This research aimed to study the production of a biodegradable film from Jicama starch (Pachyrhizus erosus (L.) Urbar) for plant bag application. The film was prepared by dissolving Jicama starch in water to the concentration of 5 wt%. To study the effect of the glycerol content the glycerol was added at 6 levels; 0 10 20 30 40 50 and 60 wt%. The film was casted in a molded and dried at 60 oC for 24 h. After drying properties of films; thickness water activity (aw) solubility tensile strength (TS) elongation (%E) puncture strength and the degradation of the films were evaluated. The thickness of the films was in the range of 0.16-0.28 mm. The aw of films ranged from 0.36-0.49. The water vapor permeability water solubility and flexibility of the film increased with the increasing of glycerol content. Tensile and puncture strength of the starch films tended to increased when the glycerol content decrease. After the films were buried under the ground (8-10 cm depth) for 12 weeks they were degraded by 100%. The Jicama starch film with 40 wt% glycerol showed the best overall properties.

The objectives of this research were to prepare the syrup from the extracted yam bean and apply this syrup for adjusting the sweetness in the orange flavor drinking yogurt. The study made a yam bean extract concentrated by 3 difference heating methods; steaming boiling and boiled-evaporating. The results showed that a proper method was boiling yam bean extracted at a temperature of 90°C for one hour. The syrup was light brown color and not very strong smell of yam bean the total soluble solid was 20 °Brix and the non-reducing sugar content was 17.80 %. The drinking yogurt which was formulated using a ratio of set yogurt: orange juice (100%): yam bean syrup at 1:1:1 had the sensory properties (9-Point Hedonic Scale) higher than the ratio of 1:1:0.5 and 1:1:1.5 (p≤0.05). This drinking yogurt had a pH at 4.2 the total soluble solid was 15 °Brix protein was 1.75 % fat was 2.1% and non-reducing sugar content was 5.39 %. The microbiological properties passed quality standards (drinking yogurt) of Notification of the Ministry of Public Health No. 353 B.E 2556. The study of consumer acceptance on the drinking yoghurt with yam bean syrup showed that consumers had a preference for the product at like - most like level at 72 % acceptance on the product at 97 % and would buy this product at 76 %.