共查询到20条相似文献,搜索用时 31 毫秒
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Pollyanna Amaral Viana Sebastião Tavares de Rezende Flávia Maria Lopes Passos Solimar Gonçalves Machado Gabriela Picollo Maitan Vinicio Tadeu da Silva Coelho Valéria Monteze Guimarães 《Food science and biotechnology》2011,20(3):601-606
Extracellular and intracellular α-galactosidases were produced by yeast Debaryomyces hansenii UFV-1 grown on different media with several carbon sources. D. hansenii grown in YP-medium (1% yeast extract and 2% peptone) presented maximum cell mass (8.45 mg/mL) after 36 h of cultivation,
with lactose as carbon source, followed by sucrose, glucose, raffinose, and galactose. Higher extracellular and intracellular
α-galactosidases activities were observed at 48 h of D. hansenii cultivation in YPmedium containing galactose (0.97 and 5.27 U/mL) and lactose (1.28 and 4.88 U/mL), supporting the evidence
for the model of induction for the yeast GAL/MEL regulon, such as described in Sacharomyces cereviseae. 相似文献
3.
Siti Hajar-Azhari Wan Abd Al Qadr Imad Wan-Mohtar Safuan Ab Kadir Muhamad Hafiz Abd Rahim Nazamid Saari 《Food science and biotechnology》2018,27(2):479-488
In this study, a selected γ-aminobutyric acid (GABA)-rich Malaysian strain Aspergillus oryzae NSK was collected from soy sauce koji. The strain was used to explore the effect of using renewable native sugar syrup, sugarcane, nipa, and molasses as fermentable substrates for developing a novel functional GABA soy sauce. We evaluated the strain using the chosen native sugars for 7 days using shake flask fermentation at 30 °C. The results showed optimum GABA concentration was achieved using cane molasses as the fermentable substrate (354.08 mg/L), followed by sugarcane syrup (320.7 mg/L) and nipa syrup (232.07 mg/L). Cane molasses was subsequently utilized as a substrate to determine the most suitable concentration for A. oryzae NSK to enhance GABA production and was determined as 50% g/L of glucose standard cane molasses. Our findings indicate that cane molasses can be used as a GABA-rich ingredient to develop a new starter culture for A. oryzae NSK soy sauce production. 相似文献
4.
Mei Dong Mingtao Fan Zhe Zhang Ying Xu Aixia Li Panxue Wang Kun Yang 《European Food Research and Technology》2014,239(6):995-1001
This study was designed to characterize a β-glucosidase from Oenococcus oeni 31MBR, a strain widely used in Chinese winemaking. An intracellular β-glucosidase (EC 3.2.1.21) was partially purified using a combination of ammonium sulfate precipitation and chromatographic methods. A single band was obtained in SDS-PAGE electrophoresis, indicating that the enzyme was highly purified and had an estimated molecular mass of 38.9 kDa. The enzyme exhibited highest activity at pH 4.5–5.0. The optimum temperature was 45 °C. Ethanol promoted the activity of this enzyme up to three times. Among the several metal ions assayed, only Mn2+ exhibited a partial promotion effect. The K m and V max values for p-nitrophenyl-β-d-glucopyranoside were 1.05 mmol/L and 0.957 nmol/min, respectively. Up to now, this study contains the first characterization of a native β-glucosidase purified from crude extracts of O. oeni 31MBR. 相似文献
5.
In this study, different solvent extracts of skullcap (Scutellaria baicalensis) were assayed for their total phenol content (TPC), antioxidant activity [determined as DPPH radical scavenging activity,
superoxide dismutase (SOD)-like activity, oxygen radical absorbance capacity (ORAC) assay, and comet assay], and α-glucosidaseinhibitory
activity. The TPC of skullcap ranged from 9.06 mg/g gallic acid equivalents (GAE) for acetone extract (AE) to 91.8 mg/g GAE
for methanol extract (ME). AE, which had a low TPC, exhibited the highest DPPH radical scavenging activity and SOD-like activity.
TPC positively correlated with the ORAC assay (r=0.96, p<0.001). All skullcap extracts significantly reduced the hydrogen peroxide-induced DNA damage in human leukocytes. ME with
a high TPC and ORAC value showed the highest α-glucosidase inhibition. The difference in the biological activities of the
extracts may be due to the differences in their chemical structure or polarity. Therefore, the results obtained indicate that
might be a potential source of compounds with health-protective effects. ME, in particular, might be a prospective therapeutic
agent for diabetes. 相似文献
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Xiaoling Song Krysty Munns Sheng Qiang Robert Blackshaw Ranjana Sharma 《European Food Research and Technology》2009,228(6):939-944
Oilseed rape (Brassica napus L.) is an important agronomic crop used for oil, food and animal feed. Glyphosate resistant B. napus is tolerant to the herbicide glyphosate and has been widely adopted due to higher economic returns. However, a concern for
growing transgenic B. napus is the potential escape of cp4 epsps transgene via cross fertilization with wild and/or weedy species including Brassica juncea, especially in China, where B. juncea is prevalent. We assessed transgene inheritance and quantification upon wild B. juncea × transgenic B. napus outcrossing from three backcross (BC) generations and their progenies using real-time PCR. Under in vitro conditions, a stable
inheritance and similar cp4 epsps copy number between different generations (BC2, BC3 and BC4) and their progenies were observed. A marginally higher copy
number was observed when B. juncea was used as the paternal as compared to when it was used as maternal parent. This study demonstrates stable inheritance of
the glyphosate resistance trait and the production of fit out crossed offspring in cases of wild type B. juncea × transgenic B. napus. 相似文献
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Growth stress is important to achieve upright growth and avoid exterior influence on living trees. However, many problems are also triggered by the release of growth stress during wood processing, such as end split of log, distortion of board and inaccurate sawing. In order to evaluate the possibility of these problems to occur in poplar clone 107, a new breeding poplar clone in China, surface longitudinal growth strain (SLGS) and internal longitudinal growth strain (ILGS) both of straight and inclined trees were measured for depicting distributing patterns of growth strain both in peripheral and radial directions. Besides that, according to one-way ANOVA analysis, individual tree and peripheral position have a significant effect on SLGS in inclined trees, whereas such effect is insignificant in straight trees. Fiber morphology and shrinkage of wood sample beneath the SLGS testing positions were determined to illustrate the relationships between these properties with SLGS. The results suggested that growth stress is a poor indicator of fiber morphology and wood shrinkage properties for straight trees but a good one for inclined trees. Both the positive SLGS and ILGS are unexpectedly found at the opposite wood side of inclined trees. It is speculated that when the reorientation of inclined trees is insufficiently supported by exerting tensile stress at tension wood side, compressive stress will be formed at the opposite wood side as a complement. 相似文献
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Anna Rafaela Cavalcante Braga Patrícia Aveiro Gomes Susana Juliano Kalil 《Food and Bioprocess Technology》2012,5(5):1653-1663
Seven strains of the genus Kluyveromyces were screened for β-galactosidase activity and Kluyveromyces marxianus ATCC 16045 was selected as the best enzyme producer for culture medium optimization. The production of β-galactosidase by submerged cultivation was evaluated using a factorial design and response surface methodology. The culture medium containing whey and parboiled rice effluent was formulated to maximize the production of β-galactosidase. The effects of the initial pH and the concentrations of whey lactose, peptone, (NH4)2SO4, yeast extract, and parboiled rice effluent on enzyme production were studied using a 2 IV 6-2 fractional design. A CCRD (24 trials plus axial and central points) was used for the four variables selected from the fractional design (lactose, peptone, (NH4)2SO4 and yeast extract), with β-galactosidase activity as the response. The optimum conditions established for production were a whey (lactose) concentration of 120 g/L, a yeast extract concentration of 5 g/L, a peptone concentration of 15 g/L, a (NH4)2SO4 concentration of 15 g/L, a parboiled rice effluent concentration of 30 g/L, and a pH value of 4.0. Under these conditions, the highest enzymatic activity of 10.4 U/mL was measured, being 9.5–9.7 as the values predicted by the proposed model, showing an enzymatic activity increase of 30% using alternative sources of lactose and nitrogen for β-galactosidase production. 相似文献
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The hydrolysis of -oryzanol, a cholesterol-lowering and antioxidative mixture of steryl ferulates (mainly 24-methylenecycloartanyl ferulate 1, cycloartenyl ferulate 2, campesteryl ferulate 3, and -sitosteryl ferulate 4) occurring in rice, by commercially available enzyme preparations was investigated. Lipase preparations from different sources did not accept -oryzanol as substrate. Cholesterol esterases, however, catalyzed a sterol-specific reaction, i.e., -sitosterol and campesterol were liberated from 3 and 4, whereas 1 and 2 remained unhydrolyzed. The same specificity profile was observed for hydrolysis of -oryzanol in artificial pancreatic juice and in reactions catalyzed by pancreatic acetone powders. The data indicate that pancreatic cholesterol esterase is involved in the hydrolysis of -oryzanol in vivo. They also provide a perspective for tailoring the composition of steryl ferulate mixtures on a large scale. 相似文献
10.
L. Chaires-Martínez J. A. Salazar-Montoya E. G. Ramos-Ramírez 《European Food Research and Technology》2008,227(6):1669-1676
The aim of this work was to carry out the physicochemical and functional characterization of the purified galactomannan obtained
from mesquite seed’s endosperm (MSG). From the seeds, a MSG content of 13/100 g with a purity of 94/100 g was determined.
The dispersions of MSG samples (up to 5 g/100 mL) exhibited a shear thinning non-Newtonian behavior, with 35.68 mPa.s of viscosity,
and surface tension values between 43.5 and 61.06 dynes/cm. The chromatographic analysis revealed a 1.1:1 mannose/galactose
ratio, with a molecular weight between 900,000 and 1,000,000 Da. The calorimetric analysis showed a specific vitreous transition
temperature of 52.92 °C. The values of apparent viscosity were superior to those of commercial galactomannans, which indicates
that MSG can be used too as a thickening agent. The obtained results provide information, which contribute to a better knowledge
of MSG, in order to consider its sustainable exploitation in a future. 相似文献
11.
A helix tube photobioreactor with a volume of 10 L was designed and manufactured. The facade of the reactor was designed as
three-layer frame. The illumination helixes units were 16, illumination area volume was 1.5 L, illuminate specific area was
95 m−1. A marine micro-alga Dunaliella salina was used as a model organism in this study. Results showed that the optimum inoculum concentration was OD630 = 0.15 and the optimum circulation rate of culture fluid was 630 mL/h for the bioreactor. In continuous cultivation, in order
to determine the optimum collection of alga solution for the highest yield of β-carotene, three different alga solution collection
and addition fresh culture medium volumes were applied: 0.8, 1.5, 2.0 L/day. The biomass and extraction of β-carotene were
determined in different cultivation periods. The result suggested that the optimum daily harvest of alga solution was 1.5 L/day
for the cultivation of D. salina to obtain the highest production of β-carotene. 相似文献
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Araça-boi (Eugenia stipitata), bacuri (Platonia insignis) and cupuaçu (Theobroma grandiflorum) are three exotic fruits typical of the Amazonian region. Their pulps are very much appreciated by the inhabitants and have been recently exported. The present paper reports on the chemical composition of these pulps: the gross composition (carbohydrates, protein, fat, ash and dietary fibre contents) has been determined, together with a more detailed analysis of sugars, amino acids, fatty acids and minerals. Altogether, the data indicate that these fruit pulps of Amazonian origin are of nutritional interest and should be promoted at least at a regional level. 相似文献
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María Dolores González Paula Laura Lanzelotti Cecilia María Luis 《Food Analytical Methods》2017,10(10):3275-3284
Origanum × majoricum Cambess. is the most commonly grown oregano in Argentina. The aim of this work was to explore and describe its polyphenolic profile by high-performance liquid chromatography with diode array detection (HPLC-DAD) to support identification by classical microscopy. Remarkable homogeneity was found when defining the HPLC-DAD fingerprint with 17 characteristic common peaks. Eleven spectroscopically identified compounds were located. The method was successfully applied for the characterization of 22 samples from different productive regions of Argentina. The genetic inheritance from both progenitors of this hybrid oregano was evidenced by the presence of compounds coming from Origanum majorana L. and Origanum vulgare L. This method, combined with statistical multivariate analysis, was also useful to recognize two groups within the samples. Although O. × majoricum Cambess. must be considered the only hybrid between two species, two origins considering the subspecies level of O. vulgare L. have been morphologically differentiated for the hybrid, both with O. majorana L. These formulas were differentiated by their HPLC-DAD fingerprints. The Argentine hybrids studied appeared consistently grouped under these two profiles. 相似文献
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To investigate the influence of moisture content (MC) and steaming temperature on defects developing during steaming prior to kiln drying, mass loss, heat transfer, microstructures, extractives, and chemical transformation of Eucalyptus grandis?×?E. urophylla specimens (with moisture content of 120, 70, 60, 50, 40, 30, 20%) were observed in this study. Specimens of each experimental moisture content were steamed at 80, 100, and 120?°C for 4 h after pre-heating at atmospheric pressure, respectively. Results revealed that it was most beneficial to conduct steaming at 100?°C when the moisture content was approximately 50% after air drying when stagewise heating-up and continuous steaming schedule were adopted. Under this condition, there was a notable decrease in defects including edge bends, surface splits, and inner splits. Steaming was also a drying period characterized by various extents of mass loss. Changes in microstructures and extractive contents proved the increasing permeability of steamed wood. Deacetylation and crosslinking reactions happened in the hemicellulose of the sample materials, which contributed to the loss of hemicellulose after treatment. 相似文献
15.
Luana Fernandes Susana Casal José A. Pereira Ermelinda L. Pereira Jorge A. Saraiva Elsa Ramalhosa 《Food science and biotechnology》2018,27(4):987-996
Edible flowers, such as pansies, are becoming more popular, but they are highly perishable. So, postharvest technologies are needed, being edible coatings a good alternative. Thus, the aim of this study was to evaluate the effect of alginate coating on physico-chemical and microbiological quality of pansies during cold storage (4 °C for 0, 7, 14, 21 days). Coated pansies maintained good appearance until 14 days of storage, 7 days more than uncoated ones. Flavonoids, hydrolysable tannins and monomeric anthocyanins, as well antioxidant activity, were higher in coated pansies when compared to uncoated ones, on all assayed storage times. Furthermore, after 14 days of storage, uncoated pansies presented microorganism counts higher than coated, namely yeasts and moulds, suggesting an effective barrier protection of the alginate coating treatment. In summary, alginate coating has potential for extending shelf-life and improving physico-chemical and microbiological quality of pansies. 相似文献
16.
This study investigated acceptability and consumer segmentation of soy sauce and famous Korean dish, bulgogi. A total of 123 participants evaluated intensity of 18 attributes and sensory liking of 4 commercial soy sauce samples and bulgogi samples made by aforementioned soy sauces. The overall results showed that appearance liking was the only significant different attribute among soy sauce samples and there were no significant differences among bulgogi samples. Furthermore, there was little correlation between overall liking of soy sauce and bulgogi samples. However, different segments of consumer groups were found by cluster analysis. Four and five subgroups of consumers were identified on evaluation of soy sauce samples and bulgogi samples, respectively. These results demonstrated that consumers’ different preference pattern. In conclusion, this study specified characteristics of commercial soy sauce perceived by consumers and consumers’ acceptability toward soy sauces and bulgogi made using soy sauces. 相似文献
17.
Comparative typing analysis of 25 Lactobacillus delbrueckii subsp. bulgaricus strains, isolated from traditional yoghurts in Turkey, was performed by RAPD–PCR (randomly amplified polymorphic DNA–PCR)
and MLST (multilocus sequence typing). RAPD–PCR analyses were performed using two primers; M13 and 1254. Primer 1254 produced
better results than primer M13. The bands produced by primer 1254 were brighter and easier to interpret, and a higher number
of bands were produced. In addition, clusters produced by primer 1254 were grouped according to the source of isolation. MLST
analysis was performed using three genes, β-gal, pheS and rpoA, and isolates were successfully characterized at strain level. To our knowledge, MLST analyses were used for the first time
for strain level discrimination in L. delbrueckii subsp. bulgaricus. It enabled a detailed understanding of L. delbrueckii subsp. bulgaricus strains by using allele and sequence types’ analysis. Both MLST and RAPD allowed for the typing of clusters according to
the isolation source, while RAPD provided an increased differentiation. However, by increasing the number of genes analyzed,
the discriminatory power of MLST could be increased. 相似文献
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Ian D. Fisk Konstantinos Gkatzionis Mita Lad Christine E. R. Dodd David A. Gray 《European Food Research and Technology》2009,228(4):613-621
The effect of irradiation (0–20 kGy) on hemp and sunflower seeds was assessed, with specific reference to the oxidatively
labile lipid component (unsaturated fatty acids and tocochromanols). Total protein, lipid, and solids content of the seeds
did not vary with irradiation dose. Lipid hydroperoxide concentration increased significantly in the sunflower seeds (48 mmol kg−1 lipid) and a significant increase in volatile secondary oxidation products was measured in both seeds (e.g. hexanal, heptanal,
1-penten-3-ol) with increasing irradiation dose. Irradiation at 5 kGy sterilised the seeds of all microbial contamination
and irradiation doses of 20 kGy prevented germination. A loss of the antioxidant tocopherol was shown with increasing irradiation
doses, although this was selective for specific tocopherol isoforms (α-tocopherol, β-tocopherol and γ-tocopherol). 相似文献
20.
The antigenic response of thermally denatured and aggregated -lactoglobulin was determined by an indirect competitive enzyme-linked immunosorbent assay using polyclonal antibodies from the egg yolk of chicken immunized with heat-denatured -lactoglobulin as a measure for the potential antigenicity/allergenicity. The heat denaturation and the aggregation of heated whey protein isolate solutions were followed by reversed-phase high-performance liquid chromatography and photon correlation spectroscopy. Thermally modified whey proteins showed a remarkable increase of antigenicity when heated to 90 °C, possibly as a consequence of the exposure or formerly hidden epitopes. Above 90 °C, the antigenic response decreased owing to the loss of conformational epitopes and masking of sequential epitopes in the course of aggregation to particles. When large and compact particles were formed, the antigenicity was reduced remarkably. Depending the heating conditions applied, the structure and the size of whey protein particles and thus the potential allergenicity may be modulated in a wide range. 相似文献