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Grape seeds and grape seed oil meal


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Common names 

Grape seeds, grapeseeds, grapeseed meal, grape seed meal, grape seed oil meal, grape seed oil cake, defatted grape seeds, defatted grapeseeds [English]; pépins de raisin, farine de pépins de raisin, tourteau de pépins de raisin [French]; granilla de uva, semilla de uva, semilla de uva sin desengrasar, harina de granilla de uva [Spanish] 


Vitis sylvestris C. C. Gmel.


Grape seeds are a by-product of the pressing of grapevine (Vitis vinifera L.) berries for making wine or grape juice. Grape seed oil meal is the by-product of oil extraction from grape seeds. Grape seeds and grape seed oil meal are fibrous, tannin-rich by-products of limited nutritional value, even for ruminant livestock. Since the 2000s, these products have received renewed interest due to their potential as sources of polyunsaturated fatty acids and beneficial antioxidants.

Note: this datasheet only contains information about grape seeds and grape seed oil meal. It does not provide information about feed additives based on grape seed extracts.


Grape berries usually contain two seeds which represent up to 6% of berry weight, though the number and weight of seeds vary according to berry weight and maturity. The wine-making or juice extraction processes yield grape pomace, which contains about 17% of grape seeds on fresh weight (38-52% of dry matter). Grape seeds are valuable: they contain 8-20% of a high-quality dietary oil rich in polyunsaturated fatty acids and vitamin E, and 5-8% polyphenols with potential antioxidant properties (Ye ZhiJing et al., 2016). Grape seeds are often separated from the pomace, by loosening the pulp from the seeds in a breaker, after which a vibrating sieve separates the seed from the skin (Göhl, 1982). The seeds can then be used directly or processed for the production of oil or extracts rich in tannins. Grape seed oil production is carried out by mechanical pressure (screw press) followed or not by solvent extraction, yielding grape seed oil meal (Rombaut et al., 2014).


Grape seeds separated from the grape pomace are mostly used to produce a high-value edible oil. They have also become a source of polyphenols, marketed under names such as "grape seed extracts". Grape seeds and grape seed oil meal are occasionally used to feed livestock.


Grapevine is native from a region comprising northeastern Afghanistan to the southern borders of the Black sea and Caspian Sea. It was domesticated there around 4000 BCE and later spread to the Mediterranean Basin, Western Europe, India, China and Japan. Grapevine was introduced in the Americas by the Spaniards. Grapevine is now cultivated worldwide. In some cases, it hybridized with native Vitis species, resulting in cultivars adapted to local conditions. Grapevine is grown in both hemispheres, predominantly within 20 and 50° N and within 20 and 40°S. Grapevine can grow in tropical areas at altitudes between 300 and 2000 m. However, growth and fruit production are poorer above 1200 m. Grapevine requires a long, sunny, and warm season for the grapes to ripen, and a relatively severe winter that promotes plant dormancy. Grapevine withstands winter frost down to -20°C but light frost of -3 to -5°C kills regrowth during spring and hampers harvest. Temperatures of 25-30°C are optimal for shoot and berry summer growth. Hot and dry summer is best suited for fruit production as it prevents diseases. Grapevine grows on most soils, light or heavy, deep or shallow, fertile or not, but responds to better soils with higher yields. Soil pH should be between 5 and 8; values slightly below 7 are considered best. Light soils promote early ripening and a high sugar content. Soil texture is more important than soil fertility: deep and well-drained soils are preferred as they favour extensive root development. Grapevine is tolerant of drought stress and still survives and grows in semi-arid places where other crops fail. Grapevine is a full sunlight species, but it is necessary that its leaves protect the fruits from sun scorch. Grapevine should be sheltered or planted where strong winds do not occur (Ecocrop, 2016; Ketsa et al., 1991).


Grape is one of the world's most important fruit crop in area, production and value. In 2012, grapes were cultivated on more than 7 million ha that produced 69 million t of fruits with an average yield of 9.6 t/ha. 40 million t of grapes were used for wine (about 90%) and juice (fresh or concentrated) production, 24 for fresh fruit and 5 for dried grapes (raisin) (OIV, 2016; Castellucci et al., 2013). The most important producers were China (9.6 million t), USA (6.6 million t), Italy (5.8 million t), France (5.3 million t), Spain (5.2 million t), Turkey (4.2 million t), Chile (3.2 million t), Argentina (2.8 million t) and Iran (2.1 million t). The EU represents 75% of grape production and 57% of wine production. The main wine producers are Italy, France, Spain (where most of grape production is used for wine) and the USA. China is mostly a producer of fresh fruit (FAO, 2016). It is difficult to estimate the amount of grape seeds released as by-product, since the proportion of seeds separated from the pomace is unknown. Assuming a wordwide production of 40 million t of fresh grapes used for wine, and a seed proportion of 1-6%, the potential amount of grape seeds can be estimated between 0.4 and 2.4 million t.

Grape seed oil is extracted by continuous mechanical pressure (screw pressing) and/or by a solvent process. Mechanical pressing achieves lower yields than solvent extraction, but ensures a higher oil quality. It is used generally for economic reasons (small production or boutique products) (Rombaut et al., 2014; Bekhit et al., 2016). Like for other oil meals, grape seed oil meal obtained by mechanical extraction can retain significant amounts of oil, while solvent-extracted grape seed oil meal should contain very little oil.

Nutritional aspects
Nutritional attributes 

Grape seeds

Grape seeds have a low protein content (9-11% DM) and very large amounts of fibre (NDF > 65%, ADF > 50% DM, crude fibre > 33% DM) and especially lignin (37-55% DM). They contain 8-20% DM oil (Rombaut et al., 2014). The oil content varies greatly among cultivars and is also affected by the stage of berry development: oil content increases up to the onset of ripening and remains the same until harvest. Grapeseed oil contains predominantly polyunsaturated fatty acids (64-75%). Linoleic acid (18:2) is the most abundant fatty acid, followed by oleic acid (18:1), stearic acid (18:0), and palmitic acid (C16:0) (Ye ZhiJing et al., 2016).

Grape seed oil meal

Grapeseed oil meal has a composition similar to that of grape seeds except that its oil content is lower. However, since the seeds can have an oil content as low as 8%, and oil extraction yield can be as low as 55% (Rombaut et al., 2014), it may be difficult to distinguish mechanically-extracted oil meals from whole seeds on the basis of the composition only. Oil content should be lower than 1-2% for solvent-extracted meal.

Potential constraints 


Grape seeds contain important amounts of phenolic compounds (5-8% polyphenols), notably flavonoids (Chedea et al., 2016; Ye ZhiJing et al., 2016)). The most abundant flavonoids in grape seeds are gallic acid, catechin, epigallocatechin-3-gallate, epigallocatechin, epicatechin-3-gallate, epicatechin, and proanthocyanidins (polymers of flavan-3-ols, also called condensed tannins) (Gessner et al., 2015). These compounds form complexes with proteins in the feed and with digestive enzymes leading to disruption of the digestion process and to loss of nutrients. They also interfere with mineral absorption, causing damage to the mucosal lining of the gastrointestinal tract (Bekhit et al., 2016). The high tannin content of grape seeds and grape seed oil meal is, along with fibre, one of the main contributor to their low digestibility and to their generally low nutritive value. The catechins of grape seeds are for a large part responsible for their bitterness (Letaief, 2016).

Flavonoids are recognized as antioxidants with positive effects on the prevention of oxidative damage in tissues by the reduction of lipidic oxidation and/or blocking the production of free radicals (Letaief, 2016). For that reason, grape seeds, grape seed oil meal are being investigated for their potential beneficial effects both on animal health and on the quality of animal products. Grape seed extracts are produced and marketed for a broad spectrum of pharmacological activities. 

Grape seeds and grape seed oil meal are poor in protein, rich in fibre and in tannins and therefore poorly digestible by ruminants. Grape seeds have a higher energy value than grape seed oil meal due to their higher lipid content and can be used at up to 20% in ruminant diets (Magnier, 1991). Some authors have considered that grape seed oil meal should not be fed to ruminants due to its poor nutritive value and that it should be used as carrier for molasses instead (El Boushy et al., 2000; Ferrando et al., 1966). However, studies have shown that grape seed oil meal can be included safely up to 10% in ruminant diets and higher inclusion rates have been reported (Magnier, 1991).


There is scarce information on the palatability of grape seeds and grape seed oil meal. It can be expected that the high tannin content is detrimental to palatability. A trial in Spain found that calves and dairy diets containing 30-50% solvent-extracted grape seed oil meal were not readily accepted at first, but were eaten readily later (Bayon, 1971).

Digestibility and degradability

A comparison of the fractions of grape pomace found that the seed fraction had the lowest in vitro OM digestibility: 13-16% vs 21-23 for the pulp fraction (Eraso Luca de Tena et al., 1992). In vivo OM digestibility values for grape seed oil meal were 24-28% (Cottyn et al., 1981). A value of 40% has been reported for the whole seeds (Magnier, 1991). Nitrogen degradability for both grape seeds and grape seed oil meal is in the 50-55% range (De Boever et al., 1984).

Effect on methane emissions

Grape seed oil meal has been investigated for its potential reducing effect on methane emissions. Using rumen simulation (Rusitec), corn distillers (DDGS) mixed with grape seed oil meal (up to 20% in the mixture, corresponding to 5% grape seed oil meal in the diet) was found to modulate favourably ruminal fermentation by lowering methane formation without adverse effect on fibre degradation. It may also be beneficial to rumen health and animal production by forming complexes with some rapidly degradable carbohydrates and thus may help to stabilize rumen pH in grain-rich diets (Khiaosa-ard et al., 2015).

Beef cattle

Grape seed oil meal

A trial in Spain found that calves given diets containing 30% solvent-extracted grape seed oil had the same growth as calves fed a cereal-based diet. Diets could include up to 50% grape seed oil meal without detrimental effects on health and carcass characteristics (Bayon, 1971). A series of trials in Belgium concluded that 10% grape seed oil meal could be successfully incorporated in complete dry rations for bull fattening, resulting in good performance and carcass characteristics. Its feed value could be compared to that of linseed chaff. Treatment with NaOH did not improve its nutritional value (Cottyn et al., 1978; Cottyn et al., 1981).


Grape seeds

Early trials found that whole grape seeds could be included up to 20% (Hogan et al., 1982) or even 30% (Accardi et al., 1977) in lamb diets. More recently, whole grape seed meal included in lamb diets at 10% dietary level produced weight gains and final live weights greater than those produced with the control feed. 20% dietary level gave feed conversion indexes similar to those obtained using the control feed. Slaughtering data, pH measurements, dissection data and meat chemical composition were not influenced by the type of feed. Increasing levels of grape seed meal decreased saturated fatty acids, increased unsaturated fatty acids and improved dietary characteristics of the meat with the best indices of atherogeniticy and thrombogenicity (Ragni et al., 2014).

In Italy, a series of experiments with dairy ewes investigated the effects of dietary inclusion of grape seeds (300 g/d), alone or in combination with linseed (220 g/d), on milk production and milk quality. These dietary treatments had no adverse effects on milk production and health status (Nudda et al., 2015). They decreased the milk concentration of de novo synthesized fatty acids C10:0, C12:0, and C14:0, showing that grape seeds could be useful to increase the concentration of polyunsaturated fatty acids with potential health benefits, especially when it was included together with linseed (Correddu et al., 2016). The addition of grape seeds (when combined with linseed) reduced the extent of light-induced oxidation of the total unsaturated fatty acids in milk (Correddu et al., 2015b). However, grape seeds were not effective in decreasing the biohydrogenation of dietary polyunsaturated fatty acids (Correddu et al., 2015a).

Grape seed oil meal

In France, grape seed oil meal given as sole feed to sheep caused weight loss and it was concluded that it was not suitable for sheep feeding (Ferrando et al., 1966). In Cyprus, lambs could be fed diets containing 40% grape seed oil meal with no detrimental effect on weight gain. However, feed intake was higher than for lambs fed the control barley-based diet and feed conversion efficiency was lower. The increased intake was reflected in increased gut-fill and correspondingly lower carcass yield (Mavrogenis et al., 1973).


Grape seeds and grape seed oil meal are not valuable feed ingredients for pigs due to their low protein content, very high fibre content and high tannin content. They can only be used at low dietary levels to provide antioxidants and polyunsaturated fatty acids to the diet. In Romania, the inclusion of 5% grape seed oil cake in growing pig diets did not affect performance and resulted in slight increases in carcass quality indicators (Ciuca et al., 2013). A maximum dietary level of 3-4% has been recommended for whole grape seeds (Magnier, 1991).


Grape seeds

Domestic poultry have been observed to select preferentially the grape seed fraction when offered grape pomace (Cornevin, 1892). In Spain, chickens of the local Penedes breed fed with a diet containing 5% grape seeds showed no differences in performance. The meat showed a higher percentage of unsaturated fatty acids due to linoleic acid, a more nutty smell, a more metallic flavour and more stringiness (Francesch et al., 2015). In Korea, the supplementation of broiler diets with 1% ground grape seeds had no negative effect on growth performance. Some antioxidant indicators including blood total antioxidant status and intestinal superoxide dismutase were markedly elevated in response to dietary grape seeds (Jang et al., 2007).

Grape seed oil meal

Grape seed oil meal is generally considered to have a too low nutritive value to be used for poultry feed (El Boushy et al., 2000). However, a Chinese study concluded that grape seed meal could be included in geese diets up to 9% dietary level (Wang BaoWei et al., 2010).


Grape seeds

Grape seeds could be used up to 15% in rabbit diets with good results (Alicata et al., 1988).

Grape seed oil meal

A series of studies in Spain found that defatted grape seed meal was found to have a valuable energy content (DE 5.5 MJ/kg DM) for rabbits compared to other lignified fibre sources. Its inclusion at moderate levels (15%) in the diet exerted a positive effect on feed intake, energy intake and average daily gain, with no impairment of cecal fermentation and mortality. The high proportion of cutin in the lignin of defatted grape seed meal possibly minimized the negative impact of lignin on cecal fermentation traits (García et al., 1999a; García et al., 1999b; García et al., 2002). It should be noted that an earlier study in Belgium found a much lower DE value (3.1 MJ/kg DM) (Maertens et al., 1985). A dehulled and defatted grape seed meal produced in Italy and containing less than 25% crude fibre and more than 20% protein could be included at up to 20% dietary level in the diets of fattening rabbits, partially replacing dehydrated alfalfa and soybean meal, without negatively affecting health and carcass quality. However, a maximum 10% inclusion rate was recommended to maintain performance (Cavani et al., 1988).

Horses and donkeys 

Grape seed oil meal was found to have a very mediocre value for horses (DM and OM digestibility of 11-12%) due to its high lignin content. Its utilisation in horses is not recommended or should be at least very limited (Wolter et al., 1980).

Nutritional tables
Tables of chemical composition and nutritional value 

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used

Main analysis Unit Avg SD Min Max Nb  
Dry matter % as fed 92.0 1.1 89.7 94.5 36  
Crude protein % DM 10.1 0.5 8.6 11.4 39  
Crude fibre % DM 42.5 4.4 33.9 52.1 44  
NDF % DM 70.5 2.2 65.4 74.7 31  
ADF % DM 59.2 2.5 53.3 64.9 32  
Lignin % DM 45.1 5.1 37.3 55.4 32  
Ether extract % DM 12.7 1.8 9.8 16.3 35  
Ash % DM 3.4 0.5 2.6 4.2 23  
Starch (polarimetry) % DM 2.1 0.8 1.0 2.9 4  
Gross energy MJ/kg DM 21.8         *
Minerals Unit Avg SD Min Max Nb  
Calcium g/kg DM 7.1 1.5 4.0 9.1 12  
Phosphorus g/kg DM 2.1 0.4 1.6 2.9 12  
Potassium g/kg DM 5.5 1.8 3.9 8.8 12  
Sodium g/kg DM 0.1 0.1 0.0 0.2 7  
Magnesium g/kg DM 1.2       1  
Zinc mg/kg DM 11       1  
Copper mg/kg DM 15 3 9 24 11  
Iron mg/kg DM 34       1  
Amino acids Unit Avg SD Min Max Nb  
Alanine % protein 4.1       1  
Arginine % protein 7.2       1  
Aspartic acid % protein 3.5       1  
Cystine % protein 1.1       1  
Glutamic acid % protein 20.5       1  
Glycine % protein 8.3       1  
Histidine % protein 1.5       1  
Isoleucine % protein 3.0       1  
Leucine % protein 6.0       1  
Lysine % protein 2.6       1  
Methionine % protein 1.1       1  
Phenylalanine % protein 2.8       1  
Proline % protein 2.5       1  
Serine % protein 3.9       1  
Threonine % protein 2.8       1  
Tyrosine % protein 1.3       1  
Valine % protein 4.2       1  
Secondary metabolites Unit Avg SD Min Max Nb  
Tannins (eq. tannic acid) g/kg DM 73.5 57.8 32.0 159.0 4  
Ruminant nutritive values Unit Avg SD Min Max Nb  
Nitrogen degradability (effective, k=6%) % 53 2 50 55 4  

The asterisk * indicates that the average value was obtained by an equation.


AFZ, 2011; Alibes et al., 1990; Alicata et al., 1988; Chapoutot et al., 1990; Kamel et al., 1985; Vargas et al., 1965; Wolter et al., 1980

Last updated on 25/10/2016 22:45:59

Main analysis Unit Avg SD Min Max Nb  
Dry matter % as fed 88.4 1.5 86.0 90.5 24  
Crude protein % DM 11.4 0.9 9.3 13.2 25  
Crude fibre % DM 49.2 6.8 38.8 59.9 26  
NDF % DM 77.5 4.5 70.9 83.6 10  
ADF % DM 66.8 5.3 58.4 73.0 9  
Lignin % DM 48.5 12.7 13.7 64.2 15  
Ether extract % DM 1.5 1.0 0.3 3.6 17  
Ether extract, HCl hydrolysis % DM 1.8 1.4 0.7 5.4 10  
Ash % DM 3.8 0.5 3.0 4.8 22  
Starch (polarimetry) % DM 2.5 0.5 2.2 3.2 4  
Total sugars % DM 0.5 0.2 0.3 0.8 5  
Gross energy MJ/kg DM 19.5 0.4 19.5 21.1 3 *
Minerals Unit Avg SD Min Max Nb  
Calcium g/kg DM 9.9 1.8 7.8 13.4 11  
Phosphorus g/kg DM 2.1 0.3 1.7 2.7 11  
Potassium g/kg DM 6.5   5.0 8.0 2  
Sodium g/kg DM 0.1 0.2 0.0 0.4 5  
Magnesium g/kg DM 0.7       1  
Manganese mg/kg DM 24       1  
Copper mg/kg DM 24 5 18 29 3  
Iron mg/kg DM 212       1  
Secondary metabolites Unit Avg SD Min Max Nb  
Tannins, condensed (eq. catechin) g/kg DM 42.8       1  
Ruminant nutritive values Unit Avg SD Min Max Nb  
OM digestibility, ruminants % 26.6   24.9 28.2 2  
Energy digestibility, ruminants % 24.8         *
DE ruminants MJ/kg DM 4.8         *
ME ruminants MJ/kg DM 3.8         *
Nitrogen digestibility, ruminants % 49.8 13.7 34.1 58.8 3  
Nitrogen degradability (effective, k=6%) % 53       1  
Rabbit nutritive values Unit Avg SD Min Max Nb  
Energy digestibility, rabbit % 22.1   14.7 26.9 2 *
DE rabbit MJ/kg DM 4.3   3.1 5.5 2  
MEn rabbit MJ/kg DM 4.0         *
Nitrogen digestibility, rabbit % 45.1       1  

The asterisk * indicates that the average value was obtained by an equation.


AFZ, 2011; Bayon, 1971; Cottyn et al., 1978; Cottyn et al., 1981; De Boever et al., 1984; De Boever et al., 1988; De Boever et al., 1994; Ferrando et al., 1966; García et al., 2002; Maertens et al., 1985; Morgan et al., 1980; Perez et al., 1984

Last updated on 25/10/2016 22:40:44

Main analysis Unit Avg SD Min Max Nb  
Dry matter % as fed 90.6 2.4 88.0 93.1 5  
Crude protein % DM 13.0 1.6 10.6 14.2 4  
Crude fibre % DM 34.4 6.4 29.0 44.0 5  
NDF % DM 64.4   62.5 66.2 2  
ADF % DM 56.0   52.1 60.0 2  
Lignin % DM 34.7       1  
Ether extract % DM 7.3 1.1 6.0 8.5 4  
Ash % DM 6.2 3.3 3.0 11.6 5  
Gross energy MJ/kg DM 19.9         *
Minerals Unit Avg SD Min Max Nb  
Calcium g/kg DM 9.0       1  
Phosphorus g/kg DM 2.7       1  
Zinc mg/kg DM 23       1  
Copper mg/kg DM 58   34 82 2  
Iron mg/kg DM 645       1  
Secondary metabolites Unit Avg SD Min Max Nb  
Tannins (eq. tannic acid) g/kg DM 43.0       1  
Ruminant nutritive values Unit Avg SD Min Max Nb  
OM digestibility, ruminants % 40.4       1  
Energy digestibility, ruminants % 38.8         *
DE ruminants MJ/kg DM 7.7         *
ME ruminants MJ/kg DM 6.2         *
Nitrogen digestibility, ruminants % 68.7       1  

The asterisk * indicates that the average value was obtained by an equation.


AFZ, 2011; Alibes et al., 1990; Ciuca et al., 2013; Woodman, 1945

Last updated on 25/10/2016 22:36:58

Datasheet citation 

Heuzé V., Tran G., 2016. Grape seeds and grape seed oil meal. Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. http://www.feedipedia.org/node/692 Last updated on October 26, 2016, 10:54