By Dr. Alejandra Aguilar & Dr. Neil Auchterlonie | Todos Santos
Fish meal is a naturally balanced feed ingredient that is high in protein, energy and minerals and a major dietary source of long chain polyunsaturated fatty acids (PUFA) (Cho and Kim 2010). It is formed from whole fish, fish by-products or fish trimmings and contributes indirectly to human nutrition when it is utilized as an ingredient for poultry/livestock as well as aquaculture feeds (Soliman et al, 2017).
According to the Mexican Office for Economic Affairs (Secretaría de Economía; abbreviated “SE”) in 2010 the market to export fishmeal was open with expectations to commercialize 120,000 tons, amount that was practically doubled in 5 years. In fact, in 2017 among the agri-food products that were exported from Mexico to China was fishmeal, having a significant increase in the export value of 163 percent.
Oxidation is a normal process that happens with all fats and oils that contain polyunsaturated fatty acids (Ismail et al, 2016). The predominant omega-3 fatty acids in fish meal (linolenic acid, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) (Rowghani et al, 2007)) are prone to oxidation. The use of antioxidants is one of the most common methods to prevent lipid oxidation (Asnaashari et al, 2014), and several antioxidants have been used in fishmeal for decades.
BHT (butylated hydroxytoluene) and Ethoxyquin are common synthetic antioxidants used in fishmeal industry, however both are under a reauthorization process under European Union legislation, and their future use as animal feed additives is uncertain. The global trade body representing fishmeal and fish oil interests, IFFO -The Marine Ingredients Organization, is looking at other available products for the stabilization of fishmeal. This includes the use of natural antioxidants from a natural source called “Tara“, among other natural antioxidants.
Tara (Caesalpinia spinosa) is a leguminous tree indigenous to South America, having 8–10 cm long red or pale yellow pods. Its pods and seeds have been used as a source of tannins and gum having a high potential for industrial and food uses. Tara pods contain the highest percentage of tannins (∼40%–60% of the total content) (Pedreschi et al, 2018) which are of the hydrolysable type, with gallic acid (GA) as the main constituent (Aguilar Galvez et al, 2014). Peru is considered the most important producer worldwide of Tara with more than 80 % of the world production (Skowyra et al, 2015). Gallic acid (3,4,5-trihydroxybenzoic acid) is an organic substance occurring in many plants either as a free molecule or as part of tannic acid molecule and serves as a precursor for the food preservative propyl gallate (PG) (Bajpai and Patil,2008). Antifungal, antibacterial and antiseptic properties have been attributed to tara tannins too (Skowyra et al, 2015).
In winemaking, the use of enological tannins (oenotannin) has received renewed attention, tannins are generally classified according to their origin into two groups: hydrolyzable tannins, derived mainly from oaks or other plant species, and condensed tannins, mainly from grapes. Gallic acid is a hydrolyzable tannin (gallotannins from tara) (Canuti et al, 2012). Tara tannins are used as a wine clarifier and as a source for obtaining the antioxidant gallic acid used in the oil industry (Skowyra et al, 2015). Initially oenotannins were proposed as coadjuvants to prevent the wine proteic instability and were officially authorized by the International Oenological Codex. However, they are also claimed to have positive effects in wine color stabilization, improve wine structure, control of laccase activity (oxidation), and elimination of reductive odors (Canuti et al, 2012; Zimdars et al, 2017). In recent studies alternatives of Sulphur dioxide (common antioxidant and antimicrobial in wine industry) have been assessed for the protection of wine aromatic volatiles, during wine storage, including the addition of gallic acid and glutathione (this latter one also proposed by IFFO as a natural antioxidant for fishmeal stabilization) (Oliveira et al, 2011).
IFFO is currently working with Peruvian manufacturers of fish meal and tannins to perform in vitro experiments in “virgin” fishmeal and establish doses that can stabilize fishmeal through time and protect from oxidation. The versatile uses of Tara in Fish and Wine Industries will increase its demand and will provide both industries with alternatives to protect from oxidation both wine and fishmeal.
Technical Team at IFFO: Dr. Neil Auchterlonie ([email protected]); Dr. Alejandra Aguilar Solis ([email protected]). References • Aguilar Galvez, A., G. Noratto, F. Chambi, F. Debaste and D. Campos. 2014. Potential of tara (Caesalpinia spinosa) gallotannins and hydrolysates as natural antibacterial compounds. Food Chemistry. 156: 301–304. • Asnaashari, M., R. Farhoosh and A. Sharif. 2014. Antioxidant activity of gallic acid and methyl gallate in triacylglycerols of Kilka fish oil and its oil-in-water emulsion. Food Chemistry. 159: 439–444. • Bajpai, B. and P. Shridhar. 2008. A new approach to microbial production of gallic acid. Brazilian Journal of Microbiology. 39:708-711. • Canuti, V., S. Puccioni, G. Giovani, M. Salmi, I. Rosi and M. Bertuccioli. 2012. Effect of Oenotannin Addition on the Composition of Sangiovese Wines from Grapes with Different Characteristics. American Journal of Enology and Viticulture. 63:220-231. • Cho, J.H. and I.H. Kim. 2010. Fish meal – nutritive value. Journal of Animal Physiology and Animal Nutrition. 95:685:692. • Ismail, A., G. Bannenberg, H. B. Rice, E. Schutt and D. MacKay. 2016. Oxidation in EPA- and DHA-rich oils: an overview. Lipid Technology. 28:55-59. • Oliveira, C.M., A. C. Silva Ferreira, V. De Freitas and A. M. S. Silva. 2011. Oxidation mechanisms occurring in wines. Food Research International. 44:1115–1126 • Pedreschi, F., I. Saavedra, A. Bunger, R. N. Zuñiga, R. Pedreschi, R. Chirinos, D. Campos and M. S. Mariotti-Celis. 2018. Tara pod (Caesalpinia spinosa) extract mitigates neo-contaminant formation in Chilean bread preserving their sensory attributes. LWT – Food Science and Technology. 95:116–122. • Rowghani, E., A.D. Boostani, H.R. Mahmoodian Fard and R. Frouzani, 2007. Effect of Dietary Fish Meal on Production Performance and Cholesterol Content of Laying Hens. Pakistan Journal of Biological Sciences, 10: 1747-1750. • Skowyra, M., U. Janiewicz, A. M. Salejda, G. Krasnowska and M. P. Almajano. 2015. Effect of Tara (Caesalpinia spinosa) Pod Powder on the Oxidation and Colour Stability of Pork Meat Batter During Chilled Storage. Food Technology and Biotechnology. 53: 419–427. • Soliman, N.F., D. M.M. Yacout and M. A. Hassaan. 2017. Responsible Fishmeal Consumption and Alternatives in the Face of Climate Changes. International Journal of Marine Science.7:130-140. • Zimdars, S., J. Hitschler, A. Schieber, and F. Weber. 2017. Oxidation of Wine Polyphenols by Secretomes of Wild Botrytis cinerea Strains from White and Red Grape Varieties and Determination of Their Specific Laccase Activity. Journal of Agricultural and Food Chemistry. 65:10582–10590. • https://www.gob.mx/se/ • https://www.gob.mx/sagarpa/jalisco/articulos/crecen-54-por-ciento-exportaciones-agroalimentarias-de-mexico-a-china-en-2017-148809?idiom=es