Turning winemakers’ trash into treasure
15 Apr 2013 by qmcqmmjcbp.d qmcqmmjcbp.d
Researchers at Oregon State University (OSU) have realised leftover pulp (called pomace) from crushed wine grapes can be turned into useful substances.
Wineries typically pay for the pulp to be taken away, but a small percentage is used in low-value products such as fertiliser and cow feed. In this research, the scientists dried and ground the pomace to create edible and non-edible products with a number of uses.
“We now know pomace can be a sustainable source of material for a wide range of goods. We foresee wineries selling their pomace rather than paying others to dispose of it. One industry’s trash can become another industry’s treasure,” said researcher Professor Yanyn Zhao, a value-added food products specialist with the OSU Extension Service.
Pomace consists of stems, skins and seeds and is full of fibre and the natural antioxidants phenolics. The researchers extracted dietary fibre and phenolics from pomace and turned it into powders that can be added to foods.
Phenolics also have antimicrobial properties and can keep fats from deteriorating, so the OSU team added the powdery fibre to yoghurts and salad dressings to extend their shelf life by up to a week, without altering the taste or flavour.
The OSU team also made colourful, edible coatings out of the pomace that can be stretched over fruit and vegetables. These coatings contain antioxidants, seal in moisture and keep bacteria at bay.
The powder can even be used to increase the nutritional value of baked products, such as muffins and brownies by replacing up to 15 per cent of the flour with the powder to increase the amount of fibre in the cakes. The researchers are now investigating changes in dough when pomace is added to yeast breads.
“Adding fibre-rich ingredients can change dough’s absorption qualities and stiffness. We’re trying to find the right balance of pomace in dough while measuring the bread for its density, volume, colour and taste,” said OSU cereal chemist Andrew Ross.
OSU is now seeking to establish partnerships with companies interested in marketing the products developed at the University.
The research is published in various journals including the Journal of Applied Polymer Science, Food Chemistry and the Journal of Food Science.
