Advancing sustainable practices based on UV-C radiation for valorising downgraded date fruit residues from date syrup production

What if the leftover pulp from date syrup production could become a treasure trove of nutrition? A new study shows that UV-C light can transform this waste into a functional ingredient powerhouse.

Date syrup production leaves behind a mountain of pomace, often discarded as waste. But this fibrous by-product is far from useless. Researchers in Algeria and Spain discovered that this residue is packed with dietary fiber and polyphenols, and a simple UV-C light treatment can make it even more valuable.

The team compared three green extraction methods—microwave, ultrasound, and water bath—to see which retained the most beneficial compounds. Microwave-assisted extraction won on fiber, keeping 24.31 g/100 g of insoluble fiber and 29.22 g/100 g of total fiber. Meanwhile, ultrasound extraction achieved the ideal insoluble-to-soluble fiber ratio of 2.96, nearly perfect for gut health.

Then came the UV-C twist. Irradiating the pomace for 20 minutes significantly boosted its polyphenol content, especially in the microwave-extracted sample. While antioxidant power measured by FRAP and ORAC stayed steady, the DPPH test showed a higher concentration needed to quench free radicals, suggesting a nuanced effect. Carbohydrates, already highest in water bath samples (50.23 g/100 g), remained stable under UV-C.

In short, date syrup pomace is a goldmine of nutrition, and UV-C light offers a clean, sustainable way to enhance its value. This could lead to new functional food ingredients from what was once waste.

Key Points

• Date pomace is rich in fiber and polyphenols.
• UV-C 20 min boosts polyphenol content significantly.
• Microwave extraction retains the most dietary fiber.