Printable Colorimetric Freshness Indicator Based on Cellulose Nanocrystal-Silver Nanoparticles (CNC-AgNPs) for Intelligent Food Packaging

Seongyoung Kwon,Seonghyuk Ko 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10

Intelligent packaging is a smart system that can monitor the product quality directly or environment change around the packaging during transportation and distribution to provide relevant information to consumers for the safety. In this study, a printable freshness indicator was well-designed and fabricated with the modification of CNC-AgNP solution prepared by hydrothermal green synthesis. The paper indicator printed with as-prepared CNC-AgNPs composited ink was successfully prepared using an inkjet printer and evaluated its colorimetric indicating capability with the chicken breast at room temperature. As a result, the indicator sensitively reacted with the spoilage gas leading to color change, which is attributed to the surface chemical reaction of AgNP with hydrogen sulfide (H₂S) caused by chicken breast deterioration. The printed freshness indicator obtained in current study was proven to be utilized effectively in intelligent packaging for all fresh foods that cause H₂S during the quality decay.

A Study of Thermal Properties of LDPE-Nanoclay Composite Films

Bumbudsanpharoke, Nattinee,Ko, Seonghyuk Korea Society of Packaging Science and Technology 2015 한국포장학회지 Vol.21 No.3

This work focused on the study of thermal properties and kinetic behavior of LDPE-nanoclay composite films. The effect of nanoclay content (0.5, 1, 3, and 5 wt%) on thermal stability and crystallization characteristics of the nanocomposites were investigated by Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The results from endothermic curve showed that the nanoclay played an important role in the crystallization of nanocomposites by acting as nucleating agent. From exothermic curve, there was a crystallization temperature shift which was attributed to crystallization process induced by nanoclay. The TGA results showed that the addition of nanoclay significantly increased the thermal stability of LDPE matrix, which was likely due to the characteristic of layered silicates/clays dispersed in LDPE matrix as well as the formation of multilayered carbonaceous-silicate char. A well-known Coats-Redfern method was used to evaluate the decomposition activation energy of nanocomposite. It was demonstrated that introducing of nanoclay to LDPE matrix escalated the activation energy of nanocomposite decomposition resulting in thermal stability improvement.

A Review on Use of Carbohydrate-based Fillers and Pigments in Packaging Paper

Bumbudsanpharoke, Nattinee,Ko, Seonghyuk Korea Society of Packaging Science and Technology 2016 한국포장학회지 Vol.22 No.3

As one of traditional packaging materials, paper and paperboard are being more popular and beneficial thanks to their environmental sustainability and have been widely used in packaging applications, from light weight infusible tissue for tea/coffee bags to heavy duty boards for the distribution. Papermakers have to design the products having a desired customized function with their paper machine. Globally, the use of filler and pigment in papermaking is now a very common practice to meet the needs of customers. Many benefits can be achieved as a result of filler addition, which mainly includes cost and energy savings. The replacement of traditional mineral fillers and pigments with biodegradable and renewable carbohydrate polymers is a very interesting and promising research topic due to the concern of environmental impact. In this review paper, the use of traditional and novel carbohydrate fillers and pigments in cellulosic paper is highlighted. It is noteworthy that there are still some challenges and technical barriers associated with the use of these organic materials in point of structural stabilities and manufacturing costs, although most of them are available in market as the commercialized products. With the emerging nanotechnologies, it is believed that the use of carbohydrate-based filler and pigment for papermaking will increase and bring technical advantages to industry.

A Study of Thermal Properties of LDPE-Nanoclay Composite Films

Nattinee Bumbudsanpharoke,Seonghyuk Ko 한국포장학회 2015 한국포장학회지 Vol.21 No.3

This work focused on the study of thermal properties and kinetic behavior of LDPE- nanoclay composite films. The effect of nanoclay content (0.5, 1, 3, and 5 wt%) on thermal stability and crystallization characteristics of the nanocomposites were investigated by Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The results from endothermic curve showed that the nanoclay played an important role in the crystallization of nanocomposites by acting as nucleating agent. From exothermic curve, there was a crystallization temperature shift which was attributed to crystallization process induced by nanoclay. The TGA results showed that the addition of nanoclay significantly increased the thermal stability of LDPE matrix, which was likely due to the characteristic of layered silicates/ clays dispersed in LDPE matrix as well as the formation of multilayered carbonaceous- silicate char. A well-known Coats- Redfern method was used to evaluate the decomposition activation energy of nanocomposite. It was demonstrated that introducing of nanoclay to LDPE matrix escalated the activation energy of nanocomposite decomposition resulting in thermal stability improvement.

Applications of Nanomaterials in Food Packaging

Bumbudsanpharoke, Nattinee,Choi, Jungwook,Ko, Seonghyuk American Scientific Publishers 2015 Journal of Nanoscience and Nanotechnology Vol.15 No.9

녹색합성법에 기인한 식품포장용 키토산-은나노 항균 복합필름의 개발

경규선(Gyusun Kyung),고성혁(Seonghyuk Ko) 한국식품과학회 2014 한국식품과학회지 Vol.46 No.3

키토산 바이오폴리머를 활용한 은나노 입자의 효과적인 녹색합성을 수행하였으며 얻어진 키토산-은나노 복합물질의 물리화학적 특성을 분석하고 키토산-은나노 복합필름을 제조, 이들의 항균성을 평가하였다. UV-Visible 흡수 spectrum과 TEM 분석을 통해 키토산 내 은나노 입자가 안정적으로 생성, 분포하고 있음을 확인하였고 키토산 및 질산은의 농도 그리고 반응시간의 변화에 따른 키토산 내 은나노 생성 특성을 조사하였다. 녹색합성된 키토산-은나노 복합물질로부터 EDS 분석 결과 0.9-8.9% 범위의 은나노를 함유한 키토산-은나노 복합필름이 얻어졌으며 FTIR 분석에 의해 은나노 합성과정에서 키토산의 활성아민기와 소량의 히드록시기가 은나노 환원반응에 참여함으로써 키토산이 은나노 입자의 합성을 위한 환원제 및 안정제로 작용하였음을 확인할 수 있었다. 이들 복합필름의 항균정성 평가 결과 순수 키토산 대조군 필름에서는 E. coli에 대한 항균성이 나타나지 않은 반면 키토산-은나노 필름에서는 뚜렷한 항균성을 보였으며 함유된 은의 농도 증가에 따라 항균력 또한 증가하였다. 본 연구결과를 통해 친환경 항균소재로서 녹색합성법에 의해 제조된 키토산-은나노 복합물질을 기능성 포장소재로 응용 가능함을 확인하였으며 향후 포장소재로서 요구되는 수분 및 가스차단성, 식품 내용물과의 반응성, 접촉안전성 및 안정성 등과 같은 다양한 요소의 체계적 연구가 뒤따라야 할 것으로 판단되며 복합필름의 연성, 강성, 내냉·내열성 등 식품포장필름 적용을 위한 지속적인 연구가 수행 될 것이다. We studied the green synthesis and antibacterial activity of chitosan-silver (Ag) nanocomposite films for application in food packaging. Green synthesis of Ag nanoparticles (AgNPs) was achieved by a chemical reaction involving a mixture of chitosan-silver nitrate (AgNO₃) in an autoclave at 0.1 MPa, 121℃, for 15-120 s. The formation of AgNPs in chitosan was confirmed by both UV-Visible spectrophotometry and transmission electron microscopy (TEM) and the effects of chitosan-AgNO₃ concentration and reaction time on the synthesis of AgNPs in chitosan were examined. The resulting chitosan-Ag composite films were characterized by various analytical techniques and their antibacterial activity was evaluated based on the formation of halo zones around films, indicating inhibition of the growth of Escherichia coli. A fourier-transform infrared (FTIR) spectroscopy analysis showed that free amino groups in chitosan acted as effective reductants and AgNP stabilizers. The composite films exhibited enhanced antibacterial activity with increasing Ag content on the surface of as-prepared composite films.

LDPE-나노 TiO₂ 복합 필름의 기능성 및 재질안정성 평가

이우석,고성혁,Lee, Wooseok,Ko, Seonghyuk 한국포장학회 2017 한국포장학회지 Vol.23 No.2

In this work, the effects of nano $TiO_2$ on functionality and stability of low density polyethylene (LDPE) composite films were investigated for food packaging application. LDPE-nano $TiO_2$ composite films were prepared with various $TiO_2$ contents (0, 0.5, 1.0, 3.0 and 5.0wt%) by melt-extrusion and their basic properties such as crystallinity, chemical bonds and surface morphology were examined by XRD, FTIR and SEM. Ultraviolet (UV) light barrier property of as-prepared LDPE-nano $TiO_2$ composite films was also studied and the presence of nano $TiO_2$ resulted in significant improvement of UV light barrier compared to the pure LDPE film. To evaluate influence of nano $TiO_2$ on LDPE properties required as packaging material, thermal, mechanical, gas barrier and optical properties of LDPE-nano $TiO_2$ composite films were characterized with various analytical techniques including TGA, UTM, OTR, WVTR and UV-vis spectroscopy. As a result, except optical property of LDPE, no significant effects were found in other properties. Opacity of pure LDPE was greatly increased with increasing concentration of nano $TiO_2$.

LDPE-나노 ZnO 복합필름의 기능성 및 재질안정성 평가

이우석,고성혁,Lee, Wooseok,Ko, Seonghyuk 한국포장학회 2018 한국포장학회지 Vol.24 No.1

In this work, nano ZnO was introduced into low density poly ethylene (LDPE) composites films with various contents (0, 0.5, 1.0, 3.0 and 5.0 wt%) by melt-extrusion. Their basic properties such as crystallinity, chemical bonds and surface morphology were examined by XRD, FTIR and SEM. XRD patterns and FTIR peaks intensity were increased in proportion to the ZnO contents. SEM images showed well dispersed nano ZnO in LDPE composite films. Antimicrobial functionality of LDPE-nano ZnO composite films was also studied and the presence of nano ZnO resulted in significant improvement of antimicrobial functionality compared to the pure LDPE film. To evaluate influence of nano ZnO on LDPE properties required as packaging material, thermal, mechanical, gas barrier and optical properties of LDPE-nano ZnO composite films were characterized with various analytical techniques including TGA, UTM, OTR, WVTR and UV-Vis spectroscopy. As a result, except optical and mechanical properties of LDPE, no significant effects were found in other properties. Opacity of pure LDPE was greatly increased with increasing concentration of nano ZnO and tensile strength was also improved at 0.5wt% ZnO content.

In Situ Bio-Inspired Synthesis of Gold Nanoparticles on Cellulose Fiber

Bumbudsanpharoke, Nattinee,Choi, Jungwook,Ko, Seonghyuk American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.7

<P>We investigated the in situ synthesis of gold nanoparticles (AuNPs) on unbleached softwood kraft pulp via a green approach without any additional reducing agents or external linker molecules. The structure and properties of the AuNPs composite fibers were characterized by UV-Vis diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The resulting cellulose fiber-AuNPs composite exhibited an obvious change in color from pale yellow to purple, wine-red and dark brown due to surface plasmon resonance of the nanogold. UV-Vis DRS and FESEM images confirmed the formation of gold nanoparticles on the fiber surface. In FTIR spectra, the intensity of a shoulder band at about 1550 to 1650 cm(-1) assigned to phenol and electron rich aromatic methoxy functional groups in lignin decreased in fiber-AuNPs composite sheets, indicating that lignin plays an essential role in cellulose fiber-based green synthesis of nanoparticles. It was also revealed that gold nanoparticles formed on the fiber were well-defined pure metallic gold, suggesting that Au3+ ions are efficiently bio-reduced to Au-0, attributed to the electron rich lignin component, and bind to the fiber surface. The preparative procedure presented here is facile and provides a simple route to synthesize and immobilize AuNPs in an environmentally friendly manner.</P>

키토산-은나노 녹색합성 복합물질을 적용한 항균 기능성 포장지 연구

경규선(Kyung Gyusun),고성혁(Ko Seonghyuk) 한국펄프·종이공학회 2014 펄프.종이기술 Vol.46 No.2