When luting indirect restorations with dual-cure resin cement (DCRC), excess cement can be easily removed by performing tack cure of DCRC for a few seconds. The purpose of this study was to evaluate whether different tack cure times affect polymerization shrinkage (PS) of the selected DCRC. One dual-cure resin cement (G-CEM LinkAce, GC) was used for measuring PS in light-cure (LC group), self-cure (SC group), and two tack-cure modes. In the first tack-cure subgroup, tack cure was performed for 1, 2, 3, and 5 seconds, followed by light cure after 2 minutes of remnant removal time in each case (TC-LC groups). In the other tack-cure subgroup, tack cure was performed for the same lengths of time, but followed by self-cure in each case (TC-SC groups). PS was measured by a modified bonded disc method for 1,800 seconds. One-way analysis of variance followed by Duncan’s post hoc test was used to determine any statistically significant differences among the test groups (α = 0.05). When the DCRC was selfcured after tack cure, PS was significantly lower than when it was only self-cured (p < 0.05); however, tack cure time did not affect PS (p > 0.05). When the DCRC was light-cured, PS was not affected by tack cure or tack cure time (p > 0.05). Therefore, tack cure within 5 seconds did not negatively affect the final PS when the DCRC was light-cured after cement remnant removal.

This study evaluated the physicochemical and microbial quality characteristic of seasonal commercial kimchi for hygienic safety levels. The pH of seasonal commercial kimchi was 3.84-6.36 and the titratable acidity and salinity of the samples were 0.21-1.16 and 1.19-1.54%, respectively. The content of nitrate and nitrite in the commercial kimchi were lower in the spring and summer, which was affected by acidic condition of the kimchi depending on fermentation. Heavy metal contents in commercial kimchi are not an issue because they were detected only at very low levels. The total aerobic bacteria and coliforms counts ranged from 5.25 to 8.44 Log CFU/g and 0.00 to 5.08 Log CFU/g, respectively. The total aerobic bacteria and coliforms were detected more in summer than in the other seasons. E. coli was detected in three of the samples tested. Food-borne pathogens were not detected in any of the samples except for B. cereus. B. cereus was detected in the fall in more than 70% of samples. These results suggest that commercial kimchi distributed in the fall maintain the quality properties and the microbiological safety of kimchi compared to the other seasons. Therefore, further studies as an effective distribution system for the particular seasons will be needed to guarantee the hygienic safety levels of commercial kimchi required by the consumers.

In this study, we established the pre-treatment conditions that could increase the γ-aminobutyric acid (GABA) content during barley germination. In the process, three different barley samples were prepared, which differed in the pre-treatedment processes. The specimens were stored at 50 for 1 h after being kept in water at room temperature for 4 h (HKW sample), kept in sufficient water for 4 h (KW sample), or left untreated (CO sample). After the pre-treatment, the barely samples were germinated for 35 h. A sample was taken from each batch in 5-h intervals, extracted with water, and physicochemical characteristics and radical scavenging activity were measured. As a result, we found that the contents of phenolic compounds (18.02-30.63 mg/100 g) and flavonoids (1.87-4.63 mg/100 g) were higher in HKW, showing similar trends. Also the GABA contents in the HKW and KW samples were higher than that in the CO sample. Furthermore, the radical scavenging activities of DPPH and ABTS were the highest in the HKW sample, having values in the ranges of 58.49-77.40% and 54.57-88.10%, respectively. All in all, we found that in order to increase the antioxidative activity and GABA content of the barley samples, it would be suitable to pre-treatment the specimens after the post-immersion heat treatment. In addition, pre-treating the KW samples is appropriate only after immersion time. Lastly, the optimum germination time of the batches was found to be 20-25 h.