Food Science and Biotechnology
Korean Society of Food Science and Technology (KOSFOST)
- Monthly
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- 1226-7708(pISSN)
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- 2092-6456(eISSN)
Domain
- Agriculture, Fishery and Food > Science of Food and Crops
- Agriculture, Fishery and Food > Food Science
Aim & Scope
The Food Science and Biotechnology (Food Sci. Biotechnol.; FSB) was launched in 1992 as the Food Biotechnology and changed to the present name in 1998. It is an international peer-reviewed journal published monthly by the Korean Society of Food Science and Technology (KoSFoST). The FSB journal covers; Food chemistry/food component analysis Food microbiology and biotechnology Food processing and engineering Food hygiene and toxicology Biological activity and nutrition in foods Sensory and consumer science s Consumer perception and sensory evaluation on processed foods are accepted only when they are relevant to the laboratory research work. As a general rule, manuscripts dealing with analysis and efficacy of extracts from natural resources prior to the processing or without any related food processing may not be considered within the scope of the journal. The FSB journal does not deal with only local interest and a lack of significant scientific merit. The main scope of our journal is seeking for human health and wellness through constructive works and new findings in food science and biotechnology field.
http://www.fsnb.or.kr/submission/ KSCI KCI SCOPUS SCI SCIEVolume 16 Issue 3
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Caking has been a serious problem in food, feed, pharmaceutical, and related industries, where dry powdered materials are produced and/or utilized. Caking of dry food powders occurs when water is redistributed or absorbed by the powders during processing and storage. The powders become sticky when their surfaces are mobilized by water, resulting in inter-particle binding, formation of clusters, and inter-particle fusion, which lead to caking. As a result of caking, the solubility of the powdered materials may decrease, lipid oxidation and enzymatic activity may increase, and sensory qualities such as flavor and crispness may deteriorate. Caking may also lead to microbial growth. For consumers, caking of powder products is a sign of poor quality and possible food safety problems. This paper provides a review of factors affecting caking, caking mechanisms, and analysis of caking based on previous studies.
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Kim, Gi-Young;Morgan, Mark;Ess, Daniel;Hahm, Byoung-Kwon;Kothapalli, Aparna;Bhunia, Arun 337
Conventional methods for pathogen detection and identification are labor-intensive and take days to complete. Biosensors have shown great potential for the rapid detection of foodborne pathogens. Fiber-optic biosensors have been used to rapidly detect pathogens because they can be very sensitive and are simple to operate. However, many fiber-optic biosensors rely on manual sensor handling and the sandwich assay, which require more effort and are less sensitive. To increase the simplicity of operation and detection sensitivity, a binding inhibition assay method for detecting Listeria monocytogenes in food samples was developed using an automated, fiber-optic-based immunosensor: RAPTOR (Research International, Monroe, WA, USA). For the assay, fiber-optic biosensors were developed by the immobilization of Listeria antibodies on polystyrene fiber waveguides through a biotin-avidin reaction. Developed fiber-optic biosensors were incorporated into the RAPTOR to evaluate the detection of L. monocytogenes in frankfurter samples. The binding inhibition method combined with RAPTOR was sensitive enough to detect L. monocytogenes ($5.4{\times}10^7\;CFU/mL$ ) in a frankfurter sample. -
Changes in the Expression of ADP-Glucose Pyrophosphorylase Genes During Fruit Ripening in StrawberryStarch contents play important roles in determining the fruit quality. Stawberry accumulates starch in the early stages and then mobilized into soluble sugars during fruit ripening. To date the molecular studies on the ADP-glucose pyrophosphorylase (AGPase), a key enzyme of starch biosynthesis, were not reported. cDNAs encoding small (FagpS) and large (FagpL1 and FaspL2) AGPase subunits were isolated from strawberry (Fragaria
${\times}$ ananassa Duch. cv. Niyobou). Both FagpS and FagpL1 cDNAs have open reading frames deriving 55-58 kDa polypeptides, where FagpL2 contains a partial fragment. Sequence analyses showed that FagpS has a glutamate-threonine-cysteine-leucine (ETCL) instead of a glutamine-threonine-cysteine-leucine (QTCL) motif found in all the dicot plants except for Citrus. In fruits, FagpS and FagpL1 were expressed in all stages with a little change in the amounts of transcripts. In the case of FagpL2, we were not able to detect any signal from all stages of fruit development and all tissues except for very a weak signal from the leaf. The results indicate that FagpL1 and FagpL2 show ubiquitous and leaf-specific expression patterns, respectively. The studies suggest that the starch contents in strawberry might be controlled by the expression of AGPase gene at both the transcriptional and post-transcriptional levels during fruit development. -
The objectives of this study were to systemically identify phenolic compounds in roasted wild ginseng (Panax ginseng C.A. Meyer) leaves and investigate their radical scavenging activities. Seven phenolic compounds were identified by NMR (H, C, COSY, HMQC, HMBC) and mass (EI-MS, FAB-MS) analyses: 5-caffeoylquinic acid, kaempferol, quercetin, 3,4-dihydroxy-benzoic acid, 4-hydroxy-benzoic acid, 3-(3,4-dihydroxyphenyl)-2-propenoic acid, and 3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid. Their concentrations ranged from 0.4 (3,4-dihydroxy-benzoic acid) to 7.5 mg (kaempferol) per 100 g of roasted leaves. Among these compounds, 5-caffeoylquinic acid, kaempferol, and quercetin were found exclusively in the leaf portions of the ginseng plants. When their antioxidant activities were measured by DPPH and superoxide anion radical scavenging activity, quercetin, and kaempferol were most effective.
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Chang, Hyun-Joo;Lee, Seung-Jun;Lee, Myung-Ki;Cho, Yong-Jin;Kim, Hyun-Jung;Kim, Chong-Tae;Chun, Hyang-Sook 355
During the traditional production process of yugwa, a Korean traditional oil-puffed snack, three bacterial isolates, 12, 37, and B1 from waxy rice slurry were characterized by using the molecular techniques, and the quality of the yugwa prepared by using three isolates was examined in relation to physical and sensory properties. Isolates 37 and B1 were identified as Lactobacillus sp. by 16S rDNA sequence analysis, while isolate 12 was as Bacillus amyloliquefaciens by gyrA sequence analysis. Waxy rice inoculated with isolate 12 demonstrated the lowest hardness and the highest peak and [mal viscosity. Yugwa prepared from isolate 12-inoculated waxy rice indicated the lowest hardness and the highest volume expansion, the key characteristics of yugwa. This result presents the possibility for the use of a starter in the commercial production of yugwa and other rice-based snacks. -
As the application of quantitative risk assessment (QRA) to food safety becomes widespread, it is now being questioned whether experimental results and simulated results coincide. Therefore, this paper comparatively analyzed experimental data and simulated data of the cross contamination, which needs summation of the simplest calculations in QRA, of chicken by Monte Carlo simulation and fuzzy math computation. In order to verify summation, the following basic operation was performed. For the experiment, thigh, breast, and a mixture of both parts were preserved for 24 hr at
$20^{\circ}C$ , and then the cell number of Salmonella spp. was measured. In order to examine the differences between experimental results and simulated results, we applied the descriptive statistics. The result was that mean value by fuzzy math computation was more similar to the experimental than that by Monte Carlo simulation, whereas other statistical descriptors by Monte Carlo simulation were more similar. -
Livers of skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacares) were investigated on the food compositional characteristics and also compared to that of Alaska pollack (Theragra chalcogramma). The proximate compositions of skipjack tuna and yellowfin tuna livers were high in crude protein, carbohydrate, and crude ash, while were low in crude lipid when compared to that of Alaska pollack liver. The results of heavy metal suggested that tuna livers appeared safe as a food resource. The total amino acid contents of skipjack tuna and yellowfin tuna livers were 17.7 and 17.1 g/100 g, respectively, and the major amino acids in both livers were aspartic acid, glutamic acid, alanine, valine, leucine, and lysine. Tuna livers were good sources of iron and zinc, while have low lipid content. The extractive nitrogen contents of skipjack tuna and yellowfin tuna livers were 526.5 and 468.2 mg/100 g, respectively, and their major free amino acids were taurine, glutamic acid, and alanine. From the results of taste value, the major taste active compounds among free amino acids were glutamic acid and aspartic acid.
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Chemical and sensory profiles of 5 Korean commercial rice wines (yakju) were developed using descriptive, physicochemical, and volatile analyses. Color, 6 aroma, and 5 taste attributes of these rice wines were evaluated by a panel of 13 judges. Sample wines were analyzed for titratable acidity, ethanol content, pH, Hunter colorimeter value, organic acids, and free sugars. Volatile analysis of the samples revealed the presence of 2 acids, 7 alcohols, 19 esters, and 5 miscellaneous compounds. Based on principal component analysis of the descriptive data, rice wines were primarily separated along the first principal component, which accounted for 57% of the total variance between the rice wines with high intensities of 'color' and 'sweet aroma' versus 'ginseng' aroma.
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The objective of this experiment was to study the influence of feed moisture content on the degree of enzymatic hydrolysis of com starch in a twin screw extruder and the saccharification yield of the dried extrudate. The feed moisture content was set at 25, 30, and 35% and
${\alpha}$ -amylase solution was directly injected into the feed section at a barrel temperature of$95^{\circ}C$ and screw speed of 250 rpm. Amyloglucosidase was used for the saccharification of the dried extrudate at a concentration of 0.055%(w/w). Expansion ratio and swelling factor of extrudates decreased with increasing the feed moisture content. Addition of${\alpha}$ -amylase during extrusion process raised reducing sugar content of extrudates which also increased with the feed moisture content. The saccharification yield of dried extrudate was higher for the extrudate with lower feed moisture content. -
This study was conducted to observe quality characteristics of whole soybean meju fermented with germinated soybean (Glycine max: Hwanggeumkong). The germination rate after 24 hr was
$23.0{\pm}1.2%$ , then increased rapidly to$90.2{\pm}1.3%$ at 36 hr of germination, and finally reached a level of$99.4{\pm}0.3%$ at 60 hr of germination. It was confirmed that the total isoflavone content immediately after soaking was 100.1 mg%, increasing during the beginning of the germination process; it continued to increase to 114.0 mg% by 24 hr of germination, but decreased thereafter. The isoflavone content at 60 hr of germination was 101.6 mg%. A total of 6 organic acids were detected, and total organic acid content ranged from 963.1-1,145.3 mg%. Differences based on the degree of germination in the raw material were insignificant. The free amino acid levels of the whole soybean meju made from non-germinated soybeans and from soybeans that had germinated 48 hr were 2,580.9 and 2,519.7 mg%, respectively. The content of glutamic acid was highest followed by aspartic acid, lysine, leucine, and proline. -
Cho, Sung-Hee;Choi, Sang-Won;Choi, Young-Sun;Kim, Hee-Jung;Park, Youn-Hee;Bae, Yong-Chul;Lee, Won-Jung 392
We investigated whether ethanol extracts of the safflower seeds containing phenolic compounds were responsible for the bone-protecting effects. Crude ethanol extract (CEE) of the safflower seeds was fed for 4 weeks at the level of 1% in diet to female Sprague-Dawley rats that had been subjected to bilateral ovariectomy (OVX). The CEE effects (OVX+CEE) were evaluated by comparing results obtained from OVX, Sham, and OVX injected with$17{\beta}$ -estradiol ($OVX+E_2$ ) groups. OVX resulted in a dramatic reduction in the trabecular bone mass of the proximal tibia (approximately 40% of the Sham group) and an increase in fat deposition in bone marrow. In$OVX+E_2$ group, the bone loss was completely prevented as well as marrow adiposity. In OVX+CEE group, approximately 80% of the bone mass was maintained compared with Sham group and fat deposition in the bone marrow was prevented. Meanwhile, the partially purified ethanol extract containing the phenolic compounds stimulated proliferation of the ROS 17/2.8 osteoblast-like cells in a dose-dependent manner, as potently as positive controls of$E_2$ and genistein. The present data demonstrate that the ethanol extracts of safflower seeds reduced bone loss caused by estrogen deficiency. The bone-protecting effect of safflower seeds seems to be mediated, at least partly, by the stimulating effect of the phenolic compounds on the growth of osteoblasts. -
The effectiveness of phage biocontrol depends on the activity of bacteriophage in a given environment. In order to investigate the infectivity and the stability of bacteriophages in representative environments, three virulent phages, Listeria phage A511, Salmonella phage Felix O1, and Escherichia coli phage T7, were subjected to different temperatures, pHs and salt concentrations (NaCl). Phage infectivity was also determined in the presence of divalent cations (
$Mg^{2+}$ or$Ca^{2+}$ ). As a result, three phages exhibited a wide range of survival rates under various environments. Phage infectivity was directly correlated with bacterial growth under the applied conditions. One exception was Felix O1 that did not kill Salmonella grown in low pH (4.5). The failure was attributed to defective adsorption of Felix O1. This finding is significant as it provides an explanation for the inefficient phage biocontrol. Therefore, such information is crucial to improve phage biocontrol of pathogens. -
In this study, we investigated the effects by age of long-tenn supplementation of Epimedium koreanum Nakai (EKN)-containing water on the in vivo antioxidant capacities of rats. All rats were reared in a conventional system, and none of the rats showed any signs of aversion to the EKN solution. Neither the mean nor maximum life spans of the rats were extended by long-tenn administration of the solution. The EKN extract caused decreases in the levels of serum thiobarbituric acid reactive substances in the rats. The activities of superoxide dismutase, catalase, and glutathione (GSH) peroxidase within the liver cytosol decreased with age in both the control and EKN-supplemented groups. GSH peroxidase activity, however, was higher at old age in the EKN-supplemented group. The activities of GSH reductase and GSH-S-transferase, and the levels of free-sulfhydryl (SH) and total-SH group gradually decreased with age in both groups. However, there was some tendency for higher levels in the EKN supplemented group at a corresponding age. These results indicate that long-tenn supplementation of EKN water extracts alone does not exhibit discernible adverse effects in rats, and has some enhancing effects on the antioxidant capacities of the blood and liver, but it does not have life-prolonging effects.
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Antimicrobial and antioxidative effects of 14 different herbal flower extracts on skin microorganisms and oxidation were tested in this research. Herbal flower extracts were prepared with 70% ethanol. Among the herbal flower extracts, roselle (Hibiscus sabdariffa L.) flower extract showed the highest antimicrobial activity against Staphylococcus epidermidis as determined by a paper disc method. The seventy % ethanol extract of roselle flower was fractionated by sequential hexane, chloroform, ethyl acetate, n-butanol, and water fractionation. The growth of S. epidermidis, Streptomyces collinus, Streptomyces coeruleoprunus, Salmonella enteritidis, Vibrio parahaemolyticus, and Malassezia pachydermatis was most efficiently inhibited by ethyl acetate fraction of roselle flower extract as determined by a paper disc method and growth inhibition curves. In addition, the ethyl acetate fraction, water fraction and butanol fraction showed free radical scavenging and DNA cleavage inhibition activities. These results demonstrate that roselle flowers hold antimicrobial and antioxidative activities against skin microorganisms and oxidants.
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The aim of this study was to determine the various bioactive components of five olive oil varieties, as well as to assess their contribution to the oxidative stability of the oils. Fatty acids,
${\alpha}$ -tocopherol,${\beta}$ -carotene, total flavonoids, total phenols, and certain phenolic compounds of extra virgin olive oils (EVOO; blended, arbequina, hojiblanca, and picual) and pure olive oil (POO) were examined. Oxidation stability was evaluated by the peroxide value (POV). The total content of all the studied antioxidant compounds was significantly higher in the EVOOs than the POO (p<0.05). Among the EVOOs, picual had the highest levels of${\alpha}$ -tocopherol ($10.18{\pm}0.40\;mg/100\;g$ ),${\beta}$ -carotene ($557{\pm}8\;{\mu}g/100\;g$ ), and total phenols ($110.7{\pm}1.3\;mg/g$ ), which correlated strongly with antioxidative capacity. Furthermore, the lowest POV occurred in picual EVOO and correlated with the highest monounsaturated fatty acid (MUFA, C16:1 and C18:1) and lowest polyunsaturated fatty acid (PUFA, C18:2 and C18:3) compositions, suggesting the ratio of MUFA to PUFA is a critical parameter for the oxidative stability of olive oil. Our results indicate that the oxidative stability and antioxidant potential of EVOO depends not only on the antioxidant vitamins, but also on the amount of phenolic compounds and fatty acid profile of the oil. -
The inhibitory effect of onion extract on polyphenol oxidase (PPO) and browning of peach juice was investigated. Various reducing agents such as L-ascorbic acid, L-cysteine, dithiothreitol, glutathione, and sodium pyrosulfite strongly inhibited polyphenol oxidase extracted from peach. The enzyme was also inhibited by addition of water extract of onion. Regardless of substrates used, the addition of heated onion extract exhibited stronger inhibitory effect on peach polyphenol oxidase activity than that of the fresh one. The inhibitory effect of onion extract was dependent on heating temperature and time. The onion extract inhibited the peach polyphenol oxidase non-competitively. The heating of onion extract in the presence of glucose, glycine stimulated the inhibitory effect of the onion extract, which suggests non-enzymatic browning products produced during heating might be responsible for the stronger inhibitory action of the heated onion extract. The retardation of peach juice browning by onion extract seems to be caused by inhibition of peach PPO.
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We analyzed the isoflavone content of domestic soybeans during steaming, boiling, fermentation, germinating cultivation, fermentation, and soybean curd production. The isoflavone content of the beans was reduced by steaming and boiling, and overall reductions ranging from 16.0 to 65.0% of initial isoflavone values were detected. After 4 days of germinating cultivation, the total isoflavones of Eunhakong increased from 1,341 to
$2,017\;{\mu}g/g$ and the total isoflavones of Guinunikong increased from 1,284 to$1,535\;{\mu}g/g$ . The isoflavone content of the vinegar beans produced from Hwangkeumkong and Black No.1 increased from 1,877 to$1,956\;{\mu}g/g$ , and from 885 to$1,956\;{\mu}g/g$ after 8 days of immersion in 4% acetic acid, respectively. During soybean curd production, significant amounts of isoflavones were lost in the whey (30-31 %) and soybean curd residue (15-20%). Only 37.4% of the isoflavones present in the original soybeans remained in the soybean curd with the hot extraction method, and 50.7% of them with the cold extraction method. Soybean curd prepared with whole soybean method, however, retained 80.7% of the initial isoflavones. -
The aim of the present study was to assess the effects of onion (Allium cepa) skin extract (OSE) on pancreatic lipase (PL), the key enzyme of the digestion and absorption of dietary fat in the small intestine, and to evaluate its potential for the inhibition of body-weight gain. OSE inhibited PL with an
$IC_{50}$ of 53.70 mg/mL, which means as potent as 0.07635% of the activity of orlistat. At 3 and 4 hr after administration of OSE, the plasma triacylglycerol concentration was significantly lower in the OSE-treated rats than control. Body-weight gain and parametrial adipose tissue weights were significantly lower in mice fed the high-fat diet (fat comprises 31% of total calories) with 5%(w/w) OSE than in control. The results suggest that OSE may be an effective nutraceutical for the inhibition of body-weight gain. -
The effects of the methanol extract of the leaves of Brassica juncea and isorhamnetin
$3-O-{\beta}-D-glucopyranoside$ , major compound isolated from the ethyl acetate fraction of this plant on hepatic lipid peroxidation and drug-metabolizing enzymes, were evaluated in rats treated with bromobenzene. The extract and isorhamnetin$3-O-{\beta}-D-glucopyranoside$ of oral administration did not show any significant effects on activities of aminopyrine N-demethylase and aniline hydroxylase, enzymes forming toxic epoxide by bromobenzene as well as on glutathione content. However, both methanol extract and isorhamnetin$3-O-{\beta}-D-glucopyranoside$ significantly recovered the decreased activities of glutathione s-transferase and epoxide hydrolase, and also reduced the lipid peroxide level in rats treated with bromobenzene. From the results, the protections of this plant against bromobenzene-induced hepatotoxicity are thought to be via enhancing the activities of epoxide hydrolase and glutathione s-transferase, enzymes removing toxic epoxide, and reducing the lipid peroxide level. -
The antioxidant activity and isoflavone content of chokong, Rhynchosia nolubilis seeds pickled in vinegar at
$4^{\circ}C$ for 2 weeks, were investigated. The polyphenol content and 2,2-diphenyl-1-pycrylhydrazyl (DPPH) radical-scavenging capacity were lower in chokong than in raw seeds. Based on isoflavone analysis, the aglycone (daidzein and genistein) content was high in chokong while the content of the corresponding glucosides (daidzin and genistin) was similar to that in raw seeds. Thermal processing, in which seeds were heated in vinegar at$121^{\circ}C$ for 20 min, reduced the polyphenol content but did not affect the DPPH radical-scavenging capacity compared to the pickling process. The heated seeds had a 2.6 to 2.7 times higher glucoside content and 51 to 55% lower aglycone content than chokong, depending on the kind of vinegar used. During pickling and thermal processing, vinegars were more effective at eluting antioxidants and isoflavones from seeds than other solutions such as acetic acid, citric acid and HCl solutions, distilled water, and phosphate buffer (pH 7.0). -
The potential antioxidant activities of methanolic extracts from soybean and rice fermented with Monascus sp. were investigated. M. pilosus IFO 480 and M. anka IFO 478 were screened as a suitable strain to promote the antioxidant activities in soybean- and rice- fermentation. The methanol extracts from soybean and rice after fermenting for 20 days at
$30^{\circ}C$ resulted in a significant increase in the antioxidant capacities expressed as radical (ABTS and DPPH) scavenging assay and peroxidation inhibition (%) by thiocyanate method and increased (p<0.01) by a 2.6 to 3.1-fold compared with those of the unfermented products. The average antioxidant potentials of Monascus-fermented soybean extracts (MFSE) were significantly (p<0.01) stronger than Monascus-fermented rice extracts (MFRE). A linear correlations between free radical scavenging activity of MFSE and the total phenolics content (r=0.84) and total flavonoids content (r=0.81) were observed. These results indicated that MFSE exhibited stronger (p<0.01) antioxidant activity and contained significantly higher levels (p<0.05) of phenolics than MFRE. -
Histone acetyltransferase (HAT) is a family of enzymes that regulate histone acetylation. Dysfunction of HAT plays a critical role in the development of cancer. Here we have screened the various plant extracts to find out the potent HAT inhibitors. The bellflower (Platycodon grandiflorum) root have exhibited approximately 30% of the inhibitory effects on HAT activity, especially p300 and CBP (CREB-binding protein) at the concentration of
$100\;{\mu}g/mL$ . The cell viability was decreased approximately 52% in LNCaP cell for 48 hr incubation. Furthermore, mRNA level of 3 androgen receptor target genes, PSA, NKX3.1, and TSC22 were decreased with bellflower root extract treatment ($100\;{\mu}g/mL$ ) in the presence of androgen. In ChIP assay, the acetylation of histone H3 and H4 in PSA promoter region was dramatically repressed by bellflower root treatment, but not TR target gene, Dl. Therefore, the potent HAT inhibitory effect of bellflower root led to the decreased transcription of AR target genes and prostate cancer cell growth with the repression of histone hyperacetylation. -
Ohba, Kiyoshi;Watanabe, Shoko;Han, Kyu-Ho;Hashimoto, Naoto;Noda, Takahiro;Shimada, Ken-Ichiro;Tanaka, Hisashi;Sekikawa, Mitsuo;Fukushima, Michihiro 463
We examined the hepatoprotective effects of colored potato flakes on acetaminophen (AAP)-induced liver damage in rats. F344/DuCrj (8 week-old) rats were fed a cholesterol-free diet with 54.9486 g of${\alpha}$ -corn starch/100g diet and were orally treated with 25% colored flakes of Kitamurasaki (KM: light purple), Northern Ruby (NR: red), and Shadow Queen (SQ: medium purple) potatoes co-administered with AAP (0.5 g/100 g diet) for 4 weeks. The hepatic thiobarbituric acid-reactive substances (TBARS) values in the KM, NR, and SQ groups were significantly lower (p<0.05) than those in the control groups with and without AAP. Furthermore, the hepatic catalase, Mn-superoxide dismutase (SOD), and Cu/Zn-SOD mRNA levels in the KM, NR, and SQ groups were higher than those in the control groups with and without AAP. The present findings suggest that colored potato flakes are useful as a prophylactic agent against oxidative liver damage. -
To evaluate the vancomycin resistance of Enterococcus spp. (VRE) from Saengsik and Sunsik, Enterococcus were isolated and identified from 25 Saengsik and 35 Sunsik samples, and resistance of Enterococcus to other antibiotics was also assessed. Thirty nine Enterococcus, 16 strains from Saengsik, and 23 strains from Sunsik, were ultimately isolated. The most frequently collected Enterococcus isolates in Saengsik were E. casseliflavus and E. hirae, and were E. casseliflavus and E. faecium in Sunsik. However, E. faecalis was not detected in those foods. Minimum inhibitory concentrations of vancomycin against the isolates were below
$4\;{\mu}g/mL$ and no strains evidenced profound levels of resistance. The isolates were found to be susceptible to vancomycin with the exception of eight E. casseliflavus and three E. gallinarum. All Enterococcus isolates proved resistant to streptomycin and chloramphenicol. 23% of the isolates were resistant to penicillin; however, all of the isolates were sensitive to tetracycline. Six and 48%, respectively, of the strains from the Saengsik and Sunsik proved resistant to erythromycin. All of E. mundtii and E. hirae isolates from Saengsik, and 20% of E. gallinarum and E. casseliflavus isolates from Sunsik were found to be ampicillin-resistant. All of E. gallinarum, E. casseliflavus, and E. faecium were rifampin-resistant. The antibiotic resistances of Enterococcus were relatively low, and this low vancomycin resistance was similar to that evidenced by Enterococcus isolates obtained from the other foods. However, there may be a need for some review of the accepted antibiotics criteria for Enterococcus and VRE in ready-to-eat foods. -
Rapid Prediction of Amylose Content of Polished Rice by Fourier Transform Near-Infrared SpectroscopyLee, Jin-Cheol;Yoon, Yeon-Hee;Kim, Sun-Min;Pyo, Byong-Sik;Hsieh, Fu-Hung;Kim, Hak-Jin;Eun, Jong-Bang 477
Fourier transform near-infrared (FT-NIR) spectroscopy and partial least squares (PLS) regression were used to predict the amylose content of polished rice. Spectral reflectance data in a wavelength range of 1,000 to 2,500 nm were obtained with a commercial spectrophotometer for 60 different varieties of Korean rice. For a comparison of this spectroscopic method to a standard chemical analysis, the amylose contents of the tested rice samples were determined by the iodine-blue colorimetric method. The highest correlation for the rice amylose ($R^2=0.94$ , standard error of prediction=0.20% amylose content) was obtained when using the FT-NIR spectrum data pre-treated with normalization, the first derivative, smoothing, and scattering correction. -
Jang, Ki-Hyo;Kang, Soon-Ah;Kim, Chul-Ho;Lee, Jae-Cheol;Kim, Mi-Hyun;Son, Eun-Wha;Rhee, Sang-Ki 482
To investigate production and hydrolysis of levan, the levansucrase enzymes from Zymomonas mobilis ATCC 10988 and Rahnella aquatilis ATCC 33071 were used. The optimum temperature of R. aquatilis levansucrase for levan formation was$37^{\circ}C$ , whereas that of Z. mobilis was$4^{\circ}C$ , under the experimental conditions. Both levansucrases also catalyzed the reverse levan hydrolysis reaction. Levan hydrolysis reactions from both levansucrases were temperature dependent; high temperature ($20^{\circ}C$ ) was more favorable than low temperature ($4^{\circ}C$ ) by 4 times. Fructose was the only product from hydrolysis reaction by both levansucrases, showing that both levansucrases mediated the hydrolysis reaction of exo-enzyme acting. In both enzymes, initial levan hydrolysis activity was almost accounted to 1% of initial levan formation activity. The results allow the estimation of the fructose release rate in enzyme processing conditions. -
Plentiful amount of spent yeast has been produced as a by-product from breweries.
${\beta}-Glucan$ was prepared from the spent brewer's yeast in a crude form with hot water extraction and subsequent enzymatic treatment. The crude${\beta}-glucan$ preparation consisted of mainly glucan (53% of total wt), containing approximately 35%${\beta}-glucan$ content of total weight. The effects of crude${\beta}-glucan$ substitution (1-9%) on pasting properties of wheat flour and starch were determined using a Rapid Visco-Analyzer (RVA). Incorporation of yeast${\beta}-glucan$ into wheat flour and starch significantly decreased peak and [mal viscosities, but slightly increased setback viscosity. The setback viscosity was considerably higher in starch/${\beta}-glucan$ suspension than in flour/${\beta}-glucan$ suspension. It was suggested that preparation of yeast${\beta}-glucan$ into aqueous dispersion might affect pasting behaviors of wheat flour and starch. -
We investigated the antioxidant activity of ethanol extracts obtained from the flowers of Elsholtzia splendens on Chinese hamster ovary CHO-K1 cells. When cells were treated with E. splendens extracts (ESEs), low concentrations (<12.5 ug/mL) of stimulated cell proliferation via radical generation. Relative mRNA expression of Cu/Zn-superoxide dismutase (SOD) and Mn-SOD in cells exposed to ESEs (1-20 ug/mL) was significantly induced in a dose-dependent manner (p<0.05). In the case of catalase, ESEs had opposing effects; that is, a low-level treatment caused a decrease, and a high-level treatment induced elevated levels (p<0.05). The results demonstrated that components of ESEs exhibit potential antioxidant properties. Also, further studies are required to clarify the active components of Elsholtzia splendens extracts responsible for such biological activities.
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Kim, So-Hyun;Yoon, Ko-Woon;Kim, Mi-Kyo;Paek, Se-Hee;Choi, Dong-Mi;Oh, Sang-Suk;Park, Jin-Byung 493
In this study, the acrylamide contents of foods were estimated via liquid chromatography (LC)/mass spectrometry (MS)/MS after the food matrix constituents had been degraded with digestive enzymes (i.e., pepsin and pancreatin) and extracted with water. The quantities of acrylamide released from samples of cereal, potato chips, peanuts, and coffee were$62{\pm}5.1,\;970,\;106{\pm}20$ , and 890 ppb, respectively. No acrylamide was detected in samples of soybean curd (tofu), fish cake, and ham. Compared to the amounts of acrylamide detected after extraction with water only, we noted no significant differences in the soybean curd, fish cake, potato chip, ham, and coffee samples. However, the quantities of acrylamide released from the cereal and peanut samples were approximately 2-fold larger following pretreatment with the digestive enzymes. This study presents a new in vitro enzymatic digestion method which allows for a more accurate estimation of the acrylamide contents of foods. -
Dynamic rheological properties of hot pepper-soybean paste (HPSP) samples mixed with guar gum and xanthan gum were evaluated at different storage temperatures (5, 15, and
$25^{\circ}C$ ) by using a dynamic rheometer. Magnitudes of storage modulus (G'), loss modulus (G"), and complex viscosity (${\eta}^*$ ) in the HPSP-gum mixtures increased with an increase in storage temperature from 5 to$25^{\circ}C$ . After 3-month storage at 5 and$15^{\circ}C$ there were no significant changes in dynamic rheological properties. The increase in dynamic moduli (G', G", and${\eta}^*$ ) with storage temperature is less pronounced at HPSP-xanthan gum mixtures in comparison to HPSP-guar gum mixtures. The slopes of G' (0.16-0.18) of HPSP-guar gum mixtures at 3-month storage were much higher than that (0.10) at 0-month storage, indicating that the elastic properties of the HPSP-guar gum mixtures can be decreased after 3-month storage. However, there were not much differences between the slopes of G' in HPSP-xathan gum mixtures. Xanthan gum was observed to be better structure stabilizer for HPSP during storage.