Wine-making waste: a natural weapon to beat bacteria

Grape pomace extract can be used as an effective anti-microbial agent to destroy pathogens and help preserve food, according to new research by Turkish scientists published in the Journal of Science of Food and Agriculture.

Grape pomace

Pomace consists of grape seeds, skin and stems, and is a rich source of polyphenols. Phenolic substances are known to reduce the risk of heart disease and cancer by inhibiting human low-density lipoproteins. Pomace is already used as an important by-product of winemaking in the production of foods such as vinegar and molasses.

Bacterial tests

Pomace from the most popular Turkish grape cultivars, Kalecik karasi and Emir, was collected and tested against 14 types of common bacteria, including Escherichia coli and Staphylococcus aureus species, by Osman Sagdic and his team at Erciyes University and Suleyman Demirel University, Turkey. The grape pomace extracts gave effective anti-bacterial results when tested on all bacteria species at a concentration of five per cent, although the effects varied according to concentration, method and cultivars used.

Natural preservatives

“The extracts can be used in food formulations to protect food against spoilage bacteria. People prefer natural preservatives in the place of synthetic counterparts in food”, says researcher Dr Sagdic.

“The world is always ready for better and more natural food preservatives. What we need to do now is to find a suitable food to put it in. The appearance and taste of the final product must be acceptable to the consumers”, says Dr Yiu-Wai Chu, Biotechnology Group, Society of Chemical Industry.