Development and Application of an ICP-AES Method for the Determination of Nutrient and Toxic Elements in Savory Snack Products after Autoclave Dissolution

Optimization of [P6,6,6,14+]3[GdCl63-] magnetic ionic liquid assisted dispersive liquid-liquid microextraction for selective and sensitive determination of cadmium in environmental water and food

A simple and green hydrophobic magnetic ionic-liquid assisted dispersive liquid-liquid microextraction (MIL-DLLME) was optimized for the determination of trace cadmium (Cd (II)) in environmental and food samples by flame atomic absorption spectrophotometer. To achieve selective and sensitive extraction of Cd (II), four MILs were prepared and tested. Extraction parameters of the MIL-DLLME including pH, type and volume of the MIL, type and volume of dispersive solvent, extraction cycle, ionic strength and sample volume were investigated in detail and optimized by Box-Behnken design. Under optimum conditions, matrix effect, recovery study, intra-day and inter-day precision were performed for the MIL-DLLM. The analytical characteristics such as limit of detection, limit of quantification and pre-concentration factor were 0.17, 0.56 and 125 ng mL-1, respectively. The validation of the MIL-DLLME was evaluated by analysis of reference materials. Moreover, the accuracy of the results in the analysis of real samples was evaluated by standard addition and quantitative recoveries (91 ± 5-101 ± 2%) were achieved. The results obtained in the analysis of both reference materials and real samples showed that the MIL-DLLME has a selective applicability for cadmium.

Heavy Metals in Foods and Beverages: Global Situation, Health Risks and Reduction Methods

Heavy metals are chemical elements with a toxic effect on the human body. The expansion of industries has led to significant increasing levels of these constituents in the environment. Intensive agriculture can also lead to an increased concentration of heavy metals as a result of using different fertilizers and pesticides. Heavy metal accumulation in soil and plants represents a serious issue because of the potential risks to consumers. There are several methods available for the removal of these toxic components from different substrates (chemical precipitation, electrodialysis, coagulation and flocculation, photocatalytic removal, and adsorption-based processes), but most procedures are expensive and difficult to perform. Thus, more research is needed on the development of low-cost methods in foods. This work represents a review on the heavy metal presence in different food substrates (such as fruits and vegetables, milk and dairy products, meat and meat derivatives, oils, and alcoholic beverages) and provides an overview of the current situation worldwide, taking into account the fact that risks for human health are induced by the intensification of industry and the high degree of pollution. Considering that the toxicological quality of food affects its acceptability, this work provides valuable data regarding the actual situation on the proposed topic.

Characterization of Tenebrio molitor Larvae Protein Preparations Obtained by Different Extraction Approaches

Edible insects have recently attracted research attention due to their nutritional value and low environmental footprint. Tenebrio molitor larva was the first insect species to be classified by European Food Safety Authority (EFSA) as safe for human consumption. However, it is thought that the incorporation of edible insect as an ingredient in a food product would be more appealing to consumers than being visible. The aim of the present study was to determine the physicochemical properties of the larvae meal and protein concentrates. Different methods to extract and recover proteins from defatted (DF) Tenebrio molitor larvae were applied; i.e., alkaline extraction (DF-ASP); isoelectric precipitation after alkaline extraction (DF-AIP); and NaCl treatment (DF-SSP), and the obtained protein fractions were characterized. The DF-ASP exhibited the highest protein extraction/recovery efficiency (>60%), while it was the most effective in decreasing the interfacial tension at the oil/water (o/w) interface. The DF-AIP had the highest protein content (75.1%) and absolute values of ζ-potential and the best ability to retain water (10.54 g/g) and stabilize emulsions at pH 3.0. The DF-SSP protein preparation had the highest oil binding capacity (8.62%) and solubility (~88%) at acidic pHs and the highest emulsifying activity (~86 m2/g). Electrophoresis of the protein preparations revealed proteins with different molecular weights, while the protein secondary structure was dominated by β-structures and α-helix. Protein concentrates with different properties were able to be recovered from Tenebrio molitor larvae, that could affect their interactions with other food ingredients and their behavior during processing or storage. These findings would be valuable guidance for the technological exploitation of larvae protein preparations in the development of food formulations.

A comparative study on selectivity and sensitivity of new chromium and copper electrodes

4-Methylcoumarin-7-yloxy-N-phenyl acetamide and 4-methylcoumarin-7-yloxy-N-4-nitrophenyl acetamide were synthesized and used as new ionophores in the carbon paste matrix to produce two novel potentiometric modified electrodes. The selectivity of the electrode changed from copper (II) to chromium (III) with the addition of a nitro group to the phenyl ring of the ionophore. The ionophores’ tendency to ions was confirmed by UV–visible spectrophotometry. Both electrodes were modified by multi-walled carbon nanotubes (MWCNTs) as an excellent modifier of carbon paste electrode (CPE). The best sensor response in the case of copper (II) selective CPE was obtained by 5% ionophore, 65% graphite powder, 5% MWCNT, and 25% paraffin oil. In addition, in the case of chromium (III) selective CPE, these conditions are 20% ionophore, 50% graphite powder, 5% MWCNT, and 25% paraffin oil. The copper (II) selective CPE showed a Nernstian slope of 32.15 mV/decade within the concentration range of 1.0 × 10^–10–1.0 × 10^–1 mol L⁻¹, while chromium (III) selective CPE showed a Nernstian slope of 19.28 mV/decade over the concentration range of 1.0 × 10^–10–7.0 × 10^–3 mol L⁻¹. The electrodes have short response time of less than 5 s and were used successfully to determine copper (II) in wastewater and to speciation of chromium (III) and chromium (VI).

Development and Validation of an ICP-AES Method for the Determination of Toxic and Nutrient Metals in Candies: Application for the Analysis of Different Samples from the Greek Market

In this study, we present the development and validation of an inductively coupled plasma-atomic emission spectrometric (ICP-AES) method for the determination of Ag, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Zn in different candies. Various wet digestion protocols were examined in order to ensure minimum consumption of chemicals and sample preparation time. Under optimized conditions, less than 10 min were required for complete sample decomposition. The ICP-AES method was validated in terms of linearity, accuracy, precision, limits of detection (LODs) and limits of quantification (LOQs). The relative recoveries for the proposed method ranged between 80.0% and 119.0%, while the relative standard deviation values were lower than 9.0%, indicating good method accuracy and precision, respectively. The LODs for the examined analytes were 0.04–2.25 mg kg−1. Finally, the proposed method was successfully employed for the analysis of hard candies, jellies and lollipops that are sold in the Greek market, which are highly likely to be consumed by children.