There are two primary sludge drying methods such as the direct heating microwave method and the indirect heating steam one. In this study, the drying treatment facility at sewage treatment plant A applied both of these drying methods. The research aimed to investigate the optimal operation approach for the drying facility, considering the input sludge and the moisture content data after the drying process. Moisture content and removal rate data were executed at the research facility from January 2016 to December 2018. First, the microwave, a direct heating drying method, performed intensive drying only on the outer surface of the sludge by directly applying heat to the sludge using far infrared rays, so effective sludge drying was not achieved. On the other hand, the steam method of the indirect heating method used steam from a gas boiler to maximize the utilization of the heat transfer area and reduce energy of the dryer, resulting in an effective sludge drying efficiency. The sludge moisture content brought into the sludge drying facility was about 80%, but the moisture content of the sludge that went through the drying facility was less than 10% of the design standard. Therefore, the steam method of the indirect heating method is more effective than the microwave method of the previous direct heating method and is more effective for maintenance It has proven that it is an efficient method of operating construction facilities.

The aim of this study was to compare the antioxidant activities and functional contents of Korean conventional and Chinese seed gingers from the Jeollabuk-do Wanju and Chungcheongnam-do Seosan regions. Ginger samples were subjected to steaming treatments for different durations (2–8 h) at 121oC using an autoclave. The antioxidant activity was evaluated by measuring total polyphenol and flavonoid contents and ABTS and DPPH radical scavenging activities, while functional ingredient contents were analyzed for gingerols and shogaols. The results showed that Wanju conventional seed ginger (WO-2) had the highest total polyphenol (85.24 mg GAE/g) and flavonoid (98.14 RE/100 g) contents, surpassing that of the control in all steamed groups at 6 h. ABTS radical scavenging activity showed a strong correlation with total polyphenol and flavonoid contents. The control groups indicated that Korean conventional seed ginger had 1.0–1.3 times higher gingerol contents compared to Chinese seed ginger. Furthermore, the content of shogaols, considered major functional ingredients, increased significantly with longer steaming durations, reaching the highest content (1,793 mg/kg) at 8 h, which was 1.0–1.8 times higher in Korean conventional seed ginger than that in Chinese seed ginger. These experiments provide valuable data supporting the excellence of Korean conventional seed ginger in the future.

The purpose of this study is to investigate the effect of superheated steam (SHS) treatment on the inactivation of an enzyme involved in the racidity of brown rice as well as the degree of rancidity during storage of brown. Brown rice was treated with SHS at temperatures of 160oC, 200oC, and 240oC, and the result showed that the degree of starch damage was higher in the brown rice treated with SHS at higher temperature. Lipoxygenase was inactivated by treating with SHS for 20 s at 160oC, 15 s at 200oC, or 5 s at 240oC. The acidity and sensory evaluation of the brown rice treated with SHS showed that the acidity was decreased as the SHS treatment increased and SHS temperature became higher. The result of the sensory evaluation showed a similar tendency. These results show that the SHS treatment has potential as a method for improving the brown rice storage quality.

Physicochemical properties of potato chip treated with superheated steam (SHS) at various temperatures (120, 150, 180, and 220oC) and durations (2, 5, 8, and 10 min) were measured to assess the potential application of SHS in the production of unfried chips. A faster drying rate was obtained at a higher SHS temperature due to a lower degree of water condensation on the surface of the potato chip. A higher temperature of SHS resulted in higher volume shrinkage, indicating the dependency of shrinkage on the volume of water loss. SHS treatment did not cause any significant defects in the appearance of potato chips although pillowing and burnt spots were observed on the surface of the sample processed at 220oC for 10 min. Damaged starch content and Rapid Visco Analyzer profiles showed that partial gelatinization occurred during SHS treatment. Potato chips treated with SHS showed the shrinkage of parenchyma cells, resulting to compressed cell layers at the surface and inside. As treatment proceeded, air cells were formed internally. These results suggested that SHS combined with post drying process would be appropriate in the production of unfried potato chips by reducing drying time without causing any deterioration in quality.

The processing properties of spent hen and broiler chicken were investigated before and after treatment to improve texture characteristics. Each treatment consisted steaming (S) with 85℃ for 20 min, Pulsed Electric Field (PEF) with 1.5 KV/cm for 4 sec, and Super Heated Steam (SH) with an oven temp. of 300℃, a steam temp. of 350℃ for 8 min. The yield of spent hen and broiler were 66.85% and 63.80% respectively in the control, but decreased in every treatment was lowest at 61.05% in the PEF treatment (p<0.05). In the color test, L value decreased, but the a and b values increased regardless of the species of spent hen or broiler. In the test of heating loss, the S treatment of spent hen had the highest result of 45.25% but lowest of 30.66% in the SH treatment of the broiler. When it was compared with various treatments, SH after PEF treatment showed the better result in terms of heating loss than the PEF or SH treatment respectively. In the test of texture, the broiler showed the lowest hardness of 5.57 kg in the SH (p<0.05). Otherwise, the spent hen resulted in 14.08 kg of hardness in steaming after PEF, but it improved significantly to 10.73 kg in SH after PEF. In the test of 9 scored sensory evaluation of overall palatability, 7.8 point was the best score with SH treatment in the broiler. The best score in spent hen was 6.3 point which was SH after PEF treatment. With this experiment, SH after PEF was the condition in the treatments to have the better texture of spent hen.

Effects of superheated steam (SHS) temperature (120, 150, 180, 220°C) and time (2, 5, 8, 10 min) on physicochemical properties of garlic chips were examined. Higher the SHS temperature, a faster drying rate was observed due to the lower extent of water condensation on the garlic chip’s surface at the initial stage of treatment. Garlic chips treated at 220°C for 10 min showed the lowest water content and water activity. However appearance of these was inappropriate due to burnt spots on the surface. Scanning electron microscope analysis showed that garlic chips treated at higher SHS temperature showed compressed smooth cell layers at the surface with more compact internal structure due to higher degree of dehydration when compared to chips treated at lower temperature. These results confirmed that SHS could be utilized as an effective drying method for the production of garlic chips. Moreover, it is recommended that SHS treatment combined with other conventional post drying process would result in garlic chips with better quality in terms of color.

Effects of superheated steam (SHS) temperature (120, 150, 180, 220°C) and time (2, 5, 8, 10 min) on product quality attributes of snack-type ginseng chips were studied. Ginseng chips dried at faster rate under a higher SHS temperature. Higher SHS temperature resulted in ginseng chips with lower moisture content and water activity. After SHS treatment, lightness (L values) and redness (a values) of ginseng chips decreased significantly whereas yellowness (b values) of those increased. Although crude saponin content in ginseng chips reduced slightly after SHS treatment, chips treated at 150°C for 5 min had the highest saponin retention among samples. Scanning electron microscope analysis revealed that SHS treatment cause the shrinkage at the surface first, forming compressed cell layers. As treatment proceeded, pores and cavities were formed internally, resulting porous structure. These results suggested that SHS treatment shows great promise in production of snack-type ginseng chips by reducing drying time without any quality deterioratio

과열증기처리한 백미로 제조한 압출스낵의 물리화학적 특성과 미세구조를 조사하여 과열증기처리 및 과열증기온도(200, 250, 350oC)가 압출스낵의 품질특성에 미치는 영향을 검토하였다. 압출스낵의 이화학적 특성 측정결과, 팽화도는 과열증기처리에 따라 증가하였으나 과열증기온도의 영향은 미미하였다. 압출스낵의 경도는 과열증기처리에 따라, 과열증기온도가 높을수록 감소하였다. 손상전분함량은 과열증기처리에 따라 78.1%에서 80-81%로 다소 증가하였으나 과열증기온도에 따른 손상전분함량의 유의 차는 없었으며, 이로써 과열증기처리가 전분호화에 미치는 영향은 크지 않은 것을 확인하였다. 과열증기처리에 따라 수분흡수지수(WAI)는 유사한 측정치를 나타낸 반면 수분용해지수(WSI)는 비교적 크게 증가하여 과열증기처리가 압출공정에서 전분분자의 저분자화를 증가시키는 것으로 판단되었다. 압출스낵의 수분흡수율은 과열증기처리에 따라 증가하였으며 과열증기온도가 높을수록 수분흡수율은 증가하였다. 압출스낵의 미세구조 관측결과, 압출스낵 내부의 기공 크기와 기공 막 두께는 과열증기처리에 따라 감소하며, 이와 같은 내부구조 변화로 인하여 과열증기처리 압출스낵의 팽화도, 경도 및 수분흡수율 측정결과는 대조구와 상이하였다. 한편 과열증기처리에 따른 압출스낵의 미세구조 변화는 과열증기처리가 쌀의 배유조직 내에 미세한 균열(stress crack)을 발생하고, 미세 균열 내의 공기가 압출과정에 유입되어 보다 많은 핵심이 생성되며, 이로 인하여 다공성이 높아지는 것으로 추정된다.

Swelling of the heat-treated netting for gillnet was estimated through the netting height in square acrylic tank. Experimental Nylon netting and PBSAT netting were heat-treated by using the high-degree vacuum method in hot water after net making. Heat-treatment temperatures were conducted with Nylon netting 105°C and PBSAT netting 62°C, 65°C, 66°C, 67°C. The swelling measurement method of a netting using the square tank was capable of the reduction measurement errors comparing with measurement methods of a mesh inner angle and the shortening rate of a mesh size. In addition, this method was available to comparison evaluation for each netting more easily. Wet type heat-treatment apparatus with high-degree vacuum was shown higher 7∼8°C inner side temperature than a setting temperature. The tensile strength and elongation of Nylon netting and PBSAT netting were shown higher wet condition than dry condition. The tensile strengths of PBSAT monofilaments in dry and wet condition were sharply decreased at heat-treatment temp. 75°C than heat-treatment temp. 74°C

본 연구는 과열증기처리 기술을 양파에 적용하여 불쾌취 를 저감화하고, 이를 통해 고품질 양파 가공품 개발 및 소재 화에 활용하기 위한 기초 자료를 확보하고자 과열증기처리 에 따른 양파의 휘발성 물질, 불쾌취 유발 물질과 항산화활 성, 조직감, 관능적 특성 등 품질특성을 분석하였다. 과열증 기처리에 의해 휘발성 향기성분 및 불쾌취와 매운맛의 지표 물질이 저감화됨을 확인하였다. 항산화활성 및 총 페놀성 화합물 함량은 다소 증가하는 경향을 보였으며, hardness, chewiness 등은 확연하게 감소하는 것으로 나타났다. 양파 추출액의 총 가용성 고형분 함량은 처리에 의해 전체적으로 증가하였으며 처리에 따라 기호도 점수가 높아지는것을 확인하였다. 결과적으로 과열증기 처리가 양파의 불쾌취 저감화에 효과적임을 확인할 수 있었다. 본 연구결과는 과 열증기 기술을 적용한 양파의 불쾌취 저감화 및 이를 통한 다양한 고품질 가공품 개발 및 소재화를 위한 중요한 기초 자료로 활용될 수 있으리라 판단되며, 과열증기오븐 처리 를 통해 불쾌취를 조절함과 동시에 생리활성능을 지니는 향기 성분 및 유용성분의 감소는 최소화하는 추가적인 연구 가 필요할 것으로 사료된다.