• Food Science and Preservation
• /
• v.5 no.4
• /
• pp.326-330
• /
• 1998

Freeze storage technique is widely used for food processing to keep freshness and quality of the product. This technique was applied to fresh, unshelled groundnut to develop a new type of product which could maintain fresh taste and nutritive values even after several months of storage. The groundnut varieties, Daepungtangkong, Daekwangtangkong and Sindaekwangtangkong were grown at the experimental field of NCES in 1996. Immatured pods or groundnut were harvested around 20 to 3o days before full maturity, washed, and steamed at 100$^{\circ}C$ for 5 min. to stop enzyme activity. After vacuum packing (at -760mmHg for 10 min.) with 0.08mm polyvinyldichloride film, the pods were immediately frozen at -70$^{\circ}C$ for 24h and transfered at -20$^{\circ}C$ for long-term storage. Physico-chemical properties of frozen vegetable groundnut were investigated at 2 months after storage and compared to those of conventionally dried groundnut. After 2 months storage, the thawed kernels were very palatable with softness and fresh taste. Acid value and hardness (measured as the compression force on the probe of a texture analyzer) were much lower in frozen vegetable groundnut than those in the air-dried ones. Presence of free sugars is one of the important factors affecting groundnut taste, and the free sugar contents were considerably decreased in the frozen vegetable groundnut compared to freshly harvested groundnut. But in dried groundnut no free sugar was detected.

• Journal of Ginseng Research
• /
• v.29 no.3
• /
• pp.131-137
• /
• 2005

Acetaminophen(APAP) is one of the most extensively used analgesics and antipyreics worldwide. In order to investigate preventive effects of white and red ginseng extracts, male ICR mice pretreated with white or red ginseng extracts(50 or 250 mg/kg/day, for 5 days, orally) before treatment with acetaminophen(800mg/kg, i.p, single dose). In an attempt to elucidate the possible mechanism of hepatoprotective effect, superoxide dismutase(SOD), catalase(CAT), hydroperoxide, malondialdehyde(MDA) contents were studied. In pretreatment with red ginseng extract(250 mg/kg), the activities of SOD, CAT were generally highest and the hydrogen peroxide content was lowest. The levels of MDA were significantly lower in white and red ginseng extract groups than those in the APAP groups. By treatment with ginseng extract, high content of hydrogen peroxide and increased lipid peroxidatiion level caused by APAP could be lowered. Also, ginseng extracts were found to increase antioxidative enzyme activity. Finally, the results suggest that the antioxidant effects of (white and red) ginseng extracts prevent oxidative damage by direct antioxidant effects involving SOD, CAT and increasing the ability to synthesize endogenous antioxidants. It was concluded that ginseng can protect against APAP intoxication through its antioxidant properties.

• Journal of Ginseng Research
• /
• v.29 no.3
• /
• pp.138-144
• /
• 2005

This study was to examine antioxidative effects of ginseng extracts on liver of high fat diet-treated mice. ICR male mice were given high fat diet with red ginseng or white ginseng extracts (500, 1500, 3000 mg/kg/day, orally) for 4 weeks. We also Investigated the relationship between lipid peroxidation and ginseng extracts on the oxidative stress. We measured the levels of malondialdehyde (MDA, a marker of lipid peroxidation), hydrogen peroxide, superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione (GSH) in liver tissue. The activities of SOD was generally low in all ginseng extract groups. But the activity of GPx was high in all ginseng extract groups. The hydrogen peroxide contents were similar in almost all groups. The level of GSH was higher in all ginseng extract group in high fat diet (FD) group. The levels of MDA (the end product of lipid peroxidation) were lower in all ginseng extract groups than in FD group. These results that the antioxidant effects of red ginseng and white ginseng extracts prevent oxidative damage by antioxidant effects involving SOD, GPx and increasing the ability of the body to synthesize endogenous antioxidants. It was concluded that ginseng can protect against oxidative stress by high fat diet through its antioxidant 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.

• 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.

• Applied Biological Chemistry
• /
• v.38 no.3
• /
• pp.278-282
• /
• 1995

The effect of Schizandrae fructus extract on the physiological properties of Saccharomyces cerevisiae was investigated. S. cerevisiae was inoculated into glucose broth, added with Schizandrae fructus extract, 0, 0.01, 0.1, 0.5 and 1%(w/v), respectively. And a 96 hours incubation was followed to investigate the changes in the growth, alcohol production, alcohol dehydrogenase and pyruvate decarboxylase activities of S. cerevisiae. The growth of S. cerevisiae was more pronounced in the broth containing 0.1 and 0.OlfS Schizandrae fructus extract than in the control. The growth was, however, inhibited in the broth containing 0.5 and 1% of the extract. The content of alcohol produced by S. cerevisiae also showed very similiar results with those of the yeast growth by addition of Schizandrae fructus extract. Alcohol dehydrogenase activities of S. cerevisiae cultured in broth treated with the extract of 0.1% and 0.01% increased by 25% and 18% than those in control group. Pyruvate decarboxylase activities in 0.1% and 0.01% treatments increased to 1.32 and 1.26 times. The activities in 0.5% and 1% treatments, however, decreased by 30% and 44%.

• Applied Biological Chemistry
• /
• v.7
• /
• pp.1-13
• /
• 1966

1) Three ${\beta}-1$, 4-mannanases were isolated from germinated guar bean through extraction, ammonium sulfate fractionation, column chromatography on cellulose derivatives and gel filltration on Sephadex G-100. They were designated as ${\beta}-1$, 4-mannanase A,B and C, respectively, in the order of isolation. 2) These enzymes were different in several aspects such as pH optimum, effect of metal ions, adsorbability on cellulose derivatives, molecular weight, Michaelis constant toward reduced ivory nut mannan A, mode of action and extent of hydrolysis of the mannan. 3) ${\beta}-1$, 4-Mannanases A and C were proposed to be two different endo-enzymes of random-splitting type producing a series of oligosaccharides from ${\beta}-1$, 4-mannans. ${\beta}-1$, 4-Mannanase B was suggested to be possibly an exe-type enzyme catalyzing a stepwise splitting from the non-reducing end of ${\beta}-1$, 4-mannans to produce mannose. 4) Guaran was subjected to hydrolysis by the purified enzymes and the consequence was discussed in connection with structural requirements of the enzymes toward substituted ${\beta}-1$, 4-mannans and their role in germinating guar seeds.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.4
• /
• pp.477-484
• /
• 2008

For the effective use of the conger eel by-products, such as head and frame, Tang, which is the Korean-type soup, from conger eel by-products (TCEB) was developed and its food component characterization was compared with that of commercial Chueotang, loach Tang. According to the results of viable cells and coliform group of TCEB heated at $115^{\circ}C$ for various times, the reasonable $F_0$ value was 8 min. The proximate composition of TCEB was 90.7% for the moisture, 4.8% for the protein, 2.6% for the lipid, and 1.5% for the ash. The extractive-nitrogen content of TCEB was 243.1 mg/100 g, which was higher than that of commercial Chueotang, 208.0 mg/100 g. The total amino acid content of TCEB was 4,310 mg/100 g and its major amino acids were glutamic acid (637.3 mg/100 g, 14.8%), glycine (409.1 mg/100 g, 9.5%) and alanine (404.4 mg/100 g, 9.3%). TCEB was not felt in the sensual fish odor and its sensual taste was good. The health functional properties for health of TCEB were 1.29 as a PF (protection factor) for antioxidative activity and 39.4% for angiotensin Ⅰ converting enzyme (ACE) inhibiting activity.

• Food Science of Animal Resources
• /
• v.29 no.6
• /
• pp.659-667
• /
• 2009

Casein is considered to be the main source of protein in milk; therefore, many studies have been conducted to identify casein-derived bioactive peptides and their physiological effects. Casein is inactive within the parent protein but can be liberated by various proteases and enzymatic hydrolysis during microbial fermentation and gastrointestinal digestion. Once absorbed, casein exhibits different bioavailabilities in the body. Specifically, casein-derived peptides function as angiotensin converting enzyme (ACE) inhibitor in the cardiovascular system; thus, they are expected to reduce and prevent hypertension. Additionally, casein-derived peptides behave as opioid-like peptides in the nervous system, which impacts relaxation. These peptides are also expected to modulate various aspects of immune functions. Finally, caseinophosphopeptide (CPP) and glycomacropeptide (GMP) may exhibit a number of nutritional effects such as the absorption of calcium, iron or zinc. Many studies have been conducted to evaluate casein-derived peptides due to their multifunctional properties and the results of these studies have contributed to the development of a wide variety of functional dairy products. The purpose of this paper was to review the generation of bioactive peptides, their absorption and metabolism, and their specific bioactive effects.

• Journal of Life Science
• /
• v.31 no.5
• /
• pp.496-501
• /
• 2021

In this study, the marine agar-degrading bacterium Pseudoalteromonas sp. JH-1 was isolated, and its growth and agarase properties were investigated. Seawater was collected from the offshore of the Yonggung Temple in Busan, and agar-degrading bacteria were isolated and cultured with marine agar medium. The bacterium Pseudoalteromonas sp. JH-1 was isolated through 16S rRNA gene sequencing. The extracellularly secreted enzyme was obtained from the culture broth of Pseudoalteromonas sp. JH-1 and was used to characterize its agarase. The extracellular agarase exhibited a maximum activity of 116.6 U/l at 50℃ and pH 6.0 of 20 mM Tris-HCl buffer. Relative activities were 31, 59, 94, 100, 45, and 31% at 20, 30, 40, 50, 60, and 70℃, respectively. Relative activities were 49, 85, 100, 86, 81, and 67% at pH 4, 5, 6, 7, 8, and 9, respectively. Residual activity was more than 85% after exposure at 20, 30, and 40℃ for 2 hr, and more than 82% after exposure at 50℃ for 2 hr. Zymogram analysis confirmed that Pseudoalteromonas sp. JH-1 produced at least two agarases of 55 and 97 kDa. As the products of α-agarase and β-agarase have antioxidation, antitumor, skin-whitening, macrophage activation, and prebiotic effects, further studies are needed on the agarase of Pseudoalteromonas sp. JH-1.