Single process for sequential extraction of products from green tea leaves

An integrated process for sequentially extracting products from green tea leaves, the integrated process comprising:

• (a) providing green tea leaves obtained from Camellia sinensis;
• (b) dipping the green tea leaves in an alkane solvent for 2 hours to 3 hours at room temperature to obtain a solution;
• (c) filtering the solution of (b) to obtain a filtrate and residual leaves;
• (d) drying the filtrate of (c) to obtain a wax as a first product;
• (e) dipping the residual leaves of (c) in alcohol followed by heating at 30° C. to 42° C. for 1 hour to 2 hours to obtain a green-colored solution and leftover leaves;
• (f) drying the green-colored solution of (e) to obtain a coloring pigment as a second product;
• (g) drying the leftover leaves of (e) followed by hydroextraction in a ratio 1:10 at 60° C. for 30 minutes to obtain a first extract and residual spent leaves;
• (h) purifying the first extract of (g) by micro filtration with a 0.1-micron to 0.5-micron pore size to obtain a purified first extract;
• (i) passing the purified first extract of (h) through a polystyrene adsorbent Resin-A or through a Resin-C;
• (j) eluting the purified first extract of (h) with alcohol to obtain a brown-colored catechin powder as a third product;
• (k) hydroextracting the residual spent leaves of (g) with sodium carbonate at 100° C. for 1 hour to obtain a second extract;
• and
• (l) cooling the second extract of (k) and recovering caffeine as a fourth product by liquid-liquid extraction of the second extract with dichloromethane solvent.