Visual determination of oxidation of edible oil by a nanofiber mat prepared from polyvinyl alcohol and Schiff's reagent

Polymeric Nanofibers via Green Electrospinning for Safe Food Engineering

Electrospun functional nanofibers enable controlled release of the loaded active ingredient and an adjustable dissolution rate. However, the widespread use of toxic organic solvents in electrospinning poses risks to human health and the environment whereas increasing production costs and complexity. This article examines the application of eco-friendly electrospinning technologies in food engineering, with a focus on water-based and melt electrospinning methods. It provides a detailed analysis of water-soluble biopolymers and synthetic polymers, highlighting their current applications and challenges in food engineering. Water-based electrospinning is proposed as a sustainable alternative, offering scalability and reduced environmental impact. This transition is essential for advancing food engineering toward more sustainable and environmentally responsible practices.

Fast visual detection of sunflower oil thermal oxidation using Polyacrylonitrile/Congo red nanofiber mats

Lipid oxidation monitoring is essential for food safety and quality, but traditional techniques are expensive and complicated for daily use. This study developed novel nanofiber mats using solution-blowing spinning technology to visually detect the oxidation of sunflower oil that was heated for six hours at 200 °C. These mats (Mat_1-9) are made from polyacrylonitrile (compatible with the used technique) containing various concentrations of Congo red as pH-sensitive dye (0.0025, 0.005, and 0.01 %) and hydroxylamine hydrochloride (0.125, 0.250, and 0.50 %) that react with volatile oxidation compounds to produce a striking color change. Results indicated an increase in peroxide and acid values after six hours. Mat_9 outperformed Mat_1 with a high color change (27.74 ± 0.2) and a response time of only 5 s, whereas Mat_1 took 65 s and had a far lesser response. These mats enable non-experts and food auditors to quickly assess oil quality while efficiently promoting food safety and consumer health.

An overview of the detection methods to the edible oil oxidation degree: Recent progress, challenges, and perspectives

Oil oxidation, the main quality-deteriorated reaction, would significantly and negatively influence its quality and safety during processing and storage. Evaluating oil oxidation degree is an effective strategy to enable early warning and ensure food safety. Herein, principles, recent progresses, advantages and shortcomings, representative applications, current challenges and promising perspectives, and summary tables of traditional (titration), instrumental (chromatography and spectroscopy), and especially rapid detection methods (chemical colorimetric methods and portable miniaturized devices) for evaluating oil oxidation degree are presented and reviewed. It is believed that rapid detection methods are the most promising practical candidate for detecting oil oxidation. Also, the interaction between advanced data-processing techniques and detection methods, and the systematic integration of whole analytical processes is proposed as next-generation perspectives in the oil oxidation evaluation. We wish to provide the knowledge of oil oxidation degree determination and enlighten novel strategies.

Classification of Sesame Oil Based on Processing-Originated Differences in the Volatile Organic Compound Profile by a Colorimetric Sensor

Fragrant edible sesame oil is popular for its unique aroma. The aroma of sesame oil is determined by its volatile organic compound (VOC) profile. Sesame oils produced by different techniques could have different VOC profiles. In addition, blending fragrant sesame oil with refined oil could also alter the VOC profile of the final product. Current practices in aroma analysis, such as sensory evaluation and gas chromatography (GC), still face many restraints. Hence, there is a need for alternatives. We present a novel 14-unit multiplexed paper-based colorimetric sensor for fragrant sesame oil VOC analysis. The sensor was designed to visualize the VOC profile as a color "fingerprint". The sensor was validated with 55 branded sesame oil samples produced by two different techniques, i.e., hot pressing and small milling; the experimental results suggested a processing dependency in color VOC fingerprints. The sensor also demonstrated the potential to detect the change in sesame oil VOC profile due to blending with refined oil, with an estimated limit of detection down to 20% v/v of the refined oil. The colorimetric sensor might be used as a simple, rapid, and cost-effective analytical tool in the production and quality control of fragrant sesame oil.

A sensitive paper-based vapor-test kit for instant formalin detection in food products

A colorimetric sensing method based on a paper-based vapor-test kit was successfully developed for the selective and sensitive real-time monitoring of formalin in food samples. The device was specifically designed to efficiently extract and detect formalin simultaneously. A microcentrifuge tube was used as the sample solution container, with the inner cap serving as the reaction and detection zone. Formalin was converted into gaseous formaldehyde through controlled heating, which was then extracted and collected on a filter paper coated with Nash's reagent. The color change on paper was used for formalin quantification using a smartphone for detection and image analysis. Under optimal conditions, our method provided a linear range of 0.5-75 mg L-1 with a detection limit of 0.11 mg L-1. This method effectively determined formalin in fresh food and vegetable samples, with recoveries ranging from 92 to 111%, demonstrating comparable accuracy to the standard method for practical food quality control and safety.

A review on colorimetric indicators for monitoring product freshness in intelligent food packaging: Indicator dyes, preparation methods, and applications

Intelligent food packaging system exhibits enhanced communication function by providing dynamic product information to various stakeholders (e.g., consumers, retailers, distributors) in the supply chain. One example of intelligent packaging involves the use of colorimetric indicators, which when subjected to external stimuli (e.g., moisture, gas/vapor, electromagnetic radiation, temperature), display discernable color changes that can be correlated with real-time changes in product quality. This type of interactive packaging system allows continuous monitoring of product freshness during transportation, distribution, storage, and marketing phases. This review summarizes the colorimetric indicator technologies for intelligent packaging systems, emphasizing on the types of indicator dyes, preparation methods, applications in different food products, and future considerations. Both food and nonfood indicator materials integrated into various carriers (e.g., paper-based substrates, polymer films, electrospun fibers, and nanoparticles) with material properties optimized for specific applications are discussed, targeting perishable products, such as fresh meat and fishery products. Colorimetric indicators can supplement the traditional "Best Before" date label by providing real-time product quality information to the consumers and retailers, thereby not only ensuring product safety, but also promising in reducing food waste. Successful scale-up of these intelligent packaging technologies to the industrial level must consider issues related to regulatory approval, consumer acceptance, cost-effectiveness, and product compatibility.

A colorimetric sensor array for rapid discrimination of edible oil species based on a halogen ion exchange reaction between CsPbBr3 and iodide

Halogen exchange of iodides with CsPbBr3 NCs generates CsPbI3, which differs in its content and directly causes different photoluminescence responses.

Mechanism, indexes, methods, challenges, and perspectives of edible oil oxidation analysis

Edible oils are indispensable food components, because they are used for cooking or frying. However, during processing, transport, storage, and consumption, edible oils are susceptible to oxidation, during which various primary and secondary oxidative products are generated. These products may reduce the nutritional value and safety of edible oils and even harm human health. Therefore, analyzing the oxidation of edible oil is essential to ensure the quality and safety of oil. Oxidation is a complex process with various oxidative products, and the content of these products can be evaluated by corresponding indexes. According to the structure and properties of the oxidative products, analytical methods have been employed to quantify these products to analyze the oxidation of oil. Combined with proper chemometric analytical methods, qualitative identification has been performed to discriminate oxidized and nonoxidized oils. Oxidative products are complex and diverse. Thus, proper indexes and analytical methods should be selected depending on specific research objectives. Expanding the mechanism of the correspondence between oxidative products and analytical methods is crucial. The underlying mechanism, conventional indexes, and applications of analytical methods are summarized in this review. The challenges and perspectives for future applications of several methods in determining oxidation are also discussed. This review may serve as a reference in the selection, establishment, and improvement of methods for analyzing the oxidation of edible oil. HighlightsThe mechanism of edible oil oxidation analysis was elaborated.Conventional oxidation indexes and their limited values were discussed.Analytical methods for the determination of oxidative products and qualitative identification of oxidized and non-oxidized oils were reviewed.

Instant and Multiple DNA Extraction Method by Microneedle Patch for Rapid and on-Site Detection of Food Allergen-Encoding Genes

DNA-based detection methods are highly promising for risk assessment in the food sector, such as tracing the existence of food allergens. However, due to the complexity of food matrices, cumbersome protocols are often needed to isolate the DNA components, which hinder the achievement of rapid and on-site detection. Herein, an instant and multiple DNA extraction method was developed based on the poly(vinyl alcohol) microneedle (MN) patch. With simple press and peel-off operations within 1 min, samples suitable for DNA-based analysis such as polymerase chain reaction (PCR) could be collected. By further combining with the recombinase polymerase amplification assay, rapid screening of the allergenic risks in complex samples such as shrimp ball and cheesecake could be achieved within 30 min. The MN-based DNA extraction method not only was a potential alternative to the traditional DNA extraction method but provided a transformative approach in realizing rapid, on-site detection of foodborne hazards in collaborating with fast DNA-based assays.