Grape seed waste seems to be the new “goodie” in the world of wine. Till some time back, whatever residue (wine folks call it pomace) was left after crushing the juice from grapes was trashed. But not anymore. Pictured left, grape pomace or the skins, pulp, seeds, and stems of the fruit after pressing
From using pomace as compost or as the basis of grapeseed oil to exploring its properties as a food preservative to converting it into flower pots – pomace is being recycled by scientists and entrepreneurs, alike, who have been thinking of innovative ways to utilise it. While it continues to be a hot topic of discussion at vineyards and wineries the world over, a few wine companies have already come up with concrete methods to use pomace.
Researchers are exploring pomace’s properties as a food preservative – studies have shown that compounds called polyphenols found in grapes and in pomace kill bacteria that can cause food to spoil.
In Northern California, pomace is used to make a flour substitute that is free of gluten. WholeVine Products, a sister company of wine producer Kendall-Jackson has collaborated with a local miller to create a special wine flour. Different grape varieties such as chardonnay, riesling and merlot are used to produce as many as 16 different varieties of this flour.
The whole process starts with the harvest in September. After the grapes are pressed, WholeVine collects the pomace; seeds and skins are then separated, dried and milled. Within the next two months, the pomace is dried (to inhibit mould) and before the polyphenols in pomace which have great health benefits start to decrease. The result, according to WholeVine is flour that is “high in iron, fibre, protein and other nutrients.”
The real problem lies not so much in producing the flour as in creating a product that’s palatable. In large quantities it can change the flavour of food. According to Oregon State University professor, Yanyun Zhao’s research, however, grape pomace flour can replace as much as 20% of regular flour in baked products like bread, brownies and muffins without altering the taste or texture.
In Australia, the Barossa Valley based Tarac Technologies – an environmental solutions company that provides services to the Australian wine industry – has used surplus pomace to make supplementary fodder for farmers looking for inexpensive alternatives animal feed.