Thesis (M.Sc.) - Asian Institute of Technology, 1993

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science.

Tamarind is a well known tropical fruit produced through out Thailand. Since it has a good potential market especiall for export, develop in gproducts from this fruit, e.g . t a marin d concentrate is the refore valuable. Processing parameters of t amarind concentrate , i. e . fruit to di sso lv in g· wa t er r ati o, wa t er t e mp e r a tur e , paddle speed, padd le c h aracter is t ic and screen size of the pulper - fin i sher on q u a lit y of tamar in d p ur ee were eva l uated. The 1 :1 fr ui t t o water r at io gave l owes t puree y i eld but high est to t al solids compared to 1: 1.5 a nd 1: 2 ratio . Hig h e r water tem p erat u re prov id e a hi g h er total sol id s in t h e pur ee . A paddle clearan ce of 10 mm a nd hi g h e r water temperat u re r es ult ed in decr ease d p ur ee an d so lid s yie l d. Pa ddl e speed did not a ff ect particle size of p ur ee w hile sc r ee n size di d. Ad ju st in g a pa ddle cleara n ce to 3 mm and u s in g· a modified padd le with a brush impr ove d pu r ee and soli ds y ield. W' ith a paddle cl earance of 3 mm, t h e op timum speed was 500 r pm while those from a paddle wit h a bru s h was 7 00 rpm. Enzy me treat e d tamarind puree a t diff erent dosag es held for 10 h ours at diff e r e nt ho ldi ng t e mperatu r es we r e s tudied for juice y ie ld. A 0.8 % pec ti c e nzym e tr ea t e d pure e h eld at 35 °C for 4 to 10 h ours was found to g i ve max imum jui ce yield of about 70 .5 %. Evapora tion of enzy me treated clarif i ed tamarind juice was done at te mp e r a tur es of 40, 50 a nd 60 °C und er a pressu r e of 20 mbar and co mp ared to un t r ea t e d jui ce a t an evapora ti ng t empe r at ur e of 40 °C . Enzyme treatm ent reduced co n s ist e n cy an d evaporat in g tim e of cla r ified tamar in d concentrate b y abo ut 12 a nd 1.3 t im es of t h e untr ea t ed sa mp le r espect i ve l y. The fl avor of all sa mpl es were not s ig nifica ntl y diff e r ent and was acceptable by tas t e rs . Un.cl ar if ied tamarind concentra t es were prepared from enzyme treated and untr eated puree, 5 a nd 10 % pulp was a l so added to e n zy me treated unclarified t amar i nd co nc e ntr ate . The samp l es had total solub le soli d s of abo u t 45.0 ° Br ix a nd a p H of 1.92. The fla vo r of a ll sa mp l es were accep t ab l e by panel te s ting.