Edible colorimetric label based on immobilized purple sweet potato anthocyanins onto edible film for packaged mushrooms freshness monitoring.

An edible colorimetric label has been developed to determine the freshness level of mushrooms, i.e. white oyster mushrooms ().

Cloth-based microfluidic devices integrated onto the patch as wearable colorimetric sensors for simultaneous sweat analysis.

Introduction: In this work, a flexible, and wearable point-of-care (POC) device integrated on a pain relief patch as wearable colorimetric sensors have been developed for sweat analysis, such as lactic acid, sodium ions, and pH simultaneously. Herein, the patch has still functioned as pain relief, while it allows for sweat monitoring during exercise, and in daily activities.

Methods: It was constructed on cotton cloth using wax printing technology (batik stamp) as cloth-based microfluidic devices (CMDs).

Development of the paper-based colorimetric sensor for simple and fast determination of quercetin in guava leaf extract.

This present study aimed to develop a paper-based colorimetric sensor in the form of paper-microzone plates (PµZP), for simple and fast quercetin determination in guava leaf extract samples. Here, N-bromosuccinimide (NBS) solution was immobilized on the microzone as a sensing probe, where quercetin solution can be dropped on it to form red-purplish color adducts which can be seen by the naked eye or captured using a flatbed scanner. The color intensity of the microzone can be quantified against a blank solution and used as analytical data in scanometric assay.

Colorimetric Paper-Based Dual Indicator Label for Real-Time Monitoring of Fish Freshness.

Research Background: Fish freshness and quality monitoring are of high importance for consumers, retailers and fishing industry. Therefore, developing novel approaches that are simple, fast, non-destructive and inexpensive to monitor fish freshness in real time is of great value. One alternative is using Intelligent or smart packaging to monitor the freshness or conditions of packaged fish.

Amperometric microbial biosensor for sugars and sweetener classification using principal component analysis in beverages.

Unlabelled: Sugar and artificial sweeteners are additives in packaged food and beverage products that are widely used, where excessive sugar consumption can cause an increase in various diseases. Detection and classification of natural sugars sucrose, fructose, glucose, and artificial sweetener aspartame are needed to determine the effects of consuming these sweeteners. This study uses an amperometric biosensor integrated biochip-D, which uses as a bioreceptor through cellular metabolic respiration activity expressed in dissolved oxygen (DO) levels.

Paper-Based Electrochemical Biosensors for Food Safety Analysis.

Nowadays, foodborne pathogens and other food contaminants are among the major contributors to human illnesses and even deaths worldwide. There is a growing need for improvements in food safety globally. However, it is a challenge to detect and identify these harmful analytes in a rapid, sensitive, portable, and user-friendly manner.

Simple monitoring of pH and urea in whole blood using wearable smart woman pad.

In this work, we used a thread-paper microfluidic device (μTPAD) system, where a threaded part for the handling of the whole blood samples and a paper part for the reaction of plasma with immobilized bioreagents integrated into woman pad as a wearable sensing device namely as smart women pad. The μTPAD as a wearable smart woman pad is developed for the detection of pH and urea in mensuration blood as real samples. This combined device was constructed to cover the elements required, that is, separation of red blood cell, conditioning, analyte reaction, and colorimetric detection.

Paper microzone plate based on DPPH as a simple colorimetric assay of the total antioxidant content of herbal extracts.

The human body needs an antioxidant-rich diet that comes from foods, beverages, and herbal products to support the physiological antioxidant systems. Thus, the development of an analytical tool for a simple assay of the total antioxidant capacity (TAC) of the rich antioxidant samples is crucial. The current work demonstrates a simple colorimetric assay of TAC of the herbal extract on the paper microzone plate (PµZP) that was constructed in the 70-well of patterned paper using the screen printing technique.

Development of an easy-to-use colorimetric pH label with starch and carrot anthocyanins for milk shelf life assessment.

An intelligent freshness indicator was developed by immobilizing anthocyanins of black carrot (ABC) within the starch matrix (total anthocyanins content of 10 mg/100 mL) to monitor freshness/spoilage of milk. The microstructural, spectral, swelling and solubility properties as well as color stability (as a function of time, temperature and light) of the indicator at different pHs were characterized. The incorporation of ABC did not change the swelling index and water solubility.

Cellulose/chitosan pH-responsive indicator incorporated with carrot anthocyanins for intelligent food packaging.

In this study, the possible use of anthocyanins of black carrot (ABC) as a chemo-responsive dye to fabricate a colorimetric pH indicator in a cellulose-chitosan matrix was investigated in order to the monitoring of spoilage in pasteurized milk. Cellulose paper was impregnated with a chitosan solution prepared by a sol-gel method containing ABC (total anthocyanins content of 10 mg/100 mL) and characterized. The swelling and water solubility increased by incorporation of ABC into the chitosan-cellulose film.

Monomyristin and Monopalmitin Derivatives: Synthesis and Evaluation as Potential Antibacterial and Antifungal Agents.

In the present work, monoacylglycerol derivatives, i.e., 1-monomyristin, 2-monomyristin, and 2-monopalmitin were successfully prepared from commercially available myristic acid and palmitic acid.

Characterization of cellulosic paper coated with chitosan-zinc oxide nanocomposite containing nisin and its application in packaging of UF cheese.

A new antimicrobial bilayer film was developed using chitosan, cellulose, and nisin. Chitosan solution containing nisin (500 and 1000μg/mL) was prepared by sol-gel method and then the solution was coated on cellulose paper by dip coating method. A chitosan-cellulose film without antimicrobial had no inhibitory effect on Listeria monocytogenes, whereas, the incorporation of nisin made a significant increase (P<0.

Rapid test for the determination of total phenolic content in brewed-filtered coffee using colorimetric paper.

This work was aimed to develop a chemical sensor for the determination of total polyphenol content (TPC) of coffee samples. The polyphenol sensor was based on co-immobilization of NaIO and MBTH in paper as a test strip. The sensor showed sensitive response to chlorogenic acid by forming pink color adduct which can be scanned and quantified by Imagej program.

Scanometry as microplate reader for high throughput method based on DPPH dry reagent for antioxidant assay.

The stable chromogenic radical 1,1'-diphenyl-2-picrylhydrazyl (DPPH) solution was immobilized on the microwell plate as dry reagent to construct a simple antioxidant sensor. Then, a regular flatbed scanner was used as microplate reader to obtain analytical parameters for antioxidant assay using one-shot optical sensors as scanometry technique. Variables affecting the acquisition of the images were optimized and the analytical parameters are obtained from an area of the sensing zone inside microwell using the average luminosity of the sensing zone captured as the mean of red, green, and blue (RGB) value using ImageJ program.

Application of class-modelling techniques to infrared spectra for analysis of pork adulteration in beef jerkys.

The use of chemometrics to analyse infrared spectra to predict pork adulteration in the beef jerky (dendeng) was explored. In the first step, the analysis of pork in the beef jerky formulation was conducted by blending the beef jerky with pork at 5-80 % levels. Then, they were powdered and classified into training set and test set.

A simple visual ethanol biosensor based on alcohol oxidase immobilized onto polyaniline film for halal verification of fermented beverage samples.

A simple visual ethanol biosensor based on alcohol oxidase (AOX) immobilised onto polyaniline (PANI) film for halal verification of fermented beverage samples is described. This biosensor responds to ethanol via a colour change from green to blue, due to the enzymatic reaction of ethanol that produces acetaldehyde and hydrogen peroxide, when the latter oxidizes the PANI film. The procedure to obtain this biosensor consists of the immobilization of AOX onto PANI film by adsorption.

A novel high throughput method based on the DPPH dry reagent array for determination of antioxidant activity.

A stable chromogenic radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) is commonly used for the determination of antioxidant activity. In this paper, DPPH was dried into 96 well microplate to produce DPPH dry reagent array plate, based on which the highly sensitive and high throughput determination of antioxidant activities was achieved. The spectrophotometric characterization of the microplate containing dried or fresh DPPH free radicals was reported.

Selective chemosensor for Hg(II) ions based on tris[2-(4-phenyldiazenyl)phenylaminoethoxy]cyclotriveratrylene in aqueous samples.

A novel chemosensor, based on tris[2-(4-phenyldiazenyl)phenylaminoethoxy]cyclotriveratrylene (TPPECTV) as chromophore, has been developed for the colorimetric determination and visual detection of Hg(II) ions. TPPECTV exhibits a pronounced chromogenic behavior toward Hg(II) ions by changing the color of the solution from yellow to red-orange upon its addition, which can be easily detected with the naked-eye. Based on this sensing scheme a colorimetric method was developed, where the absorbance linearly increases as a function of the Hg(II) concentration up to 2.

An optical fiber biosensor for chlorpyrifos using a single sol-gel film containing acetylcholinesterase and bromothymol blue.

An optical fiber biosensor consisting of acetylcholinesterase (AChE) and bromothymol blue (BTB) doped sol-gel film was employed to detect organophosphate pesticide chlorpyrifos. The main advantage of this optical biosensor is the use of a single sol-gel film with immobilized AChE and BTB. The compatibility of this mixture (AChE and BTB) with the sol-gel matrix has prevented leaching of the film.

Optical sensing systems for microfluidic devices: a review.

This review deals with the application of optical sensing systems for microfluidic devices. In the "off-chip approach" macro-scale optical infrastructure is coupled, while the "on-chip approach" comprises the integration of micro-optical functions into microfluidic devices. The current progress of the use of both optical sensing approaches in microfluidic devices, as well as its applications is described.

Development of a disposable mercury ion-selective optode based on trityl-picolinamide as ionophore.

A disposable ion-selective optode for mercury based on trityl-picolinamide (T-Pico) as neutral ionophore was developed. The sensing layer consist of plasticised PVC incorporating T-Pico as a selective ionophore for Hg2+, ETH 5418 as a chromoionophore, and potassium tetrakis[3,5-bis(trifluoromethyl)phenyl] borate as lipophilic salt. The measurement principle is based on an ion-exchange mechanism.

Simple optical fibre biosensor based on immobilised enzyme for monitoring of trace heavy metal ions.

A simple optical fibre biosensor based on immobilised enzyme for monitoring of trace heavy metal ions has been developed. The biosensor recognition system was designed based on the inhibition of urease activity, where the urease is immobilised on ultrabind membrane. The studies of inhibition by the heavy metal ions Hg(II), Ag(I), Cu(II), Ni(II), Zn(II), Co(II) and Pb(II) were performed using a fibre-optic biosensor configuration, where the pH change resulting from the bio-catalytic hydrolysis of urea was monitored at the wavelength 615 nm spectroscopically, using commercial pH indicator strip before and after the exposure to the heavy metal ions.