查看更多>>摘要：Because the probiotic and growth characteristics of probiotics are strain-specific features, it is crucial to be able to distinguish the probiotic strains from the other strains in the same species. To rapidly identify Lactobacillus rhamnosus at the strain level through PCR, a method for searching for several strain-specific sequences in the genome of a strain was investigated. The whole genomes of L. rhamnosus hsryfm 1301 and L. rhamnosus LV108 were sequenced, and gene family analysis was performed with using L. rhamnosus GG and L. rhamnosus Lc705 as reference strains. Thirty-one and 19 strain-specific open reading frames (ORFs) were found in L. rhamnosus hsryfm 1301 and L. rhamnosus LV108, respectively. Thus, strain-specific primer pairs could be designed in a more rational and controllable manner. Concatenation of several strain-specific primer pairs designed from the strainspecific ORFs (and their adjacent regions) were able to distinguish L. rhamnosus LV108 (primer pairs V2, V4, V5, and V9) or L. rhamnosus hsryfm 1301 (primer pairs H1, H2, H3, and H4) from 12 other L. rhamnosus strains. This strain-specific identification method was determined to be accurate, rapid, economical, reproducible and easy to perform.
Nematollahi, M. H.Akhavan, H. R.Hamedi, ShAfsahi, M. M....
10页
查看更多>>摘要：In the present research, the influence of the inlet parameters of a laboratory spouted bed (inlet air temperature and milk flow rate) on the physical properties (moisture content, wettability, dispersibility, particle size and density), chemical properties (protein, cholesterol, and triglyceride content) and morphology of the milk powder was evaluated and compared with properties of the commercial spray dried powder. The effect of these two inlet parameters was significant on all of the physical and chemical properties. Particle morphology of the spouted bed dried samples (flat, solid, and irregular) was entirely different from commercial spray dried milk powder (spherical, and hollow). The optimum values of the inlet air temperature and milk flow rate, calculated by RSM, were obtained 80 degrees C and 2.8 ml/min, respectively. The small error between properties predicted by the models and the experimental data indicated that the performed optimization was satisfactory.
Ilic, Dusica P.Troter, Dragan Z.Stanojevic, Ljiljana P.Zvezdanovic, Jelena B....
7页
查看更多>>摘要：Cranberry fruit (Vaccinium macrocarpon L., Ericaceae) is a valuable material for the production of juices and other fruit products, quite popular among consumers in Serbia. Different types of cranberry juice are produced in Serbia and other countries, but the chemical composition, as well as the antimicrobial and antioxidant activities of juices depend on both the used technology and the region in which cranberries are grown. Within this study, the screening of bioactive components found in cranberry juice from Serbia was performed by the UHPLC-DADMS/MS method, as well as the determination of its antibacterial and antioxidant activities. The juice was obtained by cold-pressing of ripe cranberry fruit grown in Serbia and enriched with sugar. Among the seventeen identified compounds, the most common were phenolic compounds and hexoses, followed by organic acids. The antibacterial activity of the juice was assessed by the disc diffusion method against Listeria monocytogenes, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The DPPH test was used to determine the antioxidant effect. The cold-pressed cranberry juice showed higher antibacterial activity against Gram-positive bacteria. The obtained results will be useful in promoting further progress and development of cranberry cultivation and processing in Serbia.
查看更多>>摘要：Wheat, the most common cereal from the genus Triticum, owing to its immense food value ranks as the second most important crop worldwide. A diverse range of human health benefits is obtained from phenolics of whole wheat products. Here, two methods, namely, hexane and supercritical carbon dioxide fluid extraction (SC-CO2), have been deployed for the purpose of successful extraction of phenolic acids by defatting wheat whole grain, bran, and flour. SC-CO2 yielded 5.2-9.6% higher oil than hexane extraction. Total phenolic content (TPC) and individual phenolic acids content of esterified SC-CO2 defatted wheat whole grain (SWG) samples were 0.85-2.6-fold higher than its hexane counterpart. Ferulic acid and p-coumaric acid were more abounded phenolic acids in the wheat grain. A higher antioxidant capacity in DPPH, ABTS and phosphomolybdenum assay was observed in esterified SWG that corroborated with higher reducing activity by FRAP, CUPRAC assays, and metal chelating activity. An effective inhibitory activity of esterified SWG was observed against a-amylase, tyrosinase, lipase and acetylcholinesterase. Finally, positive correlation was found between TPC and its corresponding antioxidant and enzyme inhibitory activities. In summary, phenolics rich fraction, elevated antioxidant and enzyme inhibitory activities were aided in wheat grain defatted samples enriched with SC-CO2.
查看更多>>摘要：Atlantic mackerel (Scomber scombrus) is a fatty fish with high ratio of dark muscle. The subcutaneous muscle on the dorsal and ventral side of the fillet is prone to yellow discolouration, attributed to lipid oxidation. The question is if this is solely due to the position of the muscle under the skin or if this muscle is more susceptible to oxidation than other dark muscle. The aim of the study was to evaluate if anatomical variation in the muscle of Atlantic mackerel could affect the oxidation susceptibility and/or its processability. Water and lipid content, fatty acids composition, colour and lipid oxidation (assessed by heme-iron content) and hydrolysis (assessed by free fatty acid ratios) susceptibility were determined. Heme-iron content of dark muscle differed depending on anatomical position and was higher dorsal and ventral dark muscle than in other dark muscle, indicating higher oxidation susceptibility. Furthermore, the ventral and dorsal light muscle and the medial dark muscle had lower free fatty acid content (0.57-1.15 g FFA/100 g lipids) compared to lateral and ventral dark muscle (3.40-3.62 g FFA/100 g lipids). The results indicate that lateral, ventral and dorsal dark muscle are more susceptible to lipid oxidation and hydrolysis.
查看更多>>摘要：The aim of this study was to evaluate the influence of combining extrusion and fermentation processes on the chemical and biosafety of wheat processing by-products (WPBP). Extrusion experiments were performed by testing two different temperatures (115 and 130 degrees C) and three different speeds of extruder screw (16, 20, and 25 rpm). The lactic acid bacteria (LAB) L. casei and L. paracasei were used for WPBP fermentation. A high-performance liquid chromatograph coupled to a triple quadrupole mass spectrometer was used for mycotoxin analysis and a high-performance liquid chromatograph with an ultraviolet detector was used for biogenic amine (BA) determination in WPBP. A significant effect of the type of LAB on the acidity of fermented WPBP was found. Although lower pH was observed for non-extruded fermented WPBP samples, they contained higher concentrations of (D)(-)-lactic acid. In extruded and extruded/fermented WPBP, the total BA content was two times lower than that in controls. The lowest mycotoxin concentration was found in fermented WPBP extruded at 130 degrees C using a screw speed of 20 and 25 rpm. Finally, the combination of extrusion and fermentation can be confirmed as a promising innovative pre-treatment for WPBP, potentially capable of reducing the content of BAs and mycotoxins.
De Martinis, Elaine C. P.Alves, Virginia F.Pimentel, Tatiana C.Oliveira, Carlos A. F....
9页
查看更多>>摘要：The effect of cold atmospheric pressure plasma (CAPP) on three strains of Staphylococcus aureus and one strain of Listeria monocytogenes on gel discs was studied. A plasma jet operating in argon was used and exposure times were from 5 to 120 s. Bacteria had been isolated from dairy environments. In comparison, peracetic acid (PAA, 0.5% v/v) applied on cell suspensions at the same treatment times was studied. The cell viability was measured by flow cytometry and the culturable cells were determined by plate count technique. PAA reduced nearly 7 log cycles of both microorganisms after a short time (10 s). Concurrently, membrane permeabilization, RNA and DNA damage, and lack of esterase activity could be demonstrated. CAPP showed a mild biocidal effect with a maximum reduction of 1-2 log cycle after 120 s, and no significant impact on membrane permeabilization, RNA and DNA damage, or esterase activity. Therefore, for the selected processing parameters, PAA remains as more effective treatment in terms of inactivating pathogenic bacteria in dairy environments, reaching similar to 7 log cycles reductions. Further studies should determine the effect of higher CAPP exposure times on S. aureus and L. monocytogenes strains.
查看更多>>摘要：This study aimed to investigate the effects of oxidized proteins on meat color and water holding capacity of Tan mutton stored at low temperatures and the correlation between oxidized proteins and meat quality. Compared with the fresh control group, a total of 1089 proteins were identified as shared proteins with different oxidation sites (DOSPs) in Tan mutton from three low temperature groups (-2, -18 and 4 degrees C). The number of oxidation sites in Tan mutton muscle stored at -2 degrees C was much higher than those at -18 and 4 degrees C. There were also differences in the degree and site of protein oxidation between different storage groups. Pearson's correlation analysis between 275 DOSPs and quality traits of the tan mutton muscle stored at low temperatures showed that 19 DOSPs were correlated closely with color (L*, a* and b*) and water holding (CeL, CL and DL). Among them, several proteins might be potential markers for color, and some proteins are good candidate predictors for water holding of Tan mutton muscle. Bioinformatics analysis showed that most of these proteins were structural proteins and metabolic enzymes, which may lead to the change of meat quality by affecting the microstructure and metabolic pathway of muscle.
查看更多>>摘要：Total polar compounds (TPC) have been considered as one of the most objective indicators for the evaluation of deterioration of deep-frying oils. However, the cytotoxic and dynamics features of different parts of polar compound were underestimated. The present study investigated the biohazard effect of different polar compounds from heated oils. The results indicated oxidize triglycerides monomer (ox-TGM) exhibited the most serious deleterious effect on THLE-2 cell viability, followed by triglycerides polymer (TGP) and degradation products. The investigation of polar compounds variation revealed that vegetable oil with higher saturation endured longer thermal oxidation time to achieve the discarded point of 27% TPC. As the increase of thermal oxidation time, the content of polymers and oxidized products increased linearly, while the level of degradation products was altered moderately. The canonical correspondence analysis uncovered significant positive associations between oleic acid and ox-TGM at the initial stage of thermal oxidation. Taken together, our overall findings offer an evidence that ox-TGM could be acted as an accurate indicator for the evaluation of deep-frying oil quality.
查看更多>>摘要：In order to protect the structure and membrane protein of milk fat globules (MFGs), a milk sample rich in phospholipid (PLM) was prepared by adding soybean lecithin before homogenization. Compared with normally homogenized milk (HM), the particle size of MFGs in PLM decreased from 1.35 mu m to 1.15 mu m, and the zeta-potential decreased from -11.97 mV to -13.77 mV. As a result, the storage stability increased according to a Turbiscan analysis. More surface area of the MFGs in PLM was observed to be covered by phospholipids using a laser confocal microscope, which was similar to the state of MFGs in the raw milk sample (RM). Moreover, SDSPAGE patterns showed that adding phospholipids reduced serum proteins absorption onto the MFG membrane (MFGM) and preserved more native MFGM proteins including XDH, BTN and MFGE8. The digestibility of MFG was also studied in vitro with a simulated intestine digestion system. The added phospholipids could participate in the recombination of MFGM during homogenization, promoted the stability of the newly generated MFGs and protected native membrane proteins, which would provide guidance for the optimization of dairy products functionality.
NSTL
Elsevier