Food Matrices Research Articles

Characterization of the novel phage vB_BceP_LY3 and its potential role in controlling Bacillus cereus in milk and rice

Bacillus cereus is a foodborne pathogen that induces vomiting and diarrhea in affected individuals. It exhibits resistance to traditional sterilization methods and has a high contamination rate in dairy products and rice. Therefore, the development of a new food safety controlling strategy is necessary. In this research, we isolated and identified a novel phage named vB_BceP_LY3, which belongs to a new genus of the subfamily Northropvirinae.This phage demonstrates a short latency period and remains stable over a wide range of temperatures (4–60 °C) and pH levels (4–11). The 28,124 bp genome of LY3 does not contain any antibiotic-resistance genes or virulence factors. With regards to its antibacterial properties, LY3 not only effectively inhibits the growth of B. cereus in TSB (tryptic soy broth), but also demonstrates significant inhibitory effects in various food matrices. Specifically, LY3 treatment at 4 °C with a high MOI (MOI = 10,000) can maintain B. cereus levels below the detection limit for up to 24 h in milk. LY3 represents a safe and promising biocontrol agent against B. cereus, possessing long-term antibacterial capabilities and stability.

Non-linear responses via agglomeration and aggregation of gold nanoparticles for surface-enhanced Raman spectroscopy (SERS) coupled with chemometric analysis for chlorpyrifos detection

This study investigates the behaviour of gold nanoparticles (AuNPs) when exposed to chlorpyrifos, an agricultural pesticide, and its application in detecting the pesticide via surface-enhanced Raman spectroscopy (SERS). Under synergistic addition of NaCl, AuNPs undergo agglomeration at lower chlorpyrifos concentrations but aggregation at higher concentrations, resulting in a distinctive nonlinear SERS response. A linear relationship is obtained between 0.001 and 1 ppm with detection limit (LOD) of 0.009 ppm, while an inverse response is observed at higher concentrations (1–1000 ppm) with a LOD of 1 ppm. Combining the colorimetric response of AuNP solutions, their absorbance spectra, and principal component analysis can improve detection reliability. The assay, coupled with a simple recovery method using acetonitrile swabbing, achieves high reproducibility in detecting chlorpyrifos in cucumber, even at concentrations as low as 0.11 ppm. This approach can be tailored for various chlorpyrifos concentrations not only in cucumbers but also in different food matrices.

Recent Advances in the Understanding of Stress Resistance Mechanisms in Probiotics: Relevance for the Design of Functional Food Systems.

In recent years, more and more scientific community, food producers, and food industry show increased interest in functional foods containing probiotics, which is a big challenge. The consumption of probiotics in the context of a balanced diet through the consumption of functional foods or through the intake of pharmaceutical preparations has proven to contribute to the improvement of human health, even contributing to the prevention of diseases. In order for probiotics to be considered suitable for consumption, they must contain a minimum concentration of viable cells, namely, at least 107 colony forming units of beneficial microbes per gram. Ensuring the viability of bacterial cells until the moment of consumption is the overriding priority of functional probiotic food manufacturers. Probiotic bacteria are subject to stress conditions not only during food manufacturing but also during gastrointestinal passage, which limit or even compromise their functionality. This paper first examines all the stressful conditions faced by probiotic cells in their production stages and related to the conditions present in the bioreactor fermentation and drying processes as well as factors related to the food matrix and storage. The stress situations faced by probiotic microorganisms during the gastrointestinal transit especially during stomach and intestinal residence are also analyzed. In order to understand the adaptation mechanisms of probiotic bacteria to gastrointestinal stress, intrinsic and adaptive mechanisms identified in probiotic strains in response to acid stress and to bile and bile acid stress are analyzed. In addition, improvement strategies for multiple stress tolerance of lactic acid bacteria through directions dealing with stress, accumulation of metabolites, use of protectants, and regulation of technological parameters are examined. Finally, the definition of postbiotics, inanimate microorganisms and/or their components conferring health benefits, is also introduced. Postbiotics include cell lysates, enzymes, and cell wall fragments derived from probiotic bacteria and may represent an alternative to the use of probiotics, when they do not tolerate stressful conditions.

The Potential of Multi-Screening Methods and Omics Technologies to Detect Both Regulated and Emerging Mycotoxins in Different Matrices.

Mycotoxins are well-known secondary metabolites produced by several fungi that grow and occur in different crops during both pre-harvest and post-harvest conditions. The contamination and occurrence of mycotoxins currently represent some of the major issues in the entire agri-food system. The quantification of mycotoxins in different feeds and foodstuffs is extremely difficult because of the low concentration ranges; therefore, both sample collection and preparation are essential to providing accurate detection and reliable quantification. Currently, several analytical methods are available for the detection of mycotoxins in both feed and food products, and liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) represents the most reliable instrumental approach. In particular, the fast development of high-throughput methods has made it possible to screen and analyze, in the same analytical run and with high accuracy, multiple mycotoxins, such as those regulated, masked, or modified, and emerging ones. Therefore, the aim of this review is to provide an overview of the state of the art of mycotoxins occurrence, health-related concerns, and analyses, discussing the need to perform multi-screening approaches combined with omics technologies to simultaneously analyze several mycotoxins in different feed and food matrices. This approach is expected to provide more comprehensive information about the profile and distribution of emerging mycotoxins, thus enhancing the understanding of their co-occurrence and impact on the entire production chain.

The influence of food matrix and processing methods on the bioaccessibility of lutein: A review

Lutein belongs to oxygen-containing carotenoids and has various functional activity potentials such as antioxidant, preventing age-related macular degeneration (AMD), anti-inflammation, protecting cardio-cerebrovascular, anti-diabetes, and anti-cancer. However, it is typically consumed along with the food matrix, and its bioaccessibility is relatively low. Some food processing techniques have been developed to promote the release of lutein in plant-based foods and/or accelerate the decomposition of food matrix, which may damage the activity of lutein or reduce its bioaccessibility. By appropriately changing the food matrix and food processing methods, the functional characteristics of lutein in the diet can be enhanced. Therefore, this paper detailedly reviews the influence and action mechanism of lutein existence form and amount, food matrix structure and components, and food processing methods on the bioaccessibility and chemical interactions of lutein. Meanwhile, it also focuses on improving the bioaccessibility of lutein through the design of food matrix systems such as emulsions, hydrogels, molecular complexes, and liposomes, etc. This information will assist in selecting the suitable encapsulation system for commercial applications and provide a reference for increasing the bioaccessibility of lutein in food matrix.

Mango (Mangifera indica) seeds and peel-derived hydrocolloids: Gelling ability and emulsion stabilization

Mango is a tropical fruit that is consumed worldwide and is distinguished by its sweet and juicy flesh. Unfortunately, the peels and seeds of mango fruit are often discarded despite the fact that they contain compounds that can be valorized for certain applications. In this study, a physicochemical and hydrodynamic characterization of hydrocolloids extracted from the peel and seeds of mango fruit was performed and the impact on the microstructure and rheological behavior of derived gels, as well as the ability to form emulsions, were analyzed. The physicochemical parameters and proximate compositions of the different samples showed that the hydrocolloids extracted from the seeds are rich in proteins whereas those from the peel are rich in carbohydrates. The molecular weights calculated from the hydrodynamic characterization (Mv) are 101515 g/mol and 102,580 g/mol for hydrocolloids extracted from the peel and seeds, respectively. Dispersions of these hydrocolloids in water produced hydrogels upon heating, which exhibited a shear thinning response that can be described by the Williamson model. The ability of these hydrocolloids to form thermally-induced strong gels was monitored and analyzed by means of curing tests. Throughout thermal treatments, the storage modulus showed a significant increase, especially at concentrations greater than 2.5 wt%. Mango seeds and peel-derived hydrocolloids are also able to stabilize o/w emulsions. Derived emulsions showed D50 mean diameters and zeta potential values (ζ) in the ranges from 10.04 to 82.52 μm and from -17.63 to -11.12 mV, respectively. On the basis of the observed rheological behavior of hydrogels and emulsion-forming ability, the hydrocolloids derived from mango seeds and peels possess suitable characteristics to be potentially implemented in diverse food matrices, offering functional and nutritional benefits to final consumer products.

Saliva bubbles: How saliva foam impacts aroma release and retronasal perception during oral processing

Saliva foam can be easily formed upon different oral movement, but the impact of saliva foam on aroma release and perception is less investigated. Recruited subjects were asked to chew mint-flavor gums to mimic saliva foam generation. During gum-chewing, i.) subjects' retronasal release and dynamic perception of menthol and ii) their salivary bubble number and size, were continuously monitored. In the ‘normal series’ of experiments, bubbles were generated by the oral behavior of mastication; and in the ‘defoamed series’ of experiments, a defoaming agent was simultaneously added to eliminate the bubble effect during mastication. A continuous formation and collapse of saliva bubbles in the normal group led to a stable higher release of menthol in subjects' exhalation and significantly higher mint flavor perception (p < 0.05). In the defoamed series, saliva bubble numbers were reduced drastically (1–2 orders of magnitude) and more menthol was retained in saliva, which further affected subjects' intensity perception. Multiple physiological factors including salivary protein concentration, viscosity and surface tension contributed to the individual sensory perception variations, and no single parameter could explain the exact relationship between aroma release and retronasal perception. This study provided insights on the aroma delivery in food matrix design and development.

Sourdough bread enriched with exopolysaccharides and gazpacho by-products modulates in vitro the microbiota dysbiosis

Sourdough bread enriched with soluble fiber (by in-situ exopolysaccharides production) and insoluble fiber (by gazpacho by-products addition) showed prebiotic effects an in vitro dynamic colonic fermentation performance with obese volunteer's microbiota. Bifidobacterium population was maintained whereas Lactobacillus increased throughout the colonic sections. Conversely, Enterobacteriaceae and Clostridium groups clearly decreased.Specific bacteria associated with beneficial effects increased in the ascending colon (Lactobacillus fermentum, Lactobacillus paracasei, Bifidobacterium longum and Bifidobacterium adolescentis) whereas Eubacterium eligens, Alistipes senegalensis, Prevotella copri and Eubacterium desmolans increased in the transversal and descending colon. Additionally, Blautia faecis and Ruminococcus albus increased in the transversal colon, and Bifidobacterium longum, Roseburia faecis and Victivallis vadensis in the descending colon.Bifidobacterium and Lactobacillus fermented the in-situ exopolysaccharides and released pectins from gazpacho by-products, as well as cellulosic degraded bacteria. This increased the short and medium chain fatty acids. Acetic acid, as well as butyric acid, increased throughout the colonic tract, which showed greater increases only in the transversal and descending colonic segments. Conversely, propionic acid was slightly affected by the colonic fermentation.These results show that sourdough bread is a useful food matrix for the enrichment of vegetable by-products (or other fibers) in order to formulate products with microbiota modulatory capacities.

Development of a Whole-Cell System Based on the Use of Genetically Modified Protoplasts to Detect Nickel Ions in Food Matrices.

Heavy metals are dangerous contaminants that constitute a threat to human health because they persist in soils and are easily transferred into the food chain, causing damage to human health. Among heavy metals, nickel appears to be one of the most dangerous, being responsible for different disorders. Public health protection requires nickel detection in the environment and food chains. Biosensors represent simple, rapid, and sensitive methods for detecting nickel contamination. In this paper, we report on the setting up a whole-cell-based system, in which protoplasts, obtained from Nicotiana tabacum leaves, were used as transducers to detect the presence of heavy metal ions and, in particular, nickel ions. Protoplasts were genetically modified with a plasmid containing the Green Fluorescent Protein reporter gene (GFP) under control of the promoter region of a sunflower gene coding for a small Heat Shock Protein (HSP). Using this device, the presence of heavy metal ions was detected. Thus, the possibility of using this whole-cell system as a novel tool to detect the presence of nickel ions in food matrices was assessed.

Sodium alginate/gelatin hydrogel spheres loaded with Fructus Ligustri Lucidi essential oil: Preparation, characterization and biological activity

The application of plant essential oils in the food industry is often hindered by their poor water solubility and high volatilize. Encapsulation has emerged as an effective solution to this problem. This study focuses on the preparation of Fructus Ligustri Lucidi essential oil gel spheres (FEOH) based sodium alginate and gelatin. The optimum formulation for FEOH was established by Box-Behnken Design response surface testing, resulting in a composition of 10 % FEO, 5 % TW20 and 2 % CaCl2. This formulation achieved an encapsulation efficiency of 85.56 %. FTIR and SEM results indicated the successful encapsulation of FEO within the gel spheres. Furthermore, DSC and TGA results showed that encapsulation enhanced the thermal stability of the essential oil. At room temperature, the water content of FEOH exceeded 90 %, and it showed the highest swelling ratio of 62.5 % in an alkaline medium at different pH conditions. The in vitro release behavior showed that FEOH was released up to 85.28 % in oil-based food simulants within 2 h. FEOH showed strong antibacterial activity, with a Minimum Inhibitory Concentration (MIC) of 128 mg/mL against Staphylococcus aureus and 256 mg/mL against Escherichia coli. The gel spheres obtained in this research show significant potential as food preservatives in food matrices.

Development and Optimization of Vegan Cheese Spread: Studies in Rheology and Microstructure

ABSTRACT Vegan foods are growing in the market owing to various factors such as awareness about humane production of food, sustainability and health. In this study, a vegan cheese spread was developed with main ingredients being Jackfruit seed powder, cashew kernels and sunflower oil. The product had an improved nutritional profile as compared to the counterparts in the market providing fat content at 18.19 ± 0.52 g, carbohydrates at 8.31 ± 0.58 g, dietary fiber at 5.15 ± 0.45 g, and protein at 8.82 ± 0.09 per 100 g. Rheological and microstructure studies indicated that the food matrix was undergoing dynamic rearrangements at the molecular level on storage, but was appearing stable to the eye of the observer. Product attributes scored 8 points and higher on the hedonic scale of sensory evaluation. Practical implication of this research venture is that a vegan cheese spread has been developed and characterized on laboratory scale and can be further scaled up.

Nanosupplements based on protein-polysaccharide coacervates loaded with essential oils: Evaluation of antioxidant and antidiabetic properties

Essential oils (EOs) have demonstrated potential in food products to prevent complications related to diabetes. Nevertheless, the physicochemical characteristics of pure EOs, including high volatility and low chemical stability, face significant challenges when considering their utilization as functional ingredients. Thus, this study aimed to develop nanosupplements based on protein-polysaccharide coacervates loaded with EOs, thyme (THY) and oregano (ORE), and to evaluate their colloidal, antioxidant, and α-glucosidase and α-amylase inhibitory properties following an in vitro gastrointestinal digestion process. First, heat-induced egg white protein nanoparticles (EWPn) were used to encapsulate both EOs as nanocomplexes. Second, the process to obtain nanosupplements involved the electrostatic deposition of high methoxyl pectin (HMP) onto the surface of pre-formed nanocomplexes, resulting in the production of EWPn-THY-HMP and EWPn-ORE-HMP powders through a freeze-drying process. The effects of in vitro digestion on particle size, zeta potential, stability, and bioaccessibility of systems were analyzed. HMP exhibited a slight ability to protect EWPn from gastric digestion, while encapsulation within the EWPn-HMP system prevented the chemical degradation of EOs during gastrointestinal digestion. Subsequently, the antioxidant properties and the inhibitory effects of digested systems on α-glucosidase and α-amylase activities were examined. After in vitro digestion, EWPn-THY-HMP and EWPn-ORE-HMP systems showed higher ABTS+ radical scavenging than pure EOs (around 70% vs. 30%, respectively). Additionally, reducing power activities (expressed as mg of ascorbic acid equivalents-AAE mL−1) of EWPn-THY-HMP and EWPn-ORE-HMP systems were higher (1.6 ± 0.0 mg and 1.8 ± 0.1 mg of AAE mL−1, respectively) compared to pure THY and ORE (approximately 1.5 mg of AAE mL−1 for both) after in vitro digestion. The α-glucosidase inhibitory activity of EOs decreased upon encapsulation within EWPn-HMP system from an IC50 value of 0.3–1.0 μg mL−1, approximately. However, the effect of encapsulation on α-amylase inhibitory activity was EOs-dependent, and it was higher for the EWPn-ORE-HMP system, with an IC50 value of 8.6 ± 0.2 μg mL−1. The results highlight the potential of EOs encapsulation within EWPn-HMP coacervate nanosupplements as a promising strategy to facilitate their incorporation into food matrices while preserving their antioxidant and α-glucosidase and α-amylase inhibitory properties.

Proteomics for depicting the secreted protein patterns of Lactiplantibacillus plantarum strains isolated from different food matrices

Lactiplantibacillus plantarum (formerly known as Lactobacillus plantarum), a bacterial species isolated from a wide variety of ecological niches, plays an important role in food industries, being used as a starter culture of food fermentations and contributing to improve flavor, texture, sensorial qualities, and shelf life. It also improves the nutritional and functional properties of fermented foods through the biosynthesis of bioactive compounds and several strains exhibit probiotic features. In recent years, this bacterial species has also shown great potential for controlling plant pathogenic fungi. Shotgun proteomic approach and label free quantitative analyses were used to realize a detailed catalog of the proteins secreted by five L. plantarum strains isolated from vegetable foods or dairy products and exhibiting specific function features. In particular, these strains showed in vitro inhibitory activity against bacteria and molds. Results led to identify 602 proteins differently present in the secretome of the analyzed strains. For instance, proteins of application interest such as bacteriocins, glucansucrase, glycoside hydrolase and chitin binding proteins were differentially secreted in the five strains.The information gathered in this study is a valuable contribution to increasing knowledge in relation to one of the most important bacterial species used as probiotic, for biocontrol of plant pathogenic bacteria and fungi and in different food production worldwide.

Optimization and validation of a method based on headspace-gas chromatography-ion mobility spectrometry for the rapid and visual analysis of flavor compound interactions in Baijiu

The complexity of flavor compound interactions significantly influences the overall flavor characteristics of alcoholic beverages. The vast diversity of these compounds, however, makes the screening for interactions both labor-intensive and time-consuming. To address this challenge, our study aimed to develop a rapid and visual approach using Headspace Gas Chromatography-Ion Mobility Spectrometry (GC-IMS), optimized via a Box-Behnken design and Response Surface Methodology (RSM). This method was validated through the investigation of interactions between lactic acid and 13 key flavor compounds in Baijiu. Furthermore, Gas Chromatography-Mass Spectrometry was utilized to quantify the impact of lactic acid on the volatility of these compounds, corroborating the findings from GC-IMS. Additionally, molecular docking techniques were employed to explore the interaction mechanisms between lactic acid and ethyl lactate, 3-hydroxy-2-butanone, and 2-methoxy-4-methylphenol, at the molecular level, offering insights into their potential binding configurations. Our findings offer a streamlined approach for screening flavor compound interactions, enhancing the understanding of flavor formation and facilitating future research and development in complex food matrices.

Anthocyanins from pomegranate peel (Punica granatum), chili pepper fruit (Capsicum annuum), and bougainvillea flowers (Bougainvillea spectabilis) with multiple biofunctions: Antibacterial, antioxidant, and anticancer

BackgroundNatural colorants, including natural pigments, e.g., anthocyanins, carotenoids, and chlorophylls, in novel and attractive food matrixes have become a popular trend. They impart favorite colors to food products and provide significant therapeutic effects. This study is aimed at extracting and identifying some natural pigments from different plant sources and evaluating their ability as antibacterial, antioxidant, and anticancer activities. MethodsThe anthocyanin-rich extract (ARE) is derived from three natural plant sources: pomegranate peel (Punica granatum), chili pepper fruit (Capsicum annuum), and Bougainvillea flowers. Bougainvillea spectabilis are analyzed for biochemical composition, as well as antioxidant, antibacterial, and anticancer activity, HPLC, DPPH, FRAP, disc diffusion assay, MIC, MTT, VEGFR‐2, and caspase-9 assays. ResultsAll three extracts had varying total phenolic contents, ranging from 14 to 466 mg GAE/g extract, where Punica granatum was the highest (466 mg GAE/g extract), followed by Bougainvillea spectabilis (180 mg GAE/g extract), and then Capsicum annuum (14 mg GAE/g extract). The antioxidant activity rose steadily with raising concentration. The ARE of pomegranate peels recorded highest value, followed by Bougainvillea flowers and chili pepper fruit. The MTT assay revealed an inhibitory action of the tested extracts on the proliferation of HCT-116, MCF-7, and HepG2 in a concentration-based manner. Gene expression of caspase-9 transcripts was considerably multiplied by the application of ARE of pomegranate peels. All the tested extracts inhibited VEGFR-2, and the inhibition (%) expanded gradually with increasing concentrations, achieving the highest value (80 %) at 10 μg/mL. The ARE of pomegranate peels scored highest antibacterial activity, followed by ARE of chili pepper fruit and Bougainvillea flowers. The inhibition zone diameter escalated gradually with rising concentrations of the tested samples. ConclusionThe AREs of the three studied plant sources can be used as multifunctional products with antioxidant, anticancer, and antibacterial activities that are natural, safe, and cheap.

Bioprocess Design and Evaluation of Hydrothermal Hydrolysates from Sargassum sp. for Enhancing Arthrospira platensis Growth and Protein Content

The proliferation of Sargassum biomass in various coastal areas has led to environmental and socio-economic problems. However, due to their unique composition, these biomasses offer versatile applications, prompting research into their potential in third-generation biorefineries. In this study, the hydrothermal processing of Sargassum sp. was evaluated under specific conditions at 190 °C/50 min and 150 °C/30 min. The resulting hydrolysates (liquid phase) were used as alternative culture media for cultivation. Nine treatments for the cultivation of Arthrospira platensis were assessed, varying the concentration of hydrothermal hydrolysates (HH) at 190 °C/50 min: T1 (5% v/v), T2 (10% v/v), and T3 (15% v/v). T4 (5% v/v), T5 (10% v/v), and T6 (15% v/v), maintaining the same HH conditions, and with the addition of 0.7 g/L NaNO3; and treatments T7, T8, and T9 had concentrations of 5%, 10%, and 15% of HH, respectively, at 150 °C/30 min with the addition of 0.7 g/L NaNO3, respectively. Each treatment was inoculated with 15% (v/v) of A. platensis. Growth kinetics were performed by sampling every three days for 24 days. Quantification of soluble proteins was performed for the best conditions of biomass production. The microalgae demonstrated the ability to grow under mixotrophic medium conditions and to utilize the available carbon sources in the culture medium. Treatment 4 has the highest biomass, with an Xmax (g/L) of 1.94 ± 0.06 and a protein production of 24.17 ± 0.86% (w/w). Therefore, this microalgal biomass can be used in the food matrix according to the biorefinery concept.

An oral gel suitable for swallowing: The effect of micronization on the gel properties and microstructure of κ-carrageenan

κ-Carrageenan (κ-Car) is an important material for preparing food gels and hydrogels. However, κ-Car gel has issues with high hardness and low water-holding capacity. Modification strategy of micronization is proposed for the first time to explore its influence on texture properties and gelling process of κ-Car gel, and to investigate the feasibility of κ-Car as a food matrix with low strength. κ-Car undergoing 60 min of micronization, the d(0.9) decreased by 79.33 %, SBET and Vtotal increased by 89.23 % and 95.27 %. The swelling rate and degree of gelling process increased significantly, and the microstructure changed from loose large pores to dense small pores resembling a “honeycomb”. Importantly, the hardness of gel-60, Milk-60 and PNS-60 decreased by 72.52 %, 49.25 % and 81.37 %. In addition, WHC of gel-60, Milk-60 and PNS-60 was improved. IDDSI tests showed that κ-Car gels, milk gels and PNS gels can be categorized as level 6 (soft and bite-sized), except for PNS-60, which belongs to level 5 (crumbly and moist). Furthermore, the texture and bitter masking effect of milk gels and PNS gels were improved. In conclusion, this study demonstrated that micronization can be a novel approach to improve the gel properties of κ-Car, laying the groundwork for developing dysphagia foods.

Current advances in QuEChERS extraction of mycotoxins in various food and feed matrices

Abstract Mycotoxins are common contaminants in food and feed in Africa, and their occurrence presents negative health and economic impacts. One step towards control is the adoption of highly efficient extraction methods for effective monitoring. QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) has gained popularity among researchers for multiple mycotoxin analyses. Various modifications of the original QuEChERS method have emerged as means to achieve maximum mycotoxin recoveries from different matrices, such as cereals, animal feed, nuts, edible oils, and spices. This review provides a summary of the occurrence of multiple mycotoxins in Africa as well as a summary of the QuEChERS modifications done to increase the extraction of mycotoxins from food and feed samples.

Determination of chloropropanol esters and glycidyl esters in nutritional foods by gas chromatography–tandem mass spectrometry based on acid hydrolysis and solid-phase extraction

This study presents a method based on acid transesterification and the purification by solid-phase extraction (SPE) coupled with gas chromatography–tandem mass spectrometry for quantifying 3- and 2-monochloropropanediol esters (3-MCPDE, 2-MCPDE) and glycidyl esters (GE) in nutritional foods. The fat was extracted by liquid–liquid extraction with petroleum ether and diethyl ether after the sample was hydrolysed with ammonia. Then the extract was purified by a SPE cartridge filled with the aminopropyl sorbents. It was demonstrated that the optimal elution volume for 3-MCPDE, 2-MCPDE and GE greatly depended on the sample matrix and varied from 6 to 12 mL for four different kinds of food matrices. All three analytes in the sample solution could be fully collected in the first 10–12 mL of eluate. By this way, monoacylglycerols commonly present in the samples were fully removed. Therefore, the overestimation of GE quantification was effectively eliminated. The modified analytical procedure was fully validated in a single laboratory and has been recommended as a Chinese Food Safety National Standard. In addition, two derivatisation agents, heptafluorobutyrylimidazole and phenylboronic acid, were proved to be equivalent in method accuracy and precision for the quantification of three analytes.

Characterization of the electropermeabilization induced by pulsed electric field (PEF) technology and its effect on the ultrasonic-assisted drying of yellow turnip

Obtaining snacks from the drying of surplus vegetables is an alternative to reduce waste. A combination of pulsed electric field (PEF) pretreatments and ultrasonic-assisted (US) drying could significantly enhance the process, as this is the aim of this study. PEF pretreatments of yellow turnip significantly affected the cell disintegration index (CDI) and the water holding capacity (WHC): the more intense the PEF treatment, the greater the CDI and the lower the WHC. Both parameters, CDI and WHC, showed a high degree of correlation which indicated that WHC can be an alternative index to CDI to assess PEF effects on food matrices. Regarding yellow turnip drying (40 °C), PEF pretreatments (CDI 0.25 and 0.75) and US application (20.5 kW/m3) significantly accelerated the operation, but it was the combination of both technologies that provided the shortest process (CDI 0.75). PEF could generate changes in the food matrix which enhance the US effects on mass transfer.