• Title/Summary/Keyword: Starch films

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The Environmental Degradability of Starch-Polyethylene Composite Film (전분-폴리에틸렌 복합필름의 환경분해성)

  • Kim, Young-Gi;Park, Young-Hoon;Im, Seung-Soon
    • Applied Chemistry for Engineering
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    • v.4 no.1
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    • pp.178-187
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    • 1993
  • Degradation of the starch-polyethylene composite film by an activated sludge treatment and a soil burial test was examined. The treated films had deformed structures which were resulted from the removal of starch during the treatments. The added auto-oxidant caused the degradation of the polyethylene matrices and the crosslinking reactions after the oxidation of polyethylene chains as well. As a result of soil burial test, the degradation reaction of the composite film containing corn oil as an auto-oxidant was, however, prevalent : number- and weight-average molecular weight of polyethylene decreased, while the molecular weight distribution increased.

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Mechanical Properties and Biodegradability of HDPE/TPS Blends (HDPE/TPS블렌드의 물성 및 생분해도)

  • 이상일;홍경민;서석훈;신용섭;김봉식;신부영
    • Polymer(Korea)
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    • v.26 no.1
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    • pp.145-151
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    • 2002
  • Thermoplastic starch(TPS) was prepared from mixing starch and glycerol by twin extruder. The blends were then prepared from high density polyethylene(HDPE) and TPS. Mechanical properties, thermal properties, and morphology of the blends were investigated. Their biodegradability was also studied by using aerobic composting method(ISO14855). Tensile strength, modulus and elongation at break decreased as the content of TPS increased. In particular elongation at break decreased rapidly even at the lower content of TPS. The melting temperatures of the blends were not changed, which showed that HDPE and TPS were immiscible. The morphology of the fractured surface of blend films was investigated by scanning electron microscopy(SEM). It was found that phases were separated. After composting for 45days, the biodegradability of the blends increased as the content of TPS increased.

A Study on Optimal Conditions by means of Experimental Design for Preparation of Starch/PVA Blends 1. Taguchi method (실험계획법을 이용한 전분/PVA 블렌드 제조 최적조건 탐구에 관한 연구 1. 다구찌 방법)

  • Lee, Myoung-Seok;Hong, Young-Keun
    • Elastomers and Composites
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    • v.40 no.2
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    • pp.128-135
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    • 2005
  • Optimal conditions for preparation of starch/PVA blends were investigated with the consideration of factors that may influence mechanical properties of the blends. $L_{27}(3^{13})$ experimental designs based on Taguchi method were performed and then tensile strength, strain at break, Young's modulus and tear strength of films of the blends were measured to determine the optimal conditions for preparation. Interaction effects for each factor were determined from analysis of variables. Results of $L_{27}(3^{13})$ experiments indicated that glycerol and urea were important process factors affecting optimization of the mechanical properties.

A Study on the Optimal Conditions by Means of Experimental Design for Preparation of Starch/PVA Blends 2. Multiplex Mixture Optimal Method (실험계획법을 이용한 전분/PVA 블렌드 제조 최적조건 탐구에 관한 연구 2, 다중혼합물 최적법)

  • Hong, young-Keun;Lee, Myoung-Seok
    • Elastomers and Composites
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    • v.41 no.1
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    • pp.3-9
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    • 2006
  • Optimal conditions for preparation of starch/PVA blends were investigated with the consideration of factors that may influence mechanical properties of the blends. Multiplex mixture optimal method as a statistical method were performed and then tensile strength, strain at break, Young's modulus and tear strength of films of the blends were measured to determine the optimal conditions for preparation. The mechanical properties needed for the degradable agricultural mulch were the target of this experiment. Results showed that although the strain at break was a little insufficient, the other properties were very close to the target. This means that the mechanical properties of the film from this blend as a whole are very compatible with those of the reference mulch.

Enhancement of β-cyclodextrin Production and Fabrication of Edible Antimicrobial Films Incorporated with Clove Essential Oil/β-cyclodextrin Inclusion Complex

  • Farahat, Mohamed G.
    • Microbiology and Biotechnology Letters
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    • v.48 no.1
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    • pp.12-23
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    • 2020
  • Edible films containing antimicrobial agents can be used as safe alternatives to preserve food products. Essential oils are well-recognized antimicrobials. However, their low water solubility, volatility and high sensitivity to oxygen and light limit their application in food preservation. These limitations could be overcome by embedding these essential oils in complexed product matrices exploiting the encapsulation efficiency of β-cyclodextrin. This study focused on the maximization of β-cyclodextrin production using cyclodextrin glucanotransferase (CGTase) and the evaluation of its encapsulation efficacy to fabricate edible antimicrobial films. Response surface methodology (RSM) was used to optimize CGTase production by Brevibacillus brevis AMI-2 isolated from mangrove sediments. This enzyme was partially purified using a starch adsorption method and entrapped in calcium alginate. Cyclodextrin produced by the immobilized enzyme was then confirmed using high performance thin layer chromatography, and its encapsulation efficiency was investigated. The clove oil/β-cyclodextrin inclusion complexes were prepared using the coprecipitation method, and incorporated into chitosan films, and subjected to antimicrobial testing. Results revealed that β-cyclodextrin was produced as a major product of the enzymatic reaction. In addition, the incorporation of clove oil/β-cyclodextrin inclusion complexes significantly increased the antimicrobial activity of chitosan films against Staphylococcus aureus, Staphylococcus epidermidis, Salmonella Typhimurium, Escherichia coli, and Candida albicans. In conclusion, B. brevis AMI-2 is a promising source for CGTase to synthesize β-cyclodextrin with considerable encapsulation efficiency. Further, the obtained results suggest that chitosan films containing clove oils encapsulated in β-cyclodextrin could serve as edible antimicrobial food-packaging materials to combat microbial contamination.

Oxidation of Primary Alcohol Groups of Polysaccharides with 2,2,6,6-Tetramethyl-1-Piperidine Oxoammonium Ion (2,2,6,6-Tetramethyl-1-Piperidine Oxoammonium Ion에 의한 다당류내 1차 알코올의 특이적 산화)

  • Chang, Pahn-Shick;Cho, Gye-Bong
    • Korean Journal of Food Science and Technology
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    • v.29 no.3
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    • pp.446-451
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    • 1997
  • The primary alcohol groups of four kinds of polysaccharides (com starch, rice starch, sweet potato starch, and cellulose), with different structures and water solubilities, were oxidized to carboxyl groups using 2,2,6,6-tetramethyl-1-piperidine oxoammonium ion (TEMPO) at $25^{\circ}C$. The optimum pH, TEMPO content, and NaBr content for the TEMPO/hypobromite-catalyzed oxidation of the polysaccharides were $10.5{\sim}11.0$, 10 mmol/mol primary alcohol, and 0.49 mmol/mol primary alcohol, respectively. The oxidation degree for the primary alcohol group was more than 90% for all four kinds of the polysaccharides. The oxidation process greatly increased the water solubility of the polysaccharides. Water-insoluble polysaccharide such as cellulose became water-soluble to the extent of 8.42% (w/v). And also, the polysaccharides with very low water solubility (less than 0.10% (w/v)) such as com starch, rice starch, and sweet potato starch had high water solubility of approximately 45%(w/v). The gel-forming abilities with calcium ion were determined. The oxidized polysaccharides are new anionic polymers with unique structures that could have application as gums, gels, and films.

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Microstructure of Recombinated Gels of Amylose and Amylopectin Isolated from Rice Starch (쌀전분으로부터 분리한 아밀로오스와 아밀로펙틴 혼합겔의 형태학적 구조)

  • Baek, Man-Hee;Shin, Mal-Shick
    • Korean Journal of Food Science and Technology
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    • v.31 no.5
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    • pp.1171-1177
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    • 1999
  • The changes on microstucture of recombinated gels with different ratio of amylose(A) and amylopectin(AP) which were isolated from nonwaxy rice starch were investigated by scanning electron microscope(SEM) and X-ray diffractometer. As the concentration of amylose was above 3%(1.08% of soluble amylose) in the amylose suspension, gel matrix became like a three-dimensional network. The microstructure of amylose gels showed a network including macroporous structure, but the higher the ratio of amylopectin content were, the firmer network were formed. In case of A/AP mixed gels(15%) with different amylose/amylopectin percent ratios ; 0/5, 5/10, 10/5, 15/0%, as the storage time of gels and the percent ratio of amylose content were increased, network was formed harder with thick films. While X-ray diffractograms of waxy rice starch which contained 100% amylopectin showed A type, those of purified amylose and amylopectin showed V type and amorphous patterns, respectively. Amylose(3%) gels added $2{\sim}3%$ amylopectin and A/AP mixed gels(15%) showed peak at $2{\theta}\;=\;17.0^{\circ}$which were shown B type crystallinity similar af retrograded starches. Also as the percent ratio of amylose content in mixed gels was increased, peak intensity wat increased.

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Studies on Salmonella enteritidis Contamination in Chicken Egg using Confocal Scanning Laser Microscopy (Confocal Scanning Laser Microscopy 를 이용한 계란에서의 Salmonella enteritidis 오염 연구)

  • Jang, Keum-Il;Park, Jong-Hyun;Kim, Kwang-Yup
    • Korean Journal of Food Science and Technology
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    • v.31 no.3
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    • pp.771-777
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    • 1999
  • The structural function of three egg membrane layers and cuticle layer, and the effectiveness of 5 film coatings (chitosan, starch, gelatin, dextrin, mineral oil) on the prevention of Salmonella enteritidis penetration was investigated using confocal scanning laser microscopy (CSLM). Diameters of outer membrane fibers, inner membrane fibers and limiting membrane particles in eggshell were $1.5{\sim}7.2$, $0.8{\sim}2.0$ and $0.1{\sim}1.4\;{\mu}m$, respectively and average thicknesses were 10.0, 3.5, $3.6\;{\mu}m$, respectively. Average thickness of cuticle layer was $6.0\;{\mu}m$ and cuticle layer covered $40{\sim}80%$ of total eggshell surface. Average coating films thickness for chitosan, starch, gelatin, dextrin and mineral oil were 2.2, 2.5, 3.9, 3.6 and $5.0\;{\mu}m$, respectively. After immersion process eggshell surface was almost completely covered by coating films. Chitosan coating was most effective among 5 film coatings in inhibiting growth of Salmonella enteritidis. Penetration process of Salmonella enteritidis through eggshell was investigated by multicolor imaging using CSLM and plate counting. Cuticle layer was the most important structure in blocking the penetration. Among 5 film coatings, chitosan showed the best and similar effectiveness with cuticle layer.

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Sorption Characteristics of Binary Mixture of Corn Starch- Soy Protein Isolates in Plastic film Packaging (Plastic필름 포장에 따른 옥수수 전분과 분리 대두단백질의 이성분 혼합물의 흡습특성)

  • Kim, Duck-Woong;Woo, Sang-Gyu
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.17 no.3
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    • pp.191-197
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    • 1988
  • Sorption properties of corn starch(CS) and Soy protein isolates(SPI) in plastic films packaging were investigates for binary system. The mixture were sealed in plastic films of low density polyethylene(LDPE), oriented polypropylene(OPP) and LDPE/OPP coated film and packaging effect on the changes of moisture sorption during storage at $40^{\circ}C$ were studied. The following results were obtained. The water vapor permeability of material films was $32.6g/m^2/24hrs(below\;g)$ for 0.02mm LDPE film, 14.01g for 0.04mm LDPE film, 7.30g for 0.02mm OPP film, 3.37g for 0.04mm OPP film and 4.869 for 0.02mm LDPE/0.02 mm OPP confine film at $40^{\cire}C$ 90%RH, therefore the OPP film was more effective than LDPE film on the resistance of relative humidity. And the OPP film packaging sealed mixture of food samples was also more elective then LDPE film, having same thickness for increase of water vapor permeability during storage at $40^{\cire}C$. A general increase in sorption rate was found more in SPI than CS in the packaged mixtures.

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A Study on the Characteristics of Paper-based Packaging Materials with Bioplastics for Roasted Coffee Beans (바이오 플라스틱을 적용한 종이 합지 커피 포장재의 제품 특성에 관한 연구)

  • Yu, Ha Kyoung;Joo, Minjung;Woo, Jung Hee;Oh, Jae Young;Lim, Hyo Seung
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.27 no.1
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    • pp.17-23
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    • 2021
  • Recent studies on recyclable materials in the packaging have an increased attention due to the eco-friendly policies of reducing carbon dioxide emissions in worldwide. Roasted coffee beans mostly packed in multi-layered films and papers according to their expiration date. To satisfy both recyclability and barrier properties, researches have been continued on paper-based packaging materials to enhance their properties. In this study, packaging materials for coffee beans are developed by laminating bioplastic films on papers. The tests of packaging materials were performed with mechanical properties, gas and water vaper permeability, recyclability and storage quality for coffee beans. Compared to other samples, the paper/bioplastics-based coffee package composed of starch coated papers and two bioplastics showed the lowest barrier properties, comparable mechanical strength and ability to maintain the quality of roasted coffee beans. Thus, it could be a good alternative for multi-layered packages for roasted coffee beans.