{"title":"Effect of Three Drying Methods on Antioxidant Efficiency and Vitamin C Content of Moringa oleifera Leaf Extract","authors":"Kenia Mart\u00ednez, Geniel Talavera, Juan Alonso","volume":132,"journal":"International Journal of Chemical and Materials Engineering","pagesStart":800,"pagesEnd":804,"ISSN":"1307-6892","URL":"https:\/\/publications.waset.org\/pdf\/10008255","abstract":"
Moringa oleifera<\/em> is a plant containing many nutrients that are mostly concentrated within the leaves. Commonly, the separation process of these nutrients involves solid-liquid extraction followed by evaporation and drying to obtain a concentrated extract, which is rich in proteins, vitamins, carbohydrates, and other essential nutrients that can be used in the food industry. In this work, three drying methods were used, which involved very different temperature and pressure conditions, to evaluate the effect of each method on the vitamin C content and the antioxidant efficiency of the extracts. Solid-liquid extractions of Moringa<\/em> leaf (LE) were carried out by employing an ethanol solution (35% v\/v) at 50 °C for 2 hours. The resulting extracts were then dried i<\/em>) in a convective oven (CO) at 100 °C and at an atmospheric pressure of 750 mbar for 8 hours, ii<\/em>) in a vacuum evaporator (VE) at 50 °C and at 300 mbar for 2 hours, and iii<\/em>) in a freeze-drier (FD) at -40 °C and at 0.050 mbar for 36 hours. The antioxidant capacity (EC50<\/sub>, mg solids\/g DPPH) of the dry solids was calculated by the free radical inhibition method employing DPPH\u02d9 at 517 nm, resulting in a value of 2902.5 ± 14.8 for LE, 3433.1 ± 85.2 for FD, 3980.1 ± 37.2 for VE, and 8123.5 ± 263.3 for CO. The calculated antioxidant efficiency (AE, g DPPH\/(mg solids·min)) was 2.920 × 10-5<\/sup> for LE, 2.884 × 10-5<\/sup> for FD, 2.512 × 10-5<\/sup> for VE, and 1.009 × 10-5<\/sup> for CO. Further, the content of vitamin C (mg\/L) determined by HPLC was 59.0 ± 0.3 for LE, 49.7 ± 0.6 for FD, 45.0 ± 0.4 for VE, and 23.6 ± 0.7 for CO. The results indicate that the convective drying preserves vitamin C and antioxidant efficiency to 40% and 34% of the initial value, respectively, while vacuum drying to 76% and 86%, and freeze-drying to 84% and 98%, respectively.<\/p>\r\n","references":"[1]\tL. Gopalakrishnan, K. Doriya and D. S. Kumar. \u201cMoringa oleifera: A review on nutritive importance and its medicinal application,\u201d Food Sci. Human Wellness, vol. 5, pp. 49-56, 2016.\r\n[2]\tN. Sankhyan, A. Sharma, C. A. Seth, A. Chauhan and S. Kulshrestha, \u201cDetermination and comparison of vitamin C content from Moringa oleifera by different methods,\u201d \tInt. J. Agric. Sci. Res., vol. 3, pp. 67-70, 2013.\r\n[3]\tG. Vald\u00e9s-Hern\u00e1ndez, L. Cruz-Viera and R. Comet-Rodr\u00edguez. \u201cInfluencia de las condiciones de operaci\u00f3n en la extracci\u00f3n de polifenoles a partir de hojas de Moringa oleifera Lam,\u201d Revista CENIC. Ciencias Qu\u00edmicas, vol.46, pp. 135-145, 2015.\r\n[4]\tC. S\u00e1nchez-Moreno, J. Larrauri and F. Saura-Calixto. \u201cA Procedure to Measure the Antiradical Efficiency of Polyphenols,\u201d J. Sci. Food Agric., vol. 76\t, pp. 270\u2013276, 1998.\r\n[5]\tP. H. M. Marfil, E. M. Santos and V. R. N. Telis. \u201cAscorbic acid degradation kinetics in tomatoes at different drying conditions,\u201d Food Sci. Technol., vol. 4, pp. 1642-1647, 2008.","publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 132, 2017"}