• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.4
• /
• pp.403-409
• /
• 1997

To obtain information on the accumulation of (1-3, 1-4)-$\beta$-glucans during kernel maturation, (1-3, 1-4)-$\beta$-glucan contents and (1-3, 1-4)-$\beta$-glucanase activities were determined in developing kernels of the two Korean cooking barley varieties, Neulssalbori and Saessalbori. (1-3, 1-4)-$\beta$-Glucan contents in kernels at 5 and 10 days after anthesis(DAA) were very low and the contents increased rapidly in kernels at 15 to 25 DAA. (1-3, 1-4)-$\beta$-Glucan content in kernels at harvest was about 3.5 to 4% of kernel dry matter. (1-3, 1-4)-$\beta$-Glucanase activities were relatively higher in younger kernels but the levels of the activity were very low compared with those in germinating kernels. A significant negative correlation was observed between (1-3, 1-4)-$\beta$-glucan contents and (1-3, 1-4)-$\beta$-glucanase activities. Low levels of (1-3, 1-4)-$\beta$-glucanase activites in kernels at 15 to 30 DAA, however, may indicate that (1-3, 1-4)-$\beta$-glucanases have little effect on the final content of (1-3, 1-4)-$\beta$-glucans in barley kernels. Starch contents and $\alpha$-amylase activities were also determined in developing barley kernels. Starch contents increased rapidly as kernels matured and the content at harvest was about 60% of kernel dry matter. Relativley higher levels of $\alpha$-amylase activities in kernels at the earlier developmental stage decreased rapidly as kernels matured.

• Journal of Life Science
• /
• v.27 no.9
• /
• pp.1052-1058
• /
• 2017

Gelidium amansii shows antioxidant and anti-obesity effects; however, the effect on postprandial blood glucose levels is not known. The objective of the present study was to investigate the inhibitory effect of Gelidium amansii extract (GAE) on carbohydrate-digesting enzymes and its ability to alleviate postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. Gelidium amansii was extracted with 80% ethanol and concentrated for use in this study. The ${\alpha}-glucosidase$ and ${\alpha}-amylase$ inhibition assays were performed using the colorimetric method. ICR normal and STZ-induced diabetic mice were orally administered GAE (300 mg/kg body weight) or acarbose (100 mg/kg body weight) alone or soluble starch (2 g/kg body weight). Blood samples were taken from the tail vein at 0, 30, 60 and 120 min. Our results indicated that GAE markedly inhibited ${\alpha}-glucosidase$ and ${\alpha}-amylase$ activities with $IC_{50}$ values of $0.099{\pm}0.009mg/ml$ and $0.178{\pm}0.038mg/ml$, respectively, and was a more effective inhibitor than acarbose, the positive control. Further, the postprandial blood glucose levels of STZ-induced diabetic mice in the GAE-administered group were significantly lower than those of control group mice (p<0.05). Moreover, the area under the curves (AUC) significantly decreased with GAE administration in STZ-induced diabetic mice (p<0.05). These results indicate that GAE may be effective in decreasing postprandial blood glucose levels by inhibiting carbohydrate-digesting enzymes such as ${\alpha}-amylase$ and ${\alpha}-glucosidase$. Therefore, GAE could be used as a potential functional food for alleviating postprandial hyperglycemia.

• Korean Journal of Food Science and Technology
• /
• v.23 no.6
• /
• pp.739-744
• /
• 1991

A palatable paste-type lactic fermented rice (LFR) was prepared by lactic acid fermentation after liquefaction and saccharification of cooked rice. A mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus (1 : 1) produced the LFR of the best quality. A great improvement in quality of the LFR was achieved by 0.02% each ${\alpha}-amylase$ and glucoamylase treatment during the fermentation (simultaneous saccharification and fermentation), which resulted from the increased sourness and sweetness and the decreased size of solid particles contained in the LFR. The resulted LFR was superior in quality. Physical and chemical properties of the LFR were evaluated.

• Food Science and Preservation
• /
• v.31 no.1
• /
• pp.149-160
• /
• 2024

Dextran is a glucose homo-polysaccharide with a predominantly α-1,6 glycosidic linkage of microbial source and is known to be produced primarily by lactic acid bacteria. However, it can also be obtained through the dextran dextrinase of acetic acid bacteria (Gluconobacter oxydans). The dextrin-based dextran was obtained from rice starch using G. oxydans fermentation of rice hydrolysate, and its properties were studied. Both dextrin- and rice hydrolysate-added media maintained the OD value of 6 after 20 h of incubation with acetic acid bacteria, and the gel permeation chromatography (GPC) analysis of the supernatant after 72 h of incubation confirmed that a polymeric material with DP of 480 and 405, which was different from the composition of the substrate in the medium, was produced. The glucose linkage pattern of the polysaccharide was confirmed using the proton nuclear magnetic resonance (¹H-NMR) and the increased α-1,4:α-1,6 bond ratio from 0.23 and 0.13 to 1:2.37 and 1:4.4, respectively, indicating that the main bonds were converted to α-1,6 bonds. The treatment of dextrin with a rat-derived alpha-glucosidase digestive enzyme resulted in a slow release of glucose, suggesting that rice hydrolysate can be converted to dextran using acetic acid bacteria with glycosyltransferase activity to produce high-value bio-materials with slowly digestible properties.

• Korean Journal of Food Science and Technology
• /
• v.35 no.4
• /
• pp.696-701
• /
• 2003

Rice seeds of 4 cultivars including Whachung and Nampung, of the non-waxy rice cultivars, and Shinsunchalbyeo and Whachungchabyeo, of the waxy rice cultivars, were germinated at $27^{\circ}C$ for 3 days to compare the changes in some physico-chemical properties of the starch granules and the starch-hydrolysing enzyme activities during germination, respectively. With the starch granules, the amount of long glucose chains from amylose molecules were reduced in the non-waxy rices, while the chain length increased in the waxy rices. In the distribution profile of the glucose chain length from amylose molecules, we could observed that the chain length with DP (degree of polymerization) ranged 33 to 66 increased with the decreasing rate of the chain length with that above 130, regardless of the waxiness of rices. In addition, we observed that in contrast to a increase in chain length with DP ranged 14 to 33, the amount of short chains from A chain fraction decreased. Germination induced slight reduction in the polymerization rate of starch granules, and decrease in both initiation and termination temperatures for the gelatinization. ${\alpha}-Amylase$ activity of rices germinated for 3 days found to he higher than that of malt. Especially, the activity of Shinsunchalbyeo was revealed to be highest, about two fold higher than that of malt. In contrast, ${\beta}-amylase$ of the waxy rice found to be considerably less active than malt, although the waxy showed prevalent activity as compared to the non-waxy rices.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.27 no.5
• /
• pp.509-514
• /
• 1994

A processing method for fermented paste of favorable flavor and texture using pen shell by-product was investigated. The pen shell by-product was homogenized with the addition of water and hydrolyzed with $5\%$ of Protin P(105 PU/g) at $55^{\circ}C$ for 1 hour. Flavor of the hydrolysate could be improved by thermal treatment at $100^{\circ}C$ for 40 minutes with $10\%$ of invert sugar. $2\%$ of agar-agar and $6\%$ of starch added to hydrolysate emulsified by $8\%$ of polyglycerol condensed ricinoleate(PGDR) were significantly effective for the improvement of rheological properties such as hardness, springiness and chewiness of the fermented paste. $15\%$ of table salt was finally added to the product of fermented pen shell paste. The contents of moisture, protein, lipid, carbohydrate and salinity of the product were $62.7\%,\;3.2\%,\;4.4\%,\;10.6\%\;and\;15.6\%$, respectively. The major free amino acids were glutamic acid, arginine, aspartic acid, leucine, lysine, glycine and alanine. The product was stable for the storage of 60 days at $23{\pm}3^{\circ}C$ on bacterial growth.

• Korean Journal of Food Science and Technology
• /
• v.16 no.2
• /
• pp.254-256
• /
• 1984

The amounts of husk materials from barley kernel were determined by an enzymatic method and compared with the values determined by conventional methods involving acid or alkaline treatments. The enzymatic method consists of boiling in distilled water and pressing to help squeeze out the gelatinized starch from the husk matrix, and enzymatic removal of starch by ${\alpha}-amylase$ and weighing the residual husk materials after washing 3 times with hot water and then drying at $95^{\circ}C$. Husk materials amounted about 15 of the covered barley (Gangbori and Olbori) and 10-12% of naked variety (Backdong and Sedohadaga) and the values were always somewhat higher than those obtained by the conventional methods. The husk materials prepared by the enzymatic procedure contained protein 4-8%, lipid 5-10%, ash 0.2-0.6% and crude fiber 20-40%. Although it took longer time, the enzymatic procedures can provide more intack husk materials for further characterization of the materials.

• Journal of Life Science
• /
• v.20 no.5
• /
• pp.683-690
• /
• 2010

The yeast strains of Saccharomyces diastaticus produce one of three isozymes of an extracellular glucoamylase I, II or III, a type of exo-enzyme which can hydrolyse starch to generate glucose molecules from non-reducing ends. These enzymes are encoded by the STA1, STA2 and STA3 genes. Another gene, sporulation-specific glucoamylase (SGA), also exists in the genus Saccharomyces which is very homologous to the STA genes. The SGA has been known to be produced in the cytosol during sporulation. However, we hypothesized that the SGA is capable of being secreted to the extracellular region because of about 20 hydrophobic amino acid residues at the N-terminus which can function as a signal peptide. We expressed the cloned SGA gene in S. diastaticus YIY345. In order to compare the biochemical properties of the extracellular glucoamylase and the SGA, the SGA was purified from the culture supernatant through ammonium sulfate precipitation, DEAE-Sephadex A-50, CM-Sephadex C-50 and Sephadex G-200 chromatography. The molecular weight of the intact SGA was estimated to be about 130 kDa by gel filtration chromatography with high performance liquid chromatography (HPLC) column. Sodium dedecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed it was composed of two heterogeneous subunits, 63 kDa and 68 kDa. The deglycosylation of the SGA generated a new 59 kDa band on the SDS-PAGE analysis, indicating that two subunits are glycosylated but the extent of glycosylation is different between them. The optimum pH and temperature of the SGA were 5.5 and $45^{\circ}C$, respectively, whereas those for the extracellular glucoamylase were 5.0 and $50^{\circ}C$. The SGA were more sensitive to heat and SDS than the extracellular glucoamylase.

• Korean Journal of Food Science and Technology
• /
• v.20 no.6
• /
• pp.840-844
• /
• 1988

High-protein rice flour (HPRF) was prepared by an enzymatic process using ${\alpha}-amylase$ and g1ucoamylase without cooking Process and the feasibility of HPRF as infants foods was tested. Rice flour slurry was treated with 0.25% ${\alpha}-amylase$ and 0.5% glucoamylase at $55^{\circ}C$ for 24hrs. After saccharification, the digested rice slurry was centrifuged and the precipitated paste, was then heat-dried to obtain HPRF. The protein content of the HPRF was 20.8%. On the other hand, the supernatant of glucose enriched solution was decolourized, deionized and then isomerised to furctose at $60^{\circ}C$ for 100min by using immobilized glucose isomerase column. The high-fructose solution (HFS) contained 56% glucose, 42% fructose and 2% oligosaccharide. The nutritional quality of the HPRF was compared with milk protein and soybean protein in weight gain, feed efficiency ratio (FER), protein efficiency ratio (PER) and liver weight. HPRF was almost the same in all items with milk and soybean protein, but significantly superior to rice flour group.

• Korean Journal of Food Science and Technology
• /
• v.51 no.3
• /
• pp.286-294
• /
• 2019

The purpose of this study was to investigate the possibility of enhancing the functional compounds in apple and pear pomace (APP) by fermentation with mycelia from the mushroom Lentinula edodes. A 30% (w/v) APP with added rice bran and Biji was fermented with L. edodes at $24^{\circ}C$ and 80% humidity. The cellulase and pectinase activities in the fermented APP (FAPP) were higher than those in the non-fermented control. In addition, the physiological activities of the FAPP, including DPPH, ABTS radical scavenging, and SOD-like activity, as well as the total polyphenol and ${\beta}-glucan$ contents were higher than those in the control. FAPP treatment significantly reduced LPS-induced nitric oxide (NO) levels in Raw 264.7 cell. Therefore, FAPP treatment was considered to more effectively suppress cell injury caused by inflammatory cytokines through inhibition of LPS-induced NO production. These results suggest that the levels of functional components in APP can be increased by fermentation with this mushroom mycelium. However, further studies are needed before it can be used as a functional material.