• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.9
• /
• pp.1182-1189
• /
• 2008

Changes of free sugar on Gugija-sugar leaching were investigated by adding sugar on Gugija (Lycii fructus) raw fruit. Gugija were prepared by parboiling ($40{\sim}50$ sec at hot water of $85^{\circ}C$) and unparboiling. Gugija-sugar leaching were leached after preserving (5 and 10 months at $5^{\circ}C$) Gugija-sugar mixture (ratio of raw Gugija and sugar, 1:0.2, 1:0.4, 1:0.6, 1:0.8, and 1:1/w:w). Soluble starch content of Gugija-sugar leaching increased with increasing ratio of sugar without reference to parboiling treatment, having the highest content, 2.5% at UPRGSL-4 (unparboiling Gugija:sugar, 1:0.8 leaching). Maltose content increased with increasing ratio of sugar in PRGSL, being the highest at 12.66% in PRGSL-5 (parboiling Gugija:sugar, 1:1 leaching) at 10 months leaching periods. Most of the sucrose went out of existence with increasing leaching periods; content was 4.22% on PRGSL-5 and 1.36% on UPRGSL-5. Content of glucose and fructose increased with increasing ratio of sugar; glucose content was 7.86% on PRGSL-4 and 26.22% on UPRGSL-5, at 10 months leaching periods. Fructose content was 18.46% on PRGSL-5 and 22.51% on UPRGSL-4 at 10 months leaching periods. Contents of sorbitol and glycerol increased with increasing ratios of sugar.

• Korean journal of food and cookery science
• /
• v.14 no.3
• /
• pp.225-231
• /
• 1998

Enzyme-treated glutinous rice flour, which was developed to shorten or skip a steeping process during the preparation of Yukwa, was analyzed for its physicochemical characteristics and compared with glutinous rice flour made by 28-day-steeping method. Total sugar content of the 28-day-steeped flour was the highest among all groups, on the other hand, the reducing sugar content was higher in enzyme-treated glutinous rice flour. The viscosity of enzyme-treated flours was significantly lower than that of the 28-day-steeped and particularly showed the lowest value at 65$^{\circ}C$. The contents of Ca$\^$2+/ and Mg$\^$2+/ in enzyme-treated glutinous rice flours were higher than those of the 28-day-steeped group, however, the content of P$\^$+/ was lower. Free sugar detected in glutinous rice flour prepared from 28-day-steeping method was glucose only, but enzyme-treated flours contained maltose and glucose, and the content of total free sugar was much higher than that of the 28-day-steeped group. In microscopic structure, both 28-day-steeped and enzyme-treated flours showed the particle size decreased and porous surface on some part of the flour granule.

• Korean Journal of Plant Resources
• /
• v.8 no.3
• /
• pp.325-334
• /
• 1995

The early senescence mutant induced from Gihobyeo by $\gamma-ray$ irradiation was determined. The mutated gene expression was identified with comparing the characteristic of original cultivar. The mutant had so similar the morphological characteristics to original cultivar that it couldn't be distinguished until senescence occurred at about 20 days after heading. Suddenly yellow leaves were observed within a few days due to great decreases in total chlorophyll and various carotenoid contents. Transmission electron microscopy showed the formation of starch granules, distortion of fine structure of leaf cell organelles, especially grana structures, and the decrease in grain filled after senescence occurred. But banding patterns of total proteins and isozymes have not show any differences, The early senescence mutant will be very useful for study material not only on physiological and biochemical properties of plant senescence but also on gene expression regulating senescence which gives great influence on yield potential and its stability.

• Korean Journal of Food Science and Technology
• /
• v.26 no.5
• /
• pp.596-602
• /
• 1994

To separate and concentrate mucilage from yam(Dioscorea batatas DECNE), yam was dried, microparticulated using impact mill and air-classified at different air classifying wheel speed(ACWS) in classifier. As ACWS increased from 5,000 rpm to 22,500 rpm, the contents of dietary fiber, protein and lipid of air classified microparticles(ACM) increased remarkably. Especially the ACM with ACWS over 15,000 rpm showed 36.41% dietary fiber and 16.66% protein. The dietary fiber and protein components were concentrated to $2.5{\sim}9.0$ times as compared with whole yam powder. Concomitantly the non-fibrous carbohydrate decreased from 88.31% to 16.84. The damaged starch(%), WSI and WAI of ACM of ACWS over 15,000 rpm were $1.5{\sim}3.0$ times higher than those of ACM under ACWS 15,000 rpm. The apparent viscosity of ACM was 0.0800 Pa s over ACWS 15,000 rpm and 0.0080 Pa s under ACWS 15,000 rpm. Judging from viscosity of ACM, the mucilage component of yam was concentrated to 10 times. In conclusion, the optimum process to separate and concentrate the mucilage from yam consisted of the microparticulation to $5{\sim}30{\mu}m$ and the air-classification at ACWS over 15,000 rpm.

• The Korean Journal of Food And Nutrition
• /
• v.30 no.5
• /
• pp.880-888
• /
• 2017

Palatability and texture analysis of nine Korean rice cultivars were investigated to select the most appropriate rice variety for the cooked-rice processing. The rice cultivars studied consisted of Samkwang, Seonpum, Wolbaek, Andabyeo, Dasan-1, Ilpum, Haiami, Jungsanggold and Chindle. They revealed the moisture, protein, amylose and starch contents of 10~12, 5~6, 12~19, and approximately 90%, respectively. Among the evaluated rice varieties, WB exhibited the lowest amylose content (12.7%) and Jungsanggold the next (17.2%). In the rapid-visco analyzer test, Jungsanggold, Chindle, Wolbaek and Seonpum revealed a low value of final and setback viscosities than other varieties. Using a toyo meter analyzer, Chindle, Haiami, Samkwang were selected as having high toyo palatability values, while Dasan-1, Wolbaek and Andabyeo revealed low values. Toughness and adhesiveness of all nine cooked rice varieties were highest in Jungsanggold, Chindle and Ilpum. Also, palatability of cooked rice was highest in the following order: Chindle (80.03) > Samkwang (76.21) > Jungsanggold (74.08). The results of this study suggest that Chindle may be effectively used to produce processed cooked rice.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.1
• /
• pp.137-144
• /
• 2015

Kyejang is a Korean traditional beverage manufactured from medicinal plants and fruits using honey, sugar, or starch in cold water. In this study, cinnamon-containing kyejang, which is a type of beverage Jang, was reproduced based on Imwonsibyukji's method published in 1827 in the Korean literature. Kyejang made by nuruk, cinnamon, and medicinal plants was prepared at various temperatures and periods. Kyejang was assayed for physiochemical properties (pH and acidity), contents of metabolites (organic acids, sugars, and amino acids), and sensory characteristics (aroma and taste). During fermentation, content of organic acids (e.g. lactic acid, acetic acid, and shikimic acid) increased, which lowered pH, increased acidity, and increased intensity of sour taste. In the case of free sugars, fructose and maltose levels decreased while glucose and mannitol levels increased during fermentation periods, and sweetness decreased. The main amino acid in kyejang was tryptophan, followed by asparagine, proline, and arginine. The sensory evaluation score of overall preference was highest for kyejang which was fermented at $20^{\circ}C$ for 3 days. The results will be provide the basic data of fermentation conditions for standardized manufacturing process of kyejang.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47
• /
• pp.15-32
• /
• 2002

The endeavors enhancing the grain quality of high-yielding japonica rice were steadily continued during 1980s-1990s along with the self-sufficiency of rice production and the increasing demands of high-quality rices. During this time, considerably great progress and success was obtained in development of high-quality japonica cultivars and quality evaluation techniques including the elucidation of interrelationship between the physicochemical properties of rice grain and the physical or palatability components of cooked rice. In 1990s, some high-quality japonica rice cultivars and special rices adaptable for food processing such as large kernel, chalky endosperm, aromatic and colored rices were developed and its objective preference and utility was also examined by a palatability meter, rapid-visco analyzer and texture analyzer, Recently, new special rices such as extremely low-amylose dull or opaque non-glutinous endosperm mutants were developed. Also, a high-lysine rice variety was developed for higher nutritional utility. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice and the palatability of cooked rice. The water/rice ratio (in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was average to 2.63(in v/v basis). The major physicochemical components of rice grain associated with the palatability of cooked rice were examined using japonica rice materials showing narrow varietal variation in grain size and shape, alkali digestibility, gel consistency, amylose and protein contents, but considerable difference in appearance and texture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak, hot paste and consistency viscosities of viscosities with year difference. The high-quality rice variety "IIpumbyeo" showed less portion of amylose on the outer layer of milled rice grain and less and slower change in iodine blue value of extracted paste during twenty minutes of boiling. This highly palatable rice also exhibited very fine net structure in outer layer and fine-spongy and well-swollen shape of gelatinized starch granules in inner layer and core of cooked rice kernel compared with the poor palatable rice through image of scanning electronic microscope. Gross sensory score of cooked rice could be estimated by multiple linear regression formula, deduced from relationship between rice quality components mentioned above and eating quality of cooked rice, with high probability of determination. The $\alpha$-amylose-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were IIpumbyeo, Chucheongyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tonsil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, showed the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogradation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked rice. The softer gel consistency and lower amylose content in milled rice revealed the higher ratio of popped rice and larger bulk density of popping. The stronger hardness of rice grain showed relatively higher ratio of popping and the more chalky or less translucent rice exhibited the lower ratio of intact popped brown rice. The potassium and magnesium contents of milled rice were negatively associated with gross score of noodle making mixed with wheat flour in half and the better rice for noodle making revealed relatively less amount of solid extraction during boiling. The more volume expansion of batters for making brown rice bread resulted the better loaf formation and more springiness in rice breed. The higher protein rices produced relatively the more moist white rice bread. The springiness of rice bread was also significantly correlated with high amylose content and hard gel consistency. The completely chalky and large grain rices showed better suitability far fermentation and brewing. The glutinous rice were classified into nine different varietal groups based on various physicochemical and structural characteristics of endosperm. There was some close associations among these grain properties and large varietal difference in suitability to various traditional food processing. Our breeding efforts on improvement of rice quality for high palatability and processing utility or value-adding products in the future should focus on not only continuous enhancement of marketing and eating qualities but also the diversification in morphological, physicochemical and nutritional characteristics of rice grain suitable for processing various value-added rice foods.ice foods.

• Applied Biological Chemistry
• /
• v.10
• /
• pp.1-13
• /
• 1968

Phytin is a salt(mainly calcium and magnesium) of phytic acid and its purity and molecular formula can be determined by assaying the contents of phosporus, calcium and magnesium in phytin. In order to devise a new method for the quantitative analysis of the three elements in phytin, the chelatometric method was developed as follows: 1) As the pretreatment for phytin analysis, it was ashfied st $550{\sim}600^{\circ}C$ in the presence of concentrated nitric acid. This dry process is more accurate than the wet process. 2) Phosphorus, calcium and megnesium were analyzed by the conventional and the new method described here, for the phytin sample decomposed by the dry process. The ashfied phytin solution in hydrochloric acid was partitioned into cation and anion fractions by means of a ration exchange resin. A portion of the ration fraction was adjusted to pH 7.0, followed by readjustment to pH 10 and titrated with standard EDTA solution using the BT [Eriochrome black T] indicator to obtain the combined value of calcium and magnesium. Another portion of the ration fraction was made to pH 7.0, and a small volume of standard EDTA solution was added to it. pH was adjusted to $12{\sim}13$ with 8 N KOH and it was titrate by a standard EDTA solution in the presence of N-N[2-Hydroxy-1-(2-hydroxy-4-sulfo-1-naphytate)-3-naphthoic acid] diluted powder indicator in order to obtain the calcium content. Magnesium content was calculated from the difference between the two values. From the anion fraction the magnesium ammonium phosphate precipitate was obtained. The precipitate was dissolved in hydrochloric acid, and a standard EDTA solution was added to it. The solution was adjusted to pH 7.0 and then readjusted to pH 10.0 by a buffer solution and titrated with a standard magnesium sulfate solution in the presence of BT indicator to obtain the phosphorus content. The analytical data for phosphorus, calcium and magnesium were 98.9%, 97.1% and 99.1% respectively, in reference to the theoretical values for the formula $C_6H_6O_{24}P_6Mg_4CaNa_2{\cdot}5H_2O$. Statical analysis indicated a good coincidence of the theoretical and experimental values. On the other hand, the observed values for the three elements by the conventional method were 92.4%, 86.8% and 93.8%, respectively, revealing a remarkable difference from the theoretical. 3) When sodium phytate was admixed with starch and subjected to the analysis of phosphorus, calcium and magnesium by the chelatometric method, their recovery was almost 100% 4) In order to confirm the accuracy of this method, phytic acid was reacted with calcium chloride and magnesium chloride in the molar ratio of phytic: calcium chloride: magnesium chloride=1 : 5 : 20 to obtain sodium phytate containing one calcium atom and four magnesium atoms per molecule of sodium phytate. The analytical data for phosporus, calcium and magnesium were coincident with those as determine d by the aforementioned method. The new method employing the dry process, ion exchange resin and chelatometric assay of phosphorus, calcium and magnesium is considered accurate and rapid for the determination of phytin.

• Korean Journal of Plant Resources
• /
• v.15 no.3
• /
• pp.177-187
• /
• 2002

In our experiment, selected mutants were used which showed not only the phenotype of a specific unpolished rice but also phenotypes of EM 40, LO 1050, and TAL 214. Reciprocal crosses between the mutants were conducted to select strains which would have more quantity of lipids than before. The constitution of fatty acid was also tested to figure out nutritional aspects of the mutants. In the crossing between EM 40 mutants and mutants (LO 1050) having a thick aleurone layer, the expression of EM 40 mutants has no relation with the thickness of the aleurone layer. And the lipid content of new F$_2$ strains through the crossing is 4.15 ％. The lipid content is larger than those of the parents including Kinmaze and in other crossings of this experiment. This is attributed to the fact that the new F$_2$ strains are the products of the crossing between genes responsible for the size of buds, where lipid is accumulated, and genes accountable for the thickness of the aleurone layer. In the crossing between EM 40 mutants and TAL 214 mutants, lipid content of the new F$_2$ strains is 3.8 ％, higher than 2.92 ％ of TAL 214 mutants. But the degree of lipid increase is smaller than in two other crossings. This is probably because genes expressing the phenotypes of TAL 214 affect the size of EM 40, which gets smaller. The aleurone layer of the new F$_2$ strains is 12 $\mu\textrm{m}$ thicker than the layer of TAL 214 mutants, but 6 $\mu\textrm{m}$ thinner than that of parents (LO 1050) having a thick aleurone layer. This seems to be affected by the size of a microscope. The phenotype of the new F$_2$ strains appears to be similar to that of TAL 214. The lipid content of the new F$_2$ strains is 3.85 ％, larger than 2.92 ％ of TAL 214 and 3.01 % of LO 1050. The increase may be due to the aleurone layer of LO 1050. And the size of the bud of the unpolished rice, though it is not big enough like that of LO 1050, seems to be affected by the accumulation of genes in the thick aleurone layer. The accumulation may contribute to the increase in the content of lipid. When it comes to the constitution of fatty acid, there is little difference between parents like Kinmaze and the new F$_2$ strains. But oleic acid increases while linoleic acid decreases. And the decrease in the linolenic acid seems to contribute to the increase in lipid content. This fact also raises the possibility that genes accountable for specific phenotypes could change the quality of rice if the genes are accumulated. Now, experiments on strains which have large lipid content in EM 40 type 1(ge-1, 3.68 ％), EM type 2(ge-2, 2.91 ％), thick aleurone layer(4.63 ％), and starch layer(3.44 ％) are under way to figure out the effects of gene accumulation. These experiments are likely to present the ways for increasing the lipid content.