Blackcurrant juice

The important commercial feature of these juices, especially significant with blackcurrant and tomato juices, is their ascorbic acid (or vitamin C) content, of which loss by oxidation is known to be accelerated both by heat and by metal (particularly copper) contamination. The effect of copper has been carefully investigated for pure ascorbic acid", and more recently ascorbic acid in blackcurrant juice and model systems. There are, however, oxidation inhibitors of different kinds (which may themselves be heat-sensitive) present in various fruits, which give differing results. The presence of metals will also affect flavours", may cause discoloration, and may give rise to clouding effects, as in apple juice. ... 

Worked Example 9.6 A sample of blackcurrant juice is strongly coloured to the extent that six photons are absorbed out of every seven in the incident light. What is the transmittance T of the sample ... 

Hughes, J. A., West, N. X., Parker, D. M., Newcombe, R. G., and Addy, M. (1999). Development and evaluation of a low erosive blackcurrant juice drink. Final drink and concentrate, formulae comparison in situ and overview of the concept. /. Dent. 27,345-350. 

Cao, G., Muccitelli, H.U., Sanchez-Moreno, C., and Prior, R.L., Anthocyanins are absorbed in glycated forms in elderly women a pharmacokinetic study. Am. J. Clin. Nutr., 73, 920, 2001. Matsumoto, H., Inaba, H., Kishi, M., Tominaga, S., Hirayama, M., and Tsuda, T., Orally administered delphinidin 3-rutinoside and cyanidin 3-rutinoside are directly absorbed in rats and humans and appear in the blood as the intact forms, J. Agric. Food Chem., 49, 1546, 2001. Netzel, M., Strass, G., Janssen, M., Bitsch, I., and Bitsch, R., Bioactive anthocyanins detected in human urine after ingestion of blackcurrant juice, J. Environ. Pathol. Toxicol. Oncol, 20, 89, 2001. 

Bitsch, I., Janssen, M., Netzel, M., Strass, G., and Frank, T., Bioavailability of anthocyanidin-3-glycosides following consumption of elderberry extract and blackcurrant juice, Int J. Clin. Pharmacol Ther., 42, 293, 2004. 

The normal method used to assess the acidity of a soft drink or fruit juice is titration using sodium hydroxide. Traditionally, phenolphthalein was used as an indicator to detect the end-point of the titration. However, with the ready availability of pH meters, testing is now earned out to a final pH of 8.1. A major advantage of this technique is that it allows the titration to be earned out automatically and avoids problems with coloured products, such as blackcurrant juices, where the phenolphthalein indicator end-point, colourless to pink, can be... 

Figure 10.10 HPLC analysis of a blackcurrant juice using the IFU method. Conditions column 5 xm ODS2 250 X 4.6 mm flow rate 1 ml/min solvent A = 10% formic acid, solvent B = 10% formic acid in 50% acetonitrile and 40% water gradient 0-1 min 12% B, 1-26 min horn 12% B to 30% B, 26—35 min 30% to 100% B, 38 min 100% B, 38—13 min 100% to 12% B detection at 518 nm using DAD.

Drinking of 3 doses of apple and blackcurrent juice (750, 1000, and 1500 ml) for 1 week did not affect blood plasma TAC (Y4). Consumption of extra virgin olive oil (69 g per day) either rich or poor in phenols for 3 weeks did not affect significantly blood plasma TAC (VI8). 

Netzel, M., Strass, G., Janssen, M., Bitsch, L, and Bitsch, R., Bioactive anthocyanins detected in human urine after ingestion of blackcurrant juice, J. Environ. Pathol. Toxicol. Oncol, 20, 89-95, 2001. 

Ibarz, A., Pagan, J., and Miguelsanz, R. 1992a. Rheology of clarified Fruit Juices. II, blackcurrant juices. J. Food Eng. 15 Ci-Ti. 

Another study in six healthy volunteers studied the pharmacokinetics and bioavailability of anthocyanidin-3-glycosides from either blackcurrant juice or elderberries (24). As with other studies listed previously, these investigators found very little ( 0.04% from blackcurrant juice to 0.4% from elderberry extract) of the dose recovered in the urine, suggesting low bioavailability. Though the half-life of the anthocyanidins was similar regard-... 

Continued depletion of L-ascorbic acid in stored fruit-juices may be partly due to interaction with the hydrogen peroxide initially produced by aerobic mechanisms. Indeed, introduction of hydrogen peroxide, in amounts equivalent to the L-ascorbic acid content, into three-month old, blackcurrant-juice samples, caused a 50% loss of L-ascorbic acid in one hour, probably ascribable to formation of dehydro-L-ascorbic acid. 

Kivimaki, A. S., Ehlers, P. 1., Siltari, A., Turpeinen, A. M., Vapaatalo, H., Korpela, R. Lingonberry, cranberry and blackcurrant juices affect mRNA expressions of inflammatory and atherothrombotic markers of SHR in a long-term treatment. J. Fund Foods 4, 2, 2012. 

Buchert, K., et al. Effect of enzyme-aided pressing on anthocyanin yield and profiles in bilberry and blackcurrant juices, J. Sci. Food Agric. 85, 2548-25,2005. 

The methanol content in citrus juices ranges from 24 to 47 mg/1, its content in ciders is 36-88 mg/1, and in blackcurrant juices reaches 70-176 mg/1. The methanol content of fruit wines is higher usually ranges from 20 to 240 mg/1, but, exceptionally, it may reach even more than 600 mg/1, because a further portion of the pectin is hydrolysed during the fermentation process. The amount of methanol formed in wines depends on many factors. Red wines have about twice as high a methanol content as white wines. Vodka has... 

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. 

AT-Bromosuccinimide was proposed as a titrant of ascorbic acid and the suggested method has been adapted by Evered to the determination of ascorbic acid in highly coloured solutions such as blackcurrant juices. The method has been tried by the writers but anomalous results have been obtained on certain samples where figures were considerably higher than those obtained by the official dichlorophenolindophenol method these anomalous results were confirmed in other laboratories on the same samples and are probably due to the presence of added colouring matter. 

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