Recently, the incidence and magnitude of earthquakes have been continuously increasing. NFPA 13 requires that hydroponics fire extinguishing system pipelines apply seismic isolation. Stainless steel joints have been newly developed to replace these seismic isolation joints. Therefore, in this study, a nonlinear finite element model of a pipeline with Stainless Power Joint was developed based on experimental data, and finite element analysis was performed by applying hydrostatic pressure and cyclic loading.

The curved beam has a complicated behavior compared to a straight beam due to torsional and warping. Therefor, in this study, eigenvalue analysis was performed for curved beam with different shape(I-shape, T-shape, box-shape) corresponding to the same value of the moment of inertia. As a result the curved beam with box-shape section had a larger natural frequency value than the other curved beam. Also, the dynamic analysis results showed that the largest result was obtained at 826.18MPa in the T-shape curved beam when the gyeongju earthquake was applied.

A method was established for the simultaneous determinatioin of sugar alcohols, erythritol, xylitol,sorbitol, inositol, mannitol, maltitiol, lactitol and isomalt by High Performance Liquid Chromatography (HPLC). The sugar alcohols were converted into strong ultraviolet (UV)-absorbing derivatives with p-nitrobenzoyl chloride (PNBC). HPLC was performed on Imtakt Unison US-C18 column, using acetonitrile : water (77:23) as a mobile phase and UV detection (260 nm). The calibration curves for all sugar alcohols tested were linear in the 10~200 mg/L range. The average recoveries of the sugar alcohols from three confectioneries spiked at 100 ppm of eight sugar alcohol standards ranged from 81.2 to 123.1% with relative standard deviations ranging fromo 0.2 to 4.9%. The limits of detection (LODs) were 0.5~8 μg/L and the limits of quantification (LOQs) were 2~17 μg/L. Reproducibility of 8 sugar alcohols was 0.28~1.97 %RSD. The results of the analysis of confectioneries showed that 89 samples of 130 were detected and the sugar alcohols content of samples investigated varied between 0.4 and 693.7 g/kg. A method for the simultaneous determination of eight sugar alcohols will be used as basic data for control of sugar alcohols in confectioneries, and qualilty control in food manufacturing.

산화방지제인 아스코르빈산(AA), 에리쏘르빈산(isoAA), 아스코르빌파르미테이트(AP), 아스코르빌스테아레이트(AS)에 대한 ‘식품 중 식품첨가물 분석법’을 검증하고 미비점을 개선하였다. 고속액체크로마토그래피 자외선검출기법을 이용하여 검출한계(LOD), 정량한계(LOQ), 상관계수(R2) 등을 측정하였고 돼지기름(lard), 사이다를 이용한 모델식품에서의 회수율과 재현성을 측정하였다. AA와 isoAA의 검출한계는 각각 0.46, 0.48 μg/mL이었으며, 회수율은 각각 86.35-94.78, 84.76-95.02%를 나타내었고 상관계수는 모두 0.999이상을 보였다. AP와 AS의 현 분석법은 메탄올을 용매로 사용하지만 메탄올 용매에서 AP와 AS는 불안정하였다. 냉장온도에서 에탄올을 용매로 사용 시 다른 용매에 비해 유의적으로 높은 안정성을 나타내어 기존 용매의 불안정성을 개선할 수 있었다.

The bactericidal efficacy of three common sanitizers (100 or 200 ppm of sodium hypochlorite, 100or 200 ppm of n-alkyl(C12-C18)benzyldimethyl chloride, and 50 or 100 ppm of peroxyacetic acid) against Escherichia coli ATCC 10536 and Staphylococcus aureus ATCC 6538 was studied using the suspension test method at various exposure temperatures (4~40℃) and times(1~60min) under both dirty and clean conditions, respectively. During the suspension tests, sodium hypochlorite (200 ppm) showed higher bactericidal activity than the other sanitizers under clean conditions, with 5 log reductions against E. coli as well as S. aureus in the first 1 min of treatments at 4℃. However,the efficacy of sodium hypochlorite decreased markedly under dirty conditions due to its susceptibility to interfering substances. The efficacy of the n-alkyl(C12-C18)benzyldimethyl chloride increased considerable as the exposure temperature and time increased. The bactericidal efficacy of the n-alkyl(C12-C18)benzyldimethyl chloride might be less effective on low temperature, however, the longer time the sanitizer is in contact, the more effective the sanitization effect. Treatment with peroxyacetic acid (100 ppm) showed at least 5 log reduction against E. coli and S. aureus for 5min at 4℃ under both clean and dirty conditions. The efficacy of the peroxyacetic acid was not much altered by interfering substances and affected by changes in temperature or time.

This study was conducted to establish a method to analyze azodicarbonamide (ADA) in wheat flour. A new method using high performance liquid chromatography (HPLC) was developed for the determination of ADA in wheat flour. The recovery rate was 91.93~97.54%. The limit of detection for ADA was 0.02 mg/kg and the limit of quantification was 0.05 mg/kg. The monitoring results for ADA contents using the established methods showed that it was detected as the low value of 0.95 mg/kg in one of 51 flour samples (detection rate : 2%), but not detected in 59 bakery samples. The detected ADA level was suitable to its usage standard, compared to the standard (45 mg/kg). Although the detection rate was very low, the established analytical method of ADA will contribute to the management of ADA in processed foods such as wheat flour and bakery.

국내에서 유통되는 식용 타르색소 9종에 대하여 한국, 일본, 미국 및 JECFA의 색소시험법에 따라 비교·시험하였다. 식용색소의 물불용물 함량은 각 기관의 시험법에서 차이가 없었으며, 모두 규격기준에 적합하였다. 식용색소 녹색제3호, 적색제3호, 청색제2호 및 황색제4호의 염화물 및 황산염 함량은 각 기관의 방법에 따라 약간 달랐지만 모두 규격기준에 적합하였고, JECFA와 미국방법에서는 분석하는데 시간이 더 많이 소용되었다. 비소 함량은 한국과 일본에서 비색법으로 비교하였으며, 규격기준이 미국 및 JECFA와 달랐다. 중금속 함량은 모두 규격기준에 적합하였으나 한국은 비색법, 일본은 원자흡광도법, 미국과 JECFA는 두가지 방법을 모두 사용하였다. 비술폰화방향족제1급 아민의 함량은 분석시료 모두 0.0005%(aniline으로서)이하로서 규격기준(0.01%이하)에 모두 적합하였다.

국내에서 유통되는 식용 타르색소 9종에 대하여 한국, 일본, 미국 및 JECFA의 색소시험법에 따라 비교·시험하였다. 식용색소의 물불용물 함량은 각 기관의 시험법에서 차이가 없었으며,모두 규격기준에 적합하였다. 식용색소 녹색제3호, 적색제3호, 청색제2호 및 황색제4호의 염화물 및 황산염 함량은 각 기관의 방법에 따라 약간 달랐지만 모두 규격기준에 적합하였고, JECFA와 미국방법에서는 분석하는데 시간이 더 많이 소요되었다. 비소 함량은 한국과 일본에서 비색법으로 비교하였으며, 규격기준이 미국 및 JECFA와 달랐다. 중금속 함량은 모두 규격기준에 적합하였으나 한국은 비색법 , 일본은 원자흡광도법, 미국과 JECFA는 두 가지 방법을 모두 사용하였다. 비술폰화방향족제 1급아민의 함량은 분석시료 모두 0.0005%(aniline으로서)이하로서 규격기준(0.01%이하)에 모두 적합하였다.

보존료인 소르빈산 및 소르빈산칼륨, 안식향산 및 그 염류, 파라옥시안식향산에스테르류를 중심으로 식품첨가물의 일일추정섭취량을 평가하는 새로운 방법으로서 설문조사법을 제시하여 일일추정섭취량을 구하였을 때 조사한 보존료 모두 일일섭취허용량(ADI)의 1%미만으로 매우 안전한 수준이였다. 기존에 수행된 최대허용량을 이용한 단순추정방법 및 실제 분석치를 이용한 정밀추정방법과 비교·평가하였을 때, 설문조사법에 의한 총 일일추정섭취량은 소르빈산염류의 경우 0.39 ㎎/㎏ bw/day로 실제 분석치를 이용한 정밀조사방법에 의한 값인 0.22㎎/㎏ bw/day보다 높았으나 최대허용량을 이용한 방법에 의한 값인 1.39 ㎎/㎏ bw/day보다는 훨씬 낮았다. 또한 안식향산염류와 파라옥시안식향산에스테르의 경우도 설문조사가 0.29㎎/㎏ bw/day, 0.03㎎/㎏ bw/day으로 정밀추정방법보다는 높게 나타났으나 단순추정방법인 최대허용량을 이용한 방법보다는 훨씬 낮은 값으로 정밀추정방법에 의한 값에 가까운 결과를 보였다. 따라서 설문조사법을 간편하고 경제적이면서 섭취량을 정밀하게 추정할 수 있는 식품첨가물 섭취량 평가의 방법으로 활용할 수 있을 것으로 사료된다.

A study has been performed to estimate the average and high (90th percentile of consumers-only) daily intakes of sorbates by age-sex groups (＞ 3 years old) in Korea. The estimation of daily intakes was based on individual-based dietary intake data in `National Health and Nutrition Survey in 1998' and the contents of sorbates from samples. The estimated daily intakes (EDI) of sorbates for average consumers ranged from 0.09 mg/kg bw/day to 0.51 mg/kg bw/day corresponding to 0.4-2.1% of acceptable daily intake (ADI). For high consumers, the range of EDI of sorbates was 3.42-14.65 mg/kg bw/day corresponding to 13.7-58.6% of ADI. Foods that contributed most to the daily intakes of sorbates for all age-sex groups were processed fish products, processed meat products, and salted foods. There was an inverse relationship between age and the consumption of sorbates for average and high consumers, whereas no marked pattern was emerged by sex categories. The intake levels of sorbates even among high consumers were below the ADI in Korea.