Grape Pomace
Grape
Vitis vinifera L.
Grape pomace is obtained from the industrial processing of winemaking (crushing and pressing) of grapes and the removal of all the juice. Grape pomace typically contains the skin, residual pulp, seeds and stems. Organic solid waste represents one of the main effluents of the sector. This pomace mostly consists of dietary fiber (lignin and cell wall polysaccharides), carbohydrates and different fatty acids.
By-Products
Amount per 100 g
| Energy | 415 kcal |
| Dry matter | 92.3 g |
| Protein | 3.57-14.17 g |
| Ash | 1.73-9.7 g |
| Total dietary fiber | 17.28 – 88.70 g |
| Insoluble fiber | 16.44-63.70 g |
| Soluble fiber | 0.72-12.78 g |
| Carbohydrates | 12.20-40.53 g |
| Lipids | 1.14- 13.9 g |
| Potassium | 1184-2718 mg |
| Magnesium | 92- 644 mg |
| Phosphorus | 4- 3157 mg |
| Sodium | 87-244 mg |
| Iron | 5 – 5468 mg |
| Zinc | 2 – 2254 mg |
Source: Antonić at al., 2020
Grape pomace is characterized by a high content of different bioactive compounds because of poor extraction of winemaking. The content varies according to the grape variety (Merlot, Cabernet Sauvignon) and vine species (Vitis vinifera, Vitis labrusca, for example). Total phenolic compounds are around 3000 mg GAE / 100 g of DW, 1500 mg catechin equivalent / 100 g DW for total flavonoid content and 100 mg cyan-3-glu / 100 g of DW for total anthocyanins content.
Besides the bioactive compounds found in grape pomace, several types of fatty acids were identified, including common saturated fatty acids, monounsaturated fatty acids (MUFA), but mostly polyunsaturated fatty acids (PUFA) (around 70%), such as linoleic acid and alpha-linoleic acids.
Numerous studies have demonstrated that the polyphenolic compounds from grapes have many health benefits such as antimutagenic and anticarcinogenic activities, antioxidant and anti-inflammatory activities, prevention and delay of cardiovascular diseases, increase lifetime and retarded the onset of age-related markers. The main bioactive compounds responsible for many reported health benefits of wine and wine by-products consist of antioxidant phenolics such as phenolic acids, anthocyanins, procyanidins and resveratrol.
The intake of PUFA is related to health benefits thanks to the equilibrium between linoleic and linolenic acids that allows the normal development and prevention of chronic disease.
Grape pomace could also be used as a dietary fiber supplement in human and animal food industry and as an alternative source of antioxidants. Also, many plants' phenolic extracts have been shown to have antimicrobial activities and help to stabilize other food products.
By-Products
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