查看更多>>摘要：The purpose of this work was to reduce the oil content of potato chips by the pulsed electric field (PEF) pretreatment. The effects of PEF on oil content, color parameters, texture, microstructure, and acrylamide content of potato chips were investigated. The following appropriate pulse parameters were selected for pretreatment: the number of pulses was 2000, the pulse width was 5 mu s, the frequency was 20 Hz, and pulse direction was unidirectional pulse. The results showed that the electric field strength had a significant effect on the oil content and texture of potato chips. When pretreating the potato slices under the electric field strength of 10 kV/cm, the oil content of potato chips was reduced by 21.2%, and the hardness and crispness were significantly improved. The surface of the potato chips became smoother, and the porosity in the cross-section increased, which might be the reason for the reduced oil content of the potato chips. Finally, the potato chips prepared in current experiment had a low acrylamide content, approximately 10 ng/g (fresh weight). The above findings may provide useful information to guide the effective strategies for the practical application of PEF in reducing the oil content of fried foods.
Lee, Kyo-YeonRahman, M. ShafiurKim, Ah-NaJeong, Eun-Ji...
8页
查看更多>>摘要：This study investigated the effect of superheated steam (SHS) treatment on the yield and quality properties, including volatile compounds of perilla seeds oil (PO). SHS treatment resulted in ruptured seed coat and damaged cellular structure, increasing oil yield (78.81 g/100 g seeds), about 2.5-times higher yield than the untreated seeds (33.11 g/100 g seeds). The viscosity (similar to 89 mPa s), color parameters (L*a*b*), acid value (0.19 mg KOH/g), and peroxide value (1.02 meq/kg) of SHS-treated POs were similar with that of the untreated PO, indicating no oil rancidity by SHS treatment. SHS-treated PO showed a dramatic reduction of lipase activity from 37.44 to 0.80 mu mol/g, 3-times higher phenolic content and 5-times higher antioxidant activity than that of the untreated PO. The major volatiles were 2,4-heptadienal, 4-methyl-5-(2-methyl-2-propenyl-2(5H)-furanone, 3-(4-methyl-3-pentenyl)furan perillen, and 3-methylpentane in POs. The normalized relative intensities of the volatiles were reduced for SHS-treated PO. Thus, SHS could be an effective treatment for high oil yield without originating odor characteristics compounds in PO.
查看更多>>摘要：Staphylococcus aureus is a common foodborne pathogenic microorganism. A modified propidium monoazide (PMAxx) dye combined with recombinase aided amplification (RAA) was proposed for the rapid and real-time detection of viable S. aureus. PMAxx, a kind of nucleic acid dye is used to distinguish viable bacteria from dead bacteria. Additionally, RAA technique has the advantage of a short detection time (20 min) and uniform temperature (39 degrees C), which is of great significance for the efficient detection of S. aureus. The S. aureus nuc gene was used as primer and probe in a microplate assay. The effect of PMAxx treatment exhibited permeation of the dead cell membranes that was observed under confocal laser scanning microscope (CLSM). After the enrichment of viable target bacteria ranging from 5.4 x 10(1) to 5.4 x 10(3) CFU/mL, the LOD for viable S. aureus was 10(2) CFU/mL under 3 h enrichment and 10(1) CFU/mL under 6 h enrichment in artificially contaminated milk, respectively. In the presence of nontarget bacteria at 10(6) CFU/mL, the system could detect 10(7) CFU/mL S. aureus in milk sample. The proposed PMAxx-RAA assay exhibited potential for the accurate and rapid viable S. aureus detection in milk.
Pires de Oliveira Galdino, Isadora Kaline CameloOliveira, Marcia MunizOliveira, Aryanne Teixeirada Silva, Gabriel Monteiro...
8页
查看更多>>摘要：In this study, goat fermented milk trials were prepared with six potentially probiotic autochthonous cultures Lactobacillus rhamnosus EM1107, Lactobacillus plantarum (CNPC001, CNPC002, CNPC003 and CNPC004) and Lactobacillus mucosae CNPC007in the presence and absence of a starter culture (Streptococcus thermophilus, ST) and in the presence and absence of inulin (IN) or oligofructose (FOS), consisting of 36 trials. The fermented milk without the starter culture only achieved a lactic acid content above 0.6 g/100 g after 24 h, thus requiring the presence of ST culture for a faster acidification. After the fermentation, three trials with the best fermentative performance and visual firmness (EM1107 + ST + IN, CNPC003 + ST + IN and CNPC007 + ST + IN) were exposed to simulated conditions of the gastrointestinal tract (GIT) in vitro. All fermented milk, with Lactobacillus spp. population above 6 log CFU/g before GIT simulation, showed the highest viability losses in the gastric step. In fermented milk with Streptococcus thermophilus plus inulin, L. rhamnosus and L. mucosae performed well in the GIT assay, achieving a viability between 6.50 - 7.24 and 6.50-7.60 log CFU/g in the enteric stage, respectively. Therefore, the combination of EM1107 or CNPC007 strains with S. thermophilus and inulin is promising in the production of goat dairy products.
查看更多>>摘要：Objective: of the study was to evaluate the influence of the concentration of red cabbage extract (RCE) and sweet whey on the properties of starch films using glycerol as plasticizer. The influence of independent variables on the barrier, physical-chemical, mechanical, optical, spectroscopic and antioxidant properties of the films was evaluated. T2 (64.18% RCE and 4.36% sweet whey), T7 (50% RCE and 0.0% sweet whey) and T10 (50% RCE and 15% sweet whey) films presented good mechanical properties, high antioxidant capacity, low solubility and low water vapor permeability, and for that reason they were chosen as treatment that are suitable for use as ground beef packaging. After application as packaging in ground beef, the smallest changes in the quality parameters were noticed in the sample packed with film T2, showing that besides producing an active packaging, the presence of anthocyanins contributes to the conservation of the ground meat.
查看更多>>摘要：Low-salt fish as a traditional preserved food has gained growing popularity for the reduction in sodium consumption. Water transport, salt diffusion, and hardness changes of bighead carp fillets were investigated by low-field nuclear magnetic resonance (LF-NMR), electric resistance, and texture profile analysis (TPA) under salting concentration of 15 mg/g and 30 mg/g. The decrease of P-21 (T-21 population) by LF-NMR analysis of G0 (control) was 12.1% while that of G1 (15 mg/g) and G2 (30 mg/g) was 2.2% and 5.3%, respectively. Meanwhile, the diffusion of salt was fast in the first 30 min, and the higher the salt concentration, the lower the resistance value. Furthermore, the higher hardness in G1 was observed, reaching 2.17 times that of control. At the end of salting, the proportion of P-21 (Y1) and change of hardness (Y3) showed negative linear relationship with salt content (from 15 mg/g to 60 mg/g): Y1 = 0.0094 x + 0.9702 and Y3 = 0.1752x + 2.3544, and the resistance change rate (Y2) showed a positive correlation: Y2 = 5.9722x + 0.5625. The established model could effectively predict the hardness and water mobility of bighead carp fillets during the early stage of salting process.
查看更多>>摘要：This research describes a first approach to analyse the effects of using high-pressure processing (HPP) as a pretreatment before frozen storage and subsequent canning of fish. For it, Atlantic Chub mackerel (Scomber colias) was subjected to HPP (200, 400 and 600 MPa for 2 min) followed by freezing (-30 degrees C for 48 h), frozen storage (-18 degrees C for 0, 3, 6, 10 or 15 months), canning and canned storage (3 months at 20 degrees C). Lipid damage development (hydrolysis and oxidation) and volatile amines formation (total and trimethylamine) were determined in canned mackerel. As a result, a marked inhibitory effect (p < 0.05) on free fatty acids content was observed in canned mackerel previously subjected to different frozen storage times. This effect increased with pressure applied. Furthermore, higher average polyene values were obtained in most canned fish previously subjected to any high-pressure treatment when compared with Control canned fish. No effect (p > 0.05) on thiobarbituric acid reactive substances and trimethylamine values was noticed related to HPP. However, increasing (p < 0.05) peroxides and fluorescent compounds contents were obtained when applying the two highest pressure levels.
查看更多>>摘要：In this study, biopolymer-based antimicrobial fibrous membranes constituted by polylactic acid (PLA) and ultrasonically dispersed ZnO nanoparticles (NPs) were developed by electrospinning. The morphology, mechanical properties, thermodynamics and antimicrobial properties of membranes with different ZnO NPs content were comprehensively studied. The results showed that the best performance was achieved when the content of ZnO content was 0.5 wt% (PLA/ZnO-0.5%). Specifically, the tensile strength and elongation at break of the composite membrane were 6.85 +/- 0.19 MPa and 74.90 +/- 0.59%, respectively, and the inhibition zones of Escherichia coli and Staphylococcus aureus were 15.02 +/- 0.18 mm and 14.74 +/- 0.06 mm, respectively. In addition, an appropriate ultrasonication time of 45 min improved the thermal, ultraviolet (UV) barrier, and antibacterial properties of the composite membrane. At the 45 min ultrasonication time, the inhibition zone of PLA/ZnO-0.5% against Escherichia coli and Staphylococcus aureus was 18.11 +/- 0.15 mm and 15.80 +/- 0.11 mm, respectively. Therefore, PLA/ZnO-0.5% can be applied in food packaging to provide an antibacterial effect and UV light barrier.
查看更多>>摘要：The lactone content of Wagyu beef and imported beef in Japan was estimated using a combination of solvent extraction and gas chromatography-tandem quadrupole mass spectrometry. This method revealed that the total lactone content was higher in Wagyu than in the imported beef. The most abundant lactone in the Wagyu and imported beef was delta-hexadecalactone, followed by delta-tetradecalactone, delta-dodecalactone, and delta-decalactone. The total lactone content in the Wagyu and imported beef increased approximately twofold or threefold when the extracted fats from the beef were heated. In addition, the raw beef was heated under actual cooking conditions, such as boiling at 80 degrees C for 2 min and roasting at 180 degrees C for 30 s, and found with the increased amounts of lactones. The results showed that the cooking processes increased the lactone content in the Wagyu and imported beef, and the change in the lactone content was greater in the roasted beef than in the boiled beef. These results suggest that considerable amounts of lactone precursors remain in the raw beef.
Guerra, Andre FioravantePereira, Karen SignoriZarur Coelho, Maria Alicede Paula, Breno Pereira...
8页
查看更多>>摘要：A comparative controlled study was carried out to evaluate the performance of Saccharomyces cerevisiae var. boulardii to act as brewer's yeast for potential probiotic beer production. The yeast performance on the beer wort (cell growth, sugar consumption and products production) was compared with the conventional top-fermentation Saccharomyces cerevisiae. To improve the yeast metabolism, changes were made in the malt concentration of the wort recipe and in the ramp mash temperature profile, emphasizing beta-amylase activity to provide high glucose concentration in the wort. Next, metabolism close to conventional brewer's yeast was achieved. Saccharomyces cerevisiae var. boulardii survivability in the beer and after in vitro gastrointestinal transit was assessed as the indicative of potential probiotic properties in the beer. The yeast population did not decrease dramatically over the storage period, withstanding alive above the minimal dose prescribed to confer health benefit to the host. The present work shows an alternative method to produce potential probiotic wheat beer. However, Saccharomyces cerevisiae var. boulardii metabolism is still not completely understood, especially the metabolism on the wort sugar and the optimized conditions of the wort recipe and ramp mash temperature profile.
NSTL
Elsevier