• Korean journal of food and cookery science
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• v.32 no.4
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• pp.458-465
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• 2016

Purpose: Bokbunja (Rub coreanus Miquel), mulberry and blueberry have been reported to have powerful anti-antioxidant and anti-aging activities. The purpose of this study was to compare the quality characteristics and antioxidant activities of gravy sauce added with Bokbunja, mulberry and blueberry. Methods: Quality characteristics pH, brix, color and sensory characteristics of samples were evaluated. Antioxidant activities of samples were compared using total phenol, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical scavenging and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities. Results: Mulberry juice showed significantly (p<0.05) higher values of pH and $^{\circ}Bx$ compared to Bokbunja and blueberry juice. Bokbunja juice also had significantly (p<0.05) higher value of Color-L value than mulberry and blueberry juice. The total phenol contents and ABTS cation radical scavenging activity of Bokbunja juice were 236.50 mgGAE/100 g and 61.66%, respectively, which were significantly (p<0.05) higher than those of blueberry and mulberry juice. pH value of gravy sauce added with mulberry (MBS) was 4.67, which was significantly higher than that of the control gravy sauce (GS) and gravy sauce added with Bokbunja (BJS) which had the lowest (p<0.05) pH value 4.33. $^{\circ}Bx$ of GS (13.50) was not significantly different from that of MBS and BBS. However, BJS showed the lowest (p<0.05) value $12.33^{\circ}Bx$. Total phenol contents and ABTS cation radical scavenging activity of BJS were 78.09 mgGAE/100 g and 14.47%, respectively, which were significantly (p<0.05) higher than those of MBS or BBS. Values of sensory characteristics color, sour aroma and sour flavor of BJS were significantly (p<0.05) higher value than those of other samples. Conclusion: Bokbunja juice and gravy sauce showed higher antioxidant activities and higher acceptance test compared to blueberry and mulberry. Thus, Bokbunja has the potential to be added to as high value products in the food industry.

• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.581-587
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• 2014

The antioxidant and alcohol-degrading enzyme activities of soybean sprout sugar solutions (oligosaccharide and sucrose, $50^{\circ}Bx$) were characterized under different soaking conditions. The ratio of sugar solution to sprout content was 25%, 50%, and 75% (w/w), and the soaking times studied were 1, 3, 6, 12, and 24 h. Higher 1,1-diphenyl-2-pycrylhydrazyl (DPPH) radical-scavenging activity was detected in case of the oligosaccharide solution, compared to the sucrose solution. A similar tendency was observed for alcohol-degrading enzyme activity. When the ratio of sugar solution to sprout content was 50% (w/w), the total phenol and flavonoid contents were found to be higher, compared to those observed at 20% (w/w). However, we did not observe a significant difference between 50% and 75% (w/w). Soaking time did not significantly affect the antioxidant and alcohol-degrading enzyme activities of the solutions. As a result, when oligosaccharide solution was used for soaking soy sprouts at a ratio of >50% (w/w), higher antioxidant and alcoholdegrading enzyme activities were observed.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.6
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• pp.1007-1017
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• 2015

This study compared the physicochemical characteristics, proximate composition, taste compound, and antioxidant properties of Sikhye prepared with berries. Proximate composition and color were significantly different depending on the type of berry, whereas crude fat content and pH were not. The highest brix degree was $18.92^{\circ}Bx$ in strawberry Sikhye. Total free sugar, glucose, and fructose contents were highest in blueberry Sikhye. Titratable acidity, total acidity, and organic acid contents were highest in raspberry Sikhye. Analysis of relative antioxidative properties indicated that bokbunja Sikhye had the highest total polyphenol, flavonoid, and anthocyanin contents, highest DPPH radical scavenging ability, and highest reducing power and ferric reducing abilities in plasma. Principal component analysis suggests that bokbunja Sikhye has strong antioxidant and sweetness properties.

• The Korean Journal of Food And Nutrition
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• v.30 no.3
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• pp.609-617
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• 2017

This experiment was carried out to enhance the availability of blackberry. Since it is difficult to use blackberry as a fresh fruit, we investigated the quality characteristics of blackberry powder obtained by various drying methods (freeze drying and hot-air drying at $40{\sim}80^{\circ}C$). The L- and b-values of freeze-dried powder was higher than hot-air dried powder. The pH (3.2) was lowest and the acidity (14.4%) was highest in freeze-dried powder. In freeze drying, the brix degree was $65.7^{\circ}Bx$, but it increased from $54.7^{\circ}Bx$ to $68.5^{\circ}Bx$ with increasing temperature during hot air drying. The total polyphenol and flavonoids contents were the highest in freeze-dried powder, at 9.3 and 6.2 mg/g, respectively. The levels increased as temperature increased in hot air drying. Anthocyanin content in freeze-dried powder was 8.51 mg/g, while it sharply decreased to 1.17~2.45 mg/g in hot-air drying. Vitamin C content in freeze drying ($979.4{\mu}g/g$) was higher than that in hot-air drying ($48.3{\sim}303.2{\mu}g/g$). The sample concentration required for 50% reduction of DPPH free radical scavenging ($RC_{50}$) was $79.7{\mu}g/mL$ in freeze drying, and showed high antioxidant activity. Also it decreased from $122.4{\mu}g/mL$ to $87.7{\mu}g/mL$ with temperature increase during hot air drying. We therefore conclude from the above results that freeze drying is more suitable for the production of blackberry powder, because this method showed high value of chromaticity, total polyphenol, flavonoid, anthocyanin content, vitamin C and antioxidant activity.

• Food Engineering Progress
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• v.15 no.4
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• pp.324-331
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• 2011

Hyperspectral reflectance imaging technology was used to predict internal quality of cherry tomatoes with the spectral range of 400-1000 nm. Partial least square (PLS) regression method was used to predict firmness, sugar content, and acid content. The PLS models were developed with several preprocessing methods, such as normalization, standard normal variate (SNV), multiplicative scatter correction (MSC), and derivative of Savitzky Golay. The performance of the prediction models were investigated to find the best combination of the preprocessing and PLS models. The coefficients of determination ($R^{2}_{p}$) and standard errors of prediction (SEP) for the prediction of firmness, sugar content, and acid content of cherry tomatoes from green to red ripening stages were 0.876 and 1.875kgf with mean of normalization, 0.823 and $0.388^{\circ}Bx$ with maximum of normalization, and 0.620 and 0.208% with maximum of normalization, respectively.

• Journal of applied mathematics & informatics
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• v.38 no.1_2
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• pp.1-12
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• 2020

In this paper, we solve the difference equation $x_{n+1}={\frac{x_nx_{n-2}}{ax_n-bx_{n-2}}}$, n = 0, 1, …, where a and b are positive real numbers and the initial values x_-2, x_-1 and x₀ are real numbers. We also find invariant sets and discuss the global behavior of the solutions of aforementioned equation.

• Bulletin of the Korean Mathematical Society
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• v.35 no.2
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• pp.319-324
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• 1998

The equation AX = BX implies $A^*X\;=\;B^X$ when A and B are normal (Fuglede-Putnam theorem). In this paper, the hypotheses on A and B can be relaxed by usin a Hilbert-Schmidt operator X: Let A be p-quasihyponormal and let $B^*$ be invertible p-quasihyponormal such that AX = XB for a Hilbert-Schmidt operator X and $|||A^*|^{1-p}||{\cdot}|||B^{-1}|^{1-p}||\;{\leq}\;1$.Then $A^*X\;=\;XB^*$.

• East Asian mathematical journal
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• v.29 no.3
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• pp.327-335
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• 2013

In this paper we consider the quadratic matrix equation which can be defined by $$Q(X)=AX^2+BX+C=0$$, where X is a $n{\times}n$ unknown complex matrix, and A, B and C are $n{\times}n$ given matrices with complex elements. We first introduce a couple of condition numbers of the equation Q(X) and present normwise condition numbers. Finally, we compare the results and some numerical experiments are given.

• Journal of applied mathematics & informatics
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• v.22 no.1_2
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• pp.467-474
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• 2006

We present and study the stability and convergence of a deflation-preconditioned conjugate gradient(PCG) scheme for the interior generalized eigenvalue problem $Ax = {\lambda}Bx$, where A and B are large sparse symmetric positive definite matrices. Numerical experiments are also presented to support our theoretical results.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.41-41
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• 2021

잇꽃(Carthamus tinctorius L.)은 국화과에 속하는 두해살이 초본 식물로 한자명은 홍화(紅花), 영명으로는 Safflower를 사용하고 있다. 우리나라의 잇꽃 재배는 2010년 39ha 수준이 재배되다가 2014년에는 76ha까지 확대되었으나 점차 감소하는 추세를 보이고 있으며 2018년에는 55ha가 재배되고 있는 것으로 보고되었고 주산지는 전라남도와 경상북도로 알려져 있다. 잇꽃은 종실을 주로 한약재 원료로 사용해왔으나, 잇꽃의 어린 순을 나물용으로 생산하기 위한 재배가 늘어나는 추세이다. 본 연구는 준고랭지에서 잇꽃 나물을 생산하기 위한 재배 양식과 파종시기별 수량성 및 품질 차이를 구명하고자 수행하였다. 준고랭지에서의 가을 재배에서 파종 후 80%가 출현하기까지의 출현 소요일수는 5~7일로 나타났으며, 재배유형별 수확 도달일수는 시설 재배 9월 29일 파종이 29일로 가장 짧았고 노지 재배에서는 8월 25일 파종이 42일로 가장 길었다. 파종시기별 수확기까지의 유효적산온도는 시설 하우스에서 9월 29일 파종 후 10월 28일 수확하는 작형에서 634.4℃로 가장 낮게 나타났다. 재배 유형별 생육량을 조사한 결과 엽수 및 엽면적은 노지 재배 8월 25일 파종 작형에서 높았고 노지 9월 21일 파종 후 10월 8일 터널을 설치하는 작형에서는 경태 및 엽면적이 4.6mm, 26.2mm²로 유의하게 작은 경향을 나타냈다. 재배 유형별 건조수율은 13.8~15.1% 범위로 파종시기별로 유의한 차이를 보이지 않았으나 당도에서는 노지재배 9월 9일 파종과 9월 21일 파종에서 7.1°Bx, 7.0°Bx로 유의하게 높았고 시설 재배 9월 29일 파종에서 3.1°Bx로 가장 낮게 나타났다. 단위 면적당 생체 수량에서는 노지재배 8월 25일 파종에서 2,223.9kg/10a으로 가장 높았으며, 건조수율로 환산한 건물 수량에서도 노지 8월 25일 파종 작형에서 335.8kg/10a으로 유의하게 높게 나타났다. 노지 재배의 파종시기별 비타민 A 함량은 9월 21일 파종에서 23.3mg/100g으로 높았으며, 비타민 E 함량 또한 25.1mg/100g으로 높은 양상을 보였다.