Innovation and Winemaking By-Product Valorization: An Ohmic Heating Approach

What if the leftovers of winemaking could become a treasure trove of bioactive compounds? A new study shows that ohmic heating, a green extraction method, can unlock their potential.

In the rolling vineyards of northern Portugal, winemaking produces not just fine wines but also a mountain of by-products. These leftovers, often discarded, hold untapped value. Researchers are now turning them into opportunities, aiming for a "zero waste" strategy that transforms grape pomace and stems into functional ingredients.

Using ohmic heating (OH), a green extraction technique, scientists compared it with conventional methods. The results were striking: OH yielded a higher antioxidant capacity than conventional extraction. Both methods produced similar levels of anthocyanins, the pigments behind red wine's rich color, including delphinidin-3-O-glucoside, petunidin-3-O-glucoside, and peonidin-3-O-glucoside.

The solid fraction left after OH was also a winner, retaining more protein and fiber-bound phenols than conventional methods. This makes it a promising candidate for functional foods. Meanwhile, the liquid fraction offered a concentrated dose of bioactive compounds.

Red grape bagasse emerged as a powerhouse, with 21.91 g/100 g of sugar and 12.46 g/100 g of protein, while white bagasse had 11.01 g and 13.18 g, respectively. This research not only highlights the potential of winemaking by-products but also champions a circular economy, avoiding non-food grade solvents and turning waste into wealth.

Key Points

• Ohmic heating boosts antioxidant capacity vs. conventional extraction.
• Red grape bagasse: 21.91 g/100g sugar, 12.46 g/100g protein.
• Solid fraction rich in protein and phenols for functional foods.