• Analytical Science and Technology
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• v.8 no.4
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• pp.859-864
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• 1995

Mono- and oligosaccharides are derivatized with p-aminobenzoic ethyl ester (ABEE), strongly absorbs UV light at 254 nm, in the presence of sodium cyanoborohydride. C18-bonded silica column is used for the separation of sugar-ABEE derivatives in an isocratic mode. RP-HPLC conditions are optimized by using ternary mixture as mobile phase and $45^{\circ}C$ as a column temperature. Sugar-ABEE derivatives are separated well within a short run time (ca. 25 min) by reverse-phase partition chromatographic mode. The ($1{\rightarrow}6$) linkage type of dihexose-ABEE derivatives has shorter retention time than ($1{\rightarrow}4$)-linkage type. After acid hydrolysis of glycoproteins with 2M trifluoroacetic acid, monosaccharide composition and contents are determined. This procedure is very useful for the simultaneous analysis of neutral and amino sugars in a single chromatographic step using RP-HPLC without reacetylation of deacetylated amino sugars, which are produced by acid hydrolysis.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.139-147
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• 1999

Peptides are formed in the rumen as the result of microbial proteinase activity. The predominant type of activity is cysteine ptoteinase, but others, such as serine proteinases, are also present. Many species of protozoa, bacteria and fungi are involved in ptoteolysis; large animal-to-animal variability is found when proteinase activities in different animals are compared. The peptides formed from proteolysis are broken down to amino acids by peptidases. Different peptides are broken down at different rates, depending on their chemical composition and particularly their N-terminal structure. Indeed, chemical addition to the N-terminus of small peptides, such as by acetylation, causes the peptides to become stable to breakdown by the rumen microbial population; the microorganisms do not appear to adapt to hydrolyse acetylated peptides even after several weeks exposure to dietary acetylated peptides, and the amino acids present in acetylated peptides are absorbed from the small intestine. The amino acids present in some acetylated peptides remain available in nutritional trials with rats, but the nutritive value of the whole amino acid mixture is decreased by acetylation. The genus Prevotella is responsible for most of the catabolic peptidase activity in the rumen, via its dipeptidyl peptidase activities, which release dipeptides rather than free amino acids from the N-terminus of oligopeptides. Studies with dipeptidyl peptidase mutants of Prevotella suggest that it may be possible to slow the rate of peptide hydrolysis by the mixed rumen microbial population by inhibiting dipeptidyl peptidase activity of Prevotella or the rate of peptide uptake by this genus. Peptides and amino acids also stimulate the growth of rumen microorganisms, and are necessary for optimal growth rates of many species growing on tapidly fermented substrates; in rich medium, most bacteria use pre-formed amino acids for more than 90% of their amino acid requirements. Cellulolytic species are exceptional in this respect, but they still incorporate about half of their cell N from pre-formed amino acids in rich medium. However, the extent to which bacteria use ammonia vs. peptides and amino acids for protein synthesis also depends on the concentrations of each, such that preformed amino acids and peptides are probably used to a much lesser extent in vivo than many in vitro experiments might suggest.

• Korean Journal of Food Science and Technology
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• v.12 no.2
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• pp.88-96
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• 1980

Reaction conditions in the amino-carbonyl reaction, and the effect of amino acids on the reactivity of amino-carbonyl reaction were investigated. Results obtained are as follows : 1. When the pH of the reaction mixture was increased above the isoelectric point of an amino acid, a significant increase in the color intensity was observed. 2. The color intensity increased gradually up to 1 : 1 of the molar ratio of reactants. This result was interpreted to show that sugar and free amino group combined in 1 : 1 ratio. 3. Amino-carbonyl reaction showed a significant time and temperature-dependences. The activation energy at 0.2 M glucose and 0.2 M glycine system was 37.5 Kcal/mole. 4. Among amino acids tested, glycine, lysine and $\beta$-alanine caused a significant increase in the color intensity, but acidic amino acids showed the least color intensity. The latter was interpreted to show that one of carboxyl groups of acidic amino acid has an inhibiting effect on the reactivity of the amino group. 5. The color intensity of sugars tested was in the order of xylose>arabibose>fructose>glucose>maltose>lactose.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.126-132
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• 2021

Cheonggukjang (CGJ) is a famous traditional Korean food that is typically produced by fermenting steamed soybean seeds and has a unique flavor and taste. The objective of this study was to evaluate the effect of addition of lotus seeds on the quality and antioxidant activities of CGJ. Color value, 1,1-diphenly-2-picrylhydrazyl radical scavenging potential, and the amounts of total polyphenol, total flavonoid, mineral, and free amino acid were evaluated. The CGJ sample produced with lotus alone or a mixture of soybean and lotus produced in Korea showed relatively high antioxidant potential. The amount of essential and total free amino acids was also high in the sample prepared with lotus seeds grown in Korea. On the other hand, the total mineral content was low in the lotus-based samples. The results indicated that a mixture of an equal proportion of soybean and lotus seeds could be a good option to prepare nutritious CGJ.

• Korean Journal of Exercise Nutrition
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• v.24 no.2
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• pp.38-46
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• 2020

[Purpose] This study aimed to investigate the effects of leucine-enriched essential amino acid (LEAA) supplementation on muscle fatigue and the level of inflammatory cytokines in wheelchair basketball players after a basketball game and interval training. [Methods] Of the ten recruited wheelchair basketball players (aged 34.5±8.9 years; lean body mass of 34.3±10.0 kg) who had spinal cord injury (SCI) and had undergone amputation, nine participated in the final test. These nine athletes received LEAA supplements (3 times 4.0 g/day) or placebo treatment in a double-blind, randomized, crossover study. We measured variables related to muscular fatigue and inflammatory response before the intense exercise and 4 days after recovery. [Results] The significant effect of LEAA supplementation was inhibition of circulating IL-6 levels in the LEAA-treated group compared with the placebo group (P < .05). However, no changes were observed in the TNF-α and creatinine kinase levels. Moreover, analysis of variance analysis showed no significant difference in the relative values of muscle soreness. However, the effect size analysis with Cohen's d reported a significant improvement in the relative values of whole body and back muscle soreness. [Conclusion] Our results revealed that LEAA supplementation before and after intense exercise could help reduce muscle soreness and IL-6 levels in wheelchair basketball players.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.313-322
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• 2014

Evaluation of energy in the diet is very important in animal nutrition because food intake is strongly influenced by the energy content of the diet. This means that the intake of other nutrients, such as amino acids, is affected by their ratio to energy content. Poultry can control their energy intake over a range of energy: protein ratios. Energy: protein ratio also affects the growth and body composition. Therefore we need to know what extent the relationship between energy and dietary protein influences the bird's performance. To predict the energy value of the diet or its chemical constituents, researchers have been working on modelling using the equations of the major biochemical pathways in terms of ATP generation and utilization. The activity of feeding and the metabolism caused by digestion and assimilation of food increase the animal's heat production and it can be measured by calorimetry technique. Theoretically, surplus amino acids which are not needed for protein synthesis stimulate an additional increase in metabolic rate and lead to increased energetic costs of catabolism and excretion. However, it has sometimes been shown that there was no measurable diet-induced thermoregulatory effect when an imbalanced amino acid mixture was fed. All these aspects are discussed in this review.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.398-403
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• 1996

To produce low salt fermented anchovy by an accelerated method with Asp. oryzae and Bacillus sp. koji and taste properties after the 60 day fermentation were examined. The main free amino acids of 60 day fermented anchovy paste were valine, isoleucine, proline, alanine, lysine, glutamic acid and aspartic acid. Total amount of free amino acids was the highest in non koji anchovy paste wit 2,624.76mg%. Among the koji added samples, Asp. oryzae koji added on was the highest in the amount o free amino acids. Hypoxanthine accounted for 84.14~95.4% of total nucleotides and their related compounds; Asp. oryzae koji added anchovy paste was the highest in nucleotides other related. Citric acid and lactic acid accounted for 94.9~96.7% of total non-volatile organic acids; Asp. oryzae koji added sample was the highest in non-volatile organic acids with 287.93mg%. The Hunter a and b values gradually increased during the fermentation, but the L value decreased until day 30 or 40 and increased steadily after that. The a and b values were higher in the use of Asp. oryzae koji than in Bccillus sp. koji, but the L value was to the contrary. The Asp. oryzae koji added anchovy paste was good in the aspect of color and taste compared to others. In the aspect of odor, the anchovy paste using the mixture of Asp. oryzae and Bacillus sp. koji was the best. Overall aceptability of sensory evaluation was higher in the mixture of Asp. oryzae and Bacillus sp. koji tan in the others.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.939-943
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• 1999

Three 28 day-old $Duroc{\times}Large$ $White{\times}Landrace$ litter mate gilts weighing an average of 6.5 kg were used to study the intestinal absorption of amino acids when provided in dipeptide form or in the form of a free amino acid mixture. The pigs were given one of three treatments. The control involved a duodenal infusion containing no amino-acids (phosphate buffer plus 5% sorbitol) while the remaining two treatments involved either a duodenal infusion containing a glycine-lysine dipeptide (1 g) or a mixture of the free amino acids glycine and lysine at the same concentration as in the dipeptide. Blood was drawn from a cannula inserted in the portal vein, at 5 to 20 minute intervals, for two hours following infusion. The concentration of intact dipeptide as well as free glycine and lysine in the portal blood was determined by high performance liquid chromatography. The intact dipeptide was never detected in the portal blood at any time after infusion. Lysine appeared in the portal blood more rapidly after infusion of dipeptide than after infusion of free lysine and the concentration of lysine in portal blood was higher in the pig infused with the dipeptide than after infusion of free lysine at almost all time points measured. The cumulative absorption of lysine and glycine from the intestine during the two hour period after infusion was greater in the pig infused with dipeptide than in the pig infused with free amino acids. The results suggest that although intact dipeptide did not reach he portal circulation, a special transport mechanism for absorption of dipeptide by intestinal cells appears to be present in pigs similar to that observed in other species.

• Journal of Microbiology and Biotechnology
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• v.23 no.12
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• pp.1779-1784
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• 2013

Although enzyme-hydrolyzed silk fibroin has been reported to enhance cognitive function before, it has been still unknown which peptides can improve memory. Here we report that amino acid sequences of three novel peptides were identified from fibroin hydrolysate. Fibroin hydrolysate was obtained by hydrolysis with protease after partial hydrolysis with 5M $CaCl_2$. Synthesized peptides derived from these sequences improved scopolamine-induced memory impairments in mice. We confirmed this hydrolysate had effects that improved learning and memory abilities by performing the Rey-Kim test. From this hydrolysate of silk fibroin, amino acid sequences of eight peptides were identified by LC-MS/MS. Three peptides (GAGAGTGSSGFGPY, GAGAGSGAGSGAGAGSGAGAGY, and SGAGSGAGAGSGAGAGSGA) were synthesized to investigate whether they could improve memory. Passive avoidance test and Morris water maze test were performed, and all peptides showed memory-enhancing abilities on scopolamine-induced memory impairments in mice. In this study, we identified three novel peptides that could improve memory, and that silk fibroin hydrolysate was a mixture of various active peptides that could enhance memory.

• Applied Biological Chemistry
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• v.26 no.4
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• pp.205-210
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• 1983

To investigate the characteristics of amino acid fortified tofu manufactured by coprecipition of cheese whey and soybean proteins, experimental tofus were made from various mixtures of whey, whey powder, and soy milk, and general and amino acid compositions and physical properties were analyzed. Physical characteristics such as elasticity, hardness, and brittleness of the whey-soybean tofu were very similar to those of traditional tofu but color of the whey-soybean tofu was lighter than that of soybean tofu. The contents of total solids and protein of traditional tofu were about 19% and 13%, respectively, while those of the whey-soy bean tofus were 17.3%$\sim$18.1% and 10.9$\sim$11.3%, respectively. The 5$\sim$15% of lactose in whey-soymilk mixture was transferred into the tofus. The Content of sulfur-bearing amino acids in the fortified tofu from 3 : 1 mixture of whey and soymilk was 3.8g/100g protein which indicated about 50% fortification of the amino acids as compared to the traditional tofu which contained 2. 54g/100g protein of the sulfur-bearing amino acids.