Liquid Foodstuffs Research Articles

Application of a Gallic Acid–Based Oxygen Scavenger Label for the Preservation of L‐Ascorbic Acid in Orange Juice

ABSTRACTCitrus juices are rich sources of antioxidants, including vitamin C, but are prone to oxidation during storage. We investigated the application of gallic acid (GA), an environmentally friendly reducing agent, as active packaging to mitigate this issue. Orange juice was packaged in airtight glass containers both with and without GA‐based oxygen scavenger (GA‐OS) label and stored at 20°C and 4°C. During the storage, we monitored oxygen levels in the headspace and dissolved oxygen concentration in the orange juice, vitamin C content and browning. In the presence of GA‐OS, oxygen levels in the headspace were reduced by half in under 1 h at 21°C and within 2 h at 4°C. Dissolved oxygen concentration decreased 50% after 8 h at 21°C and after 1.2 days at 4°C. In the absence of GA‐OS, vitamin C degraded completely within 30 days at 21°C and 45 days at 4°C. In contrast, GA‐OS nearly fully preserved vitamin C for 105 days at both temperatures. Browning, quantified by delta E, escalated in GA‐OS‐absent samples to 16.79 ± 0.16 at 21°C to 12.19 ± 0.10 at 4°C, whereas GA‐OS samples exhibited no significant browning. Our results underscore GA‐OS's efficacy in preserving the quality of liquid foodstuffs, exemplified by orange juice, suggesting its broad range applicability as active packaging.

Comparison and investigation of edible hydrophobic coatings on beeswax and carnauba wax oil gels

In our daily life, it often uses all kinds of liquid food, such as cola, fruit juice and other drinks. Whenever you finish using these, you will find that there will inevitably be residual liquid at the bottom of the bottle that cannot be poured out, resulting in a considerable waste. However, in recent years, the emergence of lubricant infused surface (LIS) can be used to solve this problem. In this research, LIS is prepared by forming an oleogel with shellac and linseed oil, which has the advantage that the experimental raw materials require low cost, the materials are easily available, and do not cause health hazards to human beings. To gain a deeper understanding of the mechanism of LIS antifouling, the effects of optimal Brazilian carnauba wax content and beeswax content on the surface morphology, water contact angle and sliding angle, chemical functional groups, transmittance, and oil-holding rate of LIS were investigated, and the effects of liquid foodstuffs antifouling were tested with optimal Brazilian carnauba wax and beeswax content, respectively.

Carboxymethylcellulose reinforced starch films and rapid detection of spoiled beverages.

The integrity of the packaging of a liquid foodstuff makes it difficult to detect spoilage. Therefore, it is important to develop a sensitive, fast and real-time material for liquid food detection. CMC, as lignocellulose derivatives and starch are widely used in the food industry. In this study, starch films with pH-responsive properties are successfully prepared from full-component starch and corn amylopectin (CA) by adding CMC. The effects of CMC on the mechanical properties, morphology characteristics, physical and chemical structures, stability and pH responsiveness of the starch films are analyzed. The starch/CMC-1.0g composite films display good electrical conductivity and reduce the resistance of the composite film by two orders of magnitude. The composite films have pH response ability; in the simulation of orange juice spoilage experiment, the CA/CMC composite film has a more sensitive current response and was more suitable for the application to liquid food quality detection. Additionally, the starch/CMC composite films have potential applications for rapid detection and real-time monitoring of the safety of liquid food.

Calculation algorithm for non-stationary pumping of liquid foodstuffs by a centrifugal pump with an open impeller

The mathematical model of pumping liquid foodstuffs by a centrifugal pump with an open impeller was proposed in this article. The liquid levels difference in the initial and final tank changes during pumping. Therefore, the pumping process is non-stationary with a slowly changing fluid flow rate. The mathematical model includes two differential equations: the balance of the pumped liquid and the dynamics of the fluid flow in the pipeline. The operating characteristics of the centrifugal pump were approximated by second-order polynomials according to the test data of the manufacturers of this equipment. The need to take into account the influence of fluid viscosity on the pump performance is shown in the article. The pump pressure is noticeably reduced, and the power consumed increases for concentrated apple juice compared to pumping water. The system of differential equations with corresponding boundary conditions was solved numerically. The flow rate very quickly reaches a value corresponding to the difference in levels at the beginning of pumping. Therefore, the problem can be solved in a quasi-stationary approximation. The change in fluid flow over time is close to linear. Therefore, it is possible to find the pumping time of a given volume by an approximate method. The approximate calculation algorithm has been proposed. It was used to calculate the pumping of a concentrated apple juice. The effect of changes in the diameter and length of the pipeline on the performance and energy efficiency of the pumping unit has been investigated.

Ion-Modified Starch Film Enables Rapid Detection of Spoiled Fruit Juices

Juice, as a liquid foodstuff, is subject to spoilage and damage due to complications during transport and storage. The appearance of intact outer packaging often makes spoilage and damage difficult to detect. Therefore, it of particular importance to develop a fast, real-time material to evaluate liquid foodstuffs. In this paper, starch films with pH response characteristics are successfully prepared by inorganic ion modification by utilizing whole starch and amylopectin as raw materials. The mechanical properties, stability properties, hydrophilic properties and pH electrical signal response indices of the films are analyzed and measured. The films exhibit good electrical conductivity values with 1.0 mL of ion addition (10 mmol/L), causing the composite film to respond sensitively to solutions with varying pH values. In the test of spoiled orange juice, the full-component corn starch (CS) film has more sensitive resistance and current responses, which is more conducive for applications in the quality monitoring of juice. The results indicate that modified starch films can potentially be applied in the real-time monitoring of the safety of liquid foodstuffs.

Food processing of egg white using ultrasonically generated microbubbles

Food processing of egg white using ultrasonically generated microbubbles

Developing a homogeneous texture dish by combining solid and liquid foodstuff matrices

A dish with a uniform texture was developed for people with a poor oral health problem: dysphagia. Its texture and color were studied, along with its consumption and cold storage with reheating. The dish was constituted by softening carrot and integrated into thickened soup. Carrot was softened by applying enzymes via freeze-thaw impregnation (FI). Soup was thickened by guar gum. The results indicate both components achieved a similar texture. Firmness and cohesiveness increased significantly as temperature dropped. Judges were unable to detect the presence or absence of carrot in the dish by a sensorial compression assay, but could detect color changes. These outcomes were also verified by a digital image analysis. The results demonstrate the feasibility of using FI treatment combined with enzymes to soften vegetables and subsequently incorporating them into thickened liquid foodstuff to develop safe, sensory-accepted and texture-modified products for specific populations.

Circular economy in the brewing chain

The main aim of this review was to check for the applicability of the concept of circular economy to brewing chain. By analyzing the beer brewing process, it was possible to identify the main brewery wastes formed and packaging materials used as well as their range of composition and yields. In order to reduce the contribution of packaging material to the carbon footprint of beer, it would be necessary to replace one-way containers used nowadays with lighter, reusable, or recycled ones. Even if the contribution of beer consumption phase was taken into account, there was no definitive solution about the less environmentally impacting beer packaging format. The direct management of polyethylene terephthalate (PET) packaging for liquid foodstuffs could make available 100% recycled PET flakes to be reconverted into food-grade bottles with minimum downcycling to other non-food usage. The countless potential uses of brewery wastes in nutritional and biotechnological fields were tested in laboratory by disregarding any cost–benefit or market analysis. This was mainly because the estimated market price of dried brewer’s spent grain (BSG) resulted to be about 450% higher than that of conventional lignocellulose residues. All the alternative uses hailed in the literature appeared to be more useful for publishing articles than for defining any economically feasible reusing procedure for all brewery wastes. Owing to their high moisture content, such wastes are so perishable as to prevent their safe usage in the human food chain. Currently, their use as-is in animal feeding is the disposal method not only economically feasible but also able to reduce the greenhouse gas load of beer packed in glass bottles (GB) by about one-third of that associated with packaging materials. Not by chance, it is practiced by most industrial and craft breweries.

From bench to worktop: Rapid evaluation of nutritional parameters in liquid foodstuffs by IR spectroscopy

We evaluated the use of attenuated total reflectance infrared spectroscopy for simultaneous in situ quantification of the nutritional composition of liquid food stuffs in the industrial kitchen context. Different methodologies were compared, including dry and wet acquisition along with instrument parameters and measurement times of 4 and 60 s. The most effective technique was 1-minute measurement, with prediction errors of 2.6, 0.7, 1.0, 2.2, 0.8, 2.4 g/100 mL and 150 Kcal, for carbohydrates, proteins, fat, sugars, saturated fat, water and energy values, respectively.The 4-second method resulted in larger errors but was more applicable for inline measurements. Dry measurements successfully predicted the fractions of proteins, fat, carbohydrates, and sugars, relative to total solids. An app was created to facilitate implementation in a kitchen environment. Compared with other techniques recommended by the FAO, the approach offered a simple alternative for simultaneous prediction of nutritional parameters in an industrial kitchen set-up.

Effect of cold plasma treatment on sterilizing rate and quality of kiwi turbid juice

AbstractPrevious studies have shown that cold plasma inactivated microorganisms located on a variety of food surfaces and food packaging materials under atmospheric pressure conditions; however, less attention has been paid to the impact of cold plasma on microorganisms in liquid food stuffs. The aim of the study is to evaluate the effect of cold plasma treatment on maintaining quality and the bactericidal effect of kiwi turbid juice, and obtain the optimal parameters. Kiwi turbid juice was treated with different treatment voltages, juice volumes, and discharge times. Tow principle components (chlorophyll and total phenols) were extracted by factor analysis and the cumulative contribution achieved was 87.017%. Three‐factor response surface methodology was used to analyze the interactions between the factors, and particle swarm optimization was used to search for the optimal parameters. The results showed that the established three‐index regression model was significant. At the optimal level of 12 kV treatment voltage, 18 ml juice volume, and 1 min discharge time, chlorophyll, total phenols, and bactericidal rate of the optimized test were 0.18 mg/g, 3.47 OD280/g, and 83.97%, respectively. This study provides key implications for applying cold plasma during kiwi turbid juice processing.Practical applicationsKiwi turbid juice is rich in nutrition, has high quality and good taste, which can greatly retain the flavor of fresh juice, and has a broad market development prospect. Sterilization is a key process in the production of kiwi turbid juice, Cold plasma processing is a potential nonthermal method which can enable extension of shelf life of kiwi turbid juice, yet retaining its freshness and organoleptic properties.

Preparation of magnetic mesoporous silica from rice husk for aflatoxin B1 removal: Optimum process and adsorption mechanism.

The liquid foodstuffs such as edible oil products remain a problem of excessive aflatoxin B1 (AFB1) content. This paper focused on the preparation of magnetic mesoporous silica (MMS) from rice husk ash for the removal of AFB1 in oil system. The MMS preparation process, adsorption conditions, structural characteristics, and adsorption mechanism were investigated. The optimum conditions for MMS preparation were pH 11.0 and 80°C for 24 h. The characterization results showed that magnetic particles were successfully embedded in the MMS and had high responsiveness to a magnetic field, which was advantageous for recyclability. The MMS had ordered uniform channels with a specific surface area of 730.98 m2/g and pore diameter of 2.43 nm. The optimum adsorption conditions were 2 h at 20°C. For AFB1 with an initial concentration of 0.2 μg/mL, the MMS adsorption capacity was 171.98 μg/g and the adsorption rate was 94.59%. The MMS adsorption isotherm fitted the Langmuir model well under the assumption of monolayer AFB1 adsorption with uniformly distributed adsorption sites on the MMS surface. The maximum amount of AFB1 adsorbed according to the Langmuir isotherm was 1118.69 μg/g. A quasi-second-order kinetic model gave a better fit to the process of AFB1 adsorption on MMS. The values of ΔH (−19.17 kJ/mol) and ΔG (−34.09, −34.61, and −35.15 kJ/mol at 283, 293, and 303 K, respectively) were negative, indicating that AFB1 adsorption on MMS was a spontaneous exothermic process. The results indicated that MMS was a promising material for AFB1 removal in oil system, and this study will serve as a guide for practical MMS applications.

APPLICATION OF THE IMPEDANCE METHOD FOR DETERMINATION OF MONOSODIUM GLUTAMATE IN FOOD PRODUCTS

The article presents the results of studying how impedance analysis can be used for determination of monosodium glutamate in order to identify food fraud. We have suggested that the parameters of complex conductivity (admittance) of a two-terminal circuit could allow detecting monosodium glutamate (E 621), an additive used in the food industry to enrich the taste. The method involves passing current of different frequencies through solid foodstuffs and a cell with liquid foodstuffs, measuring the electrical conductivity, and determining and analysing the frequency dependence of admittance. The active G component and the reactive B component of the admittance have been measured at different frequencies, from 100 Hz to 100 kHz. For the experiment, food samples were prepared in accordance with the Codex Alimentarius recommendations for the dosage of the food additive E 621: orange juice with monosodium glutamate added in the amount of 0.3%, and mashed potatoes with glutamate added in the amount of 1%, of the total weight of the products. The temperature of the tested products was 22 ± 0.2°С. The results of the studies have shown the dependences of the admittance components on the frequency for the control samples of juice and mashed potatoes and for the samples with monosodium glutamate added. The dependence of the active component and the reactive component of the foodstuff admittance have been established, with monosodium glutamate (added in the above-specified proportion) and without it. The difference is in how the dependences change in their nature. The monosodium glutamate curves both in juice and in mashed potatoes are similar. The samples containing monosodium glutamate have far higher values of the active and reactive admittance component than the control samples do, with a distinct peak of the reactive component characteristic. Therefore, impedance analysis is a possible method to detect quickly the flavour enhancer monosodium glutamate in foods of different consistency and thus identify food fraud.

Photonic crystal fiber based terahertz sensor for cholesterol detection in human blood and liquid foodstuffs

Low density lipoprotein (LDL) cholesterol is the leading cause of heart diseases, peripheral artery diseases, and stroke. An accurate, flexible, and efficient detection process is very urgent for identifying the cholesterol. In this context, an octagonal shaped hollow core with eight head star cladding structured photonic crystal fiber (PCF) has been proposed in this paper for cholesterol sensing in liquid analytes (human blood, cocking oil, liquid foods, etc.). The sensing performances of proposed PCF are evaluated through the COMSOL multiphysics software where the finite element method (FEM) has been used as a solver. The numerical investigation of the presented PCF structure exhibits highly sensitive characteristics for cholesterol detection in liquid samples and the proportion is 98.75% at 2.2 THz frequency. It also reveals negligible confinement loss of 3.14 × 10−20 cm−1 and low effective material loss of 0.0008 cm−1 at the same operating point. Furthermore, the commercial development feasibility of designed PCF in the existing manufacturing environment and other crucial optical properties such as effective area, dispersion, numerical aperture are also discussed in detail.

Heating of liquid foods in cans: Effects of can geometry, orientation, and food rheology

AbstractIn this work, the effect of geometry and orientation of food cans on the heating characteristics of processed liquid foods and the resulting lethality target values as a function of the processing times have been investigated. For this purpose, the governing differential equations have been solved numerically for elliptical and cylindrical cans of varying aspect ratios in different orientations in order to delineate their effect on the heating rate (especially of the slowest heating zone [SHZ]) and lethality values over wide ranges of rheological features including shear thinning (n < 1), Newtonian (n = 1), and shear thickening (n > 1) behaviors. The flow and heat transfer characteristics were analyzed with the help of velocity vectors, isotherm contours, average Nusselt number, SHZ temperature and heat penetration parameters, and lethality target values. Also, comparisons were made in terms of the sterilization time and heat penetration parameters to identify the preferable geometries and orientations of food cans for effective heating of non‐Newtonian foodstuffs. Finally, favorable conditions in terms of the shape and orientation of the can and the rheological properties have been delineated which lead to superior heating characteristics.Practical ApplicationsProcessed foodstuffs are produced in various forms ranging from that in solid, liquid, or as heterogeneous mixtures. Often such liquid and heterogeneous suspensions products are viscous non‐Newtonian in character and their thermal processing (including pasteurization, sterilization, etc.) tends to be much more challenging than that of their Newtonian counterparts like air and water. This work explores heating of non‐Newtonian liquid foodstuffs in cans of various shapes, geometries and in different orientations in the free convection regime. The results show that depending upon the rheological properties of the products, some orientations and/or geometries offer potential advantages in terms of shorter processing times and lethality values. This information can be of great potential in customizing the design of containers for different food products as well as of different rheological properties.

Homogeneity assessment of reference materials for sensory analysis of liquid foodstuffs. The virgin olive oil as case study

Sensory properties are critical characteristics that determine quality and can be evaluated by trained tasting panels. The panels function as multi-sensor measuring instrument and need the use of reference materials (RMs) for training.The homogeneity between units packaged from a batch of RM can be evaluated by gas chromatography coupled to flame ionization detection (GC-FID), using this instrumental technique as an alternative to sensory analysis. For this purpose, the fingerprint methodology is applied, taking into account that the homogeneity assessment will be based on evaluating the similarity between the fingerprints of the fraction of volatile organic compounds acquired from samples representative of the batch.The proposed methodology is applied with good results to evaluate the homogeneity of several RMs for sensory analysis of virgin olive oil samples, using similarity indices, control charts and exploratory analysis of multivariate data to observe the grouping RM and fingerprint regions representative of each defect.

Assessing the inactivation efficiency of Ar/O2 plasma treatment against Listeria monocytogenes cells: Sublethal injury and inactivation kinetics

A study was carried out to detect and assess possible sublethal injury and inactivation kinetics of Listeria monocytogenes suspended in phosphate-buffered saline (0.01 M PBS, pH = 7.4) by Ar/O2 plasma treatment. Results showed that both the germicidal effect and proportion of sublethally injured cells exhibited a time-dependent behavior, and post-treatment storage further extended the plasma lethality. The cytoplasmic enzymatic activity was reduced, but no considerable leakage levels of intracellular DNA and protein occurred. Incorporating the post-treatment storage for 48 h substantially decreased the intensity of intracellular reactive oxygen species (ROS) (p < 0.01) to relatively low level with no chemical residues. Moreover, the inactivation kinetics was well described by Weibull model (RMSENS = 0.074, RMSES = 0.093). The current study provided valuable information on the inactivation kinetics of L. monocytogenes and demonstrated the potential applications of plasma-mediated sterilization in liquid foodstuffs.

Phenyl propyl functionalized hybrid sol–gel reinforced aluminum strip as a thin film microextraction device for the trace quantitation of eight PCBs in liquid foodstuffs

In the present study, a low-cost, convenient and reliable thin film coating was developed as the extraction phase. The new sorbent was obtained by chemical bond formation between the hybrid sol-gel precursors and aluminum strip substrate in the first step and subsequent functionalization by phenyl propyl groups. The surface properties of the synthesized sorbent were characterized by Fourier transform infrared spectroscopy (FT–IR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Eight polychlorinated biphenyl (PCB) homologs were effectively extracted by using the self-made device in thin film microextraction (TFME) set-up followed by gas chromatography-mass spectrometry (GC-MS) determination. The influencing factors, including extraction and desorption solvent, desorption solvent volume, extraction and desorption time, extraction temperature, agitation speed, salt addition, and matrix effect were investigated. Under the optimized conditions, the limits of detection (at S/N ratio of 3) were found to be 1–3 ng L−1 and the linearity was in the range of 10–1000 ng L−1. The method precision values calculated as relative standard deviations (RSDs%), were in the range of 6.8–11.0% (intra–day), and 9.0–12.4% (inter–day). This work was successfully applied to enrichment and trace levels determination of PCB congeners in orange juice, cola drink, milk, beer, and honey. The evaluations also showed satisfactory recoveries (70.6–103.5%) for different spiked real samples.

STUDY OF THE BIOTECHNOLOGICAL POTENTIAL OF SELECTED LACTIC ACID BACTERIA CULTURES

Fermenting microflora has been selected by biotechnological activity markers, with various methodological approaches used, namely: directional selection, selection of bacteriophage-insensitive mutants, protoplast regeneration. The experimental data show a significant biotechnological potential of the selected lactic acid bacteria. They are characterized by high milk-clotting activity and yield, the ability to form aromatic compounds and/or viscous components, excellent organoleptic qualities of clots fermented by them, antago-nistic activity against pathogenic and opportunistic pathogenic microorganisms, and phage-resistance to species-specific virulent phages. The collection of industrial microorganisms of Institute of Food Resources of National Academy of Agrarian Sciences (IFR NAAS) has been supplemented with new bioactive strains, in particular, the species Streptococcus thermophilus, Lactobacillus acidophilus, Lactoba-cillus rhamnosus and Lactococcus lactis. Four bacterial compositions have been created. Three of them (Iprovit-LB-R; Iprovit-LB-A, and Iprovit-ST) are supposed to be used as functional enrichers for dry foodstuffs or as biologically active supplements. The bacterial prepara-tion Iprovit-Bifidolux is a universal composition. It can be introduced both as a fermenting culture for milk fermentation and as an enricher for dry and liquid foodstuffs. Biotechnologies for the production of dry bacterial preparations on the basis of selected strains have been field-proven at the State Research Enterprise of Starter Cultures that belongs to the IFR NAAS. The data on a wide range of clinical and therapeutic effects of the bacterial preparation Iprovit-Bifidolux allow recommending it for manufacturing functional foods.

Successive detection of benzoic acid and total parabens in foodstuffs using mercaptosuccinic acid capped cadmium telluride quantum dots

An approach for the determination of benzoic acid (BA) and total paraben content using mercaptosuccinic acid capped CdTe quantum dots (MSA-CdTe QDs) as an optical probe is presented. The levels of these preservatives in the samples of liquid foodstuff could be determined by both visible and fluorescent detection methods. For the analysis of paraben content, sample hydrolysis under alkaline conditions was required in order to obtain p-hydroxybenzoic acid (PHBA) prior to the addition of MSA-CdTe QDs. Both BA and PHBA could be quantified by their quenching of QD fluorescence, owing to the formation of hydrogen bonds between the carboxylic acid groups of the MSA-CdTe QDs and the analytes. Reverse-phase C18 solid phase extraction cartridge was exploited to reduce sample loss and organic solvent consumption in the sample preparation steps. The developed approach was successfully applied for the determination of the BA and total paraben content found in orange juice, soft drink, energy drink, beer, coconut milk, and fish sauce, giving a limit of detection of 0.3 mg/L for BA analysis, and 0.1 mg/L for PHBA (hydrolyzed form of parabens) analysis, with a linearity range from 1.0 mg/L to 500.0 mg/L. Since the concentrations of most preservatives added to products are controlled and regulated by raw, therefore, quality control is necessary to monitor the levels of these agents in products to better ensure the safety of customers.

Stable oxygen isotopes in water of concentrated liquid foodstuffs: Are the commonly determined values accurate?

Oxygen isotope analysis of water molecules of liquid foodstuffs is commonly performed under isotopic equilibrium between water in the solution and the vapour water, assuming that the liquid water activity is equal to unity and that liquid water is an ideal mixture of H2 O isotopologues. A priori this behaviour is not realistic for all foodstuffs, which frequently are very concentrated solutions. In this paper we mainly consider "balsamic vinegar" with the aim of defining an appropriate procedure of oxygen isotope ratio analysis of water molecules in these concentrated solutions. Isotope ratio mass spectrometry (IRMS) measurements of the oxygen isotope ratios (δ18 O values) were carried out on CO2 equilibrated with water molecules at 22 ± 0.1°C. Three independently calibrated, very low salinity waters were used as standards. For grape must and wine vinegar (density < 1.15 g/cm3 ) the δ18 O values for water determined directly on these solutions are "true" values. On the contrary, for balsamic vinegar with density higher than 1.15-1.20 g/cm3 , the δ18 O values obtained directly on the solutions are systematically different from those obtained on water produced by distillation of the same samples at 70°C under vacuum. In the case of balsamic vinegar with density higher than 1.15-1.20 g/cm3 , to avoid severe systematic errors, the isotopic analyses must be carried out on water obtained by distillation under stirring.