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Eco-friendly thermosensitive magnetic-molecularly-imprinted polymer adsorbent in dispersive solid-phase microextraction for gas chromatographic determination of organophosphorus pesticides in fruit samples
(2024-01-01)
Seebunrueng, Ketsarin
;
Tamuang, Suparb
;
Jarujamrus, Purim
;
Saengsuwan, Sayant
;
Patdhanagul, Nopbhasinthu
A thermosensitive magnetic-molecularly-imprinted polymer (TMMIP) was successfully prepared in an aqueous medium. The TMMIP was applied as an effective adsorbent in dispersive solid-phase microextraction for the selective enrichment of five organophosphorus pesticides (OPPs; diazinon, fenitrothion, fenthion, parathion-ethyl, and ethion) before analysis by gas chromatography. The polymerization was performed using mixed-valence iron hydroxide nanoparticles as the magnetic support, N-isopropyl acrylamide as the thermosensitive monomer, ethion as the template, and methacrylic acid as the functional monomer. The adsorption and desorption mechanisms of OPPs depend on their interactions with the adsorbents and solution temperature. Our methodology provides good linearity (0.50–2000 µg L-1), with a correlation determination of R2 > 0.9980, low limit of detection (0.25–0.50 µg L-1), low limit of quantitation (0.50–1.50 μg L−1), and high precision (%RSD < 7%). The developed method demonstrates excellent applicability for accurately and efficiently determining OPP residuals in fruit and vegetable samples with good recoveries (93–117%).
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Efficiency of ultrasonic treatment on postharvest quality and bioactive compounds of ‘kim ju’ guava fruit during short-term storage at room temperature
(2021-01-01)
Supapvanich, Suriyan
;
Kijka, Chollawit
The purpose of this recent work was to investigate the efficiency of ultrasonic (US) treatment on the postharvest quality and bioactive compounds of ‘Kim Ju’ guava fruits during storage at room temperature (RT) (28±1°C) for 6 d. The fruit samples were sonicated at 40 kHz and 150 w for 10 min. Visual appearance, colour attributes, tweight loss, total soluble solids (TSS), titratable acidity (TA), texture, pectin substances, antioxidant activity, total phenols and flavonoids contents of the fruits were monitored during storage. The fruits treated with US had better visual appearance than that of untreated fruits. US treatment could delay weight loss but it had no effect on all colour attributes, TSS and TA of fruits. Fruit softening was inhibited by US treatment due to delay in the formation of increased soluble pectin and by decreased insoluble pectin contents. Moreover, US treatment could enhance antioxidant activity and the total phenols and flavonoids contents. Nevertheless, there was no change of ascorbic acid content in fruits during storage. These results suggest that US treatment is an effective postharvest approach, which could preserve postharvest quality and level of bioactive compounds of ‘Kim Ju’ guavas during short-term storage at RT.
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Grouping marian plums harvested at different times by transmittance near-infrared spectroscopy
(2017-11-25)
Teerachaichayut, S.
;
Phonmakham, S.
;
Suktanarak, S.
Marian plum (Bouea burmanica Griff.) ‘Toon Klaow’ is one of Thailand’s favorite fruits. Marian plum’s edible quality depends strongly on its harvest time. This study investigated a non-destructive technique for classifying marian plums according to their harvest time after the day that their blossom set. The non-destructive technique used was transmittance mode, short wavelength near-infrared (SW-NIR) spectroscopy in the wavelength range 660-960 nm. Marian plum samples (n=110) were harvested at 62, 65, 68 and 73 days after flowering. The soluble solids content (SSC) and titratable acid (TA) were determined accurately by standard methods. SW-NIR spectra of these samples were obtained and analyzed by principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The following spectral pretreatments were applied, standard normal variate (SNV), smoothing (Savitsky-Golay), and first derivative, in order to obtain optimal grouping results. The PC1 and PC2 score plot of the PCA could not clearly separate some of the classified groups. For the results of PLS-DA, its cross-validated grouping accuracy was R=0.91 and RMSECV=1.28; hence, it can be concluded that SW-NIR spectroscopy has good potential for determining the harvest time of marian plums.
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Non-destructive prediction of total soluble solids, titratable acidity and maturity index of limes by near infrared hyperspectral imaging
(2017-11-01)
Teerachaichayut, Sontisuk
;
Ho, Huong Thanh
This study was implemented for non-destructive prediction of total soluble solids (TSS), titratable acidity (TA) and calculation of TSS/TA as a measure of maturity index in intact limes using laboratory-based push-broom hyperspectral imaging (HSI) in reflectance mode in the range of 929–1671 nm. Limes were scanned by the HSI system in order to develop calibration models for predicting TSS, TA and TSS/TA using partial least square regression (PLSR). Original spectra obtained optimal conditions for establishing the models for TSS and TA while smoothing spectra for TSS/TA. The accuracy of the models for TSS, TA and TSS/TA provided coefficient of determination of prediction (R2<inf>p</inf>) of 0.838, 0.694 and 0.775, respectively and root mean square errors of prediction (RMSEP) of 0.237%, 0.288% and 0.049, respectively. Image processing algorithms were then built up by interpreting predictive values, from the models, to colors in each pixel of the images. The predictive visualization of TSS, TA and TSS/TA in all portions of the limes based on a color scale was presented. The results showed that the HSI technique has the capability of predicting TSS, TA and TSS/TA of intact limes non-destructively and the results could be visualized by different colors of the predictive images.
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Quantitative prediction of nitrate level in intact pineapple using Vis-NIRS
(2015-01-01)
Srivichien, Sasathorn
;
Terdwongworakul, Anupun
;
Teerachaichayut, Sontisuk
Before pineapples are canned, the ones with high nitrate level must be sorted out first because nitrate causes black stains on the surface of the can; therefore, a nondestructive technique for sorting out pineapples is clearly needed. The use of visible and near infrared (Vis-NIR) spectroscopy for such purpose was investigated in this study. A batch of 75 pineapple fruits that would have been delivered to a canning factory was tested. Spectra were acquired using a spectrophotometer in interactance mode with wavelengths in the region of 400-2500 nm. Twelve scans of different parts of each pineapple were made. The actual amount of nitrate in the pineapple flesh was determined by HPLC. Original spectra and pretreated spectra were both used to construct calibration models with partial least squares regression (PLSR). The best model was obtained from an average spectrum pretreated with first derivative treatment at the wavelength range of 600-1200 nm. Predictions based on this model matched closely with the actual nitrate contents, with a high correlation coefficient (R) of 0.95 and a low root mean square error of prediction (RMSEP) of 1.77 ppm. These results demonstrate that Vis-NIR spectroscopy can be used for rough screening of intact pineapple.
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Measuring geometric mean diameter of fruits and vegetables using light sectioning method
(2009-01-01)
Nunak, Navaphattra
;
Suesut, Taweepol
This paper proposes a new technique to measure the geometric mean diameter (GMD) of selected fruits and vegetables calculated from a three-dimensional (3D) image by computer vision system (CVS). From a single view of the image data a linear laser light projects onto the top of the sample through the center in order to mark the measurement points. The planar metrology and the measurement between planes are employed to calculate the width and height of the samples. Homography transformation and cross ratio are the mathematical parameter applied to calibrate the image data to real world distance (in metric system). GMD of sample can be calculated from a single view of the image with this technique. The percentage of error of GMD obtained from CVS compared with GMD measurements using vernier calipers is approximately 0.03-5.14 depending on the shape of the objects. However, it can be concluded that this technique is worthwhile for measuring GMD of symmetrical objects.

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