• Korean journal of food and cookery science
• /
• v.14 no.3
• /
• pp.250-254
• /
• 1998

A variation of free sugar and amino acid contents of pears during the ripening period was determined by HPLC and amino acid analyzer. The research results are as follws: Fructose, glucose and sucrose were present in the pears. The contents of fructose was the highest, followed by glucose and sucrose in order. The contents of total sugar in Shingo and Youngsan was similar, but the contents of frucose in Shingo was lower and the contents of sucrose was higher than that of Youngsan (p＜.001). During the ripening period, the contents of fructose and glucose gradually increased during the harvesting season and then somewhat decreased. The contents of sucrose increased continually, while the contents of total free sugar reached the maximum during the harvesting season, it was 10.41%, 10.29% in Shingo and Youngsan and then decreased gradually. The contents of total free amino acid in Shingo was higher than that of Youngsan. A variation ratio and the composition of amino acid in Shingo and Youngsan during the ripening period didn＇t make a significant difference. The major free amino acid of the pears was in the order of aspartic acid, serine, threonine, histidine, glutamic acid, valine, arginine, and alanine. During the ripening period, aspartic acid, threonin, serine, methionine, isoleucine, leucine, histidine, and Iysine increased gradually. Glutamic acid, alanine, valine, arginine didn＇t show much change. The contents of total free amino acid increased during the ripening period.

• Korean Journal of Agricultural Science
• /
• v.45 no.4
• /
• pp.789-797
• /
• 2018

This study investigated the activity of crude enzymes obtained from Pyrus pyrifolia cv. Shingo on milk proteins. In the milk processing industry, there is an increasing interest in the addition of functional materials to dairy products or functional peptides isolated from milk proteins. First, Pyrus pyrifolia cv. Shingo was separated into core, flesh, and peel regions, and crude enzymes were obtained from the individual regions. The activity of the obtained crude enzymes was measured using casein and gelatin agar. The crude enzyme obtained from the flesh of Pyrus pyrifolia cv. Shingo decomposed gelatin, but the activity of the crude enzymes obtained from the peel and core regions was insignificant. On the other hand, the crude enzymes obtained from the flesh and core regions of Pyrus pyrifolia cv. Shingo had a remarkable enzymatic activity in casein agar. However, the activity of the crude enzyme obtained from the peel region was insignificant. In addition, the crude enzymes obtained from the individual regions were mixed with casein to induce reactions, and the degradation patterns were investigated through electrophoresis and high performance liquid chromatography (HPLC). According to the results, the crude enzymes from Pyrus pyrifolia cv. Shingo degraded milk proteins. Thus, the results of this study can be used in studies on functionality. Additionally, it is expected that the use of pear peels and cores in the milk processing industry would greatly contribute to the reduction of food waste.

• Food Science and Preservation
• /
• v.10 no.2
• /
• pp.162-168
• /
• 2003

The quality characteristics and distribution of Shingo pears were investigated for 3 years to establish a reasonable grade Bevel of the fruits. Shingo pears were purchased from the orchards located in five main product areas, Naju, Sangju, Ansung, Ulsan and Asan pears. Quality factory such as greenness, uniformity, defects, size, weight, sweetness, firmness, pH and titratable acidity were measured with the pears. The average greenness (100-yellowness) in Shingo pears for 3 years was 25.27% with variation of 17.72-36.57%. The average height and diameter of Shingo pears were 94.95 mm and 105.61mm, respectively. The average weight was 566.13 g, The average scores of defects on the surface of Shingo pears damaged by physical stress and by insects were 1.23 and 1.03, respectively. The average value of soluble solids content was 12.22$^{\circ}$Brix. The average firmness was 0.96 kgf. The average values of pH and titratable acidity were 5.23 and 0.10 ％, respectively. In the results of the study based on assortment of producing districts, ranges in greenness of the pears by cultivating area was 17.23%-32.15%. Defects caused by physical stress and by insects did not show significant differences between cultivating area. Soluble solids content of the pears was ranged from 11.67$^{\circ}$Brix to 12.94$^{\circ}$Brix.

• The Korean Journal of Food And Nutrition
• /
• v.31 no.6
• /
• pp.890-896
• /
• 2018

The aim of this study was to determine volatile flavor compounds in Shingo pear juice. Volatile flavor compounds were analyzed using solid-phase micro-extraction (SPME) - gas chromatography-mass spectrometry (GC-MS). The effect of inorganic salts solution on the extraction ability of the SPME fiber was treated by adding saturated $CaCl_2$ solution at the ratio of 1:20 (v/v) after 0, 60, 120 min of preparing pear juice, respectively. As a result, a total of 22 volatile compounds were identified in Shingo pear juice. Ethyl acetate was found to be the most abundant volatile compound ($13.36{\sim}19.61{\mu}g/kg$), followed in order by hexanal, ethyl hexanoate, ethyl 3-(methylthio)-2-propenoate, ethyl octanoate and 2-hexenal. Total contents of volatile flavor compounds were $31.07{\mu}g/kg$ (control), $40.93{\mu}g/kg$ (0 min), $27.62{\mu}g/kg$ (60 min) and $26.32{\mu}g/kg$ (120 min). This result indicated that the addition of saline solutions could inhibit the enzymatic reaction of volatile flavor compounds effectively when treated as soon as juice preparation.

• The Korean Journal of Food And Nutrition
• /
• v.25 no.2
• /
• pp.324-329
• /
• 2012

The evaluated physicochemical and sensory properties of freeze-dried Shingo pears(Pyus pyritolia Niitaka), cultivated at Cheonan city, prepared using different sugar concentration of blanching solution we evaluated. Sliced Shingo pears(5 mm and 7 mm thickness) were blanched in sugar solution(0, 3, 5, 7, 10%) and freeze-dried to make dried fruits snack. The firmness of the pear snack sliced in 7 mm portions was greater than the pear snacks sliced in 5mm pieces. However in sensory evaluation, pear snacks sliced in 5 mm portions showed higher scores. pH and titratable acidity showed no significant difference in the blanching process. Concentration of total phenollic compound in fresh pear was 3.7 mg% but freeze-dried pear snacks showed higher values at 15 mg%. Sensory evaluation tests showed that the scores for texture decreased as the thickness of the snack and sugar concentration of blanching solution increased; however the score increased(p<0.05). Color intensity and overall acceptability scores were highest in pear snacks sliced in 7 mm pieces and blanched with 7% sugar solution.

• Korean Journal of Food Science and Technology
• /
• v.30 no.5
• /
• pp.1006-1011
• /
• 1998

Volatile flavor components in three varieties (shingo(niitaka), mansamgil (okusankichi) and chuwhang pears) of Pear (Pyrus pyrifolia N.) were extracted for 24 hours with pentane-diethylether (1 : 1, v/v) using the LLEP (liquid-liquid extraction & perforation). Neutral fraction was separated from the extract and then analyzed by GC-FID and GC/MS equipped with a fused silica capillary column (Carbowax 20M, HP). Individual components were identified by mass spectrometry and their retention indices. The totals of 52, 47 and 22 volatiles were identified in shingo, mansamgil and chuwhang pears, respectively. Ethyl acetate, propyl acetate, hexanal, 1-hexanol, ethyl butanoate, ethyl-3-hydroxy butanoate, ethyl-2-hydroxy propanoate were the main components in each samples, though there were several differeces in composition of volatile compounds. Total contents of volatile components isolated in shingo, mansamgil and chuwhang pears were 6.972, 2.776 and 2.653 mg/kg of pears.

• Journal of Biosystems Engineering
• /
• v.27 no.2
• /
• pp.117-124
• /
• 2002

This research was conducted to develop a method to remove the effect of surface temperature of Shingo pears for sugar content measurement. Sugar content was measured by a near-infrared spectrum analysis technique. Reflected spectrum and sugar content of a pear were used for developing regression models. For the model development, reflected spectrums having wavelengths in the range of 654 to 1,052nm were used. To remove the effect of surface temperature, special sample preparation techniques and partial least square (PLS) regression models were proposed and tested. 71 Shingo pears stored in a cold storage, which had 2$^{\circ}C$ inside temperature, were taken out and left in a room temperature for a while. Temperature and reflected spectrum of each pear was measured. To increase the temperature distribution of samples, temperature and reflected spectrum of each pear was measured four times with one hour twenty minutes interval. During the experiment, temperature of pears increased up to 17 $^{\circ}C$. The total number of measured spectrum was 284. Three groups of spectrum data were formed according to temperature distribution. First group had surface temperature of 14$^{\circ}C$ and total number of 51. Second group consisted of the first and the fourth experiment data which contained the minimum and the maximum temperatures. Third group consisted of 155 data with normal temperature-distribution. The rest data set were used for model evaluation. Results shelved that PLS model I, which was developed by using the first data group, was inadequate for measuring sugar content of pears which had different surface temperatures from 14$^{\circ}C$. After temperature compensation, sugar content predictions became close to the measured values. Since using many data which had wide range of surface temperatures, PLS model II and III were able to predict sugar content of pears without additional temperature compensation. PLS model IV, which included the surface temperatures as an independent variable. showed slightly improved performance(R$^2$=0.73). Performance of the model could be enhanced by using samples with more wide range of temperatures and sugar contents.

• Journal of the Microelectronics and Packaging Society
• /
• v.19 no.4
• /
• pp.39-43
• /
• 2012

Via-filling plating and through-hole plating are absolutely imperative for manufacturing of printed-wiring board. This Paper is introducing the latest developments of our company worked on the high-performance of acid copper plating additives for them.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.3
• /
• pp.389-392
• /
• 2003

• Korean Journal of Plant Resources
• /
• v.25 no.4
• /
• pp.498-503
• /
• 2012

The aim of this study is to compare the total polyphenol, total flavonoid, and antioxidative activity among 5 cultivars of Korean pears cultivated in Korea. As a result of the analysis for the phenolic substance of 5 cultivars, such as Wonwhang, Sunwhang, Whangkeumbae, Chuwhang, and Shingo, the content of total polyphenol was higher in Shingo and Chuwhang, and the content of total flavonoid showed higher levels in Wonwhang and Sunwhang. In addition, this study found that DPPH radical-scavenging ability was the highest in Shingo and that the part of fruit skin showed more favorable reaction to radical ability than fruit flesh. It was also found that much better antioxidative activity was shown for the methanol solvent extraction than for the ethanol solvent extraction. The nitrite-scavenging ability showed the best for Wonwhang and Chuwhang of the cultivars and much better reaction for the methanol solvent extraction than for the ethanol solvent extraction just like the case of DPPH radical-scavenging ability. Further, nitrite-scavenging ability appeared much better reaction for the fruit skin than for the fruit flesh, and antioxidative activity dropped for the higher the range on the pH scale. From the results of this study, Korean pears are worthy of developing as a natural functional food and substance for beauty treatment through the research on bioactivity.