The purpose of this study was to identify the ideal storage period for frozen minced beef products and to under-stand key factors affecting their quality. Frozen minced beef products with 10 and 15% of fat content were kept at ?5, ?15, and ?23°C, and over a 6-month period, they were assessed for moisture content (MC), peroxide values (POV), acid values (AV), 2-thiobarbituric acid (TBA) value, total volatile basic nitrogen content (TVB-N), and the sensory test in order to identify the effect on quality. This helped to determine their appropriate storage duration at a given temperature. Multiple regression analysis was used to assess the correlations between storage tempera-ture, fat meat percentage, characteristic factors, and overall acceptance (OA). Five months for ?23°C, 4 months for ?15°C, and 2 months for ?5°C met 3.7 points or more of OA, in accordance with global sensory analysis stan-dards, and were determined as acceptable frozen storage durations. The very high multiple regression analysis R2 (0.97–0.99) verified the correlation between the characteristic factors and OA. In addition, TVB-N, MC, and POV, respectively, were the main quality factors affecting OA at ?5, ?15, and ?23°C (R2 > 0.8). These findings may prove useful and practical for manufacturers to improve storage and distribution practices in maintaining the quality of frozen minced beef products.

In this study, the reclaimed polypropylene (RPP) and waste ground rubber tire (WGRT) were used to simulate the thermoplastic vulcanizate (TPV) for cost reduction and resources recycling. Also, we examined the effects of dicumyl peroxide (DCP) and 2,5-dimethyl-2,5-di-(tert-butylperoxy)-hexane (DTBPH) as peroxide type cross-linking agents to enhance the properties of TPV's. The components of RPP and WGRT were fixed at 30 and 70 wt%, and DCP and DTBPH were added in the concentrations from 0.5 to 1.5 phr, respectively. RPP/WGRT composites with different contents of DCP and DTBPH were prepared by a modular intermeshing co-rotating twin screw extruder. The Young's modulus of composites were decreased with increasing peroxides contents. On the other hand, tensile strength, elongation at break, and impact strength of the composites were increased with peroxide contents. We also confirmed that interfacial adhesion between RPP and WGRT was considerably improved by adding the peroxides. Taken together, DTBPH added RPP/WGRT composites exhibited better mechanical properties rather than those of DCP added composites.

The aim of this study is to develop new materials with antimicrobial effect and flame-retardant properties. PVC/IB/ATH, a PVC composite material containing inorganic bacteriocide (IB) with silver and zinc in the zeolite pores, and aluminum trihydroxide (ATH), an environmentally friendly inorganic flame-retardant, was prepared. The antimicrobial effect of PVC/IB/ATH composite material was confirmed to be 99% as a result of turbidity analysis, shaking culture, drop-test, and double staining test using two kinds of bacteria. The flame-retardant properties of PVC/IB/ATH composites were investigated by limiting oxygen concentration index and thermogravimetric analysis, and they were increased depending on the aluminum content of ATH and IB agent. Also, the thermal properties of PVC/IB/ATH composites were slightly increased. In conclusion, the application of PVC/IB/ATH is expected in various fields such as medical industry, antibacterial system and flame-retardant materials.

Polyvinyl chloride (PVC) has been used as a general-purpose polymer because of its lower cost, good durability and mechanical properties compared to other materials. However, PVC is vulnerable to heat deformation and generates a toxic gas like hydrogen chloride. Therefore, it is important to delay or prevent the flame retardancy and thermal degradation of the PVC during the processing. It was reported that aluminum trihydroxide (ATH) improved flame retardancy as well as smoke inhibition of the virgin polymer. In this study, PVC composites by addition of ATH were compounded in a modular intermeshing co-rotating twin screw extruder. The PVC composites with different concentrations of ATH (0~5 phr) were analyzed. Flame retardancy of the PVC composite significantly increased depending on the ATH concentration. LOI of the composite also increased with the concentration of ATH. There were no significant differences for the thermal properties of the PVC composites with ATH.