WINETECH Technical Yearbook 2021

tartrate is fermented by colonic bacteria to short chain fatty acids, which then can be absorbed in the colon of humans, however, L(+)-tartrate are metabolised faster than D(–)-tartrate, with the L(+)-form excreted more efficiently than the D(–)-form (Younes et al ., 2020). AUTHENTICITY Since the beginning of the 21st century, natural tartaric acid [non-synthetic or L(+)- tartaric acid from a plant source] has been in direct competition with its synthetic equivalent, which mainly comes from the People’s Republic of China, where L(+)- tartaric acid and DL-tartaric acid are produced from benzene or butane. Benzene is a carcinogenic chemical. Also, the synthetic process employs a soluble metal catalyst (tungsten), increasing the likelihood of heavy metal contamination. As a result, therefore, maximum limits for heavy metals resulting from the use of any catalyst that could be present in L(+)-tartaric acid due to its manufacturing process must be included in the EU specifications for this food additive (Younes et al ., 2020). Synthetic tartaric acid is increasingly being used in various applications. Synthetic tartaric acid had about 50%market share in 2016, with global market demand projected to reach US$ 804.7 million by the end of 2027, with an estimated 4.8% CAGR (compound annual

growth rate) for 2019-2027. Increasing consumer demand for and consumption of plant-derived or bio-based and eco-friendly alternatives in Europe and North America, however, will hamper the growth of the synthetic tartaric acid market during the forecast period. Therefore, being able to back up “natural” claims is crucial. Verifying the botanical origin (using stable isotope analyses) of tartaric acid and that it is not of petrochemical synthetic origin (using carbon-14 analysis) is of significance. The Scientific Committee for Food (SCF) in 1990 and the Joint FAO/WHO through the Joint Expert Committee on Food Additives (JECFA 1977-1983-1990) established an acceptable daily intake (ADI) of 30 mg/ kg body weight (bw) per day for L(+)- tartaric acid (E 334) and its potassium (E 336) and sodium (E 335) salts, while the D and DL-forms of synthetic and unnatural origin are forbidden (Distillerie Mazzari S.p.A; Caviro Distillerie). In the EU, only the L(+)-form of tartrate is authorised and can be registered as a food additive (Younes et al ., 2020). Current EU legislation does not differentiate at all between the natural and the synthetic forms or sources of tartaric acid, with the sole exception of wine legislation, stating that any L(+)-tartaric acid used must be extracted from wine products and be of

agricultural origin. Canadian legislation stipulates that synthetic tartaric acid can be used as a food additive in beverages if not used as a processing aid and if the non-synthetic (natural) form is not commercially available (ICF International). In the US, only tartaric acid made from grape wine can be used as an ingredient in or on processed products labelled as “organic” or “made with organic”. SUMMARY Tartaric acid exist in different forms or isomers of natural and synthetic origin, with different properties, health benefits and effects, and pharmaceutical uses. Tartaric acid isomers have broad industrial and scientific applications in the food, wine, pharmaceutical, manufacturing, agrochemical and polyester industries. Factors such as price and availability of raw materials drive the demand and supply dynamics of tartaric acid. Global demand of the synthetic product is growing due to increased availability and lower cost. Suppliers and purchasers of tartaric acid in the local wine industry must make sure that they can confirm natural claims. REFERENCES Hronská, H., Micháliková, S. & Rosenberg, M., 2017. Microbial production of specialty C4 dicarboxylic acids from maleic anhydride.

Journal of Food and Nutrition Research 56(3), 219-231. Xuan, J. & Feng, Y., 2019. Enantiomeric tar tar i c ac id product ion us ing c i s- epoxysuccinate hydrolase: History and perspectives. Molecules 24(5), 903. Younes, M., Aquilina, G., Castle, L., Engel, K-H., Fowler, P., Fernandez, M.J.F., Fürst, P., Gürtler, R., Gundert-Remy, U., Husøy, T., Mennes, W., Shah, R., Waalkens-Berendsen, I., Wölfle, D., Boon, P., Tobback, P., Wright, M., Aguilera, J., Rincon, A.M., Tard, A. &Moldeus, P., 2020. Re-evaluation of L(+)-tartaric acid (E 334), sodium tartrates (E 335), potassium tartrates (E 336), potassium sodium tartrate (E 337) and calcium tartrate (E 354) as food additives. EFSA Journal 18(3), 6030. Technical data sheet, Distillerie Mazzari S.p.A., Italy. Natural L(+)-tartaric acid – E334, revision nr. 10 of 04/10/2012. Material technical data sheet, Caviro Distillerie, Italy. L(+)-Tartaric acid E 334, STD/01000200ENG, rev. 6, admission date 11 May 2017, pp. 1-5. Technical evaluation report, compiled by ICF International for the USDA National Organic Program. Tartaric acid – handling, 13 October 2011, pp. 1 of 12.

For further information, contact Dr Francois van Jaarsveld at VJaarsveldF@arc.agric.za.

WINETECH TECHNICAL YEARBOOK 2021 | 96