This thesis studied quantity and appropriate ratio of konjac, carrageenan, xanthan gum and alkaline agent with quantity of acid, type and quantity of sugar were used in jelly making. The first study used concentration of konjac solution 2, 3, 4 and 5 % (w/v) with alkaline agent 1.5, 2.5 and 3.5 % (w/v). The results showed 2 % (w/v) of konjac solution with alkaline agent 3.5 % (w/v) could set jelly but had off-odor and darken color. The second varied ratio of konjac with carrageenan into 50:50, 60:40 and 70:30. Beside this varied konjac with xanthan gum into ratio of 60:40 and 70:30. The both were varied quantity of mixed konjac 3 levels (2, 3 and 4 % (w/w)). The jelly that used konjac with carrageenan and konjac with xanthan gum at 60:40 in 3 % (w/w) had good texture and sensory evaluation scores nearly ideal. The third varied quantity of citric acid 4 levels (0, 0.3, 0.5 and 0.7 % (w/w)) and 2 types of sugar (sucrose and fructose) with 4 levels (15, 20, 25 and 30 % (w/w)). Jelly with konjac-carrageenan 60:40 at 3 % (w/w) added 30 % (w/w) fructose and 0.3 % (w/w) citric acid made the best jelly. In addition to 60:40 of konjac-xanthan gum 3 % (w/w) in jelly product with 30 % (w/w) sucrose no acid made the best jelly. Brought the best jelly to study with roselle, carrot and guava juice. The experimental showed that konjac-carrageenan jelly with guava juice had the highest scores in sensory evaluation (p≤0.05). The results of storage test showed jelly could stored 1 week at room temperature and more than 4 weeks at 4 ℃. Sensory evaluation were not significant (p>0.05) and consumers were acceptable when storaged at 4 weeks.
