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LWT-Food Science & Technology
Elsevier
LWT-Food Science & Technology

Elsevier

0023-6438

LWT-Food Science & Technology/Journal LWT-Food Science & Technology
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    The influence of microbial contamination on rice bran rancidity

    Yu, Cheng-weiLuo, TingCao, YuWei, Chang-hao...
    9页
    查看更多>>摘要：The storage and utilization of rice bran are severely impeded due to the rapid rancidity caused by its lipase. However, little research was carried out to explore other factors for rice bran rancidity. In this study, five Bacilli with lipid hydrolysis abilities were isolated from rice bran and then inoculated into sample to explore the influence of microbial contamination on rancidity. Fresh rice bran was divided into four groups, including control group (CG), ultraviolet group (UG), ultraviolet-uninoculated group (UUG) and ultraviolet-five Bacilli inoculated group (UIG). The final microbial amount in UIG was significantly higher than other three groups after 31 days. The rancidity of UG was restrained to 75% compared with CG during storage. And the rancidity of UIG group was accelerated significantly after being inoculated with the five isolated strains. The increase ratio of acid values between CG, UG, UUG and UIG was about 8:6:9:15. The lipase activities performed no significant difference between CG and UG, but UIG and UUG only maintained about 40.0% and 80.0% of lipase activities. In summary, microbial contamination had a non-negligible influence on rice bran rancidity, and controlling the microbial contamination should be fully considered during the processing and preservation of rice bran.
      原文链接:
    • NSTL
    • Elsevier

    The use of Raman spectroscopy and chemometrics for the discrimination of lab-produced, commercial, and adulterated cold-pressed oils

    Temiz, Havva TumayVelioglu, Serap DurakliGuner, Kadir GurbuzVelioglu, Hasan Murat...
    13页
    查看更多>>摘要：In this study, lab-produced cold-pressed oil samples of black cumin (CPBCO), almond (CPAO), and walnut (CPWO) were compared with their commercial substitutes. Additionally, adulteration of cold-pressed oils with corn and sunflower oils was determined. Chemical information and fatty acid composition of the samples were obtained using Raman spectroscopy and gas chromatography, respectively. Raman spectra were analyzed with principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). The developed PCA models for the discrimination of CPBCO, CPAO, and CPWO from the adulterated samples explained 93.35%, 96.24, and 94.25% of the cumulative variances, respectively. Root mean squared error of calibration (RMSEC), root mean squared error of cross-validation (RMSECV), and root mean squared error of cross-prediction (RMSEP) values were found to be between 0.06 and 0.21, 0.03-0.11, and 0.05-0.21; 0.08-0.24, 0.06-0.15, and 0.08-0.25; and 0.05-0.18, 0.03-0.10, and 0.09-0.20 for the PLS-DA models of CPBCO, CPAO, and CPWO adulterations. The developed PCA models for the discrimination of CPBCO, CPAO, and CPWO from commercial samples explained 99.64%, 91.27, and 92.11% of the cumulative variances, respectively. These results indicate that Raman spectroscopy coupled with chemometrics could be potentially useful both for the discrimination of cold-pressed oils and for the rapid determination of adulteration with cheaper oils.
      原文链接:
    • NSTL
    • Elsevier

    Aggregation of hen egg white proteins with additives during agitation

    Hong, TaehunIwashita, KazukiHan, JeungminNishinami, Suguru...
    10页
    查看更多>>摘要：Aggregation of hen egg white proteins (HEWPs) is an important issue in the production of egg products in the food industry. The aggregation of HEWPs during agitation is caused by the gas-liquid interface denaturation of proteins, which is different from their thermal aggregation. In this study, we investigated the mechanism of aggregation and the co-aggregation of HEWPs induced by agitation in the presence of additives. The aggregation of HEWPs caused by agitation was suppressed by amphiphilic surfactant and amphiphilic additives, rather than by the well-known aggregation suppressor, arginine. Lysozyme (LYZ) and ovalbumin (OVA) dramatically formed co-aggregates that were stabilized by disulfide bonding with denatured lysozyme during agitation. In contrast, lysozyme and ovotransferrin (OVT) formed co-aggregates to a lower extent than that observed for OVA, due to the weak interaction between these two proteins. These data indicate that the electrostatic attraction and disulfide exchange between LYZ and OVA play critical roles in the co-aggregation of HEWPs during agitation. This article proposes not only the theory and techniques that may become the basis of an appropriate processing method for safer pasteurization and transportation of HEWPs but also provides information about the aggregation of mixed proteins used in various fields.
      原文链接:
    • NSTL
    • Elsevier

    Antibacterial potency of riboflavin-mediated photodynamic inactivation against Salmonella and its influences on tuna quality

    Li, HuihuiTan, LijunChen, BowenHuang, Jiaming...
    14页
    查看更多>>摘要：This study investigated the antibacterial potency of novel riboflavin-medicated blue light-emitting diode (LED) photodynamic inactivation (PDI) against Salmonella and its biofilms, and also evaluated its potency to kill Salmonella on tuna. Results showed that the PDI inactivated >6.0 Log CFU/mL of planktonic Salmonella with 9.36 J/ cm(2) irradiation dosage and 150 mu M riboflavin. Antibacterial analysis indicated that the PDI treatment destroyed the cell wall, degraded the cytoplasmic RNA and disrupted the cell membrane functions, but barely degraded the genomic DNA of Salmonella. Meanwhile, the PDI treatment potently eradicated the biofilms of Salmonella. Additionally, the PDI effectively reduced 2.1 Log CFU/mL of Salmonella on tuna with 93.6 J/cm(2) irradiation dosage and 150 mu M riboflavin. It was also found that higher irradiation dosage promoted the transition of trapped water to free water in extra myofibrillar space, and collectively accelerated the lipid oxidation, but it had no obviously negative effect on the total protein and the total volatile basic nitrogen content of tuna. Therefore, this study deepens the understanding of the inactivation potency and mechanisms of riboflavin-mediated blue LED PDI against foodborne pathogens, as well as its effects on the food quality.
      原文链接:
    • NSTL
    • Elsevier

    Purification and antibacterial properties of a novel bacteriocin against Escherichia coli from Bacillus subtilis isolated from blueberry ferments

    Xiang, Yi-ZhouLi, Xin-YueZheng, Hai-LongChen, Jun-Yuan...
    9页
    查看更多>>摘要：The novel bacteriocin JS17 was obtained from Bacillus subtilis JSX-5, isolated from blueberry (Vaccinium uliginosum) ferments. JS17 was purified by center dot AKTA Purifier, semi-preparative reversed-phase high performance liquid chromatography, and nano liquid chromatography coupled with tandem mass spectrometry, in succession. Its molecular mass was 652.37 Da and its amino acid sequence was identified as L-F-R-A-F. A homology BLAST search confirmed JS17 as a novel bacteriocin. JS17 was found to have an extensive antibacterial activity spectrum against both Gram-positive and Gram-negative bacteria. JS17 showed heat tolerance, and it was highly stable over pH 2-10 and was sensitive to proteinase K and pepsin. This indicates that JS17 exhibits protein properties and has application potential under high temperature and acid-base conditions. The minimum inhibitory concentration and minimum bactericide concentration of JS17 against Escherichia coli were 10.56 mu g/ mL and 22.03 mu g/mL, respectively, which is lower than that of most previously described bacteriocins. Furthermore, scanning electron microscopy showed that JS17 bactericidally destroyed the cell membrane integrity of E. coli, resulting in cell dissolution and impaired membrane permeability. This study first purified B. subtilis bacteriocin from fruit ferments, suggesting the potential for using JS17 as a food bio-preservative.
      原文链接:
    • NSTL
    • Elsevier

    Structure characterization of Oudemansiella radicata polysaccharide and preparation of selenium nanoparticles to enhance the antioxidant activities

    Cui, PengjuLuo, SongmingTang, ZizhongWu, Wenjuan...
    9页
    查看更多>>摘要：Selenium nanoparticles have attracted worldwide attentions due to their bioactivities and low toxicity, but the application is limited by stability. This study focuses on the synthesis of selenium nanoparticles using polysaccharide as dispersants. Two Oudemansiella radicata polysaccharide fractions (ORP1 and ORP2) were purified by anion exchange and gel filtration chromatography. Monosaccharide composition, methylation analysis, FT-IR and NMR spectra analysis confirmed that the two fractions were mainly composed of -> 6)-beta-D-Glcp-(1 -> and -> 6)-alpha-D-Galp-(1 -> . Selenium nanoparticles (ORP1-SeNPs and ORP2-SeNPs) were prepared by adding ORP1 and ORP2 to the redox system of selenite and ascorbic acid. The synthesis conditions were optimized by single factor experiment and orthogonal experiment. The average diameter of ORP1-SeNPs and ORP2-SeNPs synthesized under the optimal conditions were 106.28 nm and 117.04 nm, and their morphology appear to be monodispersed and spherical. Moreover, stability tests indicated that particle sizes were affected by time and temperature during storage. Compared with selenium nanoparticles without polysaccharide, ORP1-SeNPs and ORP2-SeNPs exhibited higher antioxidant activities by scavenging free radicals (such as DPPH center dot, ABTS center dot+ and O-2(center dot-)).
      原文链接:
    • NSTL
    • Elsevier

    Evaluation of physical and instrumentally determined sensory attributes of Atlantic salmon portions packaged in modified atmosphere and vacuum skin

    Chan, Sherry StephanieSkare, MarenSivertsvik, MortenLerfall, Jorgen...
    8页
    查看更多>>摘要：Fresh Atlantic salmon (Salmo salar) were slaughtered and stored on ice at 0 degrees C then portioned and packaged six to eight days later in modified atmosphere (CO2:N-2 60:40) packaging (MAP), vacuum skin packaging and open air. All fillet portions were stored in refrigerated conditions at 4 degrees C. Physical and instrumentally determined sensory quality parameters, including water holding properties, pH, colour, texture and microbiological shelf life, were examined for three weeks. The results showed that both MAP and vacuum skin packaging gave comparable quality in drip loss, water holding capacity, texture and microbiological shelf life. Both packaging groups displayed increased lightness and decreased redness and yellowness throughout storage after filleting. Fillets kept in MAP had consistently lower pH with a darker, more reddish, and yellowish colour than skin packaged fillets. Fillets stored in air had the shortest microbiological shelf life (<13 days) even when they were portioned later. It is concluded that the microbiological shelf life of MAP and skin packaged fillets at 4 degrees C was around 18-20 days with a limit of 10(6) cfu/g and therefore effectively extends the microbiological shelf life of raw fillets by 1.5 times.
      原文链接:
    • NSTL
    • Elsevier

    Thermal, pasting, and rheological properties of potato starch dual-treated with CaCl2 and dry heat

    Zhang, HongcaiHe, FuliWang, TaoChen, Guibing...
    7页
    查看更多>>摘要：Potato starch (PS) was treated separately and combinedly with 3% (w/v) CaCl2 solution at 25 degrees C for 5 h and dry heat (DH) at 130 degrees C for 1, 2, and 4 h CaCl2 treatment alone significantly increased thermal transition parameters, dynamic moduli, and shear viscosity of PS. It substantially decreased the peak viscosity and breakdown of PS during pasting, but the final paste viscosity was comparable to the control due to a higher setback. Overall, DH treatment alone reduced the thermal transition parameters, paste viscosity, dynamic moduli, and shear viscosity of PS, and prolonged heating generally caused more considerable reductions. Dual treatment with CaCl2 and DH caused the most substantial decreases in examined properties of PS. It led to a complete loss of both double-helical and crystalline order of starch granules. Therefore, cooked suspensions of dual-treated PS exhibited very weak viscoelastic or non-viscoelastic behavior and extremely low shear viscosity.
      原文链接:
    • NSTL
    • Elsevier

    The effect of interfacial interactions on the rheology of water in oil emulsions oleogelled by candelilla wax and saturated triacylglycerols

    Garcia-Gonzalez, Diego OrlandoYanez-Soto, BernardoDibildox-Alvarado, ElenaOrnelas-Paz, Jose de Jesus...
    10页
    查看更多>>摘要：The effects of water-oil interfacial activity of candelilla wax (CW), glycerol monopalmitate (GMP), glycerol monooleate (GMO) and polyglycerol-polyricinoleate (PGPR) on the microstructure and rheology of W/O emulsions oleogelled with CW and fully hydrogenated soybean oil (FH) was investigated. The emulsifier with the highest interfacial activity was PGPR, followed by GMO, and GMP. Polar compounds of CW (CW-PC) also displayed interfacial activity. Interfacial interactions of the continuous lipid crystal network with the CW-PC and PGPR in W/O emulsions decreased the elastic modulus (G ') as the aqueous phase (AP) increased, indicating the water droplets behaved as inactive filler due to a weak interaction with the continuous phase. In contrast, the CW-PC and the monoglycerides had a cooperative interaction on the interfacial tension reduction. W/O emulsions produced with monoglycerols maintained or increased their G ' as the AP increased, denoting a strong interaction of water droplets and the continuous phase (i.e., active filler behavior). At constant content of AP and FH, G ' of emulsions tended to decline as the PGPR content increased, while the opposite was observed with emulsions produced with GMO. Adding 10% FH to the emulsions magnified both the active and inactive filler effects produced by GMO and PGPR, respectively.
      原文链接:
    • NSTL
    • Elsevier

    Physical and oxidative stability of food emulsions prepared with pea protein fractions

    Hinderink, Emma B. A.Schroder, AnjaSagis, LeonardSchroen, Karin...
    10页
    查看更多>>摘要：There is a growing interest in replacing dairy proteins with their plant-based counterparts in food emulsions. Plant proteins generally contain a substantial insoluble protein fraction, of which the properties may differ from the soluble proteins. Therefore, the use of a commercial pea protein isolate, its insoluble fraction and whey protein isolate to stabilize oil-in-water (O/W) emulsions is explored. In 100 g/kg O/W emulsions, the use of full pea protein isolate led to physically instable emulsions that showed droplet flocculation and coalescence, whereas its insoluble fraction and whey protein formed physically stable emulsions. The insoluble pea protein fraction was also able to physically stabilize high internal phase O/W emulsions (HIPEs) containing 700 g/kg oil, giving -10 times higher viscosity than whey protein-based HIPEs. Under oxidative conditions, whey protein-stabilized emulsions showed extensive coalescence, and fast formation of lipid oxidation products. Insoluble pea protein-stabilized emulsions, showed fast lipid oxidation, but this did not affect the physical stability. In contrast, full pea proteins-based emulsions were physically instable in oxidative conditions but showed the lowest accumulation of oxidation products. These results suggest that the constituents of commercial pea protein isolate have specific functionalities, which is important knowledge for the design of stable plant protein-based emulsions.
      原文链接:
    • NSTL
    • Elsevier