Highly-efficient selection of aptamers for detecting various HPV subtypes in clinical samples.

Nucleic acid aptamers are of great potentials in diagnostic and therapeutic applications because of their unique molecular recognition capabilities. However, satisfactory aptamers with high affinity and specificity are still in short supply. Herein, we have developed new selection methods allowing the free interactions between the targets and potential aptamers in solution. In our selection system, the protein targets (biotinylated randomly or site-specifically) were first incubated with the random DNA library, followed by the pull-down with the streptavidin magnetic beads or biolayer-interferometry (BLI) sensors. By comparing the two biotinylation strategies (random or site-specific) and two states of the targets (free or immobilized), we have found that the combination of the site-specific biotinylation and free-target strategies was most successful. Based on these highly-efficient selection strategies, HPV L1 aptamers were obtained. By designing the sandwich aptasensor assisted with RCA and CRISPR/Cas12a, we have diagnosed various HPV subtypes in clinical samples, such as easily-collected urine samples. In summary, our new strategy can allow efficient selection of aptamers with high affinity and specificity for clinical applications.

Bioactive delivery systems based on starch and its derivatives: Assembly and application at different structural levels.

Starch and modified starch, spanning various structural levels, are comprehensively reviewed, with a special emphasis on the advancement of starch and its derivative-based delivery systems for bioactive substances. The pivotal aspect highlighted is the controlled release of active ingredients by starch-based delivery systems with distinct hierarchical structures. At the molecular level, diverse categories of starch degradation products, such as dextrin and highly branched starch, serve as versatile amphiphilic carriers for encapsulating active ingredients. At the level of helical structure, the distinctive configuration of the starch-guest complex partly determines the mechanism of controlled release for diverse active components. At the crystal and particle structural level, starch assumes the role of a carrier, effectively modulating the release of active substances, and enhances the innate physiological activity of different active components. As a natural polymer molecule, starch can also generate hydrogel materials in polymer form, expanding its utility in the fields of food, materials, and even medicine.

Food liposomes: Structures, components, preparations, and applications.

This review explores liposomes, focusing on their structure, components, the characteristics influencing their stability and applicability in foods, and preparation methods. The role of phospholipids and liposome modulators in preparing liposomes of desired structure and size is emphasized. The potential of liposomes to enhance food value through liposomal encapsulation and delivery of functional substances is reviewed. Conventional and advanced liposome preparation methods are reviewed, underscoring their impact on the marketability of liposomes. The review highlights the need for research into lecithin properties and modulators that enhance liposome stability. The need to develop cost-effective and rapid liposome preparation methods is identified as a key factor in improving the marketability of food liposomes and promoting their use in foods.

Selenium-based nanozyme as a fluorescence-enhanced probe and imaging for chlortetracycline in living cells and foods.

Developing rapid monitoring methods to detect antibiotic residues in food plays an important role in safeguarding human health. This study presents the development of a novel fluorescence-enhanced detection method for chlortetracycline (CTC) using a GSH-Se nanozyme. A GSH-Se nanozyme prepared using a one-pot hydrothermal method not only possesses excellent fluorescent properties but also exhibits good glutathione peroxidase-like activity. The results show that the addition of CTC leads to a significant enhancement in the fluorescence intensity of GSH-Se, and this increase exhibits a good linear relationship with the concentration of CTC. The linear range of this method is 0.02-1 µM, and the limit of detection (LOD) for CTC was 0.02 µM. Moreover, the cell toxicity of GSH-Se is low and can be used for monitoring and imaging of CTC in cells, and satisfactory results have been obtained in the analysis of actual food samples.

Texture maintenance and degradation mechanism of ice-stored grass carp (Ctenopharyngodon idella): A scope of intramuscular connective tissue.

Although intramuscular connective tissue (IMCT) is low in fish, its impact on texture cannot be ignored due to its special location. Therefore, this study was aimed to investigate the contribution of IMCT degradation to fish softening and its mechanism induced by endogenous proteases. Results showed that IMCT honeycomb-like structure collapsed entirely on the 10th day of ice storage, along with a decrease of shear force by 36.5%. Meanwhile, IMCT and myofibrils (MF) degradation accelerated softening by 25.1% and 15.3% during 10 days of ice storage, respectively. Next, IMCT deterioration was indicated to be highly correlated with decorin degradation (0.956**), followed by elastin (0.928**) and collagen (0.904**). Ulteriorly, endogenous collagenase was shown to degrade IMCT crucial components, while endogenous cathepsins had little effect. In conclusion, this study confirmed that IMCT played an essential role in maintaining fish texture and was mainly degraded by endogenous collagenase.

Electrospun plant protein-based nanofibers in food packaging.

Electrospinning is a relatively simple technology capable to produce nano- and micron-scale fibers with different properties depending on the electrospinning conditions. This review critically investigates the fabrication of electrospun plant protein nanofibers (EPPNFs) that can be used in food and food packaging applications. Recent progress in the development and optimization of electrospinning techniques for production of EPPNFs is discussed. Finally, current challenges to the implementation of EPPNFs in food and food packaging applications are highlighted, including potential safety and scalability issues. The production of plant protein nanofibers and microfibers is likely to increase in the future as many industries wish to replace synthetic materials with more sustainable, renewable, and environmentally friendly biopolymers. It is therefore likely that EPPNFs will find increasing applications in various fields including active food packaging and drug delivery.

Chiral CDs-based fluorescence sensor for rapid and specific sensing K4[Fe(CN)6] in table salt and salted food.

Potassium ferricyanide (K4[Fe(CN)6]) as anti-caking agent plays an important role in avoiding the formation of chunks for fine particulate solids. However, inappropriate and excessive addition and decomposition of K4[Fe(CN)6] are detrimental to physical health. At present, appropriate strategies for convenient and accurate analysis of K4[Fe(CN)6] in table salt and pickled food are desirable. Herein, an efficient "ON-OFF-ON" fluorescent sensor based on chiral carbon dots was prepared by a simple one-step hydrothermal method. The chiral CDs with L-Tryptophan and D-Tryptophan as chiral source were named as L-CDs and D-CDs. Notably, the bright fluorescence of L/D-CDs could be effectively quenched by K4[Fe(CN)6] through dynamic quenching mechanism. This fluorescent sensor achieved excellent sensitive and selective detection of K4[Fe(CN)6] with a limit of detection (LOD) of 25.0 ng·mL-1. In addition, the L/D-CDs could be applied not only for selective fluorescent recognition of K4[Fe(CN)6] by the methods of portable filter paper and hydrogels, but also as fluorescent dye for repeated message encryption and decryption.

Recent advances in 3D printing properties of natural food gels: Application of innovative food additives.

Recent advances in 3D printing technology have provided a new avenue for food manufacturing. However, one challenge in 3D printing food is the limited availability of printable materials that can mimic the properties of real food. This review focused on the various 3DFP methodologies, as well as the reinforcement of natural food gel for improving printing features in 3D printed food. Also covered is the use of hydrogel-based 3D printing in the development of 3D printed food. Different 3D printing techniques can be employed to print hydrogel-based inks, each with its advantages and limitations. 3D printing of food using hydrogel-based inks has potential for customized food products development. In summary, the utilization of hydrogel-based inks in 3D printing offers a promising avenue for the development of customized food products. Although there are still challenges to overcome, such as improving the printability and mechanical properties of hydrogel-based inks, the potential benefits of this technology make it an exciting area of research.

Highly ammonia-responsive starch/PVA film with gas absorption system as the 'bridge' for visually spoilage monitoring of animal-derived food.

In the context of food waste and human diseases caused by food pollution, color renderement intelligent packaging came into being. Improving its indicator stability and sensitivity is essential for application. On the basis of our previous work, corn starch/polyvinyl alcohol was used as the matrix, the synthesized zirconium-based UiO-66 and anthocyanin-loaded ovalbumin-carboxymethylcellulose nanocomposites were embedded in to stabilize anthocyanins and improve gas adsorption performance of film. The study found that incorporating appropriate amount of UiO-66 (3%) in films resulted in uniform distribution and formation of holes. Mechanical properties, water stability and barrier properties were significantly improved, and gas adsorption capacity increased by approximately 10 times. More crucially, films that incorporate UiO-66 can react more quickly and visibly to lower concentrations of ammonia gas. The color change of SP/OVA-CMC-ACNs/3% UiO-66 film was noticeable (from purple to gray and then to green) when applied to monitor freshness of shrimp and pork.

Mechanistic elucidation of the degradation and transformation of hydroxy-α-sanshool and its conformers as the pungent dietary components in Sichuan pepper: A DFT study.

To better understand the structural changes of sanshool pungent dietary components during the process and preservation of Sichuan pepper and pungent foods, the mechanistic insights into the intrinsic degradation and transformation of 16 hydroxy-α-sanshool conformers have been explored computationally. Our results have revealed that increasing the cis-CC bond numbers in the most stable all-trans hydroxy-ß-sanshool structure causes the maximum 34.21 kJ/mol conformational energetic difference, and the existent probability of C2nnn would be lower than that of C1nnn (n = 1,2). The isomerization between the conformers could be much easier when they are excited by light radiation, as the strength of the CC bonds and their connected CC bonds becomes significantly close, and the relative energies among conformers are largely reduced. Besides, the different combination of cis/trans-CC bonds changes the delocalization degree of molecular Frontier orbitals, which consequently causes the different photochemical stability. Finally, the possible molecular oxidation degradation mechanism is proposed.

Effect of polysaccharide addition on food physical properties: A review.

The texture, flavor, performance and nutrition of foods are affected by their physical properties during processing, cooking, storage, and shelf life. In addition to chemical, physical, and enzymatic modification methods, polysaccharide addition is also considered a safe, effective, and convenient food modification strategy. However, thus far, literature review on the effects of polysaccharides on the physical properties of foods is few. Therefore, the present work reviews the effects of polysaccharides on water retention capacity, rheological property, suspension ability, viscoelasticity, emulsifying property, gelling property, stability, and starch regeneration and digestion. Furthermore, the existing problems and future recommendations during food physical property modification by polysaccharides are presented. This work aims to provide some theoretical references for future research, development, and application of polysaccharides on food physical property modification.

Nanoconfinement of functionalized ionic liquid for enhanced adsorption and rapid sensitive detection of phenylurea herbicides in food and environmental samples.

The novel ILs@CNTs was synthesized by encapsulating task-specific ionic liquids (ILs) within carbon nanotubes (CNTs) derived from ZIF-67. These hybrid materials served as multifunctional adsorbents enabling simultaneous sorptive removal, sensitive detection, molecular sieve selection, and magnetic separation. In contrast to pristine CNTs, ILs@CNTs demonstrate significantly enhanced adsorption of phenylurea herbicides (PUHs). The complex interactions between ILs@CNTs and PUHs were comprehensively analyzed using a combination of experimental results and theoretical calculations. Furthermore, a magnetic solid phase extraction-high performance liquid chromatography (MSPE-HPLC) method was developed for the determination of multiple trace PUHs in real samples. The method exhibited lower detection limits (0.02-0.03 µg L-1) and higher enrichment factors (131 < EFs < 185). Interestingly, a portable lab-in-a-syringe device was developed to facilitate rapid on-site extraction and enrichment of PUHs. Additionally, the developed methods successfully applied in river water, tea drinks, and cucumber samples, highlighting its substantial potential for rapid PUH detection.

Current analytical strategies for the determination of resveratrol in foods.

Resveratrol, a non-flavonoid polyphenolic compound, possesses various beneficial properties such as anti-cancer, anti-aging, anti-bacterial, and antioxidant effects. It is naturally produced by many plants in response to stimulation. However, the content of resveratrol in natural plants can vary significantly, ranging from micrograms to milligrams per kilogram. As the demand for resveratrol increases, the development of methods for extracting and quantifying resveratrol in food has become a rapidly growing field in recent years. This review aims to comprehensively summarize the progress made in resveratrol analysis in food over the past decade (2012-2022), with a specific focus on the latest advancements in extraction and detection technologies. The objective is to offer a valuable reference for further research and utilization of resveratrol in various food applications.

Flaxseed oleosomes: Responsiveness to physicochemical stresses, tribological shear and storage.

This study aimed to extract oleosomes (OLs) from flaxseeds and assess their response to environmental conditions during storage (pH and ionic strengths), shear and tribological stresses. Our hypothesis was that a shear-induced instability will enable OLs to exhibit favourable lubrication performance. During storage, OLs exhibited resistance to droplet aggregation for up to 6 weeks owing to the proteins (3.5-152.8 kDa molecular weights) stabilizing the OL droplets. However, presence of divalent (Ca2+) ions induced destabilization with marked increase in droplet size (p < 0.05). OLs demonstrated shear thinning behaviour, displaying an order of magnitude higher viscosity than flaxseed oil (FSO) at low shear rates (<10 s-1). Strikingly, OLs mirrored the frictional profile of FSO regardless of entrainment speeds, due to droplet coalescence, validating the hypothesis. Such kinetic stability with shear-induced coalescing feature of OLs hold strong potential for future plant-based food development, particularly in achieving desired mouthfeel characteristics.

Food Allergens of Plant and Animal Origin: Classification, Characteristics, and Properties.

Food allergy is an adverse immune response to specific foods that can be either IgE-mediated or non-IgE mediated. The causes of IgE-mediated food allergy are multifactorial and involve genetic, dietary, and environmental factors. The prevalence of food allergy has increased over the last few decades, especially in urbanized, industrialized, and Westernized countries, and the epithelial barrier hypothesis has been recently suggested as a possible explanation for this increase. Food allergens of plant and animal origin are classified into a few families and superfamilies that are widely distributed and conserved. While it is known that food allergens share common properties, such as stability to enzymes and solubility, they also exhibit differential properties, and exceptions to the common characteristics exist. In recent years, novel characteristics of food allergens have been proposed based on their immunological properties and their ability to act as adjuvants or enhancers of the immune system.This chapter provides an overview of the current knowledge of food allergy, covering their prevalence, classification of food allergens from plant and animal origins, and recent advancements in the characterization of the properties of these allergens.

Mass Cytometry in Food Allergy Research.

Mechanisms underlying food allergy are not well understood. Mass cytometry is a technique that allows the multiple analysis of cell surface markers and intracellular proteins by using the spectrum of rare metal isotopes of different atomic masses without channel overlap. Bioinformatic approaches are implemented to combine and reduce the information of more than 60 parameters to define immune cell subpopulations. To date, mass cytometry has revealed a great heterogeneity in human response to food antigens and that subpopulations of basophils and mononuclear cells might be mechanistically implicated in food allergy. This chapter reviews some fundamentals of mass cytometry and the contributions of this technique in elucidating the immune basis of food allergy, oral tolerance, food desensitization, phenotypes, and the cellular events occurring upon allergen-specific immunotherapy.

Structural Characterization of Food Allergens by Nuclear Magnetic Resonance Spectroscopy.

As allergies, especially those triggered by food, are becoming more and more prevalent, it is of increasing importance to fully understand the structures and dynamic behaviors of allergenic proteins along with their interactions with potential natural ligands. Therefore, we have established a solid routine to achieve structural characterization of food allergens, especially for birch pollen-related cross-reactive proteins from the class 10 of pathogenesis-related proteins (PR-10), by nuclear magnetic resonance (NMR) spectroscopy. Following expression of the desired allergen in Escherichia coli in isotope-labeled minimal media, the three-dimensional solution structures of these proteins can be determined, and insight into ligand binding mechanics and structural dynamic properties are accessible through NMR spin relaxation experiments.

1D-, 2D-Gel Electrophoresis, Immunoblotting, and Enzyme-Linked Immunosorbent Assay (ELISA) for the Study of Food Allergens.

Protein-based methods have been fundamental for the study of food allergens, not only from a mechanistic and diagnostic point of view, but especially with respect to allergen management and food safety. In this chapter, four individual protocols are suggested, relying on one-dimensional, two-dimensional gel electrophoresis, immunoblotting, and enzyme-linked immunosorbent assay (ELISA). The particularities of the proposed protocols are focused on previous research targeting specific allergenic foods, with cow's milk proteins as case studies. Data on the importance of protein extraction and the use of different animal-raised antibodies and/or sera of food-allergic patients are also critically discussed within method development and optimization. The protocols herein described are successful examples applied to the study of cow's milk allergens in complex matrices, although they can be easily developed and optimized for any food allergen or allergenic food.

Preparation of Blinded Food Matrixes for Clinical Oral Challenges.

Clinically, oral food challenges have value in the diagnosis and management of food allergy. Oral food challenges are used not only for diagnostic confirmation that ingestion of a specific food elicits an adverse reaction, but also for determining individual threshold doses, tracking the progress toward desensitization during immunotherapy, determining the effect of processing on the allergenicity of a specific food, assessing the allergenicity of an ingredient derived from an allergenic source, and tracking the progress toward development of age-related tolerance to a specific food. To eliminate bias in oral challenges, the food under investigation is masked in a matrix so that it is not sensorially detectable by the patient or the clinical observer. The preparation of oral challenge foods requires care in the selection of the allergenic components, the selection of the components of the matrix, the masking of the allergenic component, and the homogeneity of the allergen in the overall matrix.

Standardization of Food Allergen Measurements Using Multiplex Array Technology.

Multiplex suspension array technology enables multiple protein analytes to be measured in a single assay. In this chapter, we describe a polystyrene bead-based fluorescent multiplex array for quantitative measurements of specific food allergens. The array uses monoclonal antibodies for allergen detection and purified allergens as reference standards. Each component of the array can be standardized. The array measures up to 17 foods that are regulated in the United States, the European Union, and Japan.