A combined treatment of high-pressure carbon dioxide (HPCD) and high hydrostatic pressure (HHP) was investigated as a non-thermal processing technique to enhance the safety and shelf life of carrot juice. Aerobes were completely inactivated by a combined treatment of 4.90 MPa-HPCD and 300 MPa-HHP. A combined treatment of 4.90 MPa-HPCD and 600 MPa-HHP effectively inactivated enzymes. The residual activities of polyphenoloxidase, lipoxygenase, and pectinmethylesterase were less than 11.3%, 8.8%, and 35.1%, respectively. Cloud and color were considerably affected by HPCD, but not by HHP. Enzyme activities and the total color difference showed a strong correlation with pH, which was dependent on the pressure of carbon dioxide.

To improve the storage stability and achieve controlled release, fish oil containing docosahexaenoic acid was encapsulated using double emulsification and subsequent enzymatic gelation method, using microbial transglutaminase cross-linked proteins. Isolated soy protein was selected as a wall material because it showed better emulsion stability and higher reactivity with MTGase than other proteins. Microcapsules prepared by this method showed a high stability against oxygen and a low water solubility, which subsequently resulted in sustained release of fish oil. Results indicate that this microencapsulation process is suitable for preparing protein-based microcapsules containing sensitive ingredients for controlled release and stability improvement.

This study was performed to investigate the effects of the combined treatment of high pressure and heat on the quality of carrot juice, and to optimize the process condition. About 95% of food quality-related enzymes were lost at 400 MPa and 70 Њ Њ Њ Њ ЊC, for 10 min, while ␣ ␣ ␣ ␣ ␣-and ␤ ␤ ␤ ␤ ␤-carotene were relatively stable at the combined process. The optimum process condition was estimated at 395 to 445 MPa, 70 Њ Њ Њ Њ ЊC, for 8 to 11 min. These results indicate that the combined treatment of high pressure and mild heat could be used as an effective process for production of highquality carrot juice.

The multiple emulsion/cold dehydration method was developed for the flavor encapsulation. The effects of various process parameters on the emulsion stability and flavor retention were investigated. Microfluidizer (at 68 MPa) produced more stable emulsion with small uniform droplets than pressure-homogenizer. Increasing the gum arabic content created a highly viscous emulsion, which resulted in a stable O/W emulsion. The stability of an O/W/O multiple emulsion was highly affected by the type of emulsifiers and the most stable emulsion was prepared using the blend of Span 80 and PGPR. Well-formed microcapsules having high flavor retention (71%) was obtained when ethanol/water mixture solution of 9:1 was used as a dehydrating agent.

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Double encapsulation of single-encapsulated powder containing flavor compounds was performed by a fat coating process using molten hydrogenated palm kernel oil (melting point = 47.3°C). Double-encapsulated powder showed a 47% increase in mean particle size and a 33% reduction in moisture uptake. Single-encapsulated powder exhibited rapid limonene oxidation throughout the storage time, while double-encapsulated powder was consistently stable. SEM images of the double-encapsulated powder showed singular or aggregated particles covered with a continuous fat matrix. Thermally controlled release from the double-encapsulated powder was observed. Flavor release from the double-encapsulated powder ranged from 36.6% to 57.8% at 37°C, with an increase to 81.3 to 95.0% at 60°C.

Abstract.A novel method of polymer/low-melting-point metal alloy (LMA)/light metal fiber composite fabrication is proposed to solve problems of polymer/metal composites. The first step is mixing light metal particles with LMA at a temperature above the melting point of the LMA. The second step is cold extrusion of the LMA/light metal particles to fabricate LMA/light metal fibers. Thus, the LMA/light metal fibers with a density of ~4.5 g/cm 3 were obtained. The last step is compounding a polymer with the LMA/light metal fibers at the processing temperature of the polymer above the melting points of the LMA. The effects of the length and the cross-sectional shape of light metal fiber on the morphology of the LMA/light metal fibers in the polymer matrix were studied, as were electrical conductivities and mechanical properties of the composites. As the length and/or the cross-sectional aspect ratio of the fibers was increased, the domains of LMA/light metal fibers formed more networks so that the electrical conductivity increased, and specific surface area of the domains increased so that notched Izod impact strength was improved. Thus, the polymer/LMA/light metal fiber composites were fabricated without degrading processability even at 60 vol% loading and the electrical conductivities over 10 3 S/cm were achieved.

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