Speciation of bioaccessible (heme,ferrous and ferric) iron from school menus

A spectrophotometric method using batho-phenantroline as reagent has been optimized for iron speciation [ionic Fe(II) and Fe(III)] in the mineral soluble (bioaccessible) fraction obtained from the in vitro digestion of food dishes. The effect of the precipitant and reducing reagents, and the amount of sodium nitrite added was studied. Heme-Fe was estimated by subtraction of ionic Fe from the total bioaccessible Fe (determined by atomic absorption spectrometry). The method was applied to 13 dishes included in school menus. Soluble Fe was mainly in ionic form (49–100%). With the exception of spinach and potato omelets, a significant linear correlation (r=0.92) was obtained between Fe(II) and bioaccessible Fe. The Fe(II)/Fe(III) ratio increased with increasing meat protein content in the dish. In the analyzed dishes, heme-Fe content depended on meat content and also on the processing procedure applied.     

Speciation Analysis of Mn(II)/Mn(VII) in Tea Samples Using Flame Atomic Absorption Spectrometry After Room Temperature Ionic Liquid-Based Dispersive Liquid–Liquid Microextraction

A simple and rapid method based on dispersive liquid–liquid microextraction with room temperature ionic liquid 1,3-dibutylimidazolium hexafluorophosophate ([BBIM][PF₆]) coupled to flame atomic absorption spectrometry was developed for the speciation of Mn(II)/Mn(VII) in tea samples. The main factors affecting dispersive liquid–liquid microextraction were investigated in detail. Mn(II) and total manganese [Mn(II)+Mn(VII)] were quantitatively extracted after adjusting aqueous sample solution to pH 10.0 and 7.0, respectively. Mn(VII) was calculated by subtraction of Mn(II) from total manganese. Under the optimized conditions, the limits of detection (3σ) for Mn(II) and Mn(VII) were 0.26 and 1.86 ng/mL, and their relative standard deviations were 2.6 and 4.8 % (n?=?7, c?=?25.00 ng/mL). The proposed method was validated by the determination of Mn(II) and Mn(VII) in the certified reference material [GBW(E)08513] of tea sample and different local tea samples with satisfactory results.     

Cloud Point Extraction-Inductively Coupled Plasma Mass Spectrometry for Separation/Analysis of Aqueous-Exchangeable and Unaqueous-Exchangeable Selenium in Tea Samples

A simple method based on cloud point extraction (CPE) separation and inductively coupled plasma mass spectrometry (ICP-MS) detection was proposed for the determination of species of aqueous-exchangeable selenium and unaqueous-exchangeable selenium. When the system temperature is higher than the cloud point extraction temperature (CPT) of the surfactant of p-octyl polyethyleneglycolphenyl ether (Triton X-100), the complex of selenium(IV)–diethyl-dithiocarbamate (DDTC) (total selenium and aqueous-exchangeable selenium) could be extracted into the surfactant-rich phase, an in situ separation of selenium(IV) could be realized. Unaqueous-exchangeable selenium concentration was obtained by respectively subtracting aqueous-exchangeable selenium from the total selenium. The chemical variables affecting the CPE were optimized. Under the optimized conditions, the limit of detection (LOD) and the relative standard deviations (RSD) was 0.10 ng/mL and 3.2% (c?=?10.0 ng/mL, n?=?11), respectively, for Se(IV). The proposed method was applied to the speciation of aqueous-exchangeable and unaqueous-exchangeable selenium in tea samples with satisfactory results.     

Air-Agitated Cloud-Point Extraction Coupled with High-Performance Liquid Chromatography for Determination of Heterocyclic Aromatic Amines in Smoked Sausages

An air-agitated cloud-point extraction procedure (AACPE), which is a new generation of cloud-point extraction procedure, has been investigated for extraction and preconcentration of four heterocyclic amines (i.e., 2-Amino-3,4-dimethyl-3H-imidazo[4,5-f]quinoline (MeIQ), 2-Amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and 1-methyl-9H-pyrido[3,4-B]indole (harmane)) prior to high-performance liquid chromatography (HPLC). In order to enhance the extraction efficiency, the mixture of the aqueous sample solution and extraction solvent (Triton X-114) was repeatedly aspirated and dispensed using a syringe. Various parameters affecting the extraction efficiency of the AACPE procedure, including type and amount of salt, concentration of Triton X-114, extraction time (or number of air agitations), and centrifugation time, were investigated. No temperature controller was necessary. Under the optimum extraction condition, the linearity was achieved between 0.005 and 1.00 mg kg^?1 with the correlation coefficient (R ²) > 0.999. The low limit of detections (LODs) ranged from 0.001 to 0.003 mg kg^?1 with high enrichment factor (EF) more than 80. Matrix-matched calibration has been used for analysis of the target analytes in real samples. The applicability of the developed procedure was successfully evaluated by the determination of the heterocyclic amines in smoked sausage samples.     

Simultaneous pre-concentration of Pb and Sn in food samples and determination by atomic absorption spectrometry

A cloud point extraction (CPE) method has been developed for the pre-concentration and simultaneous determination of lead [Pb(II)] and tin [Sn(II)] using Acridine Orange as complexing reagent and mediated by nonionic surfactant (Triton X-114) by flame atomic absorption spectrometry (FAAS). The main factors affecting analytical performance of CPE have been investigated in detail. The extracted surfactant-rich phase was diluted with (1.0 mol L^?1) nitric acid in methanol, prior to subjecting FAAS. The calibration graphs obtained from Pb(II) and Sn(II) were linear in the concentration ranges of 5–1,000 and 10–5,000 μg L^?1 with detection limits of 1.40 and 2.86 μg L^?1, respectively. The relative standard deviations for 10 replicates containing 25 μg L^?1 of Pb(II) and Sn(II) were 2.15 and 2.50 %, respectively. The analytical procedure was verified by the analysis of the standard reference materials NWTMDA-61.2 (water-trace elements) and NIST SRM 1548a (typical diet). The developed method has been applied to the simultaneous determination of total Pb and Sn in canned food samples including juices, tomato paste, corn, and green pea.     

Effect of sodium selenite on the bacteria growth,selenium accumulation,and selenium biotransformation in <Emphasis Type="Italic">Pediococcus acidilactici</Emphasis>

In this study, the effect of low selenium concentrations on bacteria growth, selenium bioaccumulation, and selenium speciation in Pediococcus acidilactici was investigated. Six different sodium selenite (Na₂SeO₃) solutions with concentrations of 0, 0.5, 1, 2, 3, and 4 mg/L were added in MRS broth for 24 h. Then, the obtained bacterial pellets were weighed. The contents of total selenium and selenium species in the bacterial pellets were measured via optimized enzymatic hydrolysis and HPLC-ICP-MS. The maximum dried P. acidilactici biomass of 1.44 g/L was achieved by utilizing 1 mg/L Na₂SeO₃. By increasing sodium selenite concentrations, total selenium contents were significantly increased from 0.14 to 1.45 mg/g dry weight (p < 0.05). The findings indicated that selenium was favorably incorporated into the bacteria protein fraction and mainly formed selenocysteine. Therefore, selenium-enriched lactic acid bacterium P. acidilactici can deliver a less-toxic, more bioavailable selenium source for human and animal nutrition.     

Ionic Liquid-Based Surfactant Extraction Coupled with Magnetic Dispersive μ-Solid Phase Extraction for the Determination of Phthalate Esters in Packaging Milk Samples by HPLC

A highly selective sample cleanup procedure combining ionic liquid-based surfactant extraction (ILSE) and magnetic dispersive μ-solid phase extraction (MD-μ-SPE) was triumphantly developed for the synchronously extraction of four phthalate acid esters (PAEs) in packaging milk samples prior to high-performance liquid chromatography coupled with photodiode array detector (HPLC-DAD). In this ionic liquid (IL)-based surfactant method, 1-octyl-3-methylimidazolium hexafluorophosphate ([C₈MIM] [PF₆]) was used as extraction solvent, anionic surfactant sodium linear alkylbenzene sulfonate (LAS) was used as auxiliary extraction solvent, and then sodium chloride (NaCl) was mixed to drive phase separation. The synthesized hydrophobic diatomaceous earth-supported Fe₃O₄ magnetic nanoparticles (DSMNPs) were applied as an efficient adsorbent to retrieve the analyte-containing IL and LAS. Under the optimal extraction situations, good linearity of the approach was obtained in the concentration range from 10 to 1000 ng/mL for target analytes, and the preconcentration process was rapidly accomplished in 5 min. The limits of detection (LODs) based on a signal-to-noise ratio (S/N = 3) were ranged from 1.42 to 3.57 ng/mL with the relative standard deviations (RSDs) over the range of 1.84–3.56% (n = 5). The above-mentioned method was applied to the trace analysis of four PAEs including benzyl butyl phthalate (BBP), dicyclohexyl phthalate (DCHP), di-n-butyl phthalate (DBP), and di-n-octyl phthalate (DNOP) in packaging milk samples, and recoveries were between 89.8 and 99.7%.     

Optimized Ultrasound-Assisted Temperature-Controlled Ionic Liquid Microextraction Coupled with FAAS for Determination of Tin in Canned Foods

A simple and rapid method based on ultrasound-assisted temperature-controlled ionic liquid microextraction combined with flame atomic absorption spectrometry (FAAS) has been developed for determination of tin. In this method, Sn(IV)-ammonium pyrrolidinedithiocarbamate (APDC) complex was extracted into a small volume of 1-hexyl-3-methylimidazolium hexafluorophosphate as ionic liquid and after phase separation, the enriched analyte in the final solution is determined by FAAS. Experimental design approaches were used to obtain the best conditions. The variables of interest were temperature, pH, buffer volume, extraction time, centrifugation time and volumes of ionic liquid, methanol, and APDC. The Plackett–Burman design was employed for screening to determine the variables significantly affecting the extraction efficiency. Then, the significant factors were optimized by using a central composite design. In the optimal conditions the calibration graph was linear in the range of 0.10–6.0 mg?L^?1 with a correlation coefficient of 0.997. The limit of detection and relative standard deviation (n?=?5 for determination of 1.0 mg?L^?1) were 42 μg?L^?1 and 1.6 %, respectively. The preconcentration factor was calculated to be 52.7. Finally, the method was successfully applied to the determination of tin in various canned products including peach, pineapple and aloe vera juice, canned pea, and canned cheese.     

Determination of Total Concentrations and Chemical and Physical Fractionation Forms of Manganese in Infusions of Ground Coffees

A simple and fast method of the determination of total Mn in infusions of ground coffees was proposed and included the acidification of infusions with HNO₃ followed by the analysis by flame atomic absorption spectrometry. The method provided the precision and the accuracy better than 3 %. In addition, chemical and physical fractionation patterns of Mn in coffee infusions were assessed using solid phase extraction and ultrafiltration-based procedures, respectively. It was found that Mn in infusions of ground coffees is predominantly present in the form of cationic (64–81 % of the total content) low molecular weight (61–68 % of the total content) species. This points out that this metal is highly bioaccessible from the coffee brew.     

Selenium Speciation in Rice Samples by Magnetic Ionic Liquid-Based Up-and-Down-Shaker-Assisted Dispersive Liquid-Liquid Microextraction Coupled to Graphite Furnace Atomic Absorption Spectrometry

A novel and sensitive magnetic ionic liquid-based up-and-down-shaker-assisted dispersive liquid-liquid microextraction (MIL-UDSA-DLLME) was developed for the graphite furnace atomic absorption spectrometric measurement of inorganic selenium speciation from various rice matrixes. In the first microextraction step, the magnetic ionic liquid (1-butyl-3-methylimidazolium tetrachloroferrate, [C₄mim][FeCl₄]) was selected to extract the complex of Se(IV) and 2,3-diaminonaphthalene from aqueous solution by the assistance of up-and-down-shaker vortex agitator. After the microextraction step, the magnetic ionic liquid containing target analytes was collected at the bottom of the tube by applying an external magnetic field around the test tube. Under the optimized conditions, the method present has low detection limit (0.018 μg L^?1), wide linear dynamic range (0.03–10 μg L^?1), and good repeatability (<3.0%, n = 10) for Se(IV). The proposed methodology was applied for separation and preconcentration of inorganic selenium in standard reference materials including GBW10010 rice, GBW10043 Liaoning rice, and GBW10045 Hunan rice with satisfactory results. The developed methodology was also successfully used for the speciation of Se(IV) and Se(VI) in different rice samples with the relative recoveries within the acceptable range of 94.9–104.8% for the addition recovery tests.     

Magnetic effervescent tablet-assisted ionic liquid dispersive liquid–liquid microextraction of selenium for speciation in foods and beverages

A novel, simple and rapid method based on magnetic effervescent tablet-assisted ionic liquid dispersive liquid–liquid microextraction (MEA-IL-DLLME) followed by graphite furnace atomic absorption spectrometry (GFAAS) determination was established for the speciation of selenium in various food and beverage samples. In the procedure, a special magnetic effervescent tablet containing CO₂ sources (sodium carbonate and sodium dihydrogenphosphate), ionic liquids and Fe₃O₄ magnetic nanoparticles (MNPs) was used to combine extractant dispersion and magnetic recovery procedures into a single step. The parameters influencing the microextraction efficiency, such as pH of the sample solution, volume of ionic liquid, amount of MNPs, concentration of the chelating agent, salt effect and matrix effect were investigated and optimised. Under the optimised conditions, the limits of detection (LODs) for Se(IV) were 0.021 μg l^–1 and the linear dynamic range was 0.05–5.0 μg l^–1. The relative standard deviation for seven replicate measurements of 1.0 μg l^–1 of Se(IV) was 2.9%. The accuracy of the developed method was evaluated by analysis of the standard reference materials (GBW10016 tea, GBW10017 milk powder, GBW10043 Liaoning rice, GBW10046 Henan wheat, GBW10048 celery). The proposed method was successfully applied to food and beverage samples including black tea, milk powder, mushroom, soybean, bamboo shoots, energy drink, bottled water, carbonated drink and mineral water for the speciation of Se(IV) and Se(VI) with satisfactory relative recoveries (92.0–108.1%).     

Determination of Four Synthetic Phenolic Antioxidants in Edible Oils by High-Performance Liquid Chromatography with Cloud Point Extraction Using Tergitol TMN-6

A cloud-point extraction (CPE) method using Tergitol TMN-6 (TMN-6) non-ionic surfactant was developed for the extraction and preconcentration of propyl gallate (PG), tertiary butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) in edible oils. The optimum conditions of CPE were 1.5 % (v/v) Tergitol TMN-6, 1 % (w/v) NaCl, ultrasound-assist 15 min at 49 KHz, 20 min equilibrated at 45 °C, and centrifugation for 10 min at 3,000 rpm. The surfactant-rich phase was then analyzed by reversed-phase high-performance liquid chromatography (HPLC) with ultraviolet detection at 280 nm, under gradient separation, using methanol and 1.5 % (v/v) acetic acid. Under the study conditions, four synthetic phenolic antioxidants (SPAs) were successfully separated within 24 min. Limits of detection in the studied edible oils were in the range of 1.6 to 9.0 ng mL^?1. The high recoveries of the spiked edible oils were obtained in the range 90–98 %. The CPE method has been shown to be a potentially useful methodology for the preconcentration of the target analytes, with a preconcentration factor of 25. This method was compared with cloud point extraction (using Triton X-114) and liquid–liquid extraction (using methanol).     

Total and dialyzable levels of manganese from duplicate meals and influence of other nutrients: Estimation of daily dietary intake

Both total and dialyzable Mn levels were determined in 108 duplicate meals during 36 consecutive days. Both mineral fractions were measured by a graphite furnace atomic absorption spectrometry (GFAAS) method previously optimized. A total mean Mn fraction of 1.03 ± 0.49 mg was found in the meals. The Mn supplied by the meals is directly and significantly (p < 0.001) correlated with macronutrient content (carbohydrates, fibre and protein). The mean Mn fraction dialyzed through the dialysis membrane was 0.23 ± 0.17 mg (22.0 ± 8.93% as bioaccessible fraction). The total and dialyzable Mn fractions found for breakfasts were significantly lower (p < 0.001). Nevertheless, the Mn bioavailabilities expressed as the percentage of dialyzable element, were not significantly different among the three primary meals (breakfast, lunch and dinner). A significant correlation between the total and the dialyzable fraction of Mn in meals was found (p < 0.001, r = 0.78, r² = 0.61). The dialyzed element fractions present in meals were significantly correlated mainly with carbohydrates, protein and several amino acid levels (p < 0.01). Foods with higher carbohydrate and therefore energy contents, e.g. cereals, legumes, vegetables and fruits, would be primary sources of bioaccessible Mn in the diet. The bioaccessibility of Mn was only significant influenced by energy, carbohydrates and Se levels present in meals. The mean Mn daily dietary intake (DDI) was 3.05 ± 0.61 mg day⁻¹.     

Simultaneous determination of antimony and boron in beverage and dairy products by flame atomic absorption spectrometry after separation and pre-concentration by cloud-point extraction

A new cloud-point extraction (CPE) method was developed for the pre-concentration and simultaneous determination of Sb(III) and B(III) by flame atomic absorption spectrometry (FAAS). The method was based on complexation of Sb(III) and B(III) with azomethine-H in the presence of cetylpyridinium chloride (CPC) as a signal-enhancing agent, and then extraction into the micellar phase of Triton X-114. Under optimised conditions, linear calibration was obtained for Sb(III) and B(III) in the concentration ranges of 0.5–180 and 2.5–600 μg l^?1 with LODs of 0.15 and 0.75 μg l^?1, respectively. Relative standard deviations (RSDs) (25 and 100 μg l^?1 of Sb(III) and B(III), n = 6) were in a range of 2.1–3.8% and 1.9–2.3%, respectively. Recoveries of spiked samples of Sb(III) and B(III) were in the range of 98–103% and 99–102%, respectively. Measured values for Sb and B in three standard reference materials were within the 95% confidence limit of the certified values. Also, the method was used for the speciation of inorganic antimony. Sb(III), Sb(V) and total Sb were measured in the presence of excess boron before and after pre-reduction with an acidic mixture of KI-ascorbic acid. The method was successfully applied to the simultaneous determination of total Sb and B in selected beverage and dairy products.     

Purification of a novel protease enzyme from kesinai plant (Streblus asper) leaves using a surfactant–salt aqueous micellar two-phase system: a potential low cost source of enzyme and purification method

Serine protease from kesinai leaves was purified for the first time by a surfactant–polymer aqueous micellar two-phase system. The effectiveness of different types and concentrations of non-ionic surfactants (Pluronic series and X-114) on the partitioning behaviour of the protease was evaluated. The results showed that the enzyme preferentially partitioned into the bottom surfactant-rich phase, while the hydrophilic amino acid preferred the top aqueous phase. This distribution of the enzyme is due to the hydrophobic interaction of the serine protease with the hydrophobic lid of the micelle core in the bottom phase. The influence of different types of salts (K₂SO₄, KH₂PO₄, KCl and KNO₃) on the purification and selectivity of the enzyme was determined. The protease partitioning in the bottom phase increased in the presence of KNO₃, which confirmed that the salt was able to improve the protein solubility in bottom phase and increase the hydrophobic interaction between the two phases. In addition, the protease from the bottom phase was re-extracted to a new aqueous phase solution to remove and recycle the surfactant. Addition of potassium thiocyanate led to the partitioning of the enzyme in top aqueous phase due to high ionic strength of SCN^?, which forced the lighter micellar phase toward the upper position of the system. A high purification factor (10.3) and yield of 92 % of the enzyme were achieved in a solution of 31 % of Pluronic L61 using 0.3 % KNO₃ and 50 % crude feedstock at pH 7.0.     

The effect of emulsifier type and oil inclusion on stress-related gene expression of Salmonella typhimurium in oil-in-water emulsion

Salmonella has been associated with numerous outbreaks from contaminated food products, including emulsions. Emulsions are influenced by emulsifier type and oil presence, which can have varying degrees of stress or protection on bacteria. Although our previous research has shown that emulsifier solutions, rather than emulsions, provide a protective effect on Salmonella typhimurium after thermal treatment, the underlying mechanism remains unclear. This study selected S. typhimurium as the model microorganism and utilized the same emulsifiers (Tween 20, Tween 80, Triton X-100) to create emulsifier solutions and emulsions with the same oil fraction (60% (v/v)) to examine their effect on the expression of nine selected genes (rpoE, rpoH, otsB, proV, fadA, fabA, dnaK, ibpA, ompC) associated with stress response. Specifically, the study observed variations in gene expression under normal and thermal stress at 55°C. After 20-h incubation, Triton X-100 emulsion caused an upregulation of stress-related genes, rpoE, otsB, and fabA, suggesting stressful environment. After thermal treatment, S. typhimurium in Triton X-100 solution showed a longer 5-log reduction time with increased proV and decreased fabA and ompC expression, suggesting enhanced thermal protection compared to its emulsion. Conversely, Tween 80 solution increased fabA and ompC expression, indicating greater membrane fluidity and passive diffusion, potentially reducing thermal resistance. However, according to the upregulation of ibpA, this effect was likely mitigated by the overproduction of heat shock proteins. Notably, Triton X-100 environments exhibited the most significant gene expression changes after heat treatment, whereas Tween 80 without oil was the most inhospitable for bacterial survival. These findings inform bacterial responses under various conditions, aiding food safety strategies.     

Impact of Electron Beam on Storage Protein Subunits,In Vitro Protein Digestibility and Trypsin Inhibitor Content in Soybean Seeds

The present investigation was carried out to study the effect of 4.8, 9.2, 15.3 and 21.2 kGy of electron beam (EB)-irradiation on major storage proteins viz. glycinin (11S) and β-conglycinin (7S), in vitro protein digestibility (IVPD), and trypsin inhibitor (TI) content in seeds of three soybean genotypes. Densitometry of SDS-PAGE protein profile revealed significant (P < 0.05) reduction in α’, α and β subunits of 7S fraction at all doses. This reduction was higher (P < 0.05) than the decline observed in acidic and basic subunit of 11S fraction. Basic subunit registered significant (P < 0.05) increase at specific doses in two genotypes. All the doses induced significant (P < 0.05) increase in IVPD, and the increase due to 9.2, 15.3 and 21.2 kGy was higher (P < 0.05) compared to 4.8 kGy dose. The impact on TI content was genotype-dependent. The study showed a higher (P < 0.05) decline in the concentration of 7S fraction compared to 11S fraction and improvement in IVPD of soybean seeds due to exposure to EB-irradiation, which may influence the functional and nutritional value of soy products processed from them.     

Biobased surfactant-like molecules from organic wastes: the effect of waste composition and composting process on surfactant properties and on the ability to solubilize Tetrachloroethene (PCE)

In this work, four surfactant-like humic acids (HAs) obtained from garden lignocellulose wastes and kitchen food wastes mixed with garden-lignocellulose wastes, both before and after composting, were tested for surfactant properties and the ability to solubilize tetrachloroethene (PCE). The waste-derived HAs showed good surfactant properties, lowering the water surface tension from 74 mN m(-1) to 45.4 +/- 4.4 mN m(-1), with a critical micelle concentration (CMC) of 1.54 +/- 1.68 g L(-1), which is lower than many synthetic ionic surfactants. CMC was affected by both waste origin and composting processes. The addition of food waste and composting reduced CMC by adding alkyl-C (measured by CP MAS 13C NMR) and N- and S-HA contents (amide molecules), so that a multistep regression was found [CMC = 24.6 - 0.189 alkyl C - 2.64 (N + S); R2 = 0.77, P < 0.10, n = 6]. The four HAs solubilized PCE at the rate of 0.18-0.47 g PCE/g aqueous biosurfactant. These results were much higher than those reported in the literature for a commercial HA (0.026 g/g), but they were in line with those measured in this work for nonionic surfactants such as Tween-80 (0.69 g/g) and Triton X-100 (1.08 g/g).     

Surfactant–Solvent-Based Quaternary Component Emulsification Microextraction Followed by High-Performance Liquid Chromatography for the Simultaneous Analysis of Benzimidazole Anthelmintics in Milk Samples

A simple surfactant-solvent-based quaternary component emulsification microextraction (SSEME) method combined with high-performance liquid chromatography–photodiode array detection has been developed for the extraction, preconcentration, and determination of four benzimidazole anthelmintic (i.e., oxfendazole, mebendazole, albendazole, and fenbendazole) residues in milk samples. The quaternary component solvent of SSEME carried out in 10 mL aqueous solution were Triton X-114 (emulsifier or carrier), acetonitrile (disperser solvent), and 1-octanol (extraction solvent). The surfactant has an important role in the enhancement of the extraction efficiency of the high polar analytes. For milk sample analyses, linearity was obtained in the range of 10–200 μg/L with the determination coefficients (R ²) higher than 0.996. Preconcentration factor was obtained in the range of 21–38, corresponding to limits of detection in the range of 2.6–9.9 μg/L. Intra-day (n?=?6) and inter-day (n?=?6?×?3) precisions in the sample studied were obtained with relative standard deviation below 8.8 %. The recoveries for the spiked target anthelmintics at different concentrations (25, 50, 100, and 150 μg/L) were obtained in the range 80.1–114.1 %. The proposed SSEME method has been demonstrated that is simple, effective, and reliable for the analysis of analytes in the samples studied and can be used as an alternative green analytical technique for benzimidazole analysis.     

A New Two-Step Chromatographic Procedure for Fractionation of Potato Proteins with Potato Fruit Juice and Spray-Dried Protein as Source Materials

In an effort to purify potato proteins of superior food grade quality, a new procedure involving anion exchange (ion exchange (IEX)) and hydrophobic interaction chromatography (HIC) was established. Liquid potato fruit juice (PFJ) or re-suspended spray-dried protein was separated by IEX yielding two fractions: a protease inhibitor (PI)-rich fraction and a patatin-rich fraction. Each of these fractions was re-chromatographed on HIC, resulting in two new sub-fractions which were characterised by electrophoresis and mass spectrometry. A high-quality powder should have high lightness, low polyphenol oxidase (PPO) activity and glycoalkaloid content below 150 μg/g. The PI fraction from spray-dried powder had high lightness (L* = 83) compared to patatin (L* = 50), whereas IEX purification from PFJ resulted in a PI fraction with decreased lightness (L* = 66) and a patatin fraction with increased lightness (L* = 68). HIC fractionation led to increased lightness for patatin fraction, but decreased lightness for the PFJ PI fractions. HIC purification significantly lowered PPO activity in the fractions due to its selective affinity. The lowest total glycoalkaloid content was generally found in HIC fractions from spray-dried powder (150 μg/g), while high levels (>1000 μg/g) were found in PI fractions from PFJ. In conclusion, it was possible to obtain a PI-rich protein isolate from powder with good-quality attributes after both IEX and HIC, while for patatin, the best quality was obtained after the HIC only, and there, the colour or PPO activity may still be a problem depending on source material.