Chilling injury in pineapple fruits: physical quality attributes and antioxidant enzyme activity

Harvested fruit have high metabolic and moisture content which leads to an active biochemical reaction that contributes to decrement of nutritional value such as vitamin, proteins and lipids. The application of low temperature as a single-effective management to prolong shelf-life of fruits is a common practice which applied to keep agriculture commodities at high quality. A matured stage pineapple is very perishable and cold storage chain is crucial in maintaining the chemical and physical quality attributes in order to assure its commercial value for market. The main objective of this study is to evaluate the effect of sub-optimum cold storage scenario on changes of pineapple fruits physical quality attributes, the activity of browning enzyme and antioxidant related enzyme in 2 pineapple cultivars (cv.), Morris (Queen-type) and Josapine (hybrid of Spanish and Smooth Cayeen). Malaysian pineapple fruit cv. with different sensitivity toward CI, Morris (Queen-type) and Josapine (Smooth-Cayenne-type) were stored at sub-optimal storage temperatures (4±2°C) for 28 days to investigate the effects of CI towards physical quality attributes and antioxidant enzyme activity. The result indicated both cv. was affected with CI towards the 28 days of sub-optimum cold storage. Overall physical quality attributes indicated CI was found positively correlated with the increase of EL and TTA and on the contrary decrease its firmness, weight (% w/w), brightness (L*) and redness (A*). Similarly, a positive correlation was also deduced between CI symptoms and the activities of PPO and APX which reflect the incident of oxidative stress. The results derived from this study may serve as a basis for evaluation of better postharvest strategies to control CI during cold chain storage of pineapple fruits and thus assure the quality and nutritional value till it reaches to consumer

Sol–gel coated polypropylene hollow fiber-based liquid-phase microextraction of triazine herbicides in real water samples

A sol–gel coated hollow fiber-based liquid-phase microextraction (LPME) method was developed for the extraction of triazine herbicides. The polypropylene hollow fiber was coated with polydimethylsiloxane–divinylbenzene using sol–gel method and characterized. The developed method was compared with uncoated hollow fiber LPME method for the extraction of simazine, atrazine, and propazine prior to gas chromatography–mass spectrometry analysis. Optimized conditions for both coated and uncoated hollow fibers LPME methods were toluene as an acceptor phase, length of hollow fiber (1.5 cm), volume of acceptor phase (3.0 µL), stirring rate (1200 rpm), and no addition of salt (sodium chloride). The optimized volumes of donor phase for uncoated fiber and coated fiber were 4.0 and 4.5 mL, respectively, while the optimized extraction times were 30 min for uncoated hollow fiber and 10 min for coated hollow fiber. The developed sol–gel coated hollow fiber LPME method provided good enrichment factors (EFs) ranging from 100 to 139, good recoveries (75.27–104.47%), and good reproducibility (relative standard deviations [RSDs] < 0.83%). Meanwhile, uncoated hollow fiber LPME method showed lower EFs ranging from 80 to 90 and relatively low recoveries of 60.72–68.17%, whereas it has good reproducibility with RSDs < 0.94%. The proposed method was successfully applied to the analysis of real water samples and the analyte recoveries for spiked water samples was in the range of 42.54–78.75%

Understanding pore formation and structural deformation in carbon spheres during KOH activation

Carbon spheres (CSs) were synthesized from sucrose by hydrothermal reaction. The synthesized materials were further activated with potassium hydroxide (KOH) at different concentrations. The effects of KOH concentration on the surface area and morphology were investigated. The route for pore formation and structural deformation in carbon spheres during activation has been proposed and discussed based on micrographs and porosity trends. It was suggested that the pore formation and structural deformation phenomena were due to the intercalating power of energized K+ into the carbon. This work provides an insight of the pore formation in carbon spheres for the development of adsorbents as well as for the understanding of the structural deformation of such materials at higher KOH concentrations

Ultrasonic-assisted extraction of curcumin complexed with methyl-beta-cyclodextrin

Turmeric flavour is important in Asian cuisine; however, the production of turmeric-based ingredient with the current method of extraction of turmeric oleoresin is very laborious, time consuming and consumes large amount of solvent, coupled with limited solubility in aqueous solution, which limits its application to food system. The extract was optimised by determining the content of three marker curcuminoid compounds, namely, curcumin (C), demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC). The optimised extraction parameters for ultrasonic-assisted extraction (UAE) with aqueous extraction solvent for curcuminoids were amplitude of 100, particle size of 0.30–0.60 mm, extraction time of 20 min, extraction solvent volume of 10 mL and extraction temperature of 60 °C. The applications showed remarkable improvements in terms of reduced extraction time, solvent consumption, extraction yield and the quality of extracts. The turmeric oleoresin was successfully solubilised in aqueous solution by forming inclusion complex with methyl-ß-cyclodextrin (Mß-CD). Phase solubility studies used curcumin as a marker compounds to represent turmeric oleoresin. In the presence of Mß-CD, the curcumin was enhanced. Result from characterisation of inclusion complexes with Fourier transform infrared (FTIR) spectrometry indicates that all the mixing methods were found to be suitable for encapsulation. However, scanning electron microscopy (SEM) shows a drastic change in particle sizes, indicating a formation of a new solid phase in kneading method, implying it as the best mixing method

Rapid Determination of Non-steroidal Anti-inflammatory Drugs in Aquatic Matrices by Two-phase Micro-electrodriven Membrane Extraction Combined with Liquid Chromatography

Two-phase micro-electrodriven membrane extraction (EME) procedure for the pre-concentration of selected non-steroidal anti-inflammatory drugs (NSAIDs) in aquatic matrices was investigated. Agarose film was used as interface between donor and acceptor phase in EME which allowed for selective extraction of the analytes prior to high performance liquid chromatography-ultraviolet detection. Charged analytes were transported from basic aqueous sample solution through agarose film into 1-octanol as an acceptor phase at 9 V potential. Response surface methodology in conjunction with the central composite design showed good correlations between extraction time and applied voltage (R 2 > 0.9358). Under optimized extraction conditions, the method showed good linearity in the concentration range of 0.5-500 μg L -1 with coefficients of determination, r 2 ≥ 0.9942 and good limits of detection (0.14-0.42 μg L -1) and limits of quantification (0.52-1.21 μg L -1). The results also showed high enrichment factors (62-86) and good relative recoveries (72-114%) with acceptable reproducibilities (RSDs ≤ 7.5% n = 3). The method was successfully applied to the determination of NSAIDs from tap water and river water samples. The proposed method proved to be rapid, simple and requires low voltage and minute amounts of organic solvent, thus environmentally friendly

Chiral xenobiotics bioaccumulations and environmental health prospectives

The chiral xenobiotics are very dangerous for all of us due to the different enantioselective toxicities of the enantiomers. Besides, these have different enantioselective bioaccumulations and behaviors in our body and other organisms. It is of urgent need to understand the enantioselective bioaccumulations, toxicities, and the health hazards of the chiral xenobiotics. The present article describes the classification, sources of contamination, distribution, enantioselective bioaccumulation, and the toxicities of the chiral xenobiotics. Besides, the efforts are also made to discuss the prevention and remedial measures of the havoc of the chiral xenobiotics. The challenges of the chiral xenobiotics have also been highlighted. Finally, future prospectives are also discussed

A practical approach for linearity assessment of calibration curves under the International Union of Pure and Applied Chemistry (IUPAC) guidelines for an in-house validation of method of analysis.

Linearity assessment as required in method validation has always been subject to different interpretations and definitions by various guidelines and protocols. However, there are very limited applicable implementation procedures that can be followed by a laboratory chemist in assessing linearity. Thus, this work proposes a simple method for linearity assessment in method validation by a regression analysis that covers experimental design, estimation of the parameters, outlier treatment, and evaluation of the assumptions according to the International Union of Pure and Applied Chemistry guidelines. The suitability of this procedure was demonstrated by its application to an in-house validation for the determination of plasticizers in plastic food packaging by GC

Microwave-assisted encapsulation of blue pea flower (clitoria ternatea) colourant: maltodextrin concentration, power, and time

Blue pea flower (BPF) is one of the natural anthocyanin colourant sources in the world used in food and cosmetic products. Natural colourants are unstable and thus must be encapsulated. The BPF colourant could retain its colour during storage via microwave-assisted encapsulation. This study evaluated the effect of maltodextrin concentration, microwave power, and encapsulation time on the stability of encapsulated BPF colourant. The colourant was extracted from the BPF via microwave-assisted extraction at 770 W for 1 min. For encapsulation, the concentration of the coating material, maltodextrin, was varied from 20 % to 50 %, a microwave power from (550 to 1100) W, and an encapsulation time from (6 to 8) min. The quality of the encapsulated BPF colourant powder was characterised by total anthocyanin content (TAC), the colour parameter index b* value, and the water activity value. A TAC of 27.03 mg/L, a colour parameter index b* value of -9, a water activity of 0.4941, and an encapsulation efficiency of 73.24 % were obtained when the microwave-assisted encapsulation process was performed using 40 % MD at 770 W for 7 min. With pH adjustment, the blue BPF colourant can be turned into other pigments. The findings of this study can be used as a future reference for developing BPF colourant powder using the microwave-assisted method

Analysis of organophosphorus pesticides in vegetable samples by hollow fiber liquid phase microextraction coupled with gas chromatography-electron capture detection.

A method based on hollow fibre liquid phase microextraction (HF-LPME) coupled with gas chromatography electron capture detection (GC-ECD) has been developed for the determination of organophosphorus pesticides (OPPs) (chlorpyrifos and profenofos) in vegetable samples. In this method, a microsyringe needle with 1.5 cm polypropylene hollow fibre containing a volume of organic acceptor phase (n-dodecane) was immersed in an aqueous donor solution, and at the completion of extraction, the acceptor phase was withdrawn and transferred to GC-ECD for analysis. The effects of extraction solvent, volume of acceptor phase, and volume of donor phase were investigated. The optimized conditions for HF-LPME of the selected OPPs were n-dodecane as organic solvent, 11 mL of donor phase, and 3 µL of acceptor phase. The correlation coefficient (r2) of the calibration curves ranged from 0.998 to 0.999. The limits of detection (LOD) were between 0.099 and 0.128 µg/mL. The developed method provided excellent RSDs ranging from 0.54% to 8.00% and analyte recoveries ranging from 60.8% to 88.0%. This method was applied successfully for determination of organophosphorus pesticides in selected vegetables

Simultaneous enantioseparation of cyproconazole, bromuconazole, and diniconazole enantiomers by CD-modified MEKC

An efficient method for the simultaneous enantioseparation of cyproconazole, bromuconazole, and diniconazole enantiomers was developed by CD-modified MEKC using a dual mixture of neutral CDs as chiral selector. Three neutral CDs namely hydroxypropylb- ß-CD, hydroxypropyl-?-CD, and ?-CD were tested as chiral selectors at different concentrations ranging from 10, 20, 30 and 40 mM, but enantiomers of the studied fungicides were not completely separated. The best dual chiral recognition mode for the simultaneous separation of cyproconazole, bromuconazole, and diniconazole enantiomers was achieved with a mixture of 27 mM hydroxypropyl-ß-CD and 3mM hydroxypropyl-?-CD in 25 mM phosphate buffer (pH 3.0) containing 40 mM SDS to which methanol-acetonitrile (10%:5% v/v) was added as organic modifiers. The best separation was based on the appearance of 10 peaks simultaneously, with good resolution (Rs 1.1-15.9), and peak efficiency (N>200 000). Good repeatabilities in the migration time, peak area, and peak height were obtained in terms of RSD ranging from (0.72 to 1.06)%, (0.39 to 3.49)%, and (1.90 to 4.84)%, respectively