• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.721-723
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• 1990

The sensory properties of commercial Tangmyons(starch noodle) prepared with dropping, extrusion-dropping and extrusion-cooking methods were evaluated. In addition, the effects of corn starch on Tangmyon were also examined. Tangmyon prepared with extrusion-cooking had greater intensities in color, gloss, clarity, adhesitiveness, extensibility, slickness and gumminess, except stiffness and hardness, compared to others. Increment of corn starch addition decreased the sensory attributes of Tangmyon, except stiffness and hardness.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.189-195
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• 2002

Corn starch was modified by oxidation with sodium hypochlorite (NaOCl) as an attempt to expand the application of starches in food industry. Corn starch was oxidized with 0.25, 0.5, 0.75, 1.0 and 1.5% active Cl/g starch at pH 7.0 and $25^{\circ}C$ for 10 minutes. The size, shape and amylose content of oxidized starches were similar to those of native corn starch. As the extent of oxidation increased, solubility, swelling power and the amount of soluble amylose increased, X-ray diffraction patterns changed, and relative crystallinity decreased. In Brabender amylogram, oxidation did not chance the gelatinization temperature, but oxidized starches had a lower peak in viscosity and their cooled pastes gave less setback, compared with native corn starch.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.105.2-106
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• 2003

배 폐과를 효율적으로 활용하여 식품소재나 이를 이용한 기능성식품 개발을 위하여 배 품종별 생장시기에 따른 이화학적 특성을 조사하였다. 나주 지역에서 생산한 풍수, 신고, 추황 등 3품종을 시료로 하여 생장시기에 따라 배 무게의 증가를 관찰하였고 표면의 착색도는 Hunter 색차계로 L, a, b값을 측정하였으며 수분함량은 상압가열건조법으로 측정하였다. pH와 가용성 고형물은 각각 pH meter와 refractometer로, 총산은 적정법으로 측정하여 citric acid로 나타내었다. 총당은 phenol-황산법으로, 환원당의 함량은 DNS법으로 정량 하였고 총탄수화물의 함량과 전분의 함량은 산 가수 분해시킨 후 DNS법으로 측정하였다. 유기산과 유리당은 HPLC를 이용하여 정성, 정량 분석하였다. 풍수 과중의 증가는 거의 직선적으로 증가하였고 신고와 추황은 생장전기에는 급속히 증가하다가 후기에는 완만한 증가를 보였다. 풍수는 L, a, b값이 모두 약간의 증가를 보였고 신고와 추황은 a값이 각각 -1.80, 4.01에서 9.22, 9.70으로 증가하였으며 L, b값은 큰 변화를 나타내지 않았다. 과피의 수분함량은 약 61%에서 79%로 증가하였고 과육의 수분함량은 76%에서 90%로 증가하였다. 풍수와 추황의 경우 과육의 수분함량은 생장초기에 이미 생장후기와 비슷한 수분함량 비율을 갖고 있는 것을 알 수 있었다. 3품종 모두 생장초기 총산의 함량은 수확시기의 함량보다 높았고 추황의 경우 성장이 진행됨에 따라 과피와 과육의 총산의 함량은 감소하다가 다시 약간의 증가 추세를 나타내었다. 유기산은 주로 tartaric acid, malic acid, oxalic acid, citric acid 그리고 shikimic acid가 검출되었고 수확시기에 3품종에서 모두 malic acid 함량이 가장 높았고 malic acid와 citric acid의 함량이 풍수와 신고에서는 약 0.3%, 추황은 0.4% 이상으로 나타났다. 또한 3품종 모두에서 총산과 같은 추세로 성숙기의 유기산의 함량이 생장초기의 함량보다 많이 감소되었음을 알 수 있었다. 배의 가용성 고형물은 전체적으로 과실의 성장이 진행됨에 따라 증가하는 추세를 나타내었다. 풍수와 신고 과피의 총당과 환원당은 거의 같은 추세로 증가하였고 성숙이 가까워지면서 환원당이 감소하였다. 배 과육의 총당과 환원당 또한 거의 같은 추세로 증가를 하다가 수확 전 20일 혹은 30일부터 총당의 함량은 계속 증가하지만 환원당의 함량은 큰 변화가 없는 것으로 나타났다. 배 과실의 전반 성장과정에 있어서 전분함량은 감소하였고 총탄수화물의 함량은 과육에서는 증가하나 과피에서는 반대로 감소하는 경향을 보였다. 풍수의 전분함량은 최고 2.19%에서 0.23%로 감소하였고 신고에서는 0.43%로 추황에서는 0.48%로 감소하였다. 배 유리당은 fructose, glucose, sorbitol, sucrose 둥 4종류의 당이 검출되었고 3품종 모두에서 생장과정 중 비환원당인 sucrose 함량은 계속 증가하였고 fructose, glucose, sorbitol의 함량(추황의 sorbitol을 제외)은 생장이 촉진됨에 따라 증가하다가 다시 점차적으로 감소하였다. 이러한 결과는 총당과 환원당의 측정결과와 일치한 것으로 나타났다. 결론적으로 배의 성장에 따라 산 함량은 감소하였고 당 함량은 증가하였다.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.582-592
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• 1995

To measure rheological properties of the starch dough, an Extrusion Capillary Viscometer(ECV) cell was self-made and attached to Instron machine(Model 1140). Apparent viscosities of corn and waxy corn starch doughs were measured and their gelatinization degrees were determined by enzymatic analysis. When corn and waxy corn starch doughs with $36{\sim}52%$ moisture content were heated at $60{\sim}100^{\circ}C$, come-up time of the cold point of doughs decreased from 220 sec to 140 sec with increased in the moisture content. In the measurement range of $36{\sim}52%$ moisture content and $60{\sim}100^{\circ}C$ heating temperature, both corn and waxy corn starch doughs showed pseudoplastic flow behaviors. At the same shear rate, both shear stress and viscosity of starch dough decreased as the moisture content increased. At the moisture content above 44%, the shear stress and viscosity of starch dough decreased as the heating temperature increased from $60^{\circ}C\;to\;70^{\circ}C$, but increased as the heating temperature increased from $80^{\circ}C\;to\;100^{\circ}C$. When the moisture content increased and heating temperature, the gelatinization degree of starch dough increased from about 10% to about 62%. The gelatinization degree of waxy corn starch dough was $15{\sim}20%$ higher than that of corn starch dough under the same gelatinization conditions. The effects of moisture content on the viscosity of starch dough were examined by Arrhenius equation. As the moisture content increased, viscosity of starch dough decreased. But the effect of moisture content was greater in the range of $80{\sim}100^{\circ}C$ than in the range of $60{\sim}70^{\circ}C$ heating temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.92-97
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• 1994

The reports on the chemical composition of developing job's tears seeds is very insufficient by this time. The purpose of this study was to obtain the fundamental information on chemical component of the developing job's tears seed, including starch, sugar, oil, protein, fatty acid, Alkali Digestibility Value(ADV), 100-grain weight. Two job's tears varieties in different by maturity types were analyzed for those components from 10 days after heading to maturity, with 5-day intervals. Total sugar content in seeds followed a pattern of linear increase after heading, but it started to decreased around 15 days after heading. On the other hand, starch content continued to increased until maturity and the highest increasing occurred between 15 and 20 days after heading. The protein content of seeds was decreased, while oil content was increased through the ripening process. Starch content showed a positive correlation with 100-grain weight, ADV, oil and germination percent, but it had negative correlation between total sugar and protein contents in ripening process. Maximum starch content, 100 grain weight, and germination percent obtained by quadratic equation were attained 38 to 43 days after heading. So that the physiological maturity of job's tears seeds was considered to be 40 days after heading.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.360-368
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• 2017

The objective of this research was to elucidate the physicochemical, structural, pasting and rheological properties of potato starch isolated from a foreign potato cultivar ('Atlantic') and new domestic potato cultivars ('Goun', 'Sebong', and 'Jinsun'). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and one-dimensional nuclear magnetic resonance (1D NMR) showed that the structural properties of potato starch did not vary significantly with cultivars. RVA analysis demonstrated that the 'Atlantic' starch had the highest breakdown viscosity among all potato starches. In steady shear rheological analysis, all potato starch dispersions showed shear-thinning behaviors (n =0.63-0.72) at $25^{\circ}C$. The highest apparent viscosity (${\eta}_{a,5}$), consistency index (K), and yield stress (${\sigma}_{oc}$) were observed in the 'Goun' starch dispersion. In dynamic shear rheological analysis, storage modulus (G') and loss modulus (G") values of new domestic potato starch dispersions were higher than those of the 'Atlantic' starch dispersion.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.749-755
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• 2021

The objective of this study was to investigate the physicochemical properties of rice starch extracted from stale rice using alkaline steeping (AKL) and improved enzymatic digestion (iENZ) methods. The crude protein content (0.5-0.7%) of stale rice starch (SRS) was less than 1% by iENZ, but not so when measured by the existing ENZ methods. SRS is an intermediate amylose rice starch. AKL-SRS and iENZ-SRS exhibited typical A-type crystal packing arrangements with similar relative crystallinities. iENZ-SRS showed higher gelatinization onset and peak temperatures with a narrower gelatinization temperature range, compared to those of AKL-SRS, indicating that iENZ annealed SRS. Thus, iENZ-SRS exhibited lower swelling power and solubility, and higher pasting viscosities with delayed viscosity development. Overall, the use of stale rice as a rice starch source could make economical production of rice starch possible, and iENZ may diversify rice starch characteristics, which expands the utilization of rice starch in food and non-food industries.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.747-753
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• 2013

The physicochemical properties of sweet potato (SP) starches reclaimed from an SP-processing sludge without freezing (RC/NF) and with freezing (RC/FR) were investigated. Lab-isolated (LI) SP starch, as a control, were prepared from raw SP. RC/NF and RC/FR SP starches were recovered from SP-processing sludges by the repeated sieving and washing procedure. The total starch contents and amylopectin branch-chain distributions did not differ for three SP starches. Relative to LI and RC/NF SP starches (possessing similar physicochemical characteristics), the apparent amylose and phosphorus contents, swelling factor, and pasting viscosity were reduced for RC/FR SP starch. However, the freezing treatment altered X-ray diffraction pattern (at $5.5^{\circ}$, $11-12^{\circ}$, and $24^{\circ}$ $2{\theta}$) of RC/FR SP starch, which likely increased its gelatinization peak and completion temperatures. Its amorphous region in total diffractogram was reduced, resulting in the enhanced relative crystallinity. Overall results suggested SP starches recovered from an SP-processing sludge would have the potential to replace commercial SP starch products.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1309-1315
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• 1997

Yields of enzyme-resistant starch (RS) from three kinds of maize starches (Amioca, normal starch and Amylomaize VII) which were treated with 1 N HCl for 24 hr and physicochemical characteristics were investigated. Hydrolysis rate of maize starches decreased with increasing amylose content. Maximum wavelength $({\lambda}_{max})$ and iodine affinity were decreased by the acid treatment. The yields of RS increased with acid treatment up to 12 hr and then decreased. The yield of for 12 hr acid-treated Amioca increased 8 times more than untreated sample, but those of normal starch and Amylomaize VII slightly increased. Using SEM, acid-treated and autoclaved maize starches showed gel like structure, but RS had round and rod shape small particles. X-ray diffraction patterns of autoclaved starches showed amorphous structure in Amioca and B-type in normal starch and Amylomaize VII, and those of RS showed all completely crystalline structure.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.939-946
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• 1997

Effects of moisture content on the gelatinization and recrystallization of non-waxy and waxy rice starch gels were investigated by differential scanning calorimetry (DSC). The recrystallization rates of the starch gels containing various moisture contents $(40{\sim}70%)$ were analyzed by Avrami equation. The waxy rice starch had higher gelatinization temperature and enthalpy than non-waxy one. The highest degrees of recrystallization in both rice starch gels stored at $4^{\circ}C$ were shown at 40%, and recrystallizations above 80% moisture content were not found. The degree of recrystallization of waxy one was higher than that of non-waxy one in the range of 40 to 60% moisture content. The Avrami exponents (n) of both rice starch gels were near to 1.0 and the time constant (1/k) was increased with increasing moisture content in the range of 40 to 70% moisture content. The recrystallization rate of waxy rice starch gel was slower than that of non-waxy one. The recrystallization of rice starch gels could be explained by the change of ice melting enthalpy during storage. The Wg's, represented the maximum practical amount of plasticizing water, were about 29.9% and 28.2% for non-waxy and waxy rice starch gels, respectively.