. This research aimed to study the acidification processes of carving vegetable using acid conditioning machine under emperature and pressure control which was developed in this study. Four acidification procedures were done at normal atmospheric pressure (method 1) under vacuum pressure for 10 (method 2) and 20 min (method 3) and vacuum pressure alternating with normal atmospheric pressure for each of 1 hour. There were two main parts of acid conditioning machine including the temperature controller inside the pickle tank and heat conductor tank and the pressure controller inside the pickle tank. The pickling temperature was stabled at 40oC under the pressure of 0.5 Bar. PLC (Programmable Logic Controller) program was used to write the ladder for controlling all processes and display through SCADA system. The results showed that the acidification method by soaking the carved-rose carrot under vacuum pressure alternating with normal atmospheric pressure showed the shortest time to equilibrium by 7 hours. Then the carved-rose carrot was packed in the glass jar followed by sterilized in boiling water for 15 minutes and stored at room temperature for 7 days. Total bacteria count Escherichia coli and Yeast-mold were not exceeded than the standard limit. Staphylococcus aureus was not detected throughout the storage periods

Using of ethylenediaminetetraacetic acid (EDTA) and synthetic surfactant increase the chemical contamination in water. The co-phytotoxicity of EDTA (0-20 mg/l) and 3 synthetic surfactants; Triton X-100 (0-10xCMC) Tween 80 (0-10xCMC) and sodium dodecyl sulfate (SDS) (0-2 x CMC) on the growth of 2 duckweeds spirodela polyrrhiza and Lemma perpusilla were studied for 3 days. The results showed that the surfactant were phytotoxic on the growth of both plants while EDTA was not. SDS was the most toxic to plant especially on all chlorophyll content. Triton X-100 was only toxic to the growth of L. perpusilla and weight of S. polyrrhiza. Tween 80 was less or the least toxic to both plants. This surfactant only decreased chlorophyll a and total chlorophyll content of S.polyrrhiza and L. perpusilla. There was not any interaction between EDTA and surfactant on most toxicity tests. With these results synthetic surfactant contamination should be more concerned than co-contamination with EDTA.

The objective of this research was to find the suitable processes of carved-vegetables which packed in hermetically sealed container. Two vegetables were composed of carrot and pumpkin. There were carved into rose or leaf shape. An optimum ratio of 2 recipes of pickle solution were studied. The first one was a recipe which acidified with lactic acid (acidified-recipe) to pH <4.6. Another one was a recipe supplemented with preservative (preservative-added recipe). The results showed that an optimum ratio for acidified-recipe was composed of 7.23% vinegar 64.81% water 0.81% salt 27.00% sugar and 0.15% lactic acid which showed the final pH was 3.27. For preservative-added recipe an optimum ratio was composed of 27.03% vinegar 27.03% water 0.9% salt 45.05% sugar and 200 ppm sodium metabisulfite which showed the final pH was 3.39. Carrot pumpkin green papaya and cucumber were sanitized in peroxyacetic acid (80 mg/L 3 min). Radish was dipped in tap water for 3 min. Then all carved-vegetables were immersed in calcium chloride solution (0.5% 2 min) before preserved in acidified-recipe solution in plastic box with a lid and then stored at room temperature for 4 days. Equilibrium time pH and °Brix were studied. The results showed that pH and °Brix were decrease during 4 days storage and showed obviously tended to equilibrium. However carved-radish and cucumber were spoiled by microorganisms as a film on the surface of pickle solution and gas bubble was occurred inside a container on 4 days of the storage. Hence three carved-vegetables including carrot pumpkin and radish were used in the next experiment which preserved in preservative-added recipe. Treatment was compared with the same recipe without preservative as the control. All types of carved-vegetables had an equilibrium time for 7 days. Three parts of samples e.g. pickle solution carved-vegetables and mixed-sample showed pH lower than 4.6 and °Brix were gradually decreased during the storage. Shelf-life of all carved-vegetables stored in hermetically sealed container was up to 7 days. Total bacteria count E. coli yeast-mold were not exceeded than the standard limited by Ministry of Public Health and Staphylococcus aureus was not detected throughout 7 days of the storage.

This research work was to study the toughening modification of polylactic acid by the mixing with epoxidized natural rubber (ENR) and the increase of effectiveness of mechanical properties with a compatibilizer. Enhancement of properties in polylactic acid was evaluated by tensile and impact testings Fourier-transform Infrared Spectroscopy (FTIR) technique Differential Scanning Calorimetry (DSC) technique and Scanning Electron Microscope (SEM). For the addition of ENR it was revealed that the increase of ENR contents improved elongation at break and impact strength but decreased tensile modulus and ultimate tensile strength. Glass transition temperature (Tg) percentage crystallinity and the melting point of polylactic acid tended to decrease with the addition of ENR. Chemical change was found that position of C=O peak in polymer blend was slightly shifted as compared to the spectrum of neat polylactic acid. The optimum formulation for toughening modification was ENR content of 30 wt%. Its impact strength was 1982.55 % of neat polylactic acid. For increasing effectiveness of mechanical properties with a compatibilizer it revealed that the addition of Joncryl ® ADR-4300 as compatibilizer improved both tensile and impact properties. The optimum loading of a compatibilizer for improving mechanical properties was 0.5 wt% of polylactic acid. The decreases of crystallinity and melting point of polylactic acid with adding Joncryl ® ADR-4300 might be because Joncryl ® ADR-4300 was also chain extender of polylactic acid and it might be obstructing crystallization. The presence of Joncryl ® ADR-4300 unaffected on Tg value and chemical change.

This research work was to study the improvement of toughness of polylactic acid (PLA) and the cost reduction of raw material with addition of untreated and treated oil palm fiber (OPF). The detail of this work was divided into two parts. The first was to find the suitable condition for surface treatment of OPF with sodium hydroxide (NaOH). The second part was to study the effect of untreated and treated OPF contents on the mechanical properties of PLA. For surface treatment of OPF NaOH concentrations and immersion times were varied from 0 to 15 wt% and 0 to 30 min respectively. Aspect ratio (L/D) and surface of untreated and treated OPF were investigated by using optical microscope and scanning electron microscope (SEM) respectively. The result suggested that the most suitable condition for surface treatment of OPF was NaOH concentration of 10 wt% at immersion time of 20 min. Treated OPF was occurred microporous and had more rough as compare to untreated fiber. For the effect of untreated and treated OPF contents on the mechanical properties of PLA it was evaluated by tensile and impact testing. SEM was used for investigation of interfacial adhesion and fiber dispersion. The results showed that tensile modulus and impact strength tend to increase with adding 2.5 wt% OPF content and slightly changed at higher OPF content whereas ultimate tensile strength and elongation at break decreased with increasing fiber content. Surface treatment with NaOH led to enhancement of mechanical properties of composite due to improve interfacial adhesion and fiber dispersion.