• 한국식품영양과학회지
• /
• 제24권3호
• /
• pp.384-388
• /
• 1995

어유는 고도불포화지방산 함량이 높아 산화가 쉽게 되므로 식품가공용이나 기능성식품으로 응용되기에는 많은 제약이 따른다. 이러한 문제를 해결하기 위하여 어유의 산화안정성을 예측할 수 있는 기본 모델을 다음과 같은 식을 이용하여 제시하였다. $dp/dt=k{\cdot}p(t){\cdot}[P_{max}\;-\;p(t)]$. 상기식을 적분하면, $p(t)=P_{max}/[1\;+\;[(P_{max}/P_{(0)})\;-\;-1]{\cdot}EXP(-K_p{\cdot}t)]$. 여기서 산화온도가 50, 60와 70 및 $80^{\circ}C$ 일 때, $K_p$는 각각 0.00535, 0.01345와 0.02516 및 0.04657였다. 상기식은 대부분 측정치와 잘 일치하였다. 또한 $K_p$를 아래와 같이 온도의 함수로 표현할 수 있었다. $K_p=(1/P_{max})EXP\;[1\;-\;(8148/T)+20.1]$. 여기서 T 절대온도($^{o}K$)이다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제30권7호
• /
• pp.1021-1028
• /
• 2017

Objective: The objective of this study was to evaluate the effects of ageing time of lamb loins prior to freezing on technological characteristics and oxidation stability of coarse ground lamb loin sausage using in a model system. Methods: Lamb loins (M. longissimus lumborum, n = 25) were aged at $-1.5^{\circ}C$ for 0, 1, 2, 3, and 8 wk and then frozen for the remaining days (a total of 30 wk). The aged/frozen/thawed lamb loins were ground, and model sausages were formulated with 75% aged/frozen/thawed lamb loin, 25% water, 1.5% sodium chloride (NaCl) and 0.3% sodium tripolyphosphate. The pH and thaw/purge loss of aged/frozen/thawed lamb loins were evaluated, and protein functionality (protein solubility and emulsifying capacity), water-holding capacity and textural properties of model sausages were determined. Cooked model sausages were vacuum-packaged in a plastic bag and displayed under continuous fluorescent natural white light ($3^{\circ}C{\pm}1^{\circ}C$). Colour and lipid oxidation of the cooked model sausages were evaluated on 0 and 21 d of display storage. Results: Ageing prior to freezing had no impact on pH and purge/thaw loss of lamb loins and the colour of cooked sausages (p>0.05) made from the loins. Lamb loins aged for at least 3 wk prior to freezing numerically improved total and myofibrillar protein solubilities (p>0.05) and emulsion activity index (p = 0.009) of meat batter, but decreased cooking loss (p = 0.003) and lipid oxidation (p<0.05) of model sausages. Conclusion: This study suggests that post-mortem ageing of raw meat prior to freezing could improve water-holding capacity and lipid oxidative stability of sausage made from the meat.

• 한국식품과학회지
• /
• 제28권1호
• /
• pp.197-202
• /
• 1996

콜레스테롤을 함유하는 수용성 모형계에서 erythrosine의 첨가농도, 광도, tocopherol과 ${\beta}-carotene$의 첨가에 따른 headspace내의 산소량의 변화와 콜레스테롤 산화물의 생성량의 변화를 연구하였다. Erythrosine의 첨가량이 증가할수록 headspace내 산소량의 감소가 컸고, 각종 COP 생성량은 증가하였다. 형광등의 조도가 증가할수록 headspace내 산소량의 감소가 컸고, 이에 비례하여 콜레스테롤은 감소하였고 총 COP의 생성량은 증가하였다. 일중항 산소 소거제로 tocopherol과 ${\beta}-carotene$을 첨가하였을 때 headspace내의 산소량은 완만하게 감소하였으며, 이에 비례하여 콜레스테롤의 감소가 완만하였고 총 COP의 생성량 또한 감소하였다.

• 한국축산식품학회지
• /
• 제43권2호
• /
• pp.220-231
• /
• 2023

Although omega-3 fatty acids including docosahexaenoic acid (DHA) contain various health-promoting effects, their poor aqueous solubility and stability make them difficult to be induced in dairy foods. The aims of this research were to manufacture casein derivative-based delivery system using acid-induced gelation method with glucono-σ-lactone and to investigate the effects of production variables, such as pH and charged amount of linoleic acid, on the physicochemical properties of delivery systems and oxidative stability of DHA during storage in model milk. Covalent modification with linoleic acid resulted in the production of casein derivatives with varying degrees of modification. As pH was reduced from 5.0 to 4.8 and the charged amount of linoleic acid was increased from 0% to 30%, an increase in particle size of casein derivative-based delivery systems was observed. The encapsulation efficiency of DHA was increased with decreased pH and increased charged amount of linoleic acid. The use of delivery system for DHA resulted in a decrease in the development of primary and secondary oxidation products. An increase in the degree of modification of casein derivatives with linoleic acid resulted in a decrease in the formation of primary and secondary oxidation products than of free DHA indicating that delivery systems could enhance the oxidative stability of DHA during storage in model milk. In conclusions, casein derivatives can be an effective delivery system for DHA and charged amount of linoleic acid played a key role determining the physicochemical characteristics of delivery system and oxidative stability of DHA.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.217-217
• /
• 2011

Recently, demand for thermally stable metal nanoparticles suitable for chemical reactions at high temperatures has increased to the point to require a solution to nanoparticle coalescence. Thermal stability of metal nanoparticles can be achieved by adopting core-shell models and encapsulating supported metal nanoparticles with mesoporous oxides [1,2]. However, to understand the role of metal-support interactions on catalytic activity and for surface analysis of complex structures, we developed a novel catalyst design by coating an ultra-thin layer of titania on Pt supported silica ($SiO_2/Pt@TiO_2$). This structure provides higher metal dispersion (~52% Pt/silica), high thermal stability (~600$^{\circ}C$) and maximization of the interaction between Pt and titania. The high thermal stability of $SiO_2/Pt@TiO_2$ enabled the investigation of CO oxidation studies at high temperatures, including ignition behavior, which is otherwise not possible on bare Pt nanoparticles due to sintering [3]. It was found that this hybrid catalyst exhibited a lower activation energy for CO oxidation because of the metal-support interaction. The concept of an ultra-thin active metal oxide coating on supported nanoparticles opens-up new avenues for synthesis of various hybrid nanocatalysts with combinations of different metals and oxides to investigate important model reactions at high-temperatures and in industrial reactions.

• 대한치과보철학회지
• /
• 제45권3호
• /
• pp.339-344
• /
• 2007

Statement of problem. Various anodic oxidation techniques can be applied to dental implant surfaces. But the condition for optimal anodized surfaces has not been described yet. Purpose. The purpose of this investigation was to compare an implant that was oxidized by another method with $TiUnite^{TM}$ through resonance frequency analysis and histomorphometry. Material and methods. Turned (control), $TiUnite^{TM}$ and another oxidized fixtures, which used $Ca^{2+}$ solution for anodic oxidation, were placed in the tibiae of 5 New Zealand White rabbits. The bone responses were evaluated and compared by consecutive resonance frequency analysis once a week for 6 weeks and histomorphometry after a healing period of 6 weeks. Results. At the first week, both oxidized implants showed significantly higher implant stability quotient (ISQ) values than the control. No significant differences in resonance frequency analysis were found between the two oxidized groups for 6 weeks. The means and standard deviations of bone-to-implant contact (BIC) ratios were $71.0{\pm}4.2$ for $TiUnite^{TM}$, $67.5{\pm}10.3$ for the $Ca^{2+}$-based oxidation fixture, $22.8{\pm}6.5$ for the control. Both oxidized implants were significantly superior in osseointegration to the turned one. There was, however, no statistically significant difference between the two oxidized implants. Conclusion. $TiUnite^{TM}$ and the $Ca^{2+}$-based oxidation fixture showed superior early bone response than the control with respect to resonance frequency analysis and histomorphometry. No significant differences between the oxidized groups, however, were found in this investigation using the rabbit tibia model.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.204.2-204.2
• /
• 2014

Among various metal oxides, ZrO2 is of particular interests and has received widespread attention thanks to its ideal mechanical and chemical stability. As a cheap metal, Ag nanoparticles are also widely used as catalysts in ethylene epoxidation and methanol oxidation. However, the nature of Ag-ZrO2 interfaces is still unknown. In this work, the growth, interfacial interaction and thermal stability of Ag nanoparticles on ZrO2(111) film surfaces were studied by low-energy electron diffraction (LEED), synchrotron radiation photoemission spectroscopy (SRPES), and X-ray photoelectron spectroscopy (XPS). The ZrO2(111) films were epitaxially grown on Pt(111). Three-dimensional (3D) growth model of Ag on the ZrO2(111) surface at 300 K was observed with a density of ${\sim}2.0{\times}1012particles/cm2$. The binding energy of Ag 3d shifts to low BE from very low to high Ag coverages by 0.5 eV. The Auger parameters shows the primary contribution to the Ag core level BE shift is final state effect, indicating a very weak interaction between Ag clusters and ZrO2(111) film. Thermal stability experiments demonstrate that Ag particles underwent serious sintering before they desorb from the zirconia film surface. In addition, large Ag particles have stronger ability of inhibiting sintering.

• 한국식품과학회지
• /
• 제25권6호
• /
• pp.775-779
• /
• 1993

카로티노이드의 산화에 미치는 수분활성도와 광선의 영향을 살펴보기 위하여 첫째, 동결건조 당근분말로부터 조지질을 분리하여 $30^{\circ}C$에서 산화시켰을 때 산화반응에 따른 카로티노이드 획분의 산화안정성을 살펴보고 둘째, 포화염을 이용하여 수분 활성도를 조절한 동결건조 당근을 $30^{\circ}C$에 저장하면서 반응기간에 따른 카로티노이드의 산화를 살펴보았다. 그리고 광선의 유무에 따른 산화정도도 측정하였다. 당근 조지질을 16일 동안 저장하였을 때 조지질내에 들어 있는 카로티노이드 획분은 초기 함량의 71.8%가 파괴되어 자동산화가 현저하게 일어남을 알 수 있었다(p<0.05). 이러한 카로티노이드의 자동산화에 미치는 수분활성도와 광선의 영향을 살펴보았을 때 저장기간 35일 동안 모든 수분활성도 범위에서 자동산화는 계속 되었으며 이중 $a_{w}$ 0.42에서 최대 안정성을 나타내었고, 광선에 의한 카로티노이드의 파괴율은 비교군에 비해 더 높았으며 통계적인 유의성이 있었다(p<0.05). 이와 같은 산화반응에 따른 카로티노이드의 흡수 스펙트럼상의 변화는 흡광도의 차이만 있을 뿐 최대파장의 이동은 일어나지 않았다.

• Food Science and Biotechnology
• /
• 제18권1호
• /
• pp.79-83
• /
• 2009

Acidolysis of olive oil with omega-3 (n-3) polyunsaturated fatty acids (PUFAs) was carried out to produce a structured lipid. Novozym $435^{(R)}$ from Candida antarctica was used as the biocatalyst. Response surface methodology (RSM) was used to determine optimum conditions for lipase-catalyzed enrichment of olive oil. Three factors, 5 levels, central composite design was used. The effects of incubation time, temperature, and substrate mole ratio on incorporation ratio (n-3 fatty acids/total fatty acids, %) were investigated. From the evaluation of response surface graphs, the optimal conditions for incorporation of long chain n-3 PUFAs into olive oil were $40-60^{\circ}C$ for temperature, 30-45 hr for reaction time, and 3:1-5:1 (n-3 fatty acids/olive oil) for substrate mole ratio. Experiments conducted under optimized conditions predicted by the model equation obtained from RSM yielded structured lipids with 50.8% n-3 PUFAs. This value agreed well with that predicted by the model. Oxidative stability tests showed that the product was more susceptible to oxidation than unmodified olive oil. Antioxidant addition improved the oxidative stability of the product.

• 한국축산식품학회지
• /
• 제37권5호
• /
• pp.752-763
• /
• 2017

Marine fish skin peptides (FSP) have been widely studied due to their antioxidant and antimicrobial properties. We aimed to use a natural antioxidant, FSP, to replacing synthetic preservatives in a pork patty model, which is safer for human body. Moreover, nano-liposome technology can be applied for masking the fishy smell and improving the stability of this peptide. Therefore, in this study, the effects of FSP and FSP-loaded liposomes (FSPL) on pork patty were evaluated through the tests of thiobarbituric acid reactive substances (TBARS), color, cooking loss, texture, volatile basic nitrogen (VBN), and the pH value, during 14 d of refrigerated ($4^{\circ}C$) storage. The results showed that all FSP-treated patties had lower TBARS values than control patties, which indicated an inhibitory effect of FSP on lipid oxidation. This effect in the patties depended on the FSP concentration. However, FSPL-treated patties showed significantly higher and undesirable TBARS values compared to the control, and this effect depended on the FSPL concentration. None of the physicochemical results showed remarkable changes except the pH and VBN values. Therefore, this study provides evidence that FSP has great potential to inhibit the lipid oxidation of pork patties and is capable of maintaining the quality and extending the shelf life. However, it is necessary to study the application of FSP treatments greater than 3% to improve the antioxidant effect on pork patties and search for other coating materials and technology to reduce the drawbacks of FSP.