Effect of various heat treatments on physicochemical properties of starch-protein mixture and its application on muffin

아딘다 전남대학교 2021 국내석사

옥수수 전분은 옥수수 알의 배유에서 얻은 탄수화물로 식품, 화학, 제지, 섬유 및 기타 여러 산업에서 널리 사용된다. 옥수수 전분은 낮은 노화 특성, 낮은 페이스트 투명성 및 비수용성과 같은 특성을 가지고 있어 일부 특정 산업에서의 적용이 제한되고 있다. 따라서, 옥수수 전분의 특성을 변형하여 물리 화학적 특성을 개선하는 것이 필요하기에 본 연구에서는 효소와 칼슘 첨가와 함께 마이크로파 처리나 열수 처리와 같은 열처리 방법을 이용하여 개선하고자 하였다. 처리된 시료의 가루 특성은 열적 특성, 페이스팅 점도 특성, 겔 텍스처 특성, 유변학적 특성, 주사 전자 현미경 (SEM) 및 공초점 레이저 현미경 검사법을 통해 조사되었으며, 최적의 처리 조건을 찾기 위해 처리된 시료를 이용한 머핀의 물리적 특성 (높이, 무게 및 부피), 색도, 텍스처 및 관능 검사가 실시되었다. 전분-단백질 혼합물은 각각 총 8 분, 16 분 및 24 분 동안 20초 열처리 및 40초 방냉 주기로 마이크로파 처리되었다. 마이크로파 처리와 단백질 첨가는 옥수수 전분의 물리 화학적 특성에 유의한 영향을 미치는 것으로 나타났다. 마이크로파 처리는 시료의 호화 개시 온도(onset temperature)를 높이고 호화 및 노화 엔탈피를 낮추어 전분 구조의 안정성을 증가시킴으로써 옥수수 전분의 열적 특성을 변화시켰다. 마이크로파 처리는 또한 페이스팅 온도(pasting temperature), 최고 점도(peak viscosity), 강하점도(breakdown) 그리고 치반점도(setback)와 같은 모든 페이스트점도 지표들을 감소시켜 옥수수 전분의 페이스팅 점도 특성에 영향을 미쳤다. 페이스팅 점도 특성의 경향과 유사하게, 처리된 시료의 겔 텍스처 특성은 대조군 옥수수 전분에 비해 현저하게 감소하는 것으로 관찰되었다. 겔 경도는 주로 이액 현상과 아밀로펙틴의 결정화와 관련된 전분 겔의 노화로 인해 더 단단해진다. SEM을 통해 마이크로파 처리가 전분 표면의 손상과 파열을 일으킨다는 것이 관찰되었다. 24번 주기의 마이크로파 처리 (MWT-24) 시료는 다른 시료들에 비해 손상된 입자가 가장 많았다. 이러한 결과는 온도가 높을수록 전분 입자는 더 많이 손상된다는 것을 가리킨다. 물리적 혼합 처리 (CW-PM) 시료와 마이크로파 처리 (MWT) 시료는 30 % 의 양이 대체되어 머핀에 이용되었다. CW-PM을 첨가한 머핀은 대조군과 처리된 시료들 중에서 가장 큰 크기를 나타냈다. MWT-24를 첨가했을 때 머핀의 경도가 크게 감소한 반면, CW-PM 을 첨가했을 때는 대조군보다 높은 경도를 나타냈다. 또 다른 연구에서 전분-단백질 혼합물의 물리 화학적 특성에 대한 물리적 혼합, 열수 처리, 마이크로파 처리, 효소 및 칼슘 첨가의 효과가 조사되었다. 위에서 언급한 처리는 호화 온도를 증가시키고 용융 엔탈피와 점도 특성을 감소시켰다. 마이크로파 처리는 다른 샘플에 비해 겔 강도가 약한 결과를 보였는데, 이는 전분의 아밀로오스 함량이 낮아 겔 형성 중에 전분의 노화되는 정도가 적기 때문이다. 상호 결합된 옥수수 전분과 CaCl2는 옥수수 전분과 다른 시료들 보다 저장 탄성률(G ') 이 크고 tan δ가 작은 겔을 형성하여 변형된 전분의 겔화 능력이 향상되었음을 나타낸다. 열 처리는 전분 입자의 손상 및 약화를 초래하였다. 효소와 칼슘 첨가로 인해 더 큰 구멍을 가진 절단 구조가 나타났다. 공초점 이미지 결과에서 WPI는 전분 분자로 둘러싸여 있으며, 이는 전분과 단백질 간의 상호 작용을 나타낸다. 이 연구는 머핀 품질을 성공적으로 향상시켰으며, 처리된 가루를 이용한 머핀은 더 높은 높이와 큰 부피를 나타냈으며, 특히 마이크로파 처리 시료에서 머핀의 경도를 감소시킴으로써 머핀의 노화를 지연시켰다. 관능 검사 결과, 칼슘과 효소 처리 (Ca-AFN) 시료를 이용한 머핀이 소비자 기호도를 증가시켰다. Corn starch is a carbohydrate obtained from endosperm of the kernel, widely utilized in the food, chemical, paper, and textile industries, as well as many others. Corn starch has some properties, such as low retrogradation properties, low paste transparency and insolubility in water, which limit its application in certain industries. Therefore, it is necessary and important to modify these properties of corn starch, aiming at improving physicochemical properties of corn starch using heat treatment such as microwave and hydrothermal treatment, with enzymes and calcium addition. The flour properties of treated samples were examined for thermal properties, pasting properties, gel texture properties, rheological properties, scanning electron microscopy (SEM) and confocal laser microscopy, and muffin characteristic were investigated through the physical properties (height, weight, and volume), color, texture and sensory evaluation to find the appropriate treatment condition. Starch-protein mixtures were treated by microwave radiation in cycles of 20s radiation and 40s downtime for total of 8 min, 16 min and 24 min. Microwave treatment and protein addition showed significantly affected on physicochemical properties of corn starch. Microwave treatment changed the thermal properties of corn starch, leading to a more stabilize starch structure by increasing the onset temperature and decreasing the gelatinization and retrogradation enthalpies of microwave treated samples. Microwave treatment also influenced the pasting properties of corn starch, by decreasing all pasting properties parameters such as pasting temperature, peak viscosity, breakdown, and setback. Similar trend with pasting properties, gel texture properties of treated samples was significantly decreased, compare with corn starch as control. The gel hardness is mainly caused by retrogradation of starch gels, which is associated with the syneresis of water and crystallization of amylopectin, leading to harder gels. SEM showed that microwave treatment caused the damaged and ruptured the starch surface. Microwave treatment with 24 cycles (MWT-24) showed the most damaged granules than other samples. This observation indicated that the higher temperature, the more damaging starch granules. Physical mixture (CW-PM) and microwave treatment (MWT) samples were applied into muffin, with 30% substitution. Muffin with CW-PM addition showed bigger size among control and treated samples. Substitution of MWT-24 resulted significantly decreased the muffin hardness, while substitution of CW-PM resulted the higher hardness than control. The other study was explored the effect of physical mixing, hydrothermal treatment, microwave treatment, enzymes, and calcium addition on physicochemical properties of starch-protein mixture. The treatments mentioned above increased the gelatinization temperature and reduced the melting enthalpy and viscosity properties. Microwave treatment resulted in weaker gel strength than other samples, attributed to lower amylose content of starch which caused less retrogradation of the starch during gel formation. Cross-linked corn starch and CaCl2 forms a gel with larger storage modulus (G’) and smaller loss modulus (tan δ) than the corn starch and other samples, suggesting improved gelling-ability of the modified starch. Heating treatment exhibited damaged and eroded of starch granules. Enzyme and calcium addition resulted in truncated structure with a bigger hole. From confocal imaging result, whey protein isolate (WPI) was surrounded by starch molecules, indicated interaction between starch and protein. This study successfully improved the muffin quality; muffins with treated flour had higher height and bigger volume, also retarding the stale of muffin by decreasing the muffin hardness, especially microwave treated samples. Based on sensory evaluation, muffin with calcium chloride and enzyme treatment (Ca-AFN) sample substitution increased the consumer acceptance.

Synthesis of polysaccharide nanoparticles with well-defined size and shape through molecular self-assembly process in aqueous environment

이다희 경희대학교 대학원 2018 국내석사

Starch is an abundant, renewable, low cost, and biodegradable carbohydrate polymers, which is regarded as a promising green material for producing different sizes of crystals and particles, which have been extensively used for various bio-applications, including drug delivery, biosensing and emulsifier. Herein, the aim of this study is to develop a convenient and green approach to fabricate chitosan starch-based nanoparticles (CS-SNPS), which have a uniform shape and well-defined size ranging from 20 nm to 1 µm. The debranched starch (DS) were successfully prepared by using pullulanase that could debranch the amylopectin obtained from waxy maize starch. Importantly, we found that the chitosan polymers could enhance the assembly of DS by electrostatic interaction, leading to rapid self-assembly of uniform CS-SNPs, increasing the yield of crystals synthesis. The characteristics of CS-SNPs were evaluated via Raman spectroscopy, Zeta potential, UV/Vis spectrophotometer, X-ray diffraction (XRD) and Optical microscopy. In addition, scanning electron microscopy (SEM) analysis demonstrate that the size of CS-SNPs could be effectively controlled through mediation of the concentration of DS. The self-assembly of CS-SNPs is simple but effective method to fabricate the size-controllable particles, opening new possibilities for various applications such as drug delivery, adsorbent for water pollution and antimicrobial agent for packaging. 상기 문헌은 SEM, Spectrophotometer, Zeta potential, XRD 그리고 DSC 결과를 결과를 통해서 가지가 잘린 전분의 자기조립 동안에 키토산이 준 영향에 영향에 대하여 확 인 하는 실험이다 . 키토산 -전분 기반 입자의 형성 과정은 시간 별로 만들어 진 입자의 형태를 SEM을 통해 관찰 함으로써 확인 되었다 . 키토산을 넣지 않 고 입자를 형성하는 동안에는 응집 현상이 일어 났지만 났지만 , 키토산이 포함된 상 태에서 입자를 형성한 결과물들은 응집이 되지 않고 사이즈가 균일한 입자 들이 얻어졌다 . 특히 , 키토산과 함께 반응하여 형성된 입자의 사이즈는 마이 크로 사이즈에서 나노사이즈로 사이즈가 줄었다 . XRD와 DSC결과를 통해 만 들어진 입자의 결정성 그리고 결정구조에 차이가 없는 것으로 것으로 보아 , 입자가 입자가 만들어지는 동안에 키토산은 입자 내부에 포집되어진 것이 아니라 , 입자가 만들어진 후에 입자 표면에 흡착된 것으로 보여진다 . 이는 또한 시간 별로 형성된 입자의 표면 전하를 확인 함으로써 입증 될 수 있었다 . 더불어 , turbidity와 zeta potential 결과를 통하여 키토산이 입자 형성 과정인 성장 단계 에 영향을 준 것을 알 수 있었다 . 초기 단계인 핵 형성 단계에서는 키토산의 키토산의 유무와 상관없이 turbidity와 표면 전하의 차이는 없었다 . 하지만 , 성장 단계 동안에는 chitosan과 반응 용액의 경우 , turbidity 확연히 증가 하였으며 , 표면 전하 또한 chitosan과 형성된 입자의 상호 작용에 의해 표면전하가 표면전하가 양전하를 양전하를 띄었다 . 이러한 결과를 통해 입자가 핵 형성 그리고 성장 단계를 거칠 때, 입자들간의 유착을 키토산의 키토산의 정전기적 반발력을 통해 막아 줄 수 있었다 . 따 라서 , 이러한 이유 로 입자가 합성과정 중에 응집되지 않고 독립된 독립된 형태로 입 자의 크기가 증가 할 수 있었다 . 또한 , 입자형성에 필요한 가지 잘린 전분의 양과 debranching된 정도를 조절 함으로써 나노범위에서 마이크로 범위까지 범위까지 사이즈가 조절된 키토산 -전분 기반 입자가 형성 될 수 있음을 확인하였다. 이러한 형성된 나노대의 작은 입자들은 종이 코팅제 코팅제 , 지방대체제 , 유화안정 유화안정 유화안정 제로 응용 될 수 있다 . 또한 , 키토산의 항균 작용 그리고 소장의 융모에 부 착 될 수 있는 특성을 이용하여 , 항균 포장제 그리고 약물전달체로 사용할 수 있는 등 다양한 분야에 사용될 수 있는 가능성을 가지고 있다.

Effect of pregelatinization and dry-heating for physical modification of Indica rice starch

양유진 高麗大學校 大學院 2016 국내석사

Normal Indica rice (IR) starch was physically modified by pre-gelatinization and dry heating, freeze drying and dual modification (dry heat treatment of pre-gelatinized and freeze dry treatment of pre-gelatinized starch). The effects of the physically modified rice starches examined by pasting viscosity, thermal properties, X-ray diffraction pattern, and starch digestibility. Pregelatinized starch was conducted by pasting a starch dispersion (10% solids) at 100 ℃ for 5,10,15 min and entire dispersion dried at 80℃ oven dry or -80℃ freeze dry by carrying dry condition. Starch dried under 80℃ after pre-gelatinization showed substantial changes to that of native starches exhibiting peak viscosity, breakdown and setback and gelatinization time was shortened. In starch dried under -80℃ after pre-gelatinization, initial viscosity was increased and setback and breakdown were not represented. Viscosity of dual modified samples (dry heat treated by oven dry and freeze dry after pre-gelatinization) was measured. The dual modification with IR (pre-gelatinization and dry heating) resulted in more significant changes in pasting viscosity as compared to the corresponding unmodified and pre-gelatinized starch. However, in case of the dual modification with IR (pre-gelatinization and freeze drying), it was observed as similar pattern to that before pre-heating excepting only its initial viscosity was further reduced. Viscosity change features depending on particle and temperature condition (60℃ – 80℃) was explored by treating dry heated samples under 130℃ for 2 hours after pre-gelatinization with ethanol. Viscosity change depending on particle size was not observed and viscosity (including peak viscosity) of sample dried under 80℃ was observed to be more increased than that under 60℃. As a result of observing differential scanning calorimetry (DSC), most of the samples were changed to amorphousness by pre-gelatinization and an effect by dry heating was hardly represented and in a sample treated with ethanol, endothermic peak was observed. In addition of observing intensity of X-ray diffraction, native rice starch was observed as A-type but samples treated with pre-gelatinization and dry heating were observed to be deformed to V-type. In case of digestibility, SDS content was increased in samples treated with pre-gelatinization and dry heating and ethanol compared with samples treated with pre-gelatinized or dry heating starches. In addition, it could be confirmed that gelatinization of starch could be shortened and viscosity enhanced starch could be applied to instant diet food material by manufactured it through physical modification and its resultant increase of SDS content.

Preparation of starch nanoparticles using acid hydrolysis followed by batch-type ultrasonication

남궁훈 高麗大學校 大學院 2016 국내석사

Starch nanoparticles can be used for various purposes such as a food ingredient, pharmaceutical drug delivery system and paper coating agent. For apply starch nanoparticles to these industries, in this study, we made starch nanoparticles using batch-type ultrasonication followed by acid hydrolysis under time dependent conditions (acid hydrolysis and ultrasonication time). Waxy maize starch was hydrolyzed in aqueous sulfuric acid solution (3.16 M) for 6, 12, 18, 24, 36 and 48 h, and recovered by centrifugation. The precipitates were neutralized with 1 M of NaOH and washed twice with distilled water to remove the residual salts. The starch hydrolysates were re-dispersed into water (1.5 %, wet basis) and mildly homogenized prior to ultrasonication for good dispersion. During the ultrasonication process, the starch hydrolysates were fragmented to nanoparticle by the cavitation effect of ultrasonicator. The end product of this study was the ultrasonication treated starch hydrolysate solution. The experimental results indicated that as the acid hydrolysis time increased, the yield of starch hydrolysates decreased and crystallinity of starch hydrolysates was slightly increased in the peak intensity of the X-ray diffraction pattern. Moreover, observed under the light microscope, more cracks were detected on the surface of the starch by acid hydrolysis. And over the hydrolysis time of 36 h, starch granules had lost its shape and totally hydrolyzed. As the ultrasonication time increasing, transmittance also increased and particle size of starch decreased. However, starch nanoparticles were continuously aggregated after ultrasonication treatment. As a conclusion, acid hydrolysis for 24 h was the suitable time for breaking most of the amorphous parts in the starch. By the ultrasonication treatment, starch hydrolysates were broken and the final particle size of starch in solution was 345 nm on the DLS results (transmittance of 70%).

Development of Waxy Starch Potatoes(Solanum Tuberosum L cv Atlantic) Using Anti-Sense Inhibition of Granule-Bound Starch Synthase : Granule-Bound Starch Synthase (GBSS) 유전자 발현 억제 기술을 이용한 찰성 감자 개발 연구

서명규 成均館大學校 大學院 2003 국내박사

Starch consists of two major polymers, named amylose and amylopectin produced by higher plants. These polymers have the same basic structure but difference in thier length and degree of branching, which ultimately affects the physicochemical properties and industrial process. To make waxy starch mutants using genetic alteration by anti-sense inhibition of granule bound starch synthase (GBSS) in potato, We isolated total RNA and cloned GBSS gene using RT-PCR from potato plants. The full length cDNA of GBSS was 1,824 bp long and encoded 607 amino acids. Plant expression vector was constructed with anti-sense GBSS after the confirmation of GBSS protein expressing in Escherichia coli. The anti-sense GBSS gene was introduced into potato plants by Agrobacterium mediated transformation. Ten transgenic potatoes were sucessfully grown in field condition and harvested tubers. Transgenic potatoes showed the significant reduction of amylose contents from 12%-17% while wildtype was 25% amylose contents in potato tuber starches. The inhibition of GBSS regulated starch composition in potato will be useful for extending not only house consumption of potato but also industrial processing. The increase of reducing sugar contents and irregular structure of starch granules in transgenic potatoes maybe required more detail studies.

Restructuring starch molecules by various physical treatments

예상진 경희대학교 대학원 2023 국내박사

Starch is one of the biopolymer compounds used for various purposes in various industrial fields. However, native starch has various disadvantages such as low cold water solubility, heat instability, and retrogradation. To solve these disadvantages, it has been modified with various chemical, enzymatic, and physical treatments. However, as the number of consumers interested in health and the environment has increased recently, negative perceptions of enzymatic and chemical treatment are increasing. In line with this trend, "clean label" materials that do not add chemicals or produce by-products are drawing attention, and interest in research on physically modified starch continues to rise. The physical deformation method is divided into thermal treatment and non-thermal treatment. First, the thermal treatment and the non- thermal treatment were continuously treated, and then the drying method was applied differently. And the effect of continuous physical treatments according to the type of starch was confirmed. Through the continuous physical treatment of soaking and freezing, the effects of water penetration and ice crystal formation on starch types with different crystalline types were investigated. The results show that the internal structure of the starch can be changed through continuous thermal treatment/non-thermal treatment arrangements in the B-type starch, which is relatively easier to move water than the A-type starch. Second, by using high hydrostatic pressure treatment, which is a non-heating treatment technology widely used for various purposes in the food industry, the effect on different types of starch was confirmed. Through this investigation, it was confirmed that the ultra-high pressure sensitivity was significantly different even among starches with the same crystallinity, and it was also found that starch, which had relatively free water movement in the first study, showed strong resistance to ultra-high pressure. Through the response surface methodology, the dependence of each pressure-induced gelatinization factor was confirmed, and ultra-high pressure treatment conditions used in future experimental designs were established. Based on the conditions obtained in this way, the conventionally used heat annealing method was replaced with pressure, and through this, a new physical method, Pressure Annealing Treatment, was presented. Since the starches prepared in this way show opposite tendencies even in the same type of crystalline form, continuous research is needed because they show different effects from previous physical treatments. Third, the existing method for preparing cold water soluble starch made by heat treatment was replaced by pressure treatment, which is a non-thermal treatment method. After the crystallinity completely disappeared using pressurization, it was spray-dried to prepare amorphous granular starch (AGS). The produced P-AGS-SD exhibited significantly different physicochemical properties from the AGS produced and used in the past. It was partially dissolved in cold water but did not form a gel. When heated, a gel similar to the existing AGS was formed, but there was a difference in the hydration phenomenon and gel strength. In addition, it was confirmed that the reheating treatment showed very high viscosity stability. This research confirms that it is possible to develop a new physical modified starch with new physicochemical characteristics by arranging the heated or non-heated physical treatment individually in two or three steps. The eco-friendly material developed in this way is expected to be applied to various fields as clean label materials.

Physicochemical and digestion properties of psyllium husk powder-starch-alginates based mixtures

임소현 서울대학교 대학원 2016 국내석사

Native corn starch is utilized not only in many processed food products, but also in nonfood industrial applications. However, they have limited industrial uses due to their low process tolerance within a commercial manufacturing process. Hence, formulating starch with soluble dietary fiber is viewed as an efficient way of improving its poor processability. Psyllium husk powder can be a useful source for formulating with starches due to its highly viscous form when in contact with water and its unique therapeutic effect. This study aimed to elucidate the influences of psyllium husk powder concentration on physicochemical and digestion properties of starch and to further develop psyllium-starch-alginate beads for applications of natural polymer in food. Formulating starches with increasing psyllium husk powder concentration delayed digesting time up to 4 hrs compared to the control. The addition of psyllium husk powder brings a slow release of glucose in simulated system of small intestine. The extent of glucose binding to fiber increased from 20.54 to 79.95 as the psyllium husk powder concentration increased from 1% (w/v) to 2% (w/v). The apparent viscosity continuously increased, considerably contributing to overall rheological flow behavior. Psyllium husk powder played an important role in reducing digestibility of starch and glucose permeability. The physical properties of psyllium husk powder including water holding capacity, viscosity, and swelling capacity mainly contributed to a promising controlled glucose release behavior of psyllium husk powder-starch-alginate beads. Binary mixtures of psyllium husk powder, starch, and sodium alginate can provide potential controlled polymer-based matrix systems.

Effects of Normal Maize Starch and Waxy Maize Starch to Properties of Starch-Acrylate Emulsion Binder for Flame Retardant Expandable Polystyrene Foam

김세준 서울대학교 대학원 2021 국내석사

Starch acrylate emulsion (St-AcE) binders which contain normal maize starch and waxy maize starch were successfully polymerized. FT-IR spectroscopy analysis confirmed that starch was grafted to the acrylate copolymer matrix. Viscosity measurement, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were performed and clarified that starch concentration and types of starch affected viscosity, glass transition temperature (Tg) and thermal stability of St-AcE binders. St-AcEs, methylene diisocyanate (MDI) crosslinker, expandable graphite and aluminum tri-hydroxide were mixed together to prepare flame retardant coating suspension. Prepared suspensions were coated on the EPS beads and coated beads were steam heated in the mold to prepare flame retardant expandable polystyrene foam (FR-EPSF). Cone combustion test, horizontal combustion test and 3 point bending test were performed to evaluate flame retardant property and mechanical property of FR-EPSF samples. Scanning electron microscopy (SEM) observation was performed to observe micro-scale morphology of char residue of FR-EPSF samples after cone combustion test. FR-EPSF samples with St-AcEs showed enhanced flame retardant and mechanical property than FR-EPSF with neat acrylate copolymer binder (control). The enhanced properties affected by char forming ability of starch and crosslinking between starch and MDI. According to the thermogravimetric analysis (TGA) results, the St-AcEs recorded higher amount of char residue at 800°C than control. FT-IR spectroscopy analysis confirmed that the reaction between hydroxyl groups in starch and acrylate copolymer chain and isocyanate groups in MDI formed urethane linkage which crosslinked starch, MDI and acrylic copolymer together. TGA result of blends of St-AcEs and MDI confirmed that the formed network showed enhanced thermal stability at 370~800°C range and higher amount of char residue at 800°C compared with the TGA result of St-AcEs themselves. St-AcEs with amylopectin rich waxy maize starch showed better flame retardant property, thermal stability and mechanical property than St-AcEs with amylose rich normal maize starch in FR-EPSF system. It seems that the highly branched amylopectin formed more crosslinking with MDI than linear amylose molecules. 본 논문에서는, 옥수수 전분과 찰옥수수 전분, 두 종류의 전분을 이용해 전분-아크릴 복합 에멀젼(St-AcE)을 중합하고, 이를 난연 발포폴리스티렌폼(FR-EPSF)의 바인더로 적용하여 두 종류의 전분이 St-AcE의 물성과 FR-EPSF의 난연 성능 및 기계적 성질에 미치는 영향을 알아보고자 하였다. 아밀로오스를 28% 가량 함유한 옥수수 전분과 아밀로오스 함량이 2% 미만인 찰옥수수전분 (Amioca)을 in-situ 방법으로 스티렌, 아크릴계 모노머들과 공중합하여 St-AcE를 성공적으로 중합하였다. 적외선 분광분석 (FTIR) 을 통해 에멀젼 내에서 전분이 아크릴 고분자에 그라프팅된 것을 확인하였다. 점도 측정, 시차주사열량분석(DSC), 열중량 분석 (TGA) 를 통해 전분의 종류 및 함량에 따라 St-AcE의 점도, 유리전이온도(Tg), 열적 성질이 변화하였다. St-AcE를 메틸렌 다이페닐 다이이소시아네이트 (MDI) 가교제, 팽창흑연, 수산화알루미늄과 함께 혼합하여 난연코팅액을 만든 뒤, EPS 비드에 코팅하고, 코팅된 비드를 몰드에 넣고 스팀가열하여 FR-EPSF를 제조하였다. 제조한 FR-EPSF 샘플들로 콘연소 테스트, 수평연소시험을 실시하여 난연성능을 평가하였고, 콘연소테스트 후의 FR-EPSF 샘플들의 재 잔여물을 주사전자현미경(SEM)으로 관찰하여 FR-EPSF 재 잔여물의 미세 구조를 관찰하였다. 3점 굽힘 시험을 통해 FR-EPSF 샘플들의 기계적 성능을 평가하였다. 전분이 미함유된 아크릴 에멀젼 (control)을 바인더로 사용한 FR-EPSF 샘플 대비 St-AcE를 바인더로 사용한 FR-EPSF 샘플이 더 개선된 난연성능과 기계적 성질을 보였다. 이는 전분의 고온에서의 재 형성 능력과 MDI와 전분 간의 가교 결합의 영향으로 보인다. TGA 결과 St-AcE는 control 대비 고온 (800°C)에서 더 많은 재를 형성하는 것으로 나타났다. 전분과 MDI의 혼합물을 FT-IR로 분석한 결과, 우레탄 결합이 형성됨을 확인하였고, St-AcE와 MDI의 혼합물과 St-AcE 자체의 TGA 데이터를 비교하였을 때, St-AcE와 MDI의 혼합물이 St-AcE 자체보다 370~800°C 구간에서 더 우수한 열안정성을 보임과 동시에 800°C 에서 더 많은 재를 형성하였다. 아밀로오스 함량이 낮은 Amioca가 함유된 St-AcE로 제조한 FR-EPSF 샘플이 아밀로오스 함량이 높은 옥수수 전분을 함유한 St-AcE로 제조한 FR-EPSF 샘플 대비 더 우수한 난연성능, 열안정성 및 기계적 성질을 보였다. 이는 선형 구조의 아밀로오스보다 가지가 많은 구조의 아밀로펙틴이 MDI와 더 많은 가교 결합을 형성하기 때문인 것으로 보인다.

Phytate-mediated phosphorylation of starch using phytase and rice bran extract

이현정 고려대학교 대학원 2021 국내석사

Phytate (a constituent of cereal crops) can be used for starch modification as a natural phosphorylation agent to avoid concern about chemical modification. In this study, rice bran extract including phytate and phytase were used for phosphorylation of rice and maize starches, and the physicochemical properties of starches were investigated. Rice and maize starches were dispersed in rice bran extract and phytase at pH 7, and subjected to dry-heat treatment at 130 °C for 12 h. Characteristics of starch phosphorylated using rice bran extract were detected by rapid visco analyzer (RVA), 31P nuclear magnetic resonance (31P NMR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). Also, clarity, solubility, and swelling power of phosphorylated starch were determined. Increased phosphorus content was observed in rice and maize starches treated in the presence of rice bran extract at 130 °C. 31P NMR results indicated that residual phytate was interacted with starch in the form of monostarch monophosphate. Both rice and maize starches phosphorylated using rice bran extract, resulted in increased peak viscosity and decreased pasting temperatures, melting temperatures and enthalpy. Also, increased paste clarity, solubility, and swelling power were observed in starch phosphorylated using rice bran extract. However, the effect of phytase on the functional and physicochemical properties varied depending on botanical source of starches. As a result, rice bran extract can be effectively used for phytate-mediated phosphorylation, and phytase activity can affect physicochemical characteristics of phosphorylated starch. The starch modification using rice bran extract can be applied by replacing chemical modification in the food industry as starch can be efficiently modified using natural agent. 천연전분의 기능적, 물리화학적 특성을 개선시키기 위해 다양한 전분 변성 방법이 식품 산업에서 적용되어 왔다. 하지만, 화학적 변성방법에 대한 우려가 증가하고 있어, 이를 대체하기 위해 천연소재를 활용한 전분 변성 방법이 도입되고 있다. 따라서 본 연구에서는 쌀겨 추출물 첨가하여 쌀전분과 옥수수전분의 인산화를 유도하고 피트산 분해효소의 효과를 알아보고자 인산화 전분의 물리화학적 특성을 확인하였다. 전분을 쌀겨추출물에 pH 7 조건에서 분산하고 피트산 분해효소를 첨가하여 130 ℃에서 12시간동안 건열처리 하였다. 전분의 페이스트 특성, 결합구조, 결정성, 열전이 특성을 측정하였고, 페이스트 투명도, 용해도, 팽윤력도 확인하였다. 쌀겨 추출물과 인산화를 유도 시 전분피트산의 인산일전분을 형성하며, 인산화하였을 때 천연전분과 대조군에 비해 높은 최고점도와 낮은 호화개시온도를 보였다. 이 외에도 용융온도와 용융엔탈피가 감소하였고, 페이스트 투명도, 용해도, 팽윤력은 증가함을 확인하였다. 반면에, 피트산 분해효소의 효과는 전분의 종류와 기능적, 물리화학적 특성에 따라 다른 양상을 보였다. 따라서 본 연구에서 이용된 쌀겨추출물을 이용한 변성방법은 전분을 인산화에 적용할 수 있고, 피트산 분해효소 첨가를 통해 전분의 특성을 변화시킬 수 있음을 확인할 수 있었다. 쌀겨추출물을 이용한 변성방법은 천연소재를 활용하며 효율적으로 전분의 변성이 가능하기에 향후 식품산업에서 화학적 변성방법을 대체하여 적용이 가능할 것으로 보인다.

New drug delivery system and/or nutrient delivery system using infusion technology with starches as a carrier material

최승현 경희대학교 대학원 2022 국내박사

Drug delivery systems (DDS) and nutrient delivery systems (NDS) comprise one of the fastest growing areas in the healthcare sector, as well as an area of great promise for future technologies. The use of starches in DDS and NDS has many advantages, such as reduced side effects, better patient acceptance and improved safety. In addition, various starches have different properties depending on the species, origin, and treatment of the starch. The first, the objective of the first study was to find possibility to develop new drug delivery systems (DDS) and nutrient delivery systems (NDS), using starch as a carrier material for infusion technology. Corn, waxy rice, non-waxy rice, and potato starches were used as carrier materials. Sodium fluorescein was used as an infusion material for easy detection. Each starch suspension with sodium fluorescein was reacted in a water bath at 40, 50, and 60 ℃ for 30 min. After each reaction, the concentration of sodium fluorescein in the supernatant was measured using a fluorescence detector. Precipitated starch was observed using fluorescence microscopy. About 70% of sodium fluorescein infused in waxy rice and corn starches at 60 ℃. Additionally, the granules of these two starches were luminous by green light when exposed to a fluorescence detector, suggesting that corn and waxy rice starches can be used as carrier materials in infusion technology for DDS and NDS. The second study was to investigate the effects of concentration, temperature, and time on infusion of fluorescein into corn and waxy rice starches and their controlled release pattern. At low fluorescein concentration (1 μM), temperature significantly affected infusion efficiency. At high fluorescein concentration (50-150 μM), temperature showed little effect; fluorescein concentration significantly affected infusion efficiency. Corn starch showed relatively higher infusion efficiency than waxy rice starch at high concentration. During controlled release, 50% and 81% of infused fluorescein were released from corn and waxy rice starches, respectively, after bacterial α-amylase treatment. However, 61% and 68% of infused fluorescein were released from corn and waxy rice starches, respectively, after pancreatic α-amylase treatment. The dextrose equivalent (DE) value revealed similar patterns, suggesting that degradation of starch by different α-amylases is a major factor affecting release of fluorescein from starch granules. Moreover, granule size of starch greatly affected enzymatic hydrolysis and controlled release in this system.