Microencapsulation of Green tea Extracts and its Effects on the Physico Chemical and Functional Properties of Mango Drinks
Green tea polyphenols have been reported to possess many biological properties. Inspite of the many potential benefits of green tea extracts, their sensitivity to high temperature, pH and oxygen is a major disadvantage towards its effective utilization in the food industry. Green tea leaves from Cameron highlands Malaysia were extracted using SFE. To improve the stability, the green tea extracts was encapsulated by spray drying using different carrier materials including maltodextrin (MD) gum arabic (GA) and chitosan (CTS) and their combination at different ratios. Encapsulation efficiency, total phenolic content and antioxidant capacity were determined and were found to be in the range of 71.41 88.04% 19.32 24.90 (g100GAE) and 29. 52 38.05% respectively. Further analysis of moisture content, water activity, hygroscopicity and bulk density of the microparticles were carried out and the results ranged from; 2.31 5.11% 0.28 0.36, 3.22 4.71% and 0.22 0.28g/cm, respectively. The ability of the microparticles to swell in SGF and SIF was determined at 142.00 188.63% and 207.55 231.77% respectively. The microparticles with the best catechin efficiency, total phenolic content and antioxidant activity were selected and incorporated into mango drink and its effects on the physicochemical and functional properties of the product evaluated during storage. The pH, total solid and viscosity of the catechin microparticles supplemented range from 5.15 4.38, 12.70 14.20% and 12.55 13.99(cps) respectively. The stability of green tea bioactives in the mango drink showed degradation rate in the range of 16.47 29.72% compared to the nonencapsulated powder (46.46% The green tea extracts microparticles show good degree of stability in the mango drink and the antioxidant capacity of the mango drink was significantly p 0.05) different compared to the non encapsulated powder at the end of the storage period. Index Term Green tea catechins; Microencapsulation, Functional food; Mango drink; Stability 1.0. INTRODUCTION Tea is an infusion of Camellia sinensis only second to water in term of consumption globally. Green tea is a product from non fermented tea leaves as compared to black or oolong teas. Epidemiological data have shown that consumption of tea has an inverse relation with reduced risk of certain chronic and degenerative diseases including certain forms of cancers, cardiovascular diseases, diabetes, obesity, Alzheimer disease, weight loss etc. (Basu Lucas, 2007; Khan Mukhtar, 2007) The major constituents of green tea catechin polyphenols include catechin (C) epicatechin (EC) epigallocatechin (EGC) epigallocatechin gallate (EGCGC) epicatechin gallate (ECG) and gallic acid. Tea has been listed among functional foods because of the health promoting characteristics. Functional foods plays the role of prevention because of the ability to reduce those factors that compromise good health (Shibamoto, Kanazawa, Shahidi, 2008).Green tea catechin has been incorporated into various foods including, bread, cakes biscuits, yoghurts meat pastries etc. (Anandharamakrishnan, 2014; Yilmaz, 2006) However, green tea catechins polyphenols have been reported to be susceptible to degradation/ epimerization at certain temperature and pH of the environment which reduce the efficacy of the polyphenols (Lun, Kwok, Huang, Chen, 2003; Peters, Green, Janle, Ferruzzi, 2010) Green tea polyphenols are astringent, bitter and acrid in taste which sometimes poses problem of acceptability by the consumer (Narukawa et al. 2011) The therapeutic value of green tea presents an opportunity to positively affect the outcome of risk of disease globally. However, reports showed that the daily consumption of tea beverage and bioavailability of native catechin monomers is less than 2% (Henning et al. 2004; Henning, choo, 2008) Effective administration of tea catechin polyphenols in the body may require the use of appropriate vehicles to achieve the required dose. Moreover, it is not certain if individual can consume sufficient quantity of tea infusion that will provide the anticipated health benefits in the conventional traditional beverage. It is reported that a health conscious consumer may need to drink 10 cups (2000mL) of green tea in Japan to maintain good health. If 200mL contains 100mg of tea catechin, therefore 10 cups of tea is equivalent to 1g of tea catechins (Hara, 2011) If we then go by the Japanese recommendation the volumes of tea drinks appears too much. The burdens of consumption of high water can be reduced by simply turning the liquid into powder and then incorporate into other foods which appear to be the current trend in the