Au@Ag-labeled SERS lateral flow assay for highly sensitive detection of allergens in milk

Casein andα-lactalbumin(α-LA)are the main allergens in cow's milk,which can affect the skin,respiratory system,and gastrointestinal tract,even cause anaphylactic shock.Developing a rapid and sensitive detection method of casein andα-LA is still pursued.Herein,a surface-enhanced Raman scattering based lateral flow assay(SERS-LFA)method for rapid and highly sensitive detection of milk allergens in food was established for effectively preventing allergic symptoms.Gold@silver nanoparticles(Au@Ag NPs)were synthesized as SERS active substrate to prepare the antibody-modified SERS Probe and SERS-LFA strips toward casein andα-LA were assembled according to the sandwich mode.The detection results were calculated according to colorimetric and Raman signal.The introduction of SRES signal significantly increased the sensitivity of detection with the limit of detection(LOD)of 0.19 ng/mL and 1.74 pg/mL,and exhibited an excellent linear relationship within the range of 0.55-791.50 ng/mL and 0.1 pg/mL-100.0 ng/mL for casein andα-LA,respectively.Furthermore,SERS-LFA strips was highly specific with the recovery rates for corresponding80.36%-105.12%and 85.73%-118.22%for casein andα-LA,respectively.Therefore,the SERS-LFA could be in great potential to develop a unique allergen detection method.

Effect of Continuous Phase Viscosity on Membrane Emulsification

Oil-in-water(o/w) emulsions were produced with a membrane emulsification system. The effect of the continuous phase viscosity on the emulsification was studied. The theoretical analyses show that the continuous phase viscosity influences not only the flow field of the continuous phase but also the interfacial tension. The droplet size distribution and disperse phase flux for different continuous phase viscosity were investigated experimentally at constant wall shear stress and constant volume flow rate of the continuous phase respectively.

Global Solution for Preserving Citrus Fruit Using Natural Treatments

Different tests were carried out to assess the efficiency of replacing plant protection products used at the main application points in citrus fruit packinghouses with natural treatments. The efficiency of an aqueous treatment containing potassium sorbate was found to significantly reduce decaying in Marisol mandarins previously inoculated with Penicillium digitatum and Penicillium italicum. The same food preservative was used in conjunction with a fruit detergent and was applied on Washington Navel oranges and the reduction in the appearance of decaying was similar to that obtained using Guazatine. Finally, two different essential oils were tested. One was combined with a coating and the KS, whilst the other was applied as a fumigant. In the case of wax treatments, it was found that the combination of essential oil or KS with Imazalil at half the dose （0.1%） was equivalent to treatment with a higher dose of Imazalil （0.2%） thus making it possible to reduce the dose of plant protection products used without reducing decay control effectiveness. The treatment with a fumigant with essential oil has a level of efficiency similar to Imazalil against PI. These treatments can be considered a viable alternative to the use of plant protection products.

Pectinmethylesterase extraction from orange solid wastes: Optimization and comparison between conventional and ultrasound-assisted treatments

During orange juice production, a half of fresh oranges weight is considered as production waste (peels, pulp, seeds, orange leaves and damaged orange fruits). An alternative for the management of these wastes is their treatment by addition of lime and a latter pressing, obtaining a press cake and a press liquor rich in sugars (10°Brix) and citric acid, protein, pectin and ethanol. For non-thermal concentration of press liquor to obtain citruss molasses (65°-70°Brix), the removal of pectin is necessary. Traditionally, depectinization of juices has been done by using pectinmethylesterase (PME) enzymes from external sources. In this work it performed the extraction of PME enzymes from orange peels to obtain the optimum extraction conditions. Two different methods of solventextraction were compared (conventional andultrasound-assisted methods). For the conventional extraction experiments, a central composite design with three variables ([NaCl], pH and time) and five replicates of the center point was used. For ultrasound-assisted extraction, experiments were done at pH = 5.5 and [NaCl] = 1.25M), varying extraction time (1-30 min). Response variables were PME activity, protein content and a ratio between them, named PME effectiveness (ηPME). At the same experimental conditions (pH =5.5, [NaCl] = 1.25 M, t = 15 min) it was found that conventional extractions led to slightly better results in terms of ηPME than ultrasound-assisted extraction method.

Discoloration on Methylene Blue Solutions by Direct and Catalytic Ozonation

During textile manufacturing, huge amounts of wastewaters characterized by removed impurities and high concentrations of dye are produced. These wastewaters cause several problems when they are discharged to the environment. The use of ozone in wastewater treatment results of interest. In this work we propose to assess the discoloration rate of different synthetic wastewaters as a function of pH, dye concentration (methylene blue (MB)) and reaction time. A comparison of discoloration rate between conventional ozonation and catalytic ozonation salts of copper, zinc, silver and nickel was also performed. For the optimization of the ozonation process of colored solutions, it was used a central composite experimental design with five replicates of the center point resulting to evaluate the influence of the independent variables at different ranges of pH, [MB] and time. In the catalyst-assisted ozonation, [MB], pH and the reaction time were fixed to 100 mg/L, 5.5 and 15 min, respectively. The optimized experimental conditions to provide maximum discoloration were pH=3.3;[MB]=8.6 mg/L and time=74.3 min. Regarding the catalyst-assisted ozonation, it was found that CuSO4 catalyst gave better color reduction if compared with other catalysts assayed.