Liquid Food Matrices Research Articles

Major food constituents influence the antibacterial activity of vanillin immobilized onto silicon microparticles against Escherichia coli

Antimicrobial filtration materials based on essential oil components (EOCs) immobilized onto silicon oxide particles have been found effective for nonthermal stabilization of liquid foods (i.e., beer, juice, wine, and etc.). However, their antimicrobial efficiency depends on the food matrix. The present work aimed to assess the effect of the major constituents of liquid food matrices on the antimicrobial activity of vanillin immobilized onto silica microparticles. Silicon oxide particles were functionalized with vanillin and characterized. The maximum tolerated concentrations of different food major constituents (i.e., proteins, lipids, carbohydrates, organic acids, alcohols and minerals) were determined against Escherichia coli K12. The results showed that organic acid and alcohol had synergetic effects on vanillin-functionalized particles, and the addition of proteins, lipids or some carbohydrates inhibited their antimicrobial activity. No effects on microbial counts were found for mineral salts. The dual combinations between the synergistic and nonsynergistic food constituents showed improved antimicrobial activity compared to single compounds. The data confirmed previous in vitro experiments and could be used to predict the antimicrobial activity of the filtration system when treating real liquid food matrices.

Continuous-flow microwave heating system with high efficiency and uniformity for liquid food

Continuous-flow microwave heating has good potential in liquid food processing. Efficiency and uniformity of continuous-flow heating are critical to processing results. During continuous-flow heating, the dielectric constant of the liquid varies with increasing temperature, and the efficiency and uniformity of continuous-flow heating are compromised under significant dynamic variations in the dielectric constant of the liquid. To address these issues, this paper proposes a continuous-flow microwave heating system based on a coaxial inner conductor structure. First, a multiphysics model was developed, the parameter of the continuous-flow heating system is optimised so that the load effectively absorbs electromagnetic waves, and the heating uniformity can be enhanced due to the uniform cross-sectional electric field distribution of TEM mode in the coaxial structure. Second, experiments were performed to validate the proposed model, and the results were in good agreement with the simulation. The heating efficiency under varying dielectric constants (from 10 to 80) and loss angle tangents (from 0.1 to 0.5) of the liquid was above 90%. Then, the proposed system is compared with multimode cavity and system without waveguide coaxial conversion structure, and the proposed system is more efficient for liquid with different dielectric constants. Next, a section of metal bar was added to the center of the glass tube and the influence of the metal bar on heating effect was analysed. With the addition of the metal bar, the efficiency of the system in heating a low-dielectric-constant liquid could be effectively improved, and the heating uniformity could be increased by more than 30%. Finally, the proposed system was applied to heat liquid food and the results indicated that all of liquid food materials' efficiency larger than 90%. The continuous-flow microwave system provides the possibility for large-scale industrial production.

Assessment of whole egg fractionation by tangential flow filtration: The problem of low-density lipoprotein aggregates

Eggs are a compelling source of bioactive compounds. Membrane separation is a green technology that allow components to be obtained while preserving their biological activity. The objective of this study was to assess the application of membrane separation technology to egg products. Whole egg plasma, egg yolk plasma and egg white were tangential flow filtrated evaluating the effect of the pore size and membrane materials. Transmission of dry matter and proteins from feed to filtrate was noticed in all the processes. Nevertheless, cholesterol and carotenoids were not detected at filtrates from 750 kDa to 0.2 µm when mixed ester or polyethersulfone were the membrane materials. The interactions between egg yolk and egg white components difficult the separation. Cholesterol was part of low-density lipoproteins. These lipoproteins together with carotenoids were filtrated with modified polyethersulfone at a minimum pore size of 0.2 µm. High uncertainty was obtained due to low-density lipoproteins aggregation. Three kinds of aggregates can justify these results: low-density lipoproteins aggregated themselves, low-density lipoproteins bound to ovomucin and other smaller egg white proteins (<750 kDa), and low-density lipoproteins bound only to smaller egg white proteins. The detected chelate effect of egg white proteins could be important in vivo. Therefore, research should be led to assess the influence of cooking method and digestion of the different egg components on the bioaccessibility of nutrients and the generation of bioactive peptides. Moreover, the filtration processes analysed herein may be useful techniques for liquid food matrix studies.

Construction of a self-sufficient DNA circuit for amplified detection of kanamycin

Improper use of kanamycin can lead to trace kanamycin residues in animal-derived foods, which can pose a potential threat to public health. Isothermal enzyme-free DNA circuits have provided a versatile toolbox for detecting kanamycin residues in complicated food samples, yet they are always limited by low amplification efficiency and intricate design. Herein, we present a simple-yet-robust nonenzymatic self-driven hybridization chain reaction (SHCR) amplifier for kanamycin determination with 5800-fold sensitivity over that of the conventional HCR circuit. The analyte kanamycin-activated SHCR circuitry can generate numerous new initiators to promote the reaction and improve the amplification efficiency, thus achieving an exponential signal gain. With precise target recognition and multilayer amplification capability, our self-sustainable SHCR aptasensor facilitated the highly sensitive and reliable analysis of kanamycin in buffer, milk, and honey samples, thus holding great potential for the amplified detection of trace contaminants in liquid food matrices.

Combine thermal processing with polyvalent phage LPEK22 to prevent the Escherichia coli and Salmonella enterica contamination in food

Thermal processing is the most frequently used method to destruct bacteria in food processing. However, insufficient thermal processing may lead to the outbreak of foodborne illness. This study combined thermal processing with thermostable phage to prevent food contamination. The thermostable phages were screened which can retain activity at 70 °C for 1 h. Among them, the polyvalent phage LPEK22 was obtained to lyse Escherichia coli and Salmonella enterica, especially several multi-drug resistant bacteria. In milk (liquid food matrix), LPEK22 significantly reduced the E. coli by 5.00 ± 0.18 log10 CFU/mL and S. enterica by 4.20 ± 0.23 log10 CFU/mL after thermal processing at 63 °C for 30 min. For beef sausage (solid food matrix), LPEK22 significantly reduced the E. coli by 2.34 ± 0.17 log10 CFU/cm2 and S. enterica by 1.54 ± 0.13 log10 CFU/cm2 after thermal processing at 66 °C for 90 s. Genome analysis revealed that LPEK22 was a novel phage with a unique tail spike protein belonging to the family of Ackermannviridae. LPEK22 did not contain lysogenic, drug-resistant, and virulent genes that may compromise the safety of food application. These results determined that LPEK22, a novel polyvalent Ackermannviridae phage, could combine with thermal processing to prevent drug-resistant E. coli and S. enterica both in vitro and in foods.

Getting hot: Effect of chili pepper addition on sensory perception of liquid and solid foods.

The impact of trigeminal oral burn and pungency on taste, flavor, and mouth-feel perception of commercially available foods is underexplored. This study aimed to determine the effect of oral burn sensations evoked by the addition of chili powder to tomato soup, beef burger patties, and curried rice on taste, flavor, and mouth-feel perception. Chili powder was added to tomato soups, beef burger patties, and curried rice at four concentrations. A consumer panel comprising n=66 participants (49 women, 25.5±5.8 years, BMI 22.9±2.8kg/m2 ) assessed taste, flavor, trigeminal, and mouth-feel intensity of all samples using Rate-All-That-Apply methodology. Food matrix consistency strongly impacted oral burn sensations with solid food matrices (beef burger patties and curried rice) suppressing oral burn intensity compared to liquid food matrices (tomato soup). With increasing oral burn intensity, perceived intensity of beef flavor decreased significantly for beef burger patties. Tomato flavor, sweetness, and sourness intensity decreased significantly with increasing oral burn intensity for tomato soups. Perceived burn intensity of all food matrices and beef flavor intensity of beef burger patties differed between infrequent and frequent chili pepper consumers. We conclude that increasing oral burn intensity by the addition of chili pepper powder led to only small reductions in taste and flavor intensity of tomato soups and to little or no changes in flavor and mouth-feel perception of beef burger patties and curried rice. We suggest that reductions in taste, flavor, and mouth-feel intensity caused by oral burn might be more pronounced in liquid (tomato soup) than solid foods (beef burger patties and curried rice). PRACTICAL APPLICATION: There is a growing public and scientific interest in the development of strategies to increase the sensory appeal of healthy foods and beverages. Incorporation of trigeminal stimuli, such as chili peppers or capsaicin (pungent component of chili peppers), can be a strategy to increase sensory appeal of foods and beverages. Little is known about how trigeminal oral burn and pungency influence taste, flavor, and mouth-feel perception of commercially available foods, although it has been well established that taste, flavor, mouth-feel, and trigeminal sensations contribute to product acceptance. By investigating the sensory impact of oral burn on flavor and mouth-feel perception of foods, this study may help to better understand how trigeminal stimuli can be applied to moderate flavor and mouth-feel perception of foods to optimize sensory appeal.

The synergistic effect of thurincin H and power ultrasound: An alternative for the inactivation of Listeria innocua ATCC 33090 and Escherichia coli K-12 in liquid food matrices

Bacteriocins and power ultrasound (PU) are two technologies that could be explored conjointly as a potential food preservative. Currently, there is no information on the use of thurincin H (bacteriocin) in food matrices, neither on its own nor in combination with PU. This study aimed to evaluate the synergy of thurincin H and PU on the inactivation of Listeria innocua ATCC 33090 (L. innocua) and Escherichia coli K-12 (E. coli) in two liquid food matrices, cow milk and orange juice. Firstly, the production and purification of thurincin H were carried out. Once the pure bacteriocin was obtained, it was used to determine the minimum inhibitory concentration (MIC). Then, the action mode of the bacteriocin was determined. Finally, we evaluated the effect of the application of PU (frequency of 20–25 kHz, ultrasonic energy density of 0.914–0.943 W/cm3, and temperature of 30 ± 5 °C) in combination with thurincin H (40 μg/mL) on the inactivation of L. innocua and E. coli in orange juice and milk. According to the results, thurincin H had a MIC of 5 μg/mL, and eight times the MIC of thurincin H can act as a bactericidal agent on its own. Subsequently, it was shown that the synergistic effects of both technologies were more effective in inactivating E. coli than L. innocua in milk (>2.8 Log CFU/mL). However, these effects were notably increased in orange juice samples since the combination of PU with thurincin H achieved an inactivation of 5.5 and 3.4 Log CFU/mL for L. innocua and E. coli, respectively.

A novel analytical strategy for the determination of perfluoroalkyl acids in various food matrices using a home-made functionalized fluorine interaction SPME in combination with LC-MS/MS

In this study, a fluorine-fluorine interaction approach through fluoridating boron nitride nanosheets (BNNs) for sensing perfluoroalkyl acids (PFAAs) in multiple food matrices was developed. Through a facile hydrothermal fluorination modification, the BNNs were transferred into homogeneous fluorinated boron nitride nanoparticles (F-BNNs) with robust networks and specific surface area. After morphological modification, the particles displayed strong adsorption and sensing capabilities on PFAAs in both solid and liquid food matrix. Under the evaluation of mass spectrometry, F-BNNs based microextraction approach exhibited low method detection limits (MDLs) in the ranges of 0.9–3.9 pg mL−1 and 3.6–15.8 pg g−1 for milk and meat matrices, respectively, with satisfactory repeatability (RSD% <13.5%) and recoveries (77.7–110.5%). This work not only depicted a facile approach for preparing F-BNNs based SPME fiber, but also provided a routine analysis protocol for monitoring PFAAs in food systems.

Impact of Ultrasound Treatment and pH-Shifting on Physicochemical Properties of Protein-Enriched Barley Fraction and Barley Protein Isolate.

Ultrasonication alone or in combination with a pH-shifting method could be applied as means for improving the techno-functional properties and performance of barley protein ingredients in liquid food matrix. Ultrasound technology was utilised with and without pH-shifting to 3, 7 and 9 aiming at investigating their impact on primary protein structure, protein solubility, particle size and colloidal stability of an air-classified protein-enriched barley fraction and a barley protein isolate. Shifting the pH of sample dispersion to 9 followed by neutralisation to pH 7 improved protein solubility and colloidal stability of the isolate whereas it had less impact on the protein-enriched fraction. Ultrasound treatment improved both protein solubility and colloidal stability of the protein-enriched fraction at alkaline pH and particle size reduction by ultrasonication was observed at all the studied pH-values. For protein isolate, ultrasonication improved protein solubility at all pH-values and colloidal stability was improved at acidic and neutral pH whereas the sample was inherently stable at alkaline pH. The protein profiles of both ingredients remained unaffected by ultrasound treatment. The results suggest adopting ultrasonication as a promising tool for improving applicability of barley protein ingredients in liquid food systems.

Research and development of compacting process control system for bowl food

In order to solve the contradiction between the extrusion of solid and liquid food materials and the standardization of the volume of food materials in the bowl after compaction in the process of producing bowl food. Configuration touch screen and programmable logic controller are used as the control core of the system. Position parameters are obtained by photoelectric sensor. PLC drives the servo motor to make the linear module sliding block move, and drives the stepper motor to make the pressure plate rotate. Configuration of the touch screen to achieve the man-machine interface scheme. The force in the bowl is changed by adjusting the mechanical shape of the pressure plate. The controlled parameters of the execution program stored in PLC were obtained by orthogonal experiment. To realize the numerical control function of position, speed and force Angle in the process of food compression with digital precision. In addition, the mechanical structure of the spring cover plate is added to solve the problem of overflow of soup food materials from the bowl and its ring during the volume compression of solid and liquid food materials in the bowl.

Contribution analysis of sensory cues to oil/fat perception

AbstractOil/fat perception is an important subject of food science research. Various scientific theories have risen over the years about the mechanisms of oil/fat perception, but fundamental knowledge is still lacking. In particular, the dominating sensory cue(s) eliciting oil/fat perception is still up to debate in literature. In this study, 30 participants were recruited to test six samples (three natural oil/fats and three constituted) using three senses (smell, taste, and tactile). Responses showed that natural oil/fats were perceived as such with multimodal way of sensing. Texture and aroma cues played a bigger role compared to taste. Our findings suggest that aroma and texture and multimodal sensation are the mechanisms of oil/fat detection, while taste alone did not illicit sensations of oil/fat.Practical ApplicationsInformation provided here deals with contribution of different senses to six model compounds, giving new insight for human oil/fat perception. We consider these findings important for food scientists working in academia and industry alike. In order to keep consumer sensory satisfaction, food containing oil/fat must be designed to elicit preferable sensory responses. Our experiments were on model compounds, but when dealing with other food types either emulsions or liquid food matrices containing fat will be perceived in a similar manner.

Pulsed Light treatment below a Critical Fluence (3.82 J/cm2) minimizes photo-degradation and browning of a model Phenolic (Gallic Acid) Solution.

Pulsed light (PL) is one of the most promising non-thermal technologies used in food preservation and processing. Its application results in reduction of microbial load as well as influences the quality of food. The data about the impact of PL on bioactive compounds is ambiguous, therefore the aim of this study was to analyze the effect of PL treatment of a gallic acid aqueous solution—as a model system of phenolic abundant liquid food matrices. The effect of PL treatment was evaluated based on colour, phenolic content concentration and antioxidant activity measured by DPPH assay using a design of experiments approach. The PL fluence (which is the cumulative energy input) was varied by varying the pulse frequency and time. Using Response Surface Methodology, prediction models were developed for the effect of fluence on gallic acid properties. It was demonstrated that PL can modify the optical properties of gallic acid and cause reactions and degradation of gallic acid. However, application of PL did not significantly alter the overall quality of the model gallic acid solution at low fluence levels. Cluster analysis revealed that below 3.82 J/cm2, changes in gallic acid were minimal, and this fluence level could be used as the critical level for food process design aiming to minimize nutrient loss.

Detoxification agents based on magnetic nanostructured particles as a novel strategy for mycotoxin mitigation in food

Mycotoxins are toxic compounds that can be present in feed, food and beverages. In this work, 25 magnetic nanostructured materials were developed to remove the main types of mycotoxins from liquid food matrices. The efficiency for binding mycotoxins from contaminated aqueous solutions was studied. Nanocomposites (diameters lower to 15 μm) composed of mixtures of activated carbon, bentonite and aluminium oxide were able to eliminate up to 87% of mycotoxins with an adsorption efficiency of 450 µg/g. On the other hand, spheres with sizes below 3 mm and composed by biopolymers and activated carbon or graphene oxide removed up to 70% of mycotoxins (adsorption of 598 ng/g). These particles were tested for beer detoxification, and spheres composed of alginate and activated carbon or pectin maintain the ability to eliminate toxins from this beverage. Hence, this technology could be a useful tool for the food industry.

Removal of bisphenol A in canned liquid food by enzyme-based nanocomposites

Laccase from Trametes versicolor was immobilized on TiO2 nanoparticles; the nanocomposites obtained were used for the removal of bisphenol A (BPA) in a liquid food matrix. To achieve a high enzymatic stability over a wide pH range and at temperatures above 50 °C, the nanocomposite structures were prepared by both physical adsorption and covalent linking of the enzyme onto the nanometric support. All the nanocomposite structures retained 40% of their enzymatic activity after 60 days of storage. Proof-of-concept experiments in aqueous media using the nanocomposites resulted on a > 60% BPA removal after 48 h and showed that BPA was depleted within 5 days. The nanocomposites were tested in canned liquid food samples; the removal reached 93.3% within 24 h using the physically adsorbed laccase. For the covalently linked enzyme, maximum BPA removal was 91.3%. The formation of BPA dimers and trimers was observed in all the assays. Food samples with sugar and protein contents above 3 and 4 mg mL−1 showed an inhibitory effect on the enzymatic activity.

Application of response surface methodology to optimize solid-phase microextraction procedure for chromatographic determination of aroma-active monoterpenes in berries.

Most of scientific papers concern the qualitative or semi-quantitative analysis of aroma-active terpenes in liquid food matrices. Therefore, the procedure based on solid-phase microextraction and two-dimensional gas chromatography-time-of-flight mass spectrometry for determination of monoterpenes in fresh berries was developed. The optimal extraction conditions using divinylbenzene-carboxen-polydimethylsiloxane fiber were: temperature of 50°C, extraction time of 26min, equilibrium time of 29min. The developed procedure provides a high recovery (70.8-99.2%), good repeatability (CV<10.4%), high linearity (r>0.9915) and offers practical advantages over currently used methods: reliability of compounds identification, simplicity of extraction and at least one order of magnitude lower detection limits (0.10-0.011μg/L). The method was successfully applied to determine monoterpenes in 27 berry samples of different varieties and 4 berry products. Tukey's test revealed that monoterpenes content is a reliable indicator of fruit maturity and origin. It suggests that the method may be of interest to researchers and food industry.

SERS Detection of Ricin B-Chain via N-Acetyl-Galactosamine Glycopolymers

A novel sensing scheme is exemplified through the detection of ricin B-chain (RBC) in water and liquid food matrices: surface-enhanced Raman spectroscopy (SERS) coupled with an N-acetyl-galactosamine glycopolymer capture layer. The sensing scheme’s detection limit was well below that of the predicted oral exposure limit. Theoretical predictions of the normal Raman spectrum of the glycomonomer give insight into polymer–RBC intermolecular interactions.

Analysis of a whole diet in terms of phenolic content and antioxidant capacity: effects of a simulated gastrointestinal digestion

This work compares the phenolic contents and the total antioxidant capacity of the 36 most popular Brazilian foods submitted to aqueous extraction or in vitro digestion. The purpose was to evaluate the extent by which digestion differs from the simple aqueous extraction procedures of several food matrices. After in vitro digestion, cereals, legumes, vegetables, tuberous vegetables, chocolates and fruits showed higher phenolic contents and higher antioxidant activities than those obtained by aqueous extraction. Contrarily, the digestion caused a reduction in the phenolic contents and antioxidant activities of beverages (red wine, coffee and yerba mate). Our results suggest that the phenolics of food groups with solid and complex matrix are protected against enzymatic action and alteration in pH during the digestion, what does not occur in liquid food matrices such as the beverages. This fact would overestimate the antioxidant activities of beverages submitted solely to aqueous extraction.

Noninvasive Ultrasonic Monitoring of Ice Pigging in Pipes Containing Liquid Food Materials

AbstractThe use of ice slurry for cleaning in place can greatly reduce the amount of effluent created during industrial processes when compared with traditional flushing methods common in the food industry. Product recovery from within pipework is also improved through the use of such slurries. Noninvasive monitoring methods would allow this process to become automated and optimized for reduced effluent and increased product retrieval. For these reasons, the feasibility of using ultrasound within this context was assessed and found to be a reliable method of monitoring the fluid transitions within a section of test pipe.Practical ApplicationsThe food processing industry is increasingly adopting ice pigging as a novel, emergent technology for product recovery and waste effluent reduction. Where these methods are preferred, a noninvasive monitoring system is required for any process control to automate the diversion of product from waste. An ultrasound system has been designed to detect the change of fluids inside piping and which will serve as the monitoring arm of any control process. In principle, this system could be applied to other combinations of fluid transitions.

Validation and Determination of the Contents of Acetaldehyde and Formaldehyde in Foods.

The aim of this study was to develop an efficient quantitative method for the determination of acetaldehyde (AA) and formaldehyde (FA) contents in solid and liquid food matrices. The determination of those compounds was validated and performed using gas chromatography-mass spectrometry combined by solid phase micro-extraction after derivatization with O-(2,3,4,5,6-pentafluoro-benzyl)-hydroxylamine hydrochloride. Validation was carried out in terms of limit of detection, limit of quantitation, linearity, precision, and recovery. Then their contents were analyzed in various food samples including 15 fruits, 22 milk products, 31 alcohol-free beverages, and 13 alcoholic beverages. The highest contents of AA and FA were determined in a white wine (40,607.02 ng/g) and an instant coffee (1,522.46 ng/g), respectively.

Wet grinding and microfluidization of wheat bran preparations: Improvement of dispersion stability by structural disintegration

The enrichment of liquid food matrix with wheat bran has not yet been explored. This study investigated the impact of disintegrating wheat bran preparations on their stability at high moisture content. Three wheat bran preparations – standard bran, peeled bran and aleurone rich fraction – were modified by dry grinding, enzymatic degradation, wet grinding and microfluidization. The sedimentation of processed preparations was evaluated in water solution and related to their physical structure, solubilized compounds and suspension viscosity. In dry ground preparations mixed in water (5% w/w), most of the particles sedimented already in 5 min. Wet grinding disintegrated the physical structure of bran preparations (d50 = 10–16 μm), causing improvement of particle stability due to reduction of gravitational sedimentation. Enzymatic treatment with xylanase efficiently increased the total solubility of the bran preparations (from 18–24% to 40–50%), but the higher solubility was not related to the better stability of particles. Microfluidization of peeled bran and aleurone increased the viscosity and stability of dispersions. The higher viscosity of the microfluidized dispersions was likely correlated with the better homogenisation of the particles, and also with the modified microstructure of treated bran preparations. Disintegrated wheat bran preparations showed high potential for beverage applications.