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1.
Xavier Bonjoch Laia Calvó Marçal Soler Olaya Ruiz-Rueda L. Jesús Garcia-Gil 《Food Analytical Methods》2010,3(1):40-46
A new rapid method based on real-time PCR was developed to detect four thermophilic Campylobacter species (Campylobacter jejuni, Campylobacter coli, Campylobacter lari, and Campylobacter upsaliensis) in food samples. The assay targeted the bipA gene for C. upsaliensis and C. lari, whereas the gene encoding the ATP-binding protein CJE0832 was used to detect C. coli and C. jejuni. These genes were chosen for this assay due to their low variability and mutation rate at a species level. The multiplex
PCR showed 100% inclusivity for all 25 thermophilic Campylobacter strains tested and 100% exclusivity for 38 non-targeted strains belonging to closely related species. The newly developed
real-time PCR could detect down to 102 genomes/reaction and displayed efficiency above 97% for all species except for C. upsaliensis (90.1%). The method proved to be a reliable tool for food analysis, showing 100% sensitivity, 96% efficiency, and 92.45%
specificity when validated against the gold standard method UNE-EN ISO 10272:2006 using 200 diverse food samples (meat, fish,
fruits and vegetables, and raw milk). In artificially spiked samples, the detection limit of the method was 10 cfu/g in salad,
5 cfu/g in turkey meat, and 1 cfu/g in the rest of meat samples tested. Consequently, the newly designed molecular tool represents
a quick and safe alternative to obtain reliable results concerning the presence/absence of the main thermophilic Campylobacter in any food sample. 相似文献
2.
Ji-Eun Kang Chan-Woo Kim Soo-Hwan Yeo Seok-Tae Jeong Yong-Suk Kim Han-Seok Choi 《Food science and biotechnology》2018,27(3):715-724
Long-term aging of Yakju, a traditional Korean liquor made of rice and Nuruk (a fermentation agent), causes browning and odor and flavor development. This study investigated the effects of heat-treated Nuruk (50–80 °C, 30 min) on Yakju quality. The saccharogenic powers and glucoamylase, α-amylase, and carboxypeptidase activities were similar in non-heat-treated Nuruk and that treated at 50 °C. However, acidic protease and alcohol dehydrogenase decreased above 50 °C. The content of nitrogen-containing compounds was inversely proportional to the heat-treatment temperature. Compounds that cause off-flavors decreased at 50–60 °C, but increased at 70–80 °C, whereas compounds that provide fragrance increased at 50–60 °C. Sensory evaluation indicated that bad taste attributes were higher in Yakju produced using non-heat-treated Nuruk. Therefore, heat treatment of Nuruk at 50 °C can be adopted as a method for improving Yakju quality, as enzymatic activities that affect color, aroma, and taste are regulated. 相似文献
3.
Juan Calvo Viviana Calvente María E. Orellano Delia Benuzzi Maria I. Sanz 《Food and Bioprocess Technology》2010,3(5):644-650
Antagonistic activity of the mixtures Rahnella aquatilis–Rhodotorula glutinis and R. aquatilis–Cryptococcus laurentii was assessed against Penicillium expansum (cause of blue rot) and Botrytis cinerea (cause of grey rot) on apple fruit at 4 °C and 95% relative humidity (RH). Under these cold-storage conditions, the mixture
R. aquatilis–R. glutinis inhibited the development of B. cinerea and P. expansum in apples stored for 40 days and reduced the incidence of disease produced by these moulds to nearly zero. The other mixture,
R. aquatilis–C. laurentii, was less effective; the incidences of the grey rot and the blue rot were about 25% and 15%, respectively. Population dynamics
of the mixtures showed that the growth of R. aquatilis was strongly stimulated by the presence of the yeast R. glutinis, but in the case of the mixture R. aquatilis–C. laurentii, the same effect could not be observed. In this study, it was demonstrated that the combination of two microorganisms with
different requirements and antagonistic abilities resulted in a successful mixture against the two pathogen molds, B. cinerea and P. expansum. In addition, it was also proved that it is possible to improve the biocontrol of these pathogens without increasing the
inoculum size of the antagonist (alone or in mixtures), which was always 106cell/ml, despite the high concentration of the pathogen (106 conidia/ml) utilized. 相似文献
4.
Herbert Wieser Nicoline Vermeulen Felizitas Gaertner Rudi F. Vogel 《European Food Research and Technology》2008,226(6):1495-1502
Dough quality and baking performance of wheat dough are significantly affected by the qualitative and quantitative composition
of the gluten. Therefore, the degradation was studied of specific fractions of gluten proteins in sourdough as affected by
starter cultures. Doughs were fermented for 0, 5, and 24 h at 30 °C after addition of Lactobacillus sakei, L. plantarum, L. sanfranciscensis or Enterococcus faecalis. Chemically acidified doughs were used as controls. All doughs were analyzed quantitatively for their content of albumins,
globulins, gliadins, glutenins, and glutenin macropolymer by means of a combined extraction/HPLC procedure. Protein degradation
during sourdough fermentation was primarily due to acidic proteases present in flour. While L. sakei, L. plantarum and L. sanfranciscensis were mostly non-proteolytic, E. faecalis clearly contributed to gluten proteolysis. Single gluten protein types were clearly different in their resistance to proteolytic
activities of the dough system and E. faecalis, and, in contrast to total glutenins, the amounts of gluten macropolymer were significantly reduced already after 5 h of
incubation. When longer fermentation times were applied, gluten was substantially degraded. The strongest decrease was found
for the glutenin fraction leading to an increase of alcohol soluble oligomeric proteins in the gliadin fraction. The extent
of the decrease of monomeric gliadins was strongest for the γ-type followed by the α- and the ω-types. This indicates that
dough properties residing in specific types of gluten fractions can be influenced by the duration of fermentation and the
application of proteolytic strains. 相似文献
5.
Prashani Mudika Ekanayake Chamilani Nikapitiya Mahanama De Zoysa Ilson Whang Se Jae Kim Jehee Lee 《European Food Research and Technology》2008,227(3):897-903
Natural fermentation was tested as a method of releasing active compounds during screening for potential anticoagulant activity
in three types of algae (Pachymeniopsis elliptica, Sargassum horneri, and Ulva pertusa). Freeze dried algae samples (2.5 g) were fermented by adding 75 g of sugar and 500 mL of water and thereafter kept at room
temperature (25 °C) for 3 months. Activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT)
were measured every 2 weeks for 3 months to determine the optimum time for the highest activity. Fermented P. elliptica, (which had the highest activity) was subjected to anion exchange chromatography (DEAE-cellulose) and sepharose 4B gel permeation
chromatography. The purified sample was analyzed by agarose-gel electrophoresis and polyacrylamide gel electrophoresis (PAGE)
to confirm the purification and to determine the molecular mass, respectively. The 360 μg/mL of purified compound (Mwt > 500,000 Da)
had both APTT and PT activities (>1,000 s). However, at the concentrations of 180 μg/mL, purified compound and heparin showed
540 and >1,000 s APTT activity, respectively. Though, the purified compound of P. elliptica considered as a weaker anticoagulant than heparin, this purified anticoagulant polysaccharide could be considered as a good
alternative source as an anticoagulant. Moreover, the technique of fermentation is an inexpensive and feasible, this purified
anticoagulant polysaccharide compound could be used in pharmaceutical and biomedical industry. Further investigations need
to be performed to determine the mechanism of this novel anticoagulant compound.
The authors Prashani Mudika Ekanayake and Chamilani Nikapitiya contributed equally to this work. 相似文献
6.
Thermal inactivation of quality-related enzymes in both cauliflower crude enzyme extracts and fresh tissue samples was studied
in temperature range 50–100 °C. For crude enzyme extracts, several parameters, reaction rate constants (k) and activation energy (E
a) as well as decimal reduction time (D) and (z) values, were used to characterize the thermal stability. The rates of inactivation were found to follow first-order inactivation
kinetics. Activation energies varied between 101.18 and 208.42 kJ mol−1 with z values of 10.59–24.09 °C. The examined kinetics indicated that lipoxygenase was the most heat resistant followed by peroxidase,
polyphenol oxidase, pectin methyl esterase and ascorbic acid oxidase. Furthermore, the obtained results from the blanched
fresh tissues indicated that inactivation of lipoxygenase secured disappearing of any other enzyme activities. Therefore,
this study recommends using lipoxygenase as an indicator enzyme to optimize the thermal treatments of cauliflower products. 相似文献
7.
The various extracts from chamdanggui (Angelica gigas Nakai) and sogdan (Phlomis umbrosa Turcz) were evaluated for estrogenic activity and characterized according to HPLC profile. Chamdanggui and sogdan were individually extracted with 4 solvents (hot water, 70% ethanol, n-butanol, and dichloromethane) of differing polarities. Estrogenic activity was determined by E-screen using an estrogen-dependent
MCF-7 BUS cell. Although almost all extracts showed estrogenic effects in a concentrationdependent manner, the hot water extract
from chamdanggui (250 μg/mL) had the higher effect (138%). Among 90 fractions using HPLC separation of the hot water extract from chamdanggui, fraction 21 and 28 produced the highest estrogenic effects of 178 and 163% at 10 μg/mL, respectively. The results imply
that the hot water extract from chamdanggui could be useful as an alternative hormone replacement therapy. 相似文献
8.
Brendan A. Niemira 《Food and Bioprocess Technology》2010,3(2):257-264
The human pathogen Listeria monocytogenes forms biofilms that are relatively resistant to chemical sanitizing treatments. Ionizing radiation effectively inactivates
planktonic Listeria, but no information is available on the relative efficacy of the process against biofilm-associated Listeria. The irradiation sensitivity of planktonic or biofilm cells was determined for L. monocytogenes ATCC 43256 and ATCC 49594 and a commonly used surrogate Listeria innocua ATCC 51742. Biofilms were formed on sterile glass slides incubated for 48 h at 22°C, 28°C, or 37°C. The cultures were gamma
irradiated and the irradiation D
10 value was calculated for each combination of isolate/culture/temperature. The effect of temperature of cultivation on the
irradiation sensitivity of both planktonic cells and biofilm cells varied for each of the isolates. Depending on isolate and
temperature, biofilm cells were equally sensitive or more sensitive (P < 0.05) to irradiation. D
10 values overall tended to increase with temperature of cultivation for L. monocytogenes 49594 and L. innocua 51742, but tended to decrease with increasing temperature for L. monocytogenes 43256. The D
10 values of the various culture/temperature combinations differed significantly among the isolates examined. Irradiation effectively
eliminates both planktonic and biofilm-associated cells. The extent to which the biofilm habitat modifies the antimicrobial
efficacy of irradiation is dependent on the specific isolate examined and the temperature at which it forms. This study is
the first inquiry to show that biofilm Listeria cells are as sensitive or more sensitive to irradiation compared with planktonic cells and that this response is dependent
on biofilm formation conditions. 相似文献
9.
Chen Qi-he Liu Xiao-jie Fu Ming-liang Zhang Hong-bo 《European Food Research and Technology》2010,231(6):943-950
S. cerevisiae proteinase A (PrA) is a member of the aspartic proteinase superfamily. The roles of PrA in S. cerevisiae physiology and cell metabolism are controversial. The objective of the current study was to elucidate the effects of the
absence of PrA on key enzymes with regard to the glycolytic flux in industrial S. cerevisiae. The observed activities of hexokinase (HK), phosphofructokinase (Pfk) and pyruvate kinase (PYKi) in PrA-modified S. cerevisiae strains (SC2 and SC3) were lower than that of the wild-type strain (p < 0.01). Compared to other strains, SC3 revealed the lowest activity of three key glycolytic enzymes. Current results imply
that PrA in industrial S. cerevisiae may control the glycolytic enzymes expression (HK, Pfk and PYKi) in the direct or indirect manner and thus lead to the delay
of cell metabolism. The observed intracellular ATP levels between the wild-type strain and PrA-modified strains (SC1 and SC2)
were significantly different (p < 0.01). The pronounced differences of key glycolytic enzymes between the wild-type and PEP4-modified strains were as well characterized by SDS–PAGE. The intracellular protein concentration in the presence of PrA is
higher than those of the PrA-modified strains. As a result, the interaction mode of PrA and the glycolytic enzymes was postulated
in this work. The findings herein suggest that the glycolytic flux direction and rate may be regulated by vacuolar PrA in
industrial S. cerevisiae. The present data obtained provide insights into understanding the roles of PrA in industrial S. cerevisiae. 相似文献
10.
Leona Buňková František Buňka Michaela Hlobilová Zuzana Vaňátková Dana Nováková Vladimír Dráb 《European Food Research and Technology》2009,229(3):533-538
The aim of this paper was to study the biogenic amines (histamine, tyramine, putrescine, cadaverine, agmatine, spermine and
spermidine) production of selected technological important lactic acid bacteria (strains of the genera Lactococcus, Lactobacillus and Streptococcus). Three methods (ion-exchange chromatography (IEC), PCR and cultivation method with pH indicator) were used. Within the 39
strains of lactic acid bacteria tested, the production of tyramine (formed by tyrosine decarboxylase) was detected in eight
strains (3 strains of Lactococcus lactis subsp. lactis, three strains of Lactococcus lactis subsp. cremoris, 1 strain of Streptococcus thermophilus and 1 strain of Lactobacillus delbrueckii subsp. bulgaricus). The other tested biogenic amines were not detected. Cultivation in decarboxylation broth seems to be the least accurate
method for the detection of biogenic amines due to enhanced risk of false-positive reactions. Therefore, in order to detect
bacteria producing biogenic amines, the combination of PCR and chromatographic methods (e.g. IEC) can be recommended. 相似文献
11.
Sencer Buzrul Hami Alpas Alain Largeteau Gérard Demazeau 《European Food Research and Technology》2008,227(2):443-448
The survival curves of Escherichia coli and Listeria innocua inactivated by high hydrostatic pressure (HHP) were obtained at room temperature (∼22 °C) and at five pressure levels (400,
450, 500, 550 and 600 MPa) in whole milk. These curves were described by the Weibull model and parameters of this model were
reduced from two to one with slight loss of goodness-of-fit. The logarithm of the time constant parameter (δ) of the reduced Weibull model was described with respect to high pressure (P). This approach can be used to define a z
p
value analogous to the modeling of the classical D value (increase in pressure that results in one log unit decrease of δ values). The development of accurate survival models under high pressure, as presented here, can be very beneficial to food
industry for designing, evaluating and optimizing HHP processes as a new preservation technology. 相似文献
12.
A total of 28 basidiomycetes and 16 substrates were investigated to detect extracellular peptidases for the hydrolysis of
wheat gluten as a complex Koji substrate. In a first screening, basidiomycetes were grown in submerged cultures containing
gluten as only carbon and nitrogen source. Growth rate, protein concentration and peptidase activity were monitored. Flammulina velutipes, Armillaria mellea, Trametes versicolor, Meripilus giganteus, Fomitopsis pinicola, Phanerochaete chrysosporium and Hericium erinaceus showed high peptidase activity. To evaluate the effects of complex substrates on peptidase generation, a set of experiments
was performed using surface cultures of Flammulina velutipes. This fungus grew well on many of the substrates and yielded a maximum of over 160.000 arbitrary U mL−1 on the surface liquid released from gluten pellets. Gelatin zymography visualized a complex mixture of secreted peptidases.
Highest peptidase yield was obtained from a koji-type culture: A maximum of 63% of the gluten was converted to free amino
acids in 14 days by peptidase activities in the range of 80,000–90,000 aU mL−1. The dark brown hydrolysate smelled and tasted like meat broth with no detectable bitterness. 相似文献
13.
Corrado Costa Paolo Menesatti Jacopo Aguzzi Stefano D’Andrea Francesca Antonucci Valentina Rimatori Federico Pallottino Marco Mattoccia 《Food and Bioprocess Technology》2010,3(1):43-48
The actual Italian production of clams is chiefly sustained by the native Tapes decussatus and the fortuitously imported Tapes philippinarum. Both species are commercialized as “Vongola verace”, but the commercial value of T. philippinarum is lower. The discrimination of species by sight is usually difficult and it cannot be done by observation based on shell
morphology but only when animals open their valves hence displaying the two siphons. In this study, we propose a new, noninvasive
method to discriminate individuals of both species based on the analysis of the external shape of their shells. Accordingly,
in sympatric populations at two sites of the Po river outlet, we have chosen individuals (63 for T. decussatus and 57 for T. philippinarum) of comparable commercial size for which a certain genetic discrimination was previously done. Pictures of the left side
valve were taken for all specimens. Their profiles were analyzed with the elliptic Fourier analysis. The mean outline for
each species was graphically extracted. The coefficients of the harmonic equations were analyzed by multivariate classification
(partial least squares discriminant analysis [PLSDA]). Results showed a high percentage of correct classification of individuals
of both species (96.6%). Contour analysis reflected the overall shell shape and thus identified morphological aspects that
were difficult to recognize and quantify in sight. The high percentage of correct classifications obtained by combining the
analysis of elliptic Fourier harmonics with PLSDA demonstrated the feasibility of this method to discriminate species with
a high level of resemblance. 相似文献
14.
The histidine decarboxylating activity and production of biogenic amines by Morganella morganii (NCIMB, 10466), Klebsiella pneumoniae (NCIMB, 673) and Hafnia alvei (NCIMB, 11999) were investigated using a rapid HPLC method. Derivatisation of the bacterial samples was carried out using benzoyl chloride. A gradient elution system was used for analysis with a mixture of acetonitrile and HPLC grade water. Bacterial strains not only produce histamine in histidine-enriched broth but also the other biogenic amines. The chromatographic results show that bacterial strains are also capable of producing spermine and spermidine in histidine-enriched broth. Bacterial ammonia production by all three strains was clearly detected since ammonia is generated during the degradation of histidine. The study demonstrates that the highest histamine production was obtained by Morganella morganii, followed by Klebsiella pneumoniae, and the lowest with the Hafnia alvei. Therefore, Morganella morganii and Klebsiella pneumoniae have strong histidine decarboxylase activity since they are prolific histamine-forming bacteria 相似文献
15.
Mi Jang Jin-Woo Min Dong-Uk Yang Seok-Kyu Jung Se-Young Kim Deok-Chun Yang 《Food science and biotechnology》2011,20(1):131-135
The pH of red ginseng extracts fermented with Saccharomyces cerevisiae and Saccharomyces carlsbergensis decreased rapidly during 3 days of fermentation, with no further significant change thereafter. After 20 days of fermentation,
a relatively small difference remained in the acidity of extracts fermented with S. cerevisiae (0.54%) and S. carlsbergensis (0.58%). Reducing sugar in the S. cerevisiae and S. carlsbergensis extracts decreased from 258.6 to 45.4 and 43.2 mg/mL glucose equivalents, respectively; and ethanol contents increased from
1.5% at day 0 to 16.0 and 15.0%, respectively, at day 20. Ginsenosides Rb1, Rb2, Rc, Re, Rf, and Rg1 decreased during the fermentation with S. cerevisiae, but Rd and Rg3 increased by day 12. Ginsenosides Rb1, Rb2, Rc, Re, and Rg1 decreased gradually in the extract with S. carlsbergensis, but Rd and Rg3 were increased at day 6 and 9, respectively. 相似文献
16.
A cDNA encoding hydroperoxide lyase (HPL) was isolated from Solanum tuberosum, cloned into pQE-30 vector, and expressed in E. coli. The recombinant protein was purified by nickel affinity chromatography and showed an approximate molecular weight of 54 kDa
by SDS–PAGE analysis, which was similar to the predicted value based on the putative amino acid sequences (53.9 kDa). 13-Hydroperoxy-linolenic
acid (13-HPOT) was the preferred substrate for the enzyme compared with 13-hydroperoxy-linoleic acid (13-HPOD). The corresponding
volatile products were 2(E)-hexenal and n-hexanal tested by headspace-gas chromatography, respectively. The enzyme was optimally
active at 25 °C and pH 6.5. The K
m, V
max, and the catalytic efficiency (V
max/K
m) for 13-HPOT were 56.6 μM, 71.3 units/mg, and 1.26 units/mg · μM, respectively. Activity of the recombinant potato HPL increased
when Triton X-100, sodium chloride, or potassium chloride was added in the reaction mixture, while calcium chloride decreased
activity of the recombinant enzyme. 相似文献
17.
Four types of meju were made from 100%(w/w) defatted soybean (DFS), a mixture of 80%(w/w) defatted soybean, and 20%(w/w) glasswort (DFS-G),
a mixture of 80%(w/w) defatted soybean and 20%(w/w) rice (DFS-R), and a mixture of 60%(w/w) defatted soybean, 20%(w/w) glasswort,
and 20%(w/w) rice (DFS-GR). Four types of Korean traditional soy sauce were prepared from the 4 types of meju. Mineral and antioxidant contents in the soy sauce made of DFS-G and DFS-GR were significantly higher than others. Citric,
malic, succinic, lactic, and pyroglutamic acid contents in soy sauce made of DFS-R and DFS-GR were 1.3–1.5 times higher than
others. Total nitrogen and free amino acid contents in soy sauce were correlated with DFS concentration in the meju. The bacterial community in the non-fermented meju-making ingredients was replaced largely by Bacillus sp. in the fermented meju. The use of glasswort and rice in the meju-making process did not alter the bacterial community responsible for the fermentation of meju. 相似文献
18.
Xylanase (E.C. 3.2.1.8) was purified to apparent homogeneity from 96 h finger millet (Eleusine coracana, Indaf-15) malt by a three step purification procedure via ammonium sulphate fractionation, DEAE-cellulose ion exchange and
Sephadex G-75 gel permeation chromatographies with a recovery of 4.0% and fold purification of 60. Xylanase, having a molecular
weight of 29 ± 2 kDa was found to be monomeric on SDS-PAGE. pH optimum of the enzyme was found to be in the range of 5.0–5.5.
The activation energy was 25 kJmol−1. Xylanase showed maximum stability at 35 °C in a pH range of 5.0–6.0. K
m and V
max of purified xylanase were found to be 0.2% and 4.5 μmol min−1, respectively. Metal ions such as Ca2+, Mg2+, Mn2+, Cu2+, Fe2+, Ag2+ and Ni2+ enhanced xylanase activity at 5 mM concentration. p-chloromercuribenzoate, citric, oxalic and boric acids inhibited the enzyme in concentration dependent manner. The mode of
action of xylanase was found to be “endo” as determined by the analysis of products liberated from larchwood xylan by ESI-MS
and H1NMR. In vitro studies using Bifidobacterium and Lactobacillus sp. confirmed the prebiotic activity of the xylo-oligosaccharides. 相似文献
19.
20.
‘Qiandaowuhe’ persimmon fruits (Diospyros kaki L.) were stored at 20 °C after exposed to 20 °C (control), 44 °C (T
44), 48 °C (T
48) or 52 °C (T
52) hot air for 3 h, respectively. Firmness, weight loss, peel color, total carotenoids content, soluble solids content (SSC),
titratable acidity (TA), respiration, and ethylene production and cell wall hydrolysis enzymes activities were monitored to
determine the efficacy of hot air treatment in delaying persimmon fruit ripening. Results showed that ‘Qiandaowuhe’ persimmon
fruit displayed a typical climacteric pattern of respiration and ethylene production. Peak of CO2 and ethylene production was observed after 4 days. Fruit softening was accompanied by a progressive increase in weight loss,
total carotenoids content and decrease in h°. The activities of pectinmethylesterase (PME) and polygalacturonase (PG) sharply increased and reached maximal values after
4 and 6 days, respectively. Hot air treatment significantly delayed the onset of climacteric ethylene production, respiration,
PME and PG activities in persimmon fruit. Moreover, it also significantly retarded the increase in carotenoids content and
SSC, while decreased the firmness, h°, and TA. The hot air treatment promoted fruit weight loss. The shelf-life of persimmon ripening increased 4 days by T
44, and 6 days by T
48 or T
52. Results suggest that hot air treatments can greatly extend the postharvest life of ‘Qiandaowuhe’ persimmon fruit. 相似文献