byproducts may protect against fat buildup in vital organs.
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Lipid levels: The high cholesterol group (G2) had sky-high levels of triglycerides (TG), total cholesterol (TC), “bad” lipids like LDL and VLDL, and low levels of “good” HDL. All modified croissants reversed this trend:
- G5 (15% orange peels) and G9 (15% melon peels) reduced TG by over 55% and TC by over 50%.
- G5 slashed LDL (the “bad” cholesterol) by 65.7%.
- HDL (the “good” cholesterol) rose by 41% in G5, 36.8% in G7 (15% watermelon rinds), and 3.6% in G9.
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Liver and kidney function: High cholesterol often damages the liver, but the modified croissants lowered levels of liver enzymes (AST, ALT, ALP), with 15% additions working best—signs of healthier liver function. They also reduced urea (a waste product) by 20–22% and blood sugar by over 60% in G5, G7, and G9, bringing levels close to those of healthy rats.
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Tissue health: Under a microscope, the high cholesterol group’s liver showed severe damage—fat buildup, cell death, and inflammation. Their hearts also had damaged cells and fat deposits. In contrast, rats fed the byproduct croissants had livers and hearts that looked much healthier, with far less damage.
A Win for Health and the Planet
This study paints a hopeful picture: adding fruit byproducts to popular foods like croissants could be a simple, scalable way to tackle high cholesterol—all while reducing food waste. For Western countries, where croissants are a breakfast staple and fruit processing generates mountains of waste, this approach could align with public health goals (like reducing CVDs) and environmental targets (like cutting landfill use).
Of course, more research is needed to confirm these effects in humans, but the results are a step forward. Imagine a future where your morning croissant not only satisfies your hunger but also helps keep your heart healthy—all while giving new life to ingredients that would otherwise be thrown away. It’s a small change, but one that could make a big difference for both our bodies and the planet.
References:
Mohamed HE, Mansour SM, Aldhalmi AK, et al. Investigating the anti-hypolipidemic effects of croissants enriched with fruit byproducts in a rat model. NPJ Sci Food. 2025;9(1):130. Published 2025 Jul 8. doi:10.1038/s41538-025-00482-z