• 제목/요약/키워드: Poor stability

검색결과 529건 처리시간 0.021초

Encapsulation of Anthocyanin from Purple Potato by the Application of Food Polymers

  • Azad, Obyedul Kalam;Cho, Dong Ha;Park, Cheol Ho
    • 한국작물학회:학술대회논문집
    • /
    • 한국작물학회 2018년도 추계학술대회
    • /
    • pp.274-274
    • /
    • 2018
  • Anthocyanins has a strong antioxidant capacity but exhibit poor stability in water. Therefore, stability of anthocyanin from purple potato (Solanum tuberosum L.) was encapsulated by the application of food polymers. Solid formulation of purple potato was prepared using whey protein, tapioca and lecithin by capillary rheometer at $80^{\circ}C$. The ratio of the polymer and potato powder was 2:8. Total phenolic compound, total flavonoid, total anthocyanin and antioxidant activity was investigated by the spectrophotometer. Result revealed that total phenolic compound (TP) ($5321{\mu}g/100g$), total flavonoid (TF) ($1352{\mu}g/100g$) total anthocyanin (TA) ($764{\mu}g/100g$) and free radical antioxidant activity (DPPH) (86%) was higher in 0.01 M acetic acid mediated lecithin based formulation compared to control (Potato powder) (TP: $1357{\mu}g/100g$; TF) ($634{\mu}g/100g$, TA) ($264{\mu}g/100g\;DPPH$) (64%). Lecithin is a strong emulsifier having capacity to extract bioactive compound and encapsulate extracted compound by nonpolar tail and negatively charged head. Therefore, it would be concluded that lecithin might be used as an encapsulating agent for the bioactive compound from purple potato.

  • PDF

Mechanical and Thermal Properties of Liquefied Wood Polymer Composites (LWPC)

  • Hyun, Doh Geum;Kang, In Aeh;Lee, Sun Young;Kong, Young To
    • Journal of the Korean Wood Science and Technology
    • /
    • 제32권6호
    • /
    • pp.67-73
    • /
    • 2004
  • The influence of liquefied wood (LW) on the mechanical and thermal properties of liquefied wood-polymer composites (LWPC) was investigated in this study. The thermal behaviors of LWPC were characterized by means of thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses. LW showed significant effects on the mechanical strength properties. The increase of flexural MOE and Young's modulus was related to the increase of stiffness of LWPC. The effect of LW was also significant on the flexural and tensile MOR. The impact strength decreased with the increase of LW application level. With the increased stress concentration by the poor bonding between LW and polymer, the impact strength of LWPC decreased, compared with that of high-density polyethylene (HDPE). The thermal stability of LWPC decreased with the increase of LW content up to 40%. The melting temperature of HDPE decreased with the increase of LW loading level. Enthalpy of HDPE also decreased with the addition of LW. This study proves the thermal stability necessary for the consolidation of composition materials.

Effects of additives on the fermentation quality, in vitro digestibility and aerobic stability of mulberry (Morus alba L.) leaves silage

  • Dong, Zhihao;Wang, Siran;Zhao, Jie;Li, Junfeng;Shao, Tao
    • Asian-Australasian Journal of Animal Sciences
    • /
    • 제33권8호
    • /
    • pp.1292-1300
    • /
    • 2020
  • Objective: To explore feed resources capable of replacing regular poor-quality fodder, this study was conducted to evaluate the effects of additives on the fermentation quality, in vitro digestibility and aerobic stability of mulberry leaves silage. Methods: The mulberry leaves were ensiled either untreated (control) or treated with 1×106 cfu/g fresh matter Lactobacillus plantarum (L), 1% glucose (G), 3% molasses (M), a combination of 1% glucose and Lactobacillus plantarum (L+G), and a combination of 3% molasses and Lactobacillus plantarum (L+M). The fermentation quality and chemical composition were analyzed after 7, 14, 30, and 60 d, respectively. The 60-d silages were subjected to an aerobic stability test and fermented with buffered rumen fluid to measure the digestibility. Results: Inoculating lactic acid bacteria (LAB) resulted in more rapid increase in lactic acid concentrations and decline in pH of mulberry leaves silage as compared control. Higher acetic acid and lower ethanol and ammonia nitrogen concentrations (p<0.05) were observed in the LAB-inoculated silages as opposed to control during ensiling. The LAB-inoculated silages contained lower water-soluble carbohydrates compared with control during the first 14 d of ensiling, and lower neutral detergent fibre (p<0.05) concentrations as compared with non-LAB inoculated silages. Adding molasses alone increased (p<0.05) the digestibility of dry matter (DM). The aerobic stability of mulberry leaves silage was increased by LAB inoculation, whereas decreased by adding glucose or molasses. Conclusion: The LAB inoculation improved fermentation quality and aerobic stability of mulberry leaves silage, while adding glucose or molasses failed to affect the fermentation and impaired the aerobic stability. Inoculating LAB alone is recommended for mulberry leaves especially when ensiled at a relatively high DM.

The effect of various thread designs on the initial stability of taper implants

  • Park, Ju-Hee;Lim, Young-Jun;Kim, Myung-Joo;Kwon, Ho-Beom
    • The Journal of Advanced Prosthodontics
    • /
    • 제1권1호
    • /
    • pp.19-25
    • /
    • 2009
  • STATEMENT OF PROBLEM. Primary stability at the time of implant placement is related to the level of primary bone contact. The level of bone contact with implant is affected by thread design, surgical procedure and bone quality, etc. PURPOSE. The aim of this study was to compare the initial stability of the various taper implants according to the thread designs, half of which were engaged to inferior cortical wall of type IV bone(Group 1) and the rest of which were not engaged to inferior cortical wall(Group 2) by measuring the implant stability quotient(ISQ) and the removal torque value(RTV). MATERIAL AND METHODS. In this study, 6 different implant fixtures with 10 mm length were installed. In order to simulate the sinus inferior wall of type IV bone, one side cortical bone of swine rib was removed. 6 different implants were installed in the same bone block following manufacturer s recommended procedures. Total 10 bone blocks were made for each group. The height of Group 1 bone block was 10 mm for engagement and that of group 2 was 13 mm. The initial stability was measured with ISQ value using Osstell $mentor^{(R)}$ and with removal torque using MGT50 torque gauge. RESULTS. In this study, we found the following results. 1. In Group 1 with fixtures engaged to the inferior cortical wall, there was no significant difference in RTV and ISQ value among the 6 types of implants. 2. In Group 2 with fixtures not engaged to the inferior cortical wall, there was significant difference in RTV and ISQ value among the 6 types of implants(P < .05). 3. There was significant difference in RTV and ISQ value according to whether fixtures were engaged to the inferior cortical wall or not(P < .05). 4. Under-drilling made RTV and ISQ value increase significantly in the NT implants which had lower RTV and ISQ value in Group 2(P < .05). CONCLUSIONS. Without being engaged to the inferior cortical wall fixtures had initial stability affected by implant types. Also in poor quality bone, under-drilling improved initial stability.

울금의 색소 추출과 안정성에 관한 연구 (A Study on the Stabitity and Dyeing Condition in the Curcuma Longa L.)

  • 소황옥
    • 복식
    • /
    • 제39권
    • /
    • pp.79-89
    • /
    • 1998
  • This study was carried out the effect of stability and color extract for it's condition in the curcuma L.. dyeing. The stability is to investigate the absorbance of the curcumin, one of the major yellow pigments and the stability regarding the effect of light, oxygen temperature and pH. The dyeing condition is compared the effect of mordanting condition and the best way to extract pigment and analysed through the color-fastness rating, color-difference value test. The main results obtained are summarized as follows ; 1.The best and proper solvent to extrect curcumin pigment was a ethanol and a distilled water. 2. The light effect indicated that the absorbances of solution in absence of ligh was more stable. 3. The oxygen(O2) effect to curcumin show-ed that the condition in the absence of O2 was more stable than that in presence of O2 4. The temperature showed that the absorbnace was best stable in4$^{\circ}C$ and less changed at $25^{\circ}C$ 5. The curcumin-etanol solution was stable in pH 2~4. 6. Generally color-fastness rating to silk, wool and cotton indicated that crocking C.F. and perspiration C.F. were more than 3rd grade and dry cleaning C.F. was more than 4th grade. But light color-fastness and washing color-fastness were very poor. 7. To make good color fastness, the mordan-ting treated group and the pre-mordant conditions were more effective than others 8. When compared with color-difference value test indicated that the silk was looks like more reddish and bluish color and than the wool and cotton were greenish and bluish. As a mordant, A(C2H4OH(COOH3) and D(K2Cr2O7)were more effective to make green-ish color in the silk and the reddish color was abtained by B(Al.K(SO4)2.12H2O) and C(FeSO4.7H2O).

  • PDF

참치 기름담금 통조림의 저장중의 품질변화 (Quality Changes of Canned Tuna in Cottonseed Oil during Storage)

  • 조현덕;김상호;임진영;한봉호;정차균;류홍수
    • 한국수산과학회지
    • /
    • 제29권3호
    • /
    • pp.287-295
    • /
    • 1996
  • [ $110^{\circ}C$ ]에서 $F_0$-값을 달리하여 가열살균한 참치 기름담금 통조림을 5, 25 및 $50^{\circ}C$ 에서 120일간 저장하면서, 저장중의 품질변화를 검토하였다. $F_0$-값 5.18분 이하의 조건으로 열처리한 통조림은 저장기간이 길어짐에 따라서 관능적 품질, pH, 아미노 질소 함량, TBA-값 및 POV가 심하게 변하였다. 그러나 $F_0$-값 5.18분을 초과하여 가열살균한 제품에서는 품질변화가 거의 없었다. 따라서 전보에서 이미 보고한 바와 같이 참치 기름담금 통조림의 최적 가열살군 조건은 6분으로 판단되었다.

  • PDF

Development of Carbon Composite Bipolar Plates for Vanadium Redox Flow Batteries

  • Lee, Nam Jin;Lee, Seung-Wook;Kim, Ki Jae;Kim, Jae-Hun;Park, Min-Sik;Jeong, Goojin;Kim, Young-Jun;Byun, Dongjin
    • Bulletin of the Korean Chemical Society
    • /
    • 제33권11호
    • /
    • pp.3589-3592
    • /
    • 2012
  • Carbon composite bipolar plates with various carbon black contents were prepared by a compression molding method. The electrical conductivity and electrochemical stability of the bipolar plates have been evaluated. It is found that the electrical conductivity increases with increasing carbon black contents up to 15 wt %. When the carbon black contents are greater than 15 wt %, the electrical conductivity decreases because of a poor compatibility between epoxy resin and carbon black, and a weakening of compaction in the carbon composite bipolar plate. Based on the results, it could be concluded that there are optimum carbon black contents when preparing the carbon composite bipolar plate. Corrosion tests show that the carbon composite bipolar plate with 15 wt % carbon black exhibits better electrochemical stability than a graphite bipolar plate under a highly acidic condition. When the optimized carbon composite bipolar plate is applied to vanadium redox flow cells, the performance of flow cells with the carbon composite bipolar plate is comparable to that of flow cells with the graphite bipolar plate.

터널 굴착 중 바닥부 연약대로 인한 터널 융기 거동 사례 분석 (Upheaveal Behaviour of Tunnel Bottom in the Weatherd Fracture Zone under Tunnel Excavation)

  • 장용채;김낙영;진규동;손용민
    • 한국지반환경공학회 논문집
    • /
    • 제15권6호
    • /
    • pp.49-56
    • /
    • 2014
  • 터널 구조물 안정성은 굴착하는 지반강도에 전적으로 좌우되는 특성이 있다. 지반강도가 약한 경우에는 터널 굴착 공사중 붕락이 자주 발생하게 된다. 일반적으로 이러한 조건에서는 분할굴착 또는 사전 보강을 실시하여 굴착 중 붕락에 대비하게 된다. 그럼에도 불구하고 연약대에서는 상반굴착 중 천단부 붕락이 발생할 수 있는데 이러한 사례는 많고 붕락 부위에 대해서 보강공법 적용을 통해 복구가 가능하다. 터널 바닥부에서 융기가 발생하는 경우에는 상부구간까지 악영향을 미치므로 터널 구조물 전체적인 안정성에 치명적인 영향을 줄 수 있다. 따라서 하부구간이 불량한 경우에는 반드시 심도 있는 보강검토가 필요하다. 터널 바닥부 융기로 인해 터널 안정성에 위해한 영향을 주는 사례가 최근에 터널 장대화와 관련되어 증가하고 있으므로 보강적용 기준에 대한 연구가 필요하고 본 연구에서는 실제 현장 하부구간 융기사례들을 조사하여 거동특성과 보강방안을 분석하였다.

Shear strength behaviors of grouts under the blasting induced vibrations

  • Sagong, Myung;Choi, Il Yoon;Lee, Jun S.;Cho, Chung-sik
    • Geomechanics and Engineering
    • /
    • 제21권2호
    • /
    • pp.207-213
    • /
    • 2020
  • Umbrella Arch Method (UAM) often employed in the tunnel construction under poor rock mass conditions in Korea. Insertion of steel pipes at the periphery of the tunnel and infiltration of grouts along the pipes into the rock masses increases tunnel stability. There are two major effects of grouts expected at the tunnel face: 1) increase of face stability by enhancing the frictional resistance of discontinuities and 2) decrease of permeability along the rock masses. Increase of resistance and decrease of permeability requires a certain curing time for the grout. In Korea, we require 24 hours for curing of grout, which means no progress of excavation for 24 hours after infiltration of grouts. This step delays the tunnel construction sequences. To eliminate such inefficiency, we propose MTG (Method for Tunnel construction using Grouting technology), which uses extended length of steel pipes (14 m) compared to conventional pipe roof method (12 m). The merit of MTG is the reduction of curing time. Because of the approximately 2 m extension of the length of steel pipe, blasting can be done after infiltration of grouting. For this paper, we conducted experiments on the shear strength behaviors of grout infilled rock joint with elapsing of curing time and blasting induced vibration. The results show that blasting induced vibration under MTG does not influence the mechanical features of grout material, which indicates no influence on the mechanical behaviors of grout, contributing to the stability of tunnels during excavation. This result indicates that MTG is a cost effective and fast construction method for tunneling in Korea.

Investigation into the Efficacy of Val-SN-38, a Valine-Ester Prodrug of the Anti-Cancer Agent SN-38

  • Kwak, Eun-Young;Choi, Min-Koo;Yang, Su-Geun;Shim, Chang-Koo;Shim, Won-Sik
    • Biomolecules & Therapeutics
    • /
    • 제20권3호
    • /
    • pp.326-331
    • /
    • 2012
  • We recently reported that Val-SN-38, a novel valine ester prodrug of SN-38, had greatly improved the intracellular accumulation of SN-38 in MCF-7 cell line, probably through enhanced uptake via amino acid transporters. In the present study, the efficacy of Val-SN-38 was further investigated both in vitro and in vivo. It was found that the in vitro cytotoxic effect of Val-SN-38 was similar to that of SN-38. Moreover, Val-SN-38 exhibited an equal potency to that of SN-38 in survival experiments in vivo. Because these results seemed to be contrary to the previous finding, further investigation was performed to find out the underlying cause of the contradiction. As only the lactone form is known to have cytotoxic activity, the proportion of lactone in Val-SN-38 and SN-38 was determined, but no differences were found. However, it turned out that Val-SN-38 had poor stability compared with SN-38, which resulted in a decrease in beneficial efficacy for Val-SN-38. Overall, the present study showed that a valine-added prodrug approach could be advantageous provided that the stability of the compound can be ensured. We believe this is a noteworthy study that unravels the discrepancy between intracellular accumulation and efficacy of valine-added prodrug.