查看更多>>摘要：To assess the contamination of lettuce with norovirus in Nanjing city (China), two hundred and eighty one lettuce samples were collected between 2017 and 2018 from production sites (preharvest) and retail outlets (postharvest) and analyzed. The presence of norovirus was confirmed in 26.9% (71/264) of lettuce samples, with norovirus genogroup I detected more frequently (20.1%) than norovirus genogroup II. Norovirus was detected less frequently in lettuce samples from supermarkets (4.9%) than in samples from greengrocers or farmer markets (36.5%) and was detected both in field-grown (28.9%) and in hydroponic lettuce samples (30%). The norovirus occurrence and levels varied markedly by seasons. The norovirus was more frequently detected in the cold season, with evident correlations between norovirus contamination and ambient temperatures. Interestingly, the norovirus occurrence in loose lettuce was significantly higher (p < 0.05) than in packaged lettuce, highlighting that norovirus contamination might have occurred during lettuce production. The data of this study add to the currently limited body of information on norovirus occurrence in fresh produce in China, highlighting the need for implementation of effective food safety monitoring and management.
Niizawa, IgnacioSihufe, Guillermo A.Zorrilla, Susana E.
8页
查看更多>>摘要：Whey protein aggregates (WPAg) were designed from whey protein concentrate suspensions adjusting thermal treatment conditions to prepare microgel-stabilized emulsions. The response surface methodology (RSM) was used to design WPAg with different characteristics (size, denaturation degree, and exposure degree of surface thiol groups), considering the effect of temperature (67.9 degrees C - 83.1 degrees C), protein concentration (3.49% w/w - 6.01% w/w), and pH (6.49 - 7.76) conditions throughout the thermal aggregation process. Three types of WPAg with markedly different characteristics were obtained using the RSM models to evaluate the influence of different protein aggregates on microgel-stabilized emulsions. These microgel particles successfully stabilized the emulsions against coalescence during 14 days of storage, particularly at pH 4.7 and 7.
查看更多>>摘要：Salted (S) sea cucumbers are not only used as the ingredient in most sea cucumber products but also sold directly as the final product. Over-salted (OS) and sugar-treated (ST) sea cucumbers are usually used to adulterate salted sea cucumbers, which jeopardizes the quality and safety of salted sea cucumber products. In this study, S, OS and ST sea cucumbers were classified according to the hyperspectral data in the near-infrared range (957.3-1679.8 nm). Four preprocessing methods, including Savitzky-Golay (SG), multiplicative scatter correction (MSC), standard normal variate (SVN) and variable sorting for normalization (VSN) were established to filter the noise and scattering information in the original spectra. The approaches of regression coefficient (RC), successive projections algorithm (SPA), and two-dimensional correlation spectroscopy (2D-COS) were adopted to extract characteristic wavelengths. Subsequently, sea cucumber classification models were established on the basis of full and characteristic spectra using a support vector machine (SVM). Among the models established, the SNV2D-COS-SVM and VSN-2D-COS-SVM classification models showed optimal recognition performance. In summary, the rapid and non-destructive classification and identification of S, OS, and ST sea cucumbers were accurately realized with the near-infrared-based HSI technology, and the feasibility of using near-infrared hyperspectral technology to identify salted sea cucumber was verified.
Landim Neves, Maria IsabelQueiros, Mayara de SouzaSoares Viriato, Rodolfo LazaroBadan Ribeiro, Ana Paula...
10页
查看更多>>摘要：Lipid microparticles (LMP) made with anhydrous milk fat (AMF) and fully hydrogenated soybean oil (FHSBO) may provide crystallization and control the polymorphic stability of lipid matrices. The present study investi-gated the production of LMP and their stability during 120 days of storage at 5, 10, and 25 degrees C. LMP were produced using lipid blends 90:10 and 80:20 (AMF:FHSBO % w/w) sprayed in a double fluid atomizer at 1 bar, in a chilled chamber (1 +/- 1 degrees C), and analyzed once a week for particle size, morphology, melting behavior, and polymorphic habit. LMP presented a spherical shape and a volumetric diameter of 10 mu m. Both LMP presented melting behavior within a wide temperature range. The polymorphic habit was affected by the lipid base and the storage temperature. LMP stored at 25 degrees C tended to exhibit a more stable polymorphic form. An increase in FHSBO concentration led to an increase in stability, exhibiting the beta form, with no polymorphic changes after 14 or 21 days, remaining stable up to 120 days, for all microparticles. Our results suggested the potential of LMP for several technological applications such as crystallization inducer, structuring agent, and as wall material, due to their thermal and polymorphic stability.
查看更多>>摘要：Hyperspectral images (400-1700 nm) of apple slices during the hot-air drying were acquired. The fusion of spectral data and Gaussian Process Regression (GPR) successfully predicted vitamin C (R-squared = 0.93 and RMSE = 0.57 mg/100 g fresh-weigh), SSC (R-squared approximate to 0.99 and RMSE approximate to 2.47%), moisture content (R-squared approximate to 1 and RMSE = 0.89%), and shrinkage (R-squared approximate to 0.98 and RMSE = 3.66% for shrinkage). The chromaticity was likewise well predicted, however, GPR models failed to predict rehydration ratio and total phenolic content. As hyperspectral systems are expensive and computationally intensive, their possible substitution with multi spectral systems was investigated by finding optimal wavelengths. In this context, 1450 nm and 980 nm were singled out by using a combination of filter-based, wrapper-based, and embedded wavelength selection algorithms. The corresponding prediction accuracies for vitamin C, SSC, moisture content, and shrinkage were almost as good as those of the full spectrum. In the case of chromaticity, it is suggested to use a color camera as most of the efficient wavelengths laid in the visible range. These results indicate potential replacement of hyperspectral imaging by much simpler and lower-cost imaging sensors by which the way will be paved towards the appearance of smart dryers.
查看更多>>摘要：Mortierella alpina is the most researched fungus for production of arachidonic acid. Arachidonic acid inclusion in diet is gaining prominence due to its potential role in brain development and age-related disease conditions. The production mainly focuses on submerged fermentation with extensive use of gas chromatography which increases the cost of optimization. The present study focuses on the optimization of arachidonic acid production by M. alpina under solid-state fermentation and developing an effective mycelial staining method as an analytical tool to replace gas chromatography. The optimization method increased the Arachidonic acid yield (41.29 mg/gds) with the supplementation of 3.0% corn gluten, 3.0% flax seed oil and 0.625% of mineral mix-3 in a soybean meal based substrate at an optimum temperature of 25 degrees C and initial substrate moisture content of 70.0%. For deriving an effective analytical tool, correlation was made between the responses of statistically designed submerged fermentation and solid-state fermentation trials. The comparative regression analysis of the responses i.e., the mycelial Triphenyl tetrazolium chloride staining data and the arachidonic acid values revealed a 98.0% correlation. The submerged fermentation based mycelial staining was thus devised as an effective media optimization strategy for solid state fermentation based arachidonic acid production.
查看更多>>摘要：Sorghum starch granules were esterified with octenyl succinic anhydride (OSA) to obtain modified starches with different degrees of substitution (DS) (0.0028-0.011). The reaction took place more in the amorphous rather than crystalline regions of the starch granules. This did not change the crystalline morphology of the starch and had no significant effect on the particle size and appearance of the starch, but might affect the strength of the amorphous region. OSA modification of starch could increase its swelling power and water solubility during its swelling procedure. Rheological experiments showed that the strength of starch gels decreased with increasing substitution and the gelatinization temperature decreased from 72.2 to 61.5 degrees C. OSA-modified sorghum starch was effective in stabilizing O/W Pickering emulsions, and the ratio of oil to water phase had a large effect on emulsion stability. Under high oil phase conditions (phi = 0.6-0.65) the emulsions were stable and formed self-standing gel emulsions. Sixty-day storage and centrifugation experiments demonstrated that increasing the DS resulted in a decrease in the size of the formed emulsion droplets and an increase in the stability of the emulsions. This study presents a potential application of OSA-esterified sorghum starch as a novel emulsifier to stabilize Pickering emulsions.
查看更多>>摘要：Protective cultures (PCs) are capable of inhibiting the growth of foodborne pathogens, including Listeria monocytogenes, in food products. However, their ability to attenuate pathogen virulence in food remains uninvestigated. In this study, we used an immunomagnetic separation approach to isolate the effect of pre-exposure to commercially produced PCs in milk as a model food on the subsequent ability of L. monocytogenes to survive simulated gastrointestinal conditions and infect human Caco-2 epithelial cells. Pre-exposure to two cultures of Lactiplantibacillus plantarum reduced the ability of L. monocytogenes to survive simulated gastrointestinal conditions with counts 2.7 log CFU/mL lower than control. The ability of L. monocytogenes to invade Caco-2 cells was also reduced by 1.5 and 2.3 log CFU/mL compared to control after exposure to Lactococcus lactis subsp. lactis and a strain of Lactiplantibacillus plantarum, respectively. All Lactococcus lactis and Lactiplantibacillus plantarum cultures were able to limit the pathogen translocation across Caco-2 cells by 1.5-2.1 log CFU/mL less than that of control. When coupled with their antimicrobial activities against L. monocytogenes, these results demonstrate the ability of PCs to enhance the safety of food products by also attenuating the pathogen virulence, thereby impeding its ability to cause infection upon ingestion.
查看更多>>摘要：The objective of this research was to develop novel oleogels based on pumpkin seed oil and natural waxes. Crystallization and gelation of 4, 5, 6 and 8 % of beeswax and carnauba wax in pumpkin seed oil were investigated, and their physical properties were evaluated using an oleogel prepared with sunflower oil and beeswax as reference. In order to obtain a complete three-dimensional network, after a cooling stage a setting stage was necessary at 25 degrees C for no longer than 60 min. Oleogels produced with pumpkin seed oil and beeswax were weaker than those made with sunflower seeds; pumpkin seed oil-based oleogels structured by carnauba wax presented higher viscoelastic properties, retained more oil and were firmer than oleogels based on beeswax. Based on scaling theory, all the oleogels followed a strong-link regime and the fractal dimension of the network (D) was comparable to fats widely used in food production. Therefore, pumpkin seed oil can be used to create novel oleogels.
查看更多>>摘要：This study shows the development of a powdered non-dairy probiotic 40:60% (w/w) acerola:siriguela mixed juice. The mixed juice enriched with the probiotic Lactobacillus rhamnosus LPAA 01, Lactobacillus casei LPAA 02 and Lactobacillus plantarum LPAA 03 strains was microencapsulated by spray drying using 140 degrees C air inlet temperature, 0.60 L/h feed flow rate and 10% (w/w) 5 dextrose equivalent maltodextrin. Microcapsules were analyzed in terms of physicochemical characteristics, chemical composition, in vitro bioaccessibility, microbial viability and stability at 5 and 25 degrees C for 45 days. Viable cell counts were >6 log CFU.g(-1) for up to 20 days at 5 degrees C and 14 days at 25 degrees C, and physicochemical properties of microparticles were shown to be in acceptable ranges. Each specific primer pair showed unique amplification, confirming the survival of all the three probiotics. The levels of phenolic compounds, with the exception of quercetin, as well as antioxidant activity by ORAC method increased after exposure to simulated gastrointestinal conditions.
NSTL
Elsevier