Pectin extracted from apple pomace and citrus peel by subcritical water

Purpose of reviewIntake of dietary phytochemicals has frequently been associated with health benefits. Noninfectious diseases including cardiovascular disease (CVD), cancer and diabetes are major causes of death, whereas dementia cases are also increasing to ‘epidemic’ proportion. This review will f

The role of phytochemicals as micronutrients in health and disease.

Molecularly imprinted polymers (MIPs) have emerged over the past few decades as interesting synthetic alternatives due to their long-term chemical and physical stability and low-cost synthesis procedure. They have been integrated into many sensing platforms and assay formats for the detection of various targets, ranging from small molecules to macromolecular entities such as pathogens and whole cells. Despite the advantages MIPs have over natural receptors in terms of commercialization, the striking success stories of biosensor applications such as the glucose meter or the self-test for pregnancy have not been matched by MIP-based sensor or detection kits yet. In this review, we zoom in on the commercial potential of MIP technology and aim to summarize the latest developments in their commercialization and integration into sensors and assays with high commercial potential. We will also analyze which bottlenecks are inflicting with commercialization and how recent advances in commercial MIP synthesis could overcome these obstacles in order for MIPs to truly achieve their commercial potential in the near future.

MIPs for commercial application in low-cost sensors and assays - An overview of the current status quo

Fluorescence carbon nanomaterials-based sensors for accurate tracing of pesticides in environmental, food and biological samples have gained considerable interest in the past decade years to protect ecosystem, guarantee food safety and prevent disease, making it a trending hot-spot. This review focuses on recent advances and new trends of pesticides monitoring (including organophosphorus, neonicotinoids and carbamates pesticides) on the base of fluorescence carbon nanomaterials, with particular emphasis on zero-dimensional (0-D) carbon dots/graphene quantum dots, 2-D carbon nitride nanosheets and 3-D carbon-based metal/covalent organic frameworks. These fluorometric strategies are classified by several main recognition unit, including enzyme, antibody, aptamer and molecularly-imprinted polymers, offering great performance for pesticides with a limit of detection down to pg mL−1 level. Beyond performance comparison of these emerging sensors with other strategies, we discuss the existing hurdles and present challenges to practical sensor designs, followed by exploring future perspectives for breakthroughs in fluorescence carbon nanomaterials-based sensors.

Biosensors based on fluorescence carbon nanomaterials for detection of pesticides

Carbon quantum dots (CQDs) with stable physicochemical properties are one of theemerging carbon nanomaterials that have been studied in recent years. In addition to the excellentoptical properties such as photoluminescence, photobleaching resistance and light stability, thismaterial also has favorable advantages of good biocompatibility and easy functionalization, whichmake it an ideal raw material for constructing sensing equipment. In addition, CQDs can combinedwith other kinds of materials to form the nanostructured composites with unique properties, whichprovides new insights and ideas for the research of many fields. In the field of food analysis,emerging CQDs have been deeply studied in food composition analysis, detection and monitoringtrace harmful substances and made remarkable research progress. This article introduces andcompares the various methods for CQDs preparation and reviews its related sensing applicationsas a new material in food components analysis and food safety inspection in recent years. It isexpected to provide a significant guidance for the further study of CQDs in the field of foodanalysis and detection. CQDs; synthesis; fluorescent sensing; food analysis.

Fluorescent Carbon Quantum Dots-Synthesis,Functionalization and Sensing Application in FoodAnalysis.

Digital image colorimetry on smartphone for chemical analysis: A review

The rapid detection of organophosphorus pesticide residues in food is crucial to food safety. One type of novel, magnetic, molecularly-imprinted polymeric microsphere (MMIP) was prepared with vinyl phosphate and 1-octadecene as a collection of dual functional monomers, which were screened by Gaussian09W molecular simulation. MMIPs were used to enrich organic phosphorus, which then detected by fluorescence quenching in vinyl phosphate-modified carbon dots (CDs@VPA) originated from anhydrous citric acid. MMIPs and CDs@VPA were characterized by TEM, particle size analysis, FT-IR, VSM, XPS, adsorption experiments, and fluorescence spectrophotometry in turn. Through the fitting data from experiment and Gaussian quantum chemical calculations, the molecular recognition properties and the mechanism of fluorescence detection between organophosphorus pesticides and CDs@VPA were also investigated. The results indicated that the MMIPs could specifically recognize and enrich triazophos with the saturated adsorption capacity 0.226 mmol g-1, the imprinting factor 4.59, and the limit of recognition as low as 0.0006 mmol L-1. Under optimal conditions, the CDs@VPA sensor has shown an extensive fluorescence property with a LOD of 0.0015 mmol L-1 and the linear range from 0.0035 mmol L-1 to 0.20 mmol L-1 (R2 = 0.9988) at 390 nm. The mechanism of fluorescence detection of organic phosphorus with CDs@VPA sensor might be attributable to hydrogen bonds formed between heteroatom O, N, S, or P, and the O-H group, which led to fluorescent quenching. Meanwhile, HN-C=O and Si-O groups in CDs@VPA system might contribute to cause excellent blue photoluminescence. The fluorescence sensor was thorough successfully employed to the detection of triazophos in cucumber samples, illustrating its tremendous value towards food sample analysis in complex matrix.

https://www.mdpi.com/2073-4360/11/11/1770/pdf

Vinyl Phosphate-Functionalized, Magnetic, Molecularly-Imprinted Polymeric Microspheres' Enrichment and Carbon Dots' Fluorescence-Detection of Organophosphorus Pesticide Residues.

Compared with epigallocatechin gallate (EGCG), its epimer gallocatechin gallate (GCG) is more stable and more bioactive, even when least contained in green tea. In this study, EGCG can be selectively epimerized into GCG catalyzed by a phosphate buffer (pH 5.8) at 60 °C for 2 h with the highest yield of 65.6 %. A plausible mechanism for this conversion was also presented. To evaluate the anti-diabetic activity of GCG, we had investigated an oral glucose tolerance test and determined the plasma levels of glucose, insulin, triglyceride, and free fatty acid in a streptozotocin-induced diabetic rat model system. The results suggested that both GCG and EGCG might have anti-diabetic effects by increasing sensitivity of insulin, and GCG is more active than EGCG.

Epimerization of epigallocatechin gallate to gallocatechin gallate and its anti-diabetic activity

The overuse of cartap in tea tree leads to hazardous residues threatening human health. A colorimetric determination was established to detect cartap residues in tea beverages by silver nanoparticles (AgNP) sensor with magnetic molecularly imprinted polymeric microspheres (Fe3O4@mSiO2@MIPs) as recognition elements. Using Fe3O4 as supporting core, mesoporous SiO2 as intermediate shell, methylacrylic acid as functional monomer, and cartap as template, Fe3O4@mSiO2@MIPs were prepared to selectively and magnetically separate cartap from tea solution before colorimetric determination by AgNP sensors. The core-shell Fe3O4@mSiO2@MIPs were also characterized by FT-IR, TEM, VSM, and experimental adsorption. The Fe3O4@mSiO2@MIPs could be rapidly separated by an external magnet in 10 s with good reusability (maintained 95.2% through 10 cycles). The adsorption process of cartap on Fe3O4@mSiO2@MIPs conformed to Langmuir adsorption isotherm with maximum adsorption capacity at 0.257 mmol/g and short equilibrium time of 30 min at 298 K. The AgNP colorimetric method semi-quantified cartap ≥5 mg/L by naked eye and quantified cartap 0.1–5 mg/L with LOD 0.01 mg/L by UV-vis spectroscopy. The AgNP colorimetric detection after pretreatment with Fe3O4@mSiO2@MIPs could be successfully utilized to recognize and detect cartap residues in tea beverages.

/pdf/rapid-colorimetric-detection-of-cartap-residues-by-agnp-56s1ro6scd.pdf

Rapid Colorimetric Detection of Cartap Residues by AgNP Sensor with Magnetic Molecularly Imprinted Microspheres as Recognition Elements.

Excessively intaking caffeine can harm human health, and it is imperative to develop a rapid method to identify caffeine for food safety. The magnetic molecularly imprinted polymeric microspheres (MMIPs) were prepared to pretreat samples before silver nanoparticles (AgNPs) colorimetric detection of caffeine. Using Fe3O4 as supporting core, mesoporous SiO2 as intermediate shell, a-methylacrylic acid as functional monomer and caffeine as template, the prepared MMIPs were characterised by transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer. Adsorption process followed Langmuir adsorption isotherm with maximum adsorption capacity at 38.8 mg g 1 under 298 K. The MMIPs extract caffeine from beverages, then the AgNPs colorimetric method rapidly screened and semi-quantified caffeine ≥5 mg L 1 by naked eye, and accurately quantified caffeine ranging 0.1–5 mg L 1 by UV-vis spectroscopy at 393 nm, which were consistent with HPLC analytical results. Thus, this method might be used to rapidly enrich and analyse caffeine in beverages.

Rapidly colorimetric detection of caffeine in beverages by silver nanoparticle sensors coupled with magnetic molecularly imprinted polymeric microspheres

Yaping Guo

Papers

Digital image colorimetry on smartphone for chemical analysis: A review

Vinyl Phosphate-Functionalized, Magnetic, Molecularly-Imprinted Polymeric Microspheres' Enrichment and Carbon Dots' Fluorescence-Detection of Organophosphorus Pesticide Residues.

Epimerization of epigallocatechin gallate to gallocatechin gallate and its anti-diabetic activity

Rapid Colorimetric Detection of Cartap Residues by AgNP Sensor with Magnetic Molecularly Imprinted Microspheres as Recognition Elements.

Rapidly colorimetric detection of caffeine in beverages by silver nanoparticle sensors coupled with magnetic molecularly imprinted polymeric microspheres