查看更多>>摘要：Lactobacillus plantarum, which exerts a variety of pmbiotic functions, has been recognized as a supplement for human foods with a widespread application. In this work, the cholesterol-lowering mechanisms of marine L. plantarum Lp10 were investigated by combining the analyses of transcriptome and quantitative real-time PCR. Results indicated that bile salt hydrolase (BSH) activity and extracellular polysaccharides (EPSs) adsorption were both responsible for cholesterol reduction. In this process, 11.1 million clean reads and 384 differentially expressed genes, including 79 up-regulated genes and 225 down-regulated genes, were obtained by transcriptome analysis. It was considered that EPS adsorption was mainly responsible for the cholesterol reduction without the influence of bile salt. Further analysis showed that the co-precipitation of cholesterol and deconjugated bile acids induced by BSH1 and BSH2 may play important role in the tolerance and reduction of cholesterol of strain under the stress condition with bile salt, in which, interestingly, the expressions of bsh3 and bsh4 were suppressed. In conclusion, the cholesterol-lowering mechanisms of marine L. plantarum Lp10 was investigated and it was considered as a potential strain for the application in cholesterol reduction.
Okubanjo, Sewuese S.Ye, AiqianWilde, Peter J.Singh, Harjinder...
9页
查看更多>>摘要：Droplet-stabilized emulsions (DSEs) consist of large lipid droplets (the core) stabilized by smaller, protein-coated lipid droplets (the shell) and this structure effectively protects unsaturated lipids from oxidation. This study investigated and compared performance of an antioxidant (butylated hydroxyanisole- BHA) when incorporated either in shell droplets or in the core lipid of DSEs. Emulsions consisted of a core of polyunsaturated fatty acid (PUFA) oil emulsified with shell emulsions that contained either low (olive oil), or high (trimyristin) melting point lipids. Oxidation of emulsions was accelerated with a fluorescent lamp in the presence of ferrous iron (500 mu mol/L) for eleven days, and PUFA oxidation was monitored via the formation of conjugated dienes, lipid hydroperoxides and hexanal. At 500 mg/kg BHA, oxidation was slower in DSEs with BHA-in-shell droplets than in emulsions with BHA-in-core PUFA oil, but the reverse trend was observed at 50 mg/kg BHA. Trimyristin DSEs processed below the shell lipid melting temperature gave the greatest oxidation resistance at both BHA levels. Results suggest that incorporating BHA into shell droplets of DSEs can be more effective than incorporating it into core PUFA oil, and BHA performance in DSEs may be dependent on its concentration, transfer mechanism and proximity to reaction sites.
查看更多>>摘要：Raspberry extract (RE) is a raspberry product with high anthocyanins and low sugar. In the present study, to evaluate the metabolic behavior of phenolic compounds of RE under in vitro digestion (gastric (GF), gastric to intestinal (G-IF), and colonic fermentation (CF)), the changes of 30 phenolic compounds were investigated by High Performance Liquid Chromatography-Mass Spectrometry. The results showed that phenolic compounds were relatively stable in GF, but rapidly decreased in G-IF and CF. Five anthocyanins accounted for 61.1% of total polyphenol contents (TPCs). Among them, anthocyanins bound to glucose or with two hydroxyl groups on B-ring were metabolized more quickly. The catabolic activity of the human microbiota resulted in the production of a series of low molecular weight phenolics, such as hydroxybenzoic acids. Ellagic acid, accounting for 17.7% of TPCs, was rapidly metabolized to umlithin B and urolithin C in CF. Moreover, urolithin C showed the highest antioxidant activity in all ellagic acid metabolites by DPPH assay. Consequently, the metabolic behavior of phenolic compounds was mainly influenced by pH and intestinal microbiota, which provided the basis for further in vivo and in vitro study and efficient utilization of the extract.
查看更多>>摘要：Six extra virgin olive oils (EVOOs) available on Croatian market and twelve home-made Croatian extra virgin olive oils were characterized in this paper. Eleven home-made extra virgin olive oils were obtained from the cultivar Oblica and only one was from the domestic cultivar Buharica. All home-made samples were produced on the island Brae . in Dalmatia and were collected directly from the producers. The main goal of the study was to recognize the aroma markers of bioactive food components present in Croatian extra virgin olive oils. After statistical analysis, which was performed with the Kendall test of independence, only eighteen volatile compounds were chosen to describe the statistical relationship of selected components and their volatile markers. For instance, 3-hexenyl acetate, 2,4-hexadienal, trans-2-hexenal, alpha-copaene were identified as volatile markers of fatty acids. Nonanol, 1-octanol, 2-octenal, heptanoic acid, and hexanoic acid were identified as volatile markers of some phenolic acids. (E)-beta-ocimene, nonanal, and 6-methyl-5-hepten-2-one were recognized as phytosterol volatile markers.
查看更多>>摘要：The population of Listeria monocytogenes and the expression of five virulence and stress-related genes in pres-surized dry-cured ham were monitored throughout storage at 4 degrees C. L. monocytogenes strains 52 (serotype 1/2a) and 57-2 (serotype 4b) exhibited a moderate resistance to high pressure processing (HPP) at 450 MPa for 10 min or 600 MPa for 5 min. The low water activity (a(w)) of sliced dry-cured ham (a(w) = 0.88) diminished the efficacy of the treatments, with pathogen reductions lower than 1.5 log units. Regarding gene expression, a strain-dependent difference in gene transcription pattern was observed. All target genes (prfA, plcA, lily, sigB and lmo1421) were hardly downregulated for strain 52 immediately after pressurization, whereas were upregulated for strain 57-2. The initial overexpression exhibited by 57-2 was attenuated during the storage and after 30 d at 4 degrees C, virulence and stress-related genes were repressed, with fold changes up to 5.3, especially for 600 MPa treated samples.
查看更多>>摘要：Ready-to-eat vegetables such as lettuce are prone to bacterial contamination, predominantly from Escherichia coli and Listeria monocytogenes, the leading causes of foodborne illnesses globally. Chlorine is widely used as a decontaminant in the fresh produce industry, however, potential carcinogenic risks limit its usage. As an alternative, green methods and hurdle technology are gaining interest. In this paper, the efficacy of a combination of nisin, oregano and ultrasound on the reduction of E. coli and L. monocytogenes on lettuce was studied using response surface methodology/Box-Behnken model design, and was found to be reliable (p < 0.05). A combination of 771.2 IU/g nisin, 0.185% v/v oregano and 14.65 min ultrasound was the most effective treatment on both pathogens, showing log reductions of 3.43 and 9.20 CFU/mL for E. coli and L. monocytogenes, respectively. The treated lettuce samples did not show any significant differences in textural properties; however, mild colour changes and a slight increase in the electrolyte leakage rate was observed, within permissible limits. Interestingly this is the first report on the combination of nisin, oregano and ultrasound, as a promising alternative to chemical treatments for the reduction of E. coli and L. monocytogenes on lettuce, without compromising its appearance and quality.
Mukhopadhyay, SudarsanSokorai, KimberlyUkuku, Dike O.Jin, Tony...
8页
查看更多>>摘要：The microbial safety of fresh produce continues to be a real concern. Novel nonthermal technologies are required to lessen the risk of pathogen contamination. The objective of this research was to develop and evaluate the effects of direct and in-package pulsed light (PL) treatment on the survival of E. coli O157:H7 in Romaine lettuce. Treatment influence on reduction of background microbial loads of Romaine lettuce was also explored. A three strain-cocktail of E. coli O157:H7 was selected for inoculum preparation for their link with foodborne outbreaks. Surface inoculated Romaine lettuce pieces (2.5 x 2.5 cm) was subjected to pulsed light treatment for a maximum of 1 min (63 J/cm(2)). Polyethylene (PE) films of 0.00254, 0.00508 and 0.00762 cm thickness with ample UV transmission (54-83%) ability were used for packaging. PL treatment of 10 s, equivalent to a dose of 10.5 J/cm(2), was considered optimum beyond which wilting of leaves was observed. Both direct and in-package treatment provided greater than 1 log reduction of the pathogen in 1 s (1.05 J/cm(2)). Direct treatment resulted in 2.68 +/- 0.37 log CFU/g reduction of E. coli O157:H7 at optimal dose, whereas log reductions were decreased to 2.52 +/- 0.19, 2.31 +/- 0.34 and 2.18 +/- 0.25 log CFU/g for Romaine lettuce in 0.00254, 0.00508 and 0.00762 cm thickness packaging enclosures respectively. The decrease in log reductions was not significantly (P > 0.05) affected by film thickness. No significant difference (P > 0.05) in E. coli O157:H7 decontamination efficacy between packaged and unpackaged Romaine lettuce was observed due to PL treatment. The initial total aerobic bacteria and mold and yeast populations were also reduced significantly (P < 0.05) by >1 log, due to the treatment. Overall, the results of this work demonstrate that PL treatment may be used to enhance microbial safety and reduce post processing contamination of packaged Romaine lettuce.
Barbut, ShaiTiensa, Brian E.Marangoni, Alejandro G.
6页
查看更多>>摘要：Partial and full replacement of pork fat with canola oil organogels was done to improve nutritional and sensory properties of liver pate. Sensory analysis revealed that 100% replacement could not be differentiated from the control in terms of hardness, oiliness, cohesiveness, and off-flavours. Oil loss results revealed good retention for pates made with up to 60% organogels. Microscopy showed a gradual increase in fat globule size as more pork fat was replaced, and that could be one of the reasons for higher oil losses. Back extrusion (also a measure of spreadability), showed that organogel replacement (0-100%) provided similar values to the control pate. Colour evaluation showed that using canola oil organogels lowered the L* value and increased a* and b* values compared to the control pate. Overall, 60% pork fat replacement is recommended, based on oil retention and maintaining the textural properties with no effect on sensory properties and colour but with almost 40% reduction in saturated fat.
Kandpal, B. K.Milton, A. Arun PrinceMomin, Kasanchi M.Ghatak, Sandeep...
8页
查看更多>>摘要：Staphylococcus aureus is one of the most common and leading causes of food poisoning and also responsible for multifarious diseases in humans. Rapid and on-site detection of S. aureus is of specific importance in developing countries. In the present study, a polymerase spiral reaction (PSR) assay was developed for sensitive, rapid and visual detection of S. aureus and validated in meat using pork as a model. The specificity of the PSR assay was ascertained by using 18 S. aureus and 17 non-S.aureus strains. The PSR assay was 100- and 10-fold more sensitive than conventional end-point PCR and real-time PCR, respectively. The limit of detection of the PSR assay was 19.9 x 10(3) CFU/g of pork without enrichment and 19.9 CFU/g after 6 h enrichment. The detection of 19.9 CFU/g of pork was attained within 8 h. Real-world or field applicability of the developed assay was evaluated by screening 76 raw and processed pork samples. Seeing its rapidity, simplicity, cost-effectiveness, user-friendliness and sophisticated-equipment free nature, this assay has the prospective to turn into the assay of choice for regular detection of S. aureus in foods in less-advanced laboratories. To our knowledge, this is the first report to use PSR for the detection of S. aureus.
查看更多>>摘要：In the present study, the prospect of alternate carbon and nitrogen sources was ascertained for plantaricin (PL) and lactic acid (LA) production from the probiotic lactic acid bacteria Lactobacillus plantarum CRA52. The alternate carbon sources used in the present study were whey permeate (WP) and palmyra palm sugar (PJ), and the alternate nitrogen source was whey protein hydrolysate (WPH). Experimental use of WP as carbon source and WPH as nitrogen source led to enhanced production of LA and PL, with the yield being 17.69 gL(-1) and 462.32 AUmL(-1) respectively. WP and WPH concentration ratio of 2:1 was found to be optimal for the production of PL and LA. Kinetic modeling revealed that Aiba substrate inhibition model exhibited best fit for the experimental data. On performing a medium based process economic analysis, WP and WPH-based medium were economical for the production of LA. The present investigation validates the potential of WP-WPH based medium for heightened economical production of PL and LA. It is envisaged that this study will lend fundamental insights in order to leverage the innate nutritional potential of raw products such as PJ and WP for economical production of industrially relevant products.
NSTL
Elsevier