Blackcurrant seed oil

Values for it are listed by the AOCS (1997), which indicates that campesterol is high at 25-30%, stigmasterol is absent, and high levels of A5-avenosterol and 24-methylene cholesterol are present however, a source is not given for these values and they should be confirmed. This publication also lists blackcurrant seed oil as containing 7.2-10.4% campesterol 0.5-1.0% stigmasterol 70-85% (3-sitosterol 2-5% A5-avenosterol 0.5—4.5% A7-stigmasterol and 0.4-2% A7-avenasterol. 

The seed oil moderately enhanced immune function through reducing the production of prostaglandin E2, suggesting that blackcurrant seed oil may have potential in preventing cancer, cardiovascular disease, and other health problems. 

Watson, J., Byars, M.L., McGill, P., and Kelman, A.W. 1993. Cytokine and prostaglandin production by monocytes of volunteers and rheumatoid arthritis patients treated with dietary supplements of blackcurrant seed oil. Br. J. Rheumatol. 32, 1055-1058. 

The detailed analysis of the spectra of mixtures is not trivial. Beside other parts of the spectrum a very complex region is that attributable to the double bonds. The partial NMR spectrum shown in Fig. 4.13 is from blackcurrant seed oil. All four unsaturated Cig fatty acids (18 1, 18 2, a-18 3 and y-18 3) are differentiated as well as their distribution in the Sn-1/3 and Sn-2 positions. 

FIG. 5 Calorimetric curves of three oils with different stabilities, oxidized at 130°C under oxygen flow. ( ) Safflower oil (-) blackcurrant seed oil (---) Nujol. Instru-... 

A major rate-limiting step in the conversion of ALA to EPA and other long-chain n-3 PUFA is considered to be the first A -desaturation. This is demonstrated effectively by consideration of data from studies involving feeding 18 4n-3, the product of the A -desaturation of ALA, to humans or animals. In one study, a group of 32 stroke patients supplemented their diets with one of three diets for 3 weeks (1) a mixture of 7.5% blackcurrant seed oil [rich in 18 4n-3 and y-linolenic acid (GLA 18 3n-6)], 50% soybean oil, and 42.5% medium-chain... 

Blackcurrant seed oil is a by-product from the production of blackcurrant juice and jelly, and production is estimated to be -50-100 tonnes/year. 

Table 6. Distribution of GLA between the s -l, 2, and 3 positions of TAG in evening primrose, borage, and blackcurrant seed oils...

In addition to the fatty acid content, the triacylglycerol composition and the distribution of the fatty acids between the sn-l, sn-2 andsn-3 positions may affect the nutritional value of the oils. In blackcurrant seed oil, stearidonic acid is mainly located in the sn- or sn-3 position (Kallio etal., 1997), usually the sn-i position (Lawson and Hughes, 1988). The proportion of stearidonic acid is about 8% in Onosmodium hispidissimum (false cromwell) and about 90% of it is equally distributed between the sn-2 and sn-3 positions (MacKenzie et al, 1993). 

Blackcurrant seed oil supplementation increases EPA levels slightly in human plasma lipids (Spielmaim et al., 1989). An 8-week supplementation with blackcurrant seed oil significantly decreased plasma total cholesterol and LDL cholesterol levels and increased plasma HDL cholesterol levels in hyperlipidemic patients (Spielmaim et al., 1989). Blackcurrant oil also reduces the tendency of human platelets to aggregate (Kockmann et al., 1989). 

Animal and human studies have shown that PUFA significantly lower blood pressure. In hypertensive rats, blackcurrant seed oil effected a greater reduction of blood pressure than did borage oil or evening primrose oil in a 7-week study (Engler, 1993). Whether this was due to the stearidonic acid remains open. Blackcurrant oil decreased significantly the resting diastolic blood pressure in mildly hypertensive men when compared with safflower oil in a double-blind, parallel study (Defeme and Leeds, 1996). 

The functional food concept based on stearidonic acid is relevant due to the common use of blackcurrant seed oil (Ribes nigrum) and some other food-quality seed oils. Novel plant-breeding and development techniques should make it possible to produce oils with selected composition such as a canola oil with a high content of selected fatty acids (Kabakibi et al., 2001), but only when we know what we want. 

Deferne, JL and Leeds, AR (1996) Resting blood pressure and cardiovascular reactivity to mental arithmetic in mild hypertensive males supplemented with blackcurrant seed oil. J. Human Hypertension, 10, 531-537. 

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