Robichaud, VBagheri, L.Salmieri, S.Aguilar-Uscanga, B. R....
5页
查看更多>>摘要：The aim of this study was to assess the effect of gamma-irradiation on the microbial inactivation of selected foodborne pathogens (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli 0157:H7, and Salmonella Typhimurium) in combination with 2.5% sodium citrate, 0.5% sodium carbonate and 0.75% citric acid as food additives in frozen and powdered infant formula (IF). The study demonstrated that gamma-irradiation alone was more efficient against pathogens in frozen IF. A hurdle technology with sodium carbonate induced a high radio-sensitization in powdered and frozen IF against all pathogens, compared to other additives that induced a lower radiosensitization effect. Contrarily to other pathogens, spore-producing B. cereus was more radiosensitized in powdered IF by carbonate, citrate, and citric acid, with radiosensitivity values up to 4.1. E. coli was strongly radiosensitized in presence of carbonate and citrate in frozen IF with values up to 2.4. This study demonstrated that the use of food additives - mainly sodium carbonate - in combination with gamma-irradiation can be a good way to reduce the time of irradiation treatment to assure the safety of the IF product.
Paes, Mariana SchincariolPessoa Filho, Pedro de AlcantaraTadini, Carmen Cecilia
7页
查看更多>>摘要：Sorption isotherms of sorbitol osmotically pre-treated cambuci slices were obtained at (40, 50, and 60) degrees C using DDI (dynamic) method. The curves were classified as type III and the fruits showed hydrophobic behavior at water activities (a(w)) lower than 0.4. The pre-treatment with sorbitol as osmotic solute resulted in changes in the sorption behavior indicating that this solute acts as a humidifier due to the water-binding property. The equilibrium moisture content (X-eq) was determined at (20, 30, and 40) % of relative humidity (RH). The results showed that the RH, pre-treatment and temperature significantly affected the X-eq (p < 0.05). In general, X-eq decreased at lower RH showing that a higher driving force contributes to larger water removal. The experimental data were fitted to BET, GAB, and zeta models that showed a good fit. The isosteric heat of sorption (Delta H-s) was calculated and reinforced the water-binding property of sorbitol as, for the same X-eq, the Delta H-s obtained by cambuci pre-treated samples were greater than by control ones.
查看更多>>摘要：This study aimed to investigate the mechanism underlying the influence of mild glycation on the digestibility and anaphylactic effect of beta-lactoglobulin (beta LG) and its digests through LC Orbitrap MS/MS. Three glycated sites were discovered after glycation with fructose, whereas only lysine47 (K47) was glycated with maltose. After digestion, the intrinsic fluorescence intensity decreased and red shifted, and the degree of hydrolysis (DH) values showed no significant difference among digests. beta LG glycated with Fru showed the lowest IgG and IgE-binding abilities. Meanwhile, the IgG and IgE-binding abilities further decreased and showed no apparent difference among digests. These results were attributed to the proximity to the IgG-binding epitope, the high glycation degree of K47, and mild glycation. Therefore, mild glycation could reduce the anaphylaxis of proteins before digestion, but did not influence the anaphylactic effect of the digests.
查看更多>>摘要：In this study, Fourier-transform infrared (FT-IR) spectral data was combined with variable selection methods to measure tartrazine adulteration in tea powder. Partial least square (PLS) regression and its variants such as backward interval PLS (BiPLS), genetic algorithm PLS (GA-PLS), and competitive adaptive reweighted sampling PLS (CARS-PLS) for variable selection were established as calibration models for the quantitative prediction of tartrazine. A simple and efficient real-coded GA (RCGA) was also implemented as a variant of GA-PLS regression. The performance of these models was adjudged based on root mean square errors (RMSE) for both cross-validation (RMSECV) and prediction (RMSEP) along with their respective correlation coefficients (R-C and R-P). The developed RCGA-PLS was observed to be a robust technique to achieve a model with low RMSECV and RMSEP values of 0.8331 and 0.923, respectively. This model uses 30 selection variables (1.19% of full variable count) to predict tartrazine in the range of 0-30 mg/g with a correlation coefficient of 0.987. This study demonstrated that FT-IR spectroscopy, combined with the developed RCGA-PLS procedure for variable selection could be a robust technique for the rapid detection of tartrazine in tea samples.
查看更多>>摘要：chilled meat is extremely susceptible to microbial contamination during processing and storage. Therefore, a new edible starch-based antibacterial composite film with thyme oil microemulsions(ME) or microcapsules(TMS) was prepared. The slow-release characteristic, bacteriostatic property and the preservation effect on chilled meat of the films were evaluated. The results showed that the cumulative release rates of composite films containing 5% microemulsion and 5% microcapsule were much less than the film containing 5% thyme oil. The antibacterial effect of film containing thyme oil microemulsion (ME-S) was stronger than that of film containing thyme oil microcapsule (TMS-S), but both of their antibacterial effect increased as the concentration increased. The overall fresh-keeping effect of composite films on chilled meat at 0-4 was blank < PE film <2.5% TMS-S <2.5% ME-S <5% ME-S <5% TMS-S. The shelf life of composite film containing 5% (v/v) microcapsules for chilled meat could reach about 14 days at 4, while the blank control group and the PE film group were 6 days and 10 days, respectively. The new antibacterial composite film provided a theoretical reference for the production process and practical application of thyme oil potato starch-based antibacterial composite film.
查看更多>>摘要：Inorganic nanoparticles (NPs), such as silica (SiO2), zinc oxide (ZnO), and silver (Ag) NPs, are often added to food products and food packaging materials through which they can be ingested and passed into the gastrointestinal tract. The aim of this study was to investigate the amounts of adsorbed inorganic NPs and the antibacterial effects of different doses of these NPs on Lactobacillus plantarum (L. plantarum) and Lactobacillus fermentum (L. fermentum). Transmission electron microscopy (TEM) showed that inorganic NPs change the morphology of probiotics and destroy their cell membranes; this finding was further confirmed by confocal laser scanning microscopy (CLSM). After ZnO NPs adsorbed to L. plantarum, the mass change (Delta m) reached 169.3 ng/cm(2) according to quartz crystal microbalance with dissipation (QCM-D) measurements. The loss of intracellular nucleic acid from L. fermentum with NPs followed a dose-dependent trend. After treatment with NPs, the cell membrane permeability of L. plantarum increased. These results suggest that food-grade NPs have bactericidal effects on L. plantarum and L. fermentum.
查看更多>>摘要：The objective of this study was to evaluate the behavior of slow and fast-darkening carioca beans during storage, and the profile of phenolics and saponins, aiming to identify which compounds may be involved in the browning process of the integument of these grains. Cultivars Madreperola and Dama presented the lowest total color difference (Delta E) and the highest luminosity (L*) values during storage time indicating to be slow-darkening cultivars. In contrast, the cultivars Notavel and Imperador rapidly darkened with storage time, evidenced by the highest Delta E and lowest L*. Regarding the content of phenolic during storage, it was observed a reduction for free phenolics in fast-darkening beans and the maintenance/increase in slow-darkening beans. In the PCA of the phenolic profile, Notavel and Imperador were similar, differing from Dama and Madreperola, indicating that fastdarkening grains have similar phenolic profile. The OPLS/DA indicated that aged grains from bright beans had more kaempferol than darker beans. For saponins, the cultivars Imperador and Notavel presented higher content of Soyasaponin Bd, which might be related to the darkening process. Besides, kaempferol was found at higher concentrations in slow-darkening aged grains and can be a chemical marker of darkening in carioca beans.
Rocha, Andre R. F. da S.Sousa, Herbert G.do Vale Junior, Erasmo P.de Lima, Francisca L....
7页
查看更多>>摘要：The growing microbial resistance to antibiotics and the adverse effects of the frequent use of antimicrobials in oral medicine require products as natural therapeutic alternatives. Croton betaceus and C. lundianus can be viable for in-depth studies in search of new biopmducts. This study evaluated the antioxidant and antimicrobial potential of ethanol extract and leaf fractions of Croton spp. The disk diffusion assay, FRAP and DPPH, were used for antimicrobial and antioxidant analysis, respectively. In addition to phytochemical prospecting and toxicity testing. Secondary metabolites with biological activities were found. Researched extracts and fractions have the potential to inhibit the growth of oral pathogens (Gram-positive, Gram-negative and yeast) in different concentrations. Enterococcus faecalis is the most susceptible to the extract. All fractions showed antioxidant potential. The hexane fraction (BHX and LHX) of both species can inhibit the growth of pathogens in low concentrations, and has a high antioxidant power. The fractions of the extracts of C. betaceus and C. lundianus have important biological activities that can be applied in the development of new antimicrobials for industry and other biotechnological applications.
查看更多>>摘要：To improve pepper powder product flavor, headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) was used to detect flavor substances in pepper powder, including dried pepper powder, baked pepper powder (BPP) and Maillard treated pepper powder (MTPP). Fifty-three flavor compounds were identified, mainly comprising alcohols, esters, aldehydes, ketones, etc. Volatile organic compound type and content in BPP and MTPPs differed from dried pepper powder, with more types present in MTPPs than BPP. Partial least-squares discrimination analysis and principal component analysis were employed to identify relationships between flavor substances and sample type, and evaluate different exogenous Maillard's flavoring reaction affects. Dried pepper powder was positively related with most flavor compounds, and Maillard reaction substrate combinations of lysine-xylose, lysine-lactose, valine-fructose, and valine-xylose exhibited high correlation with several characteristic compounds, whereas no characteristic compounds exhibited high correlations in BPP. Thus, adding exogenous Maillard reaction substrate offers a mechanism to improve BPP flavor quality.
查看更多>>摘要：Ninety-two yeasts isolated from cheeses and different dairies in the Marche region (Italy) were identified and characterized as potential functional co-starter cultures. The prevalent isolates were Debaryomyces hansenii (58%), Candida zeylanoides (25%) and Yarrowia lipolytica (5.5%), while other species belonging to the Candida, Kluyveromyces, Moniliella and Yamadazyma genera were minorities. The yeasts identified were subjected to typing analysis with the purpose of clustering the biotypes to detect the strain specificity for each dairy. Furthermore, the occurrence of some functional and/or probiotic properties was evaluated. D. hansenii, C. zeylanoides and Y. lipolytica showed 16, 4 and 2 different biotypes, respectively. Y. lipolytica biotype II and Candida parapsilosis biotype I exhibited high antioxidant activities. The unique Kluyveromyces lactis biotype showed a minimal ability to grow in the presence of bile salts at 37 degrees C and pH 2.5, but it exhibited high antioxidant activity. Most of the D. hansenii and C. zeylanoides biotypes showed relevant preliminary probiotic and technological traits. Thus, considering these preliminary evaluations, selected strains of C. zeylanoides, Y. lipolytica and K. lactis could be proposed in association with lactic acid bacteria as innovative co-starters that are able to develop functional cheeses characterized by a distinctive aroma.
NSTL
Elsevier