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1.
Yongxin She Jing Wang Yongquan ZhengWeiqiang Cao Rongyan WangFengshou Dong Xingang LiuMingrong Qian Hu ZhangLiqing Wu 《Food chemistry》2012,132(1):502-507
A method has been developed for the simultaneous determination of the concentration of nonylphenol (4-NP), nonylphenol monoethoxylates (NP1EO) and nonylphenol diethoxylates (NP2EO) in vegetables and crops by liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS/MS). These target compounds were extracted from vegetable and crop samples with acetonitrile, and then the extracts were cleaned using solid phase extraction with graphitised carbon black tandem primary secondary amine (PSA) cartridges. The MS method enabled highly reliable identification by monitoring the corresponding ammonium adduct [M+NH4]+ in the positive mode for NP1EO and NP2EO, and the deprotonated molecule [M−H]− in the negative mode for 4-NP. Recoveries for the spiked samples ranged from 65% to 118%. The limit of detection (LOD) of 4-NP, NP1EO and NP2EO was 3, 5 and 0.1 μg kg−1, respectively. This method would be useful for the quick and routine detection of the residues of 4-NP, NP1EO and NP2EO in vegetables and crops. 相似文献
2.
目的建立一种数字聚合酶链式反应(PCR)检测贝类和浆果中甲肝病毒的方法。方法样品经蛋白酶K消化-聚乙二醇法进行甲肝病毒富集后,使用高纯度病毒核酸试剂盒进行RNA提取,之后对甲肝病毒进行数字PCR检测。结果本方法对甲肝病毒有典型扩增,重复性和稳定性良好,对于草莓样品中甲肝病毒的检测灵敏度为25.30 CCID_(50)/20 g,树莓样品中甲肝病毒的检测灵敏度为6.32 CCID_(50)/20 g,贝类样品中甲肝病毒的检测灵敏度为12.54 CCID_(50)/2 g,表明其灵敏度高。结论该方法快速、准确、灵敏,适合测定贝类和浆果食品中甲肝病毒。 相似文献
3.
Thermal inactivation of hepatitis A virus in suspension and in dried mussels (Mytilus edulis)
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We examined the effects of three different temperatures (60, 85 and 100 °C) and durations of time (1 min at 100 ° C to 30 min at 60 ° C) on hepatitis A virus (HAV) in suspension and dried mussels (Mytilus edulis). In suspension, 3.61, 4.48, 5.06 and 5.66 log10 tissue culture infectious dose (TCID)50/mL were reduced by 60 ° C for 5 min, 60 ° C for 15 min, 60 ° C for 30 min and 85 ° C for 3 min, respectively. In dried mussels, 1.34, 1.94, 3.16, 2.36, 3.53 and 4.38 log10TCID50/mL were reduced by 60 ° C for 5 min, 60 ° C for 15 min, 60 ° C for 30 min, 85 ° C for 3 min, 85 ° C for 6 min and 85 ° C for 10 min, respectively. HAV inactivation from suspension and dried mussels was achieved by 85 ° C for 6 min and 15 min, respectively, and also by a 1 min at 100 ° C. At 60, 85 and 100 ° C, the 1‐log (D‐values) inactivation from both suspension and dried mussels was 6.33 and 7.93, 0.98 and 3.05, and 0.28 and 0.38 min, respectively. A higher temperature and/or a thermal treatment time shorter than 85 ° C for 6 min (100 ° C for 1 min) could be used for commercial target foods for complete HAV inactivation. 相似文献
4.
Grape seed extract (GSE) is reported to have antibacterial properties with few current studies on antiviral activity. Recently, we reported the effects of GSE against foodborne viral surrogates in vitro. This study evaluated the application of GSE (commercial Gravinol-S) against hepatitis A virus (HAV) and human norovirus surrogates, feline calicivirus (FCV-F9) and murine norovirus (MNV-1), on model produce. Washed and air-dried lettuce (3 × 3 cm2) and jalapeno peppers (25–30 g) were inoculated with FCV-F9, MNV-1, or HAV at high (∼7 log10 PFU/ml) or low (∼5 log10 PFU/ml) titers, and treated with 0.25, 0.5, 1 mg/ml GSE or water for 30 s to 5 min. Treatments were stopped/diluted with cell-culture media containing 10% heat-inactivated fetal bovine serum and evaluated using plaque assays. At high titers, FCV-F9 was reduced by 2.33, 2.58, and 2.71 log10 PFU on lettuce; and 2.20, 2.74, and 3.05 log10 PFU on peppers after 1 min using 0.25, 0.50, and 1 mg/ml GSE, respectively. Low FCV-F9 titers could not be detected after 1 min at all three GSE concentrations. Low titer MNV-1 was reduced by 0.2–0.3 log10 PFU on lettuce and 0.8 log10 PFU on peppers, without reduction of high titer. GSE at 0.25–1 mg/ml after 1 min caused 0.7–1.1 and 1–1.3 log10 PFU reduction for high and low HAV titers, respectively on both commodities. Instrumental color analysis showed no significant differences between treated and untreated produce. GSE shows potential for foodborne viral reduction on produce as part of hurdle technologies. 相似文献
5.
A.P. Souza N.R. St-Pierre M.H.R.M. Fernandes A.K. Almeida J.A.C. Vargas K.T. Resende I.A.M.A. Teixeira 《Journal of dairy science》2017,100(6):4574-4586
Requirements for growth in the different sexes remain poorly quantified in goats. The objective of this study was to develop equations for estimating net protein (NPG) and net energy (NEG) for growth in Saanen goats of different sexes from 5 to 45 kg of body weight (BW). A data set from 7 comparative slaughter studies (238 individual records) of Saanen goats was used. Allometric equations were developed to determine body protein and energy contents in the empty BW (EBW) as dependent variables and EBW as the allometric predictor. Parameter estimates were obtained using a linearized (log-transformation) expression of the allometric equations using the MIXED procedure in SAS software (SAS Institute Inc., Cary, NC). The model included the random effect of the study and the fixed effects of sex (intact male, castrated male, and female; n = 94, 73, and 71, respectively), EBW, and their interactions. Net requirements for growth were estimated as the first partial derivative of the allometric equations with respect to EBW. Additionally, net requirements for growth were evaluated based on the degree of maturity. Monte Carlo techniques were used to estimate the uncertainty of the calculated net requirement values. Sex affected allometric relationships for protein and energy in Saanen goats. The allometric equation for protein content in the EBW of intact and castrated males was log10 protein (g) = 2.221 (±0.0224) + 1.015 (±0.0165) × log10 EBW (kg). For females, the relationship was log10 protein (g) = 2.277 (±0.0288) + 0.958 (±0.0218) × log10 EBW (kg). Therefore, NPG for males was greater than for females. The allometric equation for the energy content in the EBW of intact males was log10 energy (kcal) = 2.988 (±0.0323) + 1.240 (±0.0238) × log10 EBW (kg); of castrated males, log10 energy (kcal) = 2.873 (±0.0377) + 1.359 (±0.0283) × log10 EBW (kg); and of females, log10 energy (kcal) = 2.820 (±0.0377) + 1.442 (±0.0281) × log10 EBW (kg). The NEG of castrated males was greater than that of intact males and lower than that of females. Using degree of maturity for estimating NPG and NEG, we could remove the differences between sexes. These results indicate that NPG and NEG differ among sexes in growing Saanen goats, and this difference should be accounted for by feeding systems. Including the degree of maturity as predictor cancels out those differences across sexes in protein and energy requirements. 相似文献
6.
Chitosan is known to have bactericidal and antifungal activity. Although human noroviruses are the leading cause of non-bacterial gastroenteritis, information on the efficacy of chitosan against foodborne viruses is very limited. The objective of this work was to determine the effectiveness of different molecular weight chitosans against the cultivable human norovirus and enteric virus surrogates, feline calicivirus, FCV-F9, murine norovirus, MNV-1, and bacteriophages, MS2 and phiX174. Five purified chitosans (53, 222, 307, 421, ∼1150 kDa) were dissolved in water, 1% acetic acid, or aqueous HCl pH = 4.3, sterilized by membrane filtration, and mixed with equal volume of virus to obtain a final concentration of 0.7% chitosan and 5 log10 PFU/ml virus. Virus-chitosan suspensions were incubated for 3 h at 37 °C. Untreated viruses in PBS, in PBS with acetic acid, and in PBS with HCl were tested as controls. Each experiment was run in duplicate and replicated at least twice. Water-soluble chitosan (53 kDa) reduced phiX174, MS2, FCV-F9 and MNV-1 titers by 0.59, 2.44, 3.36, and 0.34 log10 PFU/ml respectively. Chitosans in acetic acid decreased phiX174 by 1.19–1.29, MS2 by 1.88–5.37, FCV-F9 by 2.27–2.94, and MNV-1 by 0.09–0.28 log10 PFU/ml, respectively. Increasing the MW of chitosan corresponded with an increasing antiviral effect on MS2, but did not appear to play a role for the other three tested viral surrogates. Overall, chitosan treatments showed the greatest reduction for FCV-F9, and MS2 followed by phiX174, and with no significant effect on MNV-1. 相似文献
7.
Lee Ann Weinstein Florence Capaldo-Kimball Michael J. Leibowitz 《Yeast (Chichester, England)》1993,9(4):411-418
The cytoplasmically inherited M double-stranded (ds) RNA genome segment of killer virus of Saccharomyces cerevisiae is heat-curable in some yeast strains but not in others. Temperature sensitivity is conferred on both M1 and M2 dsRNA satellite virus segments by the L-A-HN allele of the killer helper virus genome, but not by the L-A-H allele. Both diploidy and mating type heterozygosity of the host cell are also correlated with increased virus curability. 相似文献
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The efficiency of different commercial RNA extraction kits for the detection of hepatitis A virus (HAV) from seeded strawberry samples was assessed by standard RT-PCR and real time RT-PCR (RT-qPCR). The best results with standard RT-PCR were achieved with Aurum™ Total RNA extraction kit (BioRad), obtaining a detection limit of 5-6.25 pfu/mg of tissue. A slightly lower sensitivity was rendered by the RNeasy® Plant mini kit (Qiagen) (10-12.5 pfu/mg tissue), while the Total Quick RNA Cells and Tissues kit version mini (Talent) rendered a detection limit of 50-100 pfu/mg of tissue. The other tested commercial kits showed worse detection limits (>500 pfu/mg). With RT-qPCR and ten fold diluted RNA all the kits showed an increase of sensitivity, detecting the kits from Qiagen, Talent and BioRad down to 0.05 pfu/mg of strawberry homogenate. These findings indicate that the use of Aurum™ Total RNA extraction kit, with standard RT-PCR technique or RT-qPCR, can not only be labor and time saving but also helpful to improve the sensitivity for the HAV detection from fruits and to facilitate the standardization of detection methods among laboratories. 相似文献
10.
《Journal of dairy science》2021,104(11):11553-11566
The first studies concerning nutrient requirements for preweaned dairy calves were from the 1920s and 1930s; however, few studies were published in the following decades. We aimed to determine energy and protein requirements of preweaning Holstein and Holstein × Gyr dairy calves in a multistudy meta-regression. We used a database composed of individual measurements of 166 preweaned male calves (138 submitted to treatments and 28 used as the reference group) from 4 studies that used the methodology of comparative slaughter. Animals with less than 15/16 of Holstein genetic composition were considered crossbred Holstein × Gyr, whereas other animals were considered Holstein. Net energy requirements for maintenance (NEM) were determined by the regression between heat production and metabolizable energy intake (MEI). The metabolizable energy requirements for maintenance were calculated by the iterative method, and the efficiency of use of metabolizable energy for maintenance was obtained by NEM divided by the metabolizable energy requirements for maintenance. Net energy requirements for gain (NEG) were estimated using a regression of the retained energy (RE) as a function of empty body weight (EBW) and empty body gain (EBG). The efficiency of use of metabolizable energy for gain was estimated by the regression of RE as a function of MEI, but with partitioning the MEI into MEI from liquid feed and MEI from starter feed. Additionally, the effect of a liquid feed (milk or milk replacer) was tested on the slope of the regression. The metabolizable protein requirements for maintenance (MPM) were estimated using the intercept of the regression between the metabolizable protein intake (MPI) and average daily gain. The MPM was determined as the ratio between the intercept and the metabolic body weight. Net protein requirements for gain (NPG) were estimated by the regression between retained protein, EBG, and RE. The efficiency of use of metabolizable protein for gain was estimated by the regression of the retained protein as a function of MPI, but with partitioning the MPI into MPI from liquid feed and MPI from starter feed. Additionally, the effect of a liquid feed (milk or milk replacer) was tested on the regression slope. Breed did not influence any of the nutrient requirements' estimates. The NEM was estimated as 70.2 kcal/metabolic body weight per day. The efficiency of use of metabolizable energy for maintenance observed was 66%. The NEG was estimated by the equation NEG = 0.0901 × EBW0.75 × EBG0.9539. The efficiency of use of metabolizable energy for gain was estimated as 57.6, 49.3, and 41.2% for milk, milk replacer, and starter feed, respectively. The MPM was estimated as 4.22 g/EBW0.75 per day, and the NPG was determined by the equation: NPG = 30.06 × EBG + 70.98 × RE. The efficiency of use of metabolizable protein for gain was estimated as 71.9, 59.2, and 44.4% for milk, milk replacer, and starter feed, respectively. We concluded that no differences were observed in energy and protein requirements between Holstein and Holstein × Gyr crossbred cows. The efficiencies of use of metabolizable energy and protein are greater for milk when compared with milk replacer and starter feed. Therefore, we propose that the equations generated herein should be used to estimate energy and protein requirements of preweaned Holstein and Holstein × Gyr crossbred dairy calves raised under tropical conditions. 相似文献
11.
Liyan Ma Xiaoge Tang Kunlun Huang 《Journal of the science of food and agriculture》2013,93(5):1049-1054
BACKGROUND: The gene sb401 encoding a lysine‐rich protein has been successfully integrated into the genome of maize (Zea mays), its expression showing as increased levels of lysine and total protein in maize seeds. As part of a nutritional assessment of transgenic maize, nutritional composition, especially unintended changes in key nutrients such as proximates, amino acids, minerals and vitamins as well as in antinutrient (phytate phosphorus), and protein nutritional quality were compared between transgenic maize (inbred line 642 and hybrid line Y642) and conventional quality protein maize (QPM) Nongda 108. RESULTS: The contents of total protein, lysine, some other amino acids, several minerals and vitamin B2 in transgenic inbred line 642 and hybrid line Y642 were significantly higher than those in conventional QPM. Water‐soluble protein and G2‐glutelin were significantly promoted in transgenic maize Y642. CONCLUSION: Insertion of the lysine‐rich sb401 gene increased the total protein and lysine content of transgenic maize varieties, leading to an improved amino acid score and therefore an improvement in the nutritive value of maize. © 2013 Society of Chemical Industry 相似文献
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Accuracy of near infrared spectroscopy for prediction of chemical composition, salt content and free amino acids in dry-cured ham 总被引:2,自引:0,他引:2
Prevolnik M Škrlep M Janeš L Velikonja-Bolta S Škorjanc D Čandek-Potokar M 《Meat science》2011,88(2):299-304
The capability of near infrared (NIR) spectroscopy was examined for the purposes of quality control of the traditional Slovenian dry-cured ham “Kraški pršut.” Predictive models were developed for moisture, salt, protein, non-protein nitrogen, intramuscular fat and free amino acids in biceps femoris muscle (n = 135). The models' quality was assessed using statistical parameters: coefficient of determination (R2) and standard error (se) of cross-validation (CV) and external validation (EV). Residual predictive deviation (RPD) was also assessed. Best results were obtained for salt content and salt percentage in moisture/dry matter (RCV2 > 0.90, RPD > 3.0), it was satisfactory for moisture, non-protein nitrogen, intramuscular fat and total free amino acids (RCV2 = 0.75–0.90, RPD = 2.0–3.0), while not so for protein content and proteolysis index (RCV2 = 0.65–0.75, RPD < 2.0). Calibrations for individual free amino acids yielded RCV2 from 0.40 to 0.90 and RPD from 1.3 to 2.9. Additional external validation of models on independent samples yielded comparable results. Based on the results, NIR spectroscopy can replace chemical methods in quality control of dry-cured ham. 相似文献
14.
J Owusu-Kwarteng F Akabanda DS Nielsen K Tano-Debrah RL Glover L Jespersen 《Food microbiology》2012,32(1):72-78
Fura is a millet-based spontaneously fermented dumpling produced and consumed in parts of West Africa, particularly Nigeria, Burkina Faso and Ghana. From eight traditional fura production sites in northern Ghana, 862 lactic acid bacteria were isolated and identified to species level using a combination of genotypic and phenotypic methods including (GTG)5-based PCR fingerprinting and 16S rRNA gene sequencing, multiplex PCR by means of recA gene sequence comparison, conventional morphological characteristics and carbohydrate fermentation profiling. During millet dough fermentation, pH decreased from 5.6–6.4 to 4.1–3.7 and total lactic acid bacteria (LAB) counts increased from 4.4–5.3 to 7.9–9.2 log10 (cfu/g). The initial stages of the fermentation were characterized by co-dominance of homo- and heterofermentative species of Pediococcus acidilactici, Weisella confusa, Lactobacillus fermentum, Lactobacillus reuteri, Lactobacillus salivarius, and Lactobacillus paraplantarum whereas L. fermentum was dominating at the end of the fermentation. L. fermentum was predominant in all fermentations (p < 0.05) and a high uniformity was observed among production sites regarding the dominance of L. fermentum. L. fermentum and W. confusa were isolated in all production sites and almost at all fermentation stages indicating that they are indigenous to traditional fura processing. The other LAB bacteria species which comprised a minor proportion of the total LAB occurred occasionally and in an irregular pattern among the production sites. 相似文献
15.
Equivalent processes were determined for the pasteurization of crabmeat, from the blue crab (Callinectes sapidus), in cans and flexible pouches containing 113.5g, 227.0g, and 454.0g of product. F185 values were calculated for z values of 8, 10, 12, 14, 16, 18, 20, and 22. Based on the heating characteristics of the traditional container used for pasteurized crabmeat (401 × 301), equivalent processes for nontraditional containers were determined. 相似文献
16.
The suspensions containing starch submicron particles prepared through a novel high pressure homogenization and mini-emulsion cross-linking technology were spray dried to obtain cross-linked starch submicron particles. Dryer inlet temperature and feed flow rate were varied to investigate their effect on moisture content, glass transition temperature (Tg), morphology of the starch submicron particles. The residual moisture content of the particles was below 10% (w/w) and particle had collapsed morphology. The Tg of these submicron particles varied between 54 and 57 °C corresponding to moisture contents of 9.78% and 8.31%, respectively and the cross-linking and the high hydrogen bond density in these submicron particles strongly affected the moisture dependence in their Tg. The X-ray diffraction and FT-IR experiments revealed that these starch submicron particles were in amorphous glassy state, fully cross-linked and had very high extent of hydrogen bonding. 相似文献
17.
Chitradurga O. Mohan Chandraairi N. Ravishankar Teralandur K. Srinivasa Gopal & Jagannath Bindu 《International Journal of Food Science & Technology》2008,43(2):200-207
Prawn ‘kuruma’ was prepared from Indian white shrimp (Fenneropenaeus indicus), packed in conventional 301 × 206 and 401 × 411 aluminium cans and in thin profile retort pouches having a three-layer configuration of 12.5 μ polyester, 12.5 μ aluminium foil and 85 μ cast polypropylene of size 16 × 20 cm and 17 × 30 cm. The physico-chemical tests conducted on these containers showed their suitability for thermal processing. Prawn to kuruma ratio of 65:35 was maintained in all the containers and heat processed to equal lethality in an over pressure autoclave with the facility to record the time–temperature data, F0 value and cook value. The process time was calculated by using formula method. The processing in 16 × 20 cm and 17 × 30 cm retortable pouch resulted in 35.67% and 56.56% reduction in process time compared with 301 × 206 and 401 × 411 cans, respectively, with equal pack weight. The amino acid content did not vary considerably in both containers. In the canned samples the reduction of sulfhydryl content was 50.54% more when compared with the pouched product. Products packed in pouches were found to be superior to canned products with regard to sensory and textural attributes such as colour, firmness, hardness, chewiness, and overall acceptability. 相似文献
18.
A total of 85 walnut samples collected between October 2012 and April 2013 in different provinces of Turkey were analysed for the presence of aflatoxins (AFs). The method involved methanol–water extraction, clean-up with immunoaffinity columns and a sensitive high-performance liquid chromatography coupled with fluorescence detection after post-column derivatisation. The method was validated for selectivity, linearity, trueness, precision, limit of detection and limit of quantification (LOQ), which met the performance criteria as set by EC regulation No. 401/2006. LOQs were 0.07, 0.04, 0.09 and 0.05 µg kg–1 for AFB1, AFB2, AFG1 and AFG2, respectively. AFs were present in 9.4% of walnut samples (8/85) at total AFs levels ranging from 0.09 to 15.4 µg kg–1. Only one of eight walnut samples exceeded the European Union limit of 2 and 4 µg kg–1 for AFB1 and total AFs, respectively. 相似文献
19.
Gordon J Provan Lorraine Scobbie Andrew Chesson 《Journal of the science of food and agriculture》1997,73(2):133-142
Internodes of the maize cell line W401 and bm1 and bm3 mutants expressed in W401 were harvested 5 days after anthesis (A5) and at silage (S) stage. The normal maize had a higher total phenolic (TP) content (80·5–90·5 g kg-1 cell wall DM) than both bm1 and bm3 mutants (74·4–86·4 and 66·0– 84·2 g kg-1 cell wall DM, respectively). TP were inversely related to cellulase digestibility with values of 85·4–91·5, 89·3–92·1 and 91·3–94·1% for normal, bm1 and bm3. Marked differences in p-coumaric acid concentrations were found ranging from 20·9 to 26·3 g kg-1 cell wall DM for normal, 14·9 to 15·3 g kg-1 for bm1 to 10·1 to 14·4 g kg-1 for bm3. The ferulate pattern was entirely different with the bm1 genotype providing the lowest total (9·1–10·7 g kg-1) and etherified (1·9–2·3 g kg-1) values. Although the bm3 contained more total ferulate (11·5–13·1 vs 10·9–11·7 g kg-1), the normal variety had a significantly greater amount of etherified ferulate (2·8–3·4 vs 3·2–4.1 g kg-1) implying a greater extent of cross-linking between wall polymers. Recovery of guaiacyl and syringyl residues was greatest in the normal maize with the bm1 occupying the middle position between the two extremes. Calculated S: G ratios from 4 M NaOH digestion and NMR were in good agreement with the normal line giving the highest ratio, bm1 intermediate and bm3 the lowest. Colorimetric analysis revealed a large increase in the aldehyde content of the in situ bm1 lignin compared to normal and bm3 genotypes although NMR failed to reveal significant numbers of aldehydic resonances. © 1997 SCI. 相似文献
20.
Modulated temperature differential scanning calorimetry was used to investigate the specific heat capacity (C p ) of 10 Australian honeys within the processing and handling temperatures. The values obtained were found to be different from the literature values at certain temperatures, and are not predictable by the additive model. The C p of each honey exhibited a cubic relationship (P < 0.001) with the temperature (T, C). In addition, the moisture (M, %), fructose (F, %) and glucose (G, %) contents of the honeys influenced their Cp. The following equation (r2 = 0.92) was proposed for estimating Cp of honey, and is recommended for use in the honey industry and in research: 相似文献