A cell-based electrochemical taste sensor for detection of Hydroxy-α-sanshool.

The Transient Receptor Potential Vanilloid 1 (TRPV1) has been identified as a suitable candidate for a spicy taste (Zanthoxylum plant) sensor. In this study, we investigated the response of TRPV1 expressed on human HepG2 cell membranes following stimulation with Hydroxy-α-sanshool. A three-dimensional (3D) cell-based electrochemical sensor was fabricated by layering cells expressing hTRPV1. l-cysteine/AuNFs electrodes were functionalized on indium tin oxide-coated glass (ITO) to enhance the sensor's selectivity and sensitivity. HepG2 cells were encapsulated in sodium alginate/gelatin hydrogel to create a 3D cell cultivation system, which was immobilized on the l-cysteine/AuNFs/ITO to serve as biorecognition elements. Using differential pulse voltammetry (DPV), the developed biosensor was utilized to detect Hydroxy-α-sanshool, a representative substance in Zanthoxylum bungeanum Maxim. The result obtained from DPV was linear with Hydroxy-α-sanshool concentrations ranging from 0 to 70 µmol/L, with a detection limit of 2.23 µmol/L. This biosensor provides a sensitive and novel macroscopic approach for TRPV1 detection.

Simultaneous quantitation of free fatty acid in rice by synergetic data fusion of colorimetric sensor arrays, NIR, and MIR spectroscopy.

This study evaluated the feasibility of colorimetric sensor array (CSA), near-infrared (NIR) and mid-infrared (MIR) spectroscopy for quantitation of free fatty acids in rice using data fusion. Purposely, different data sets of low-level (CSA-NIRLL, CSA-MIRLL, and NIR-MIRLL) and mid-level (CSA-NIRML, CSA-MIRML, and NIR-MIRML) fusion were adopted to enhance the statistical parameters. The model performance was evaluated using coefficient of determination for prediction, (R2p), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD). Synergetic low-level and mid-level fusion model yielded 0.7707 ≤ R2p ≤ 0.8275, 14.4 ≤ RMSEP ≤ 16.3 and 2.19 ≤ RPD ≤ 2.48; and 0.7788 ≤ R2p ≤ 0.8571, 12.4 ≤ RMSEP ≤ 16.8 and 2.12 ≤ RPD ≤ 2.88, respectively. The CSA-NIRML model delivered an optimal performance for prediction of free fatty acid. The integration of CSA, NIR and MIR was feasible and could improve the prediction accuracy of free fatty acids in rice.

Classification of Black Mahlab seeds (Monechma ciliatum) using GC-MS and FT-NIR and simultaneous prediction of their major volatile compounds using chemometrics.

The identification of geographical origin is an important factor in assessing the quality of aromatic and medicinal seeds such as Black Mahlab (Monechma ciliatum). However, at present, there are no studies concerning Black Mahlab Seeds (BMSs). To identify the geographical origin of BMSs, we have used gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FT-NIR) combined with chemometrics. Chemometrics analysis showed that FT-NIR and GC-MS can be used to discriminate the geographical origin of BMSs. FT-NIR coupled with the partial least squares regression (PLSR) was applied to develop the calibration models. The calibration models had a coefficient of determination (Rc2) of 0.82 for coumarin and 0.81 for methyl salicylate. The prediction model (Rp2) values ranged from 0.83 for coumarin to 0.77 for methyl salicylate. Overall, the chemometrics presented correct classification, and PLSR accurately predicted the volatiles, with an RMSEP range of 0.9 to 0.16 for the two volatiles targeted.

Intelligent colorimetric pH sensoring packaging films based on sugarcane wax/agar integrated with butterfly pea flower extract for optical tracking of shrimp freshness.

A novel pH colorimetric film was prepared from various sugarcane wax (SW) concentrations (1, 1.5 and 2% w/v) on agar matrix (Agr) combined with butterfly pea flower (BF) extract for monitoring the shrimp freshness. A combination of BF anthocyanins with SW as lipid (hydrophobic) showed different changes in color under acidic conditions (pH 2-6) with slight changes under alkalinity (pH 7-12), which matched the visual color changes of two different ammonia vapors (50 and 100 mmol/l). FTIR, XRD spectra, and SEM micrographs revealed that SW was effectively fixed into the Agr-BF network during the film-forming process. The different homogenized SW films enhanced the physical and mechanical properties without significant differences in elongation and water vapor permeability. Remarkably, SW films displayed complete protection against UV-vis light (0%) and valuable reduction in visible light. This study presents SW colorimetric films as promising natural derivatives for smart packaging in tracking food freshness.

In situ prediction of phenolic compounds in puff dried Ziziphus jujuba Mill. using hand-held spectral analytical system.

A low cost hand-held spectral analytical system was developed for in situ screening of phenolics and flavonoids in puff dried Ziziphus jujuba (Z. Jujuba) samples. Standards of gallic acid, caffeic acid, l-epicatechin, phloridzin and cianidanol were used to quantify the individual phenolics and flavonoids using high performance liquid chromatography-diode array detector (HPLC-DAD). The synergy interval partial least square with ant colony optimization (Si-ACO-PLS) was attempted to optimize and capture informative variables for the prediction of target compounds. The model performance was evaluated using correlation coefficients of prediction (Rp); root mean square error of prediction (RMSEP) and residual predictive deviation (RPD). The Si-ACO-PLS yielded optimal performance, 0.8540 ≤ Rc ≤ 0.9250, 0.8360 ≤ Rp ≤ 0.9056, 0.84 ≤ RMSEP ≤ 16.30 and 2.03 ≤ RPD ≤ 2.26. The hand-held spectral analytical system coupled with Si-ACO-PLS proved to the reliable, rapid and cost-effective method to quantify the phenolics and flavonoids in Z. Jujuba.