Evaluation of macro and micronutrient elements content from soft drinks using principal component analysis and Kohonen self-organizing maps

An introductory review on the application of principal component analysis in the data exploration of the chemical analysis of food samples

Principal component analysis (PCA) is currently one of the most used multivariate data analysis techniques for evaluating information from food analysis. In this review, a brief introduction to the theoretical principles that underlie PCA will be given, in addition to presenting the most commonly used computer programs. An example from the literature was discussed to illustrate the use of this chemometric tool and interpretation of graphs and parameters obtained. A list of recently published articles will also be presented, in order to show the applicability and potential of the technique in the food analysis field.

Direct determination of Cu, Cr, and Ni in river sediments using double pulse laser-induced breakdown spectroscopy: Ecological risk and pollution level assessment

Double pulse laser-induced breakdown spectroscopy (DP LIBS) has attracted much attention for analyzing trace elements due to its higher sensitivity when compared to single pulse laser-induced breakdown spectroscopy (SP LIBS). However, the development of quantitative methods in LIBS for the analysis of complex samples, such as sediments, is a great challenge due to the matrix effects that are very accentuated in this technique. In this study, different spectral treatments and calibration strategies were investigated to obtain calibration models that allow determinations with satisfactory accuracy and precision of Cr, Cu, and Ni in river sediments from different hydrographic basins. The best model developed for Cr was using MMC without spectral normalization and for Cu and Ni it was using MMC with spectral normalization, and using inverse regression, an increase in the accuracy of the determinations of all analytes was obtained. These models showed limit of quantification (LOQ) of 7.87 mg kg^-1, 1.62 mg kg^-1, and 2.21 mg kg^-1 and root mean square error of prediction (RMSEP) of 7.54 mg kg^-1, 14.53 mg kg^-1, and 8.29 mg kg^-1 for Cr, Cu, and Ni, respectively. Therefore, the models have adequate sensitivity and precision for the quantification of the potentially toxic elements (PTEs) evaluated, since, according to Brazilian legislation, the lower concentration of threshold effect level (TEL) for Cr, Cu, and Ni is <37.3 mg kg^-1, <35.7 mg kg^-1, and <18 mg kg^-1, respectively. The concentrations of Cr, Cu, and Ni determined by DP LIBS allowed to obtain a partial ecological risk assessment of the studied sediments. Also, the chemometric tool Kohonen self-organizing map (KSOM) were used for data interpretation.

Evaluation of the Chemical Composition and Antioxidant Activity of Mulberry (Morus alba L.) Fruits from Different Varieties in China

Mulberry (Morus alba L.) fruit is a fruit with nutritional and medicinal value. It is widely cultivated in different regions of China, which may result in differences in its chemical composition. In this research, 25 mulberry fruit samples from six provinces in China were investigated. The contents of anthocyanins were evaluated by high-performance liquid chromatography (HPLC). The contents of two main anthocyanins, cyanidin-3-O-glucoside (C3G) and cyanidin-3-O-rutinoside (C3R), ranged from 0.656 ± 0.006 mg/g to 4.367 ± 0.243 mg/g and from 0.226 ± 0.007 mg/g to 1.649 ± 0.013 mg/g, respectively. Additionally, the contents of total phenolic, total flavonoid, vitamin C, titratable acids, reducing sugars and antioxidant capacity (FRAP, DPPH, scavenging and hydroxyl radical scavenging activity) were also assessed. The results and principal component analysis showed that the Zhongsang 5801 variety from Sichuan, Dechang had the greatest health value with the highest active compound contents. Based on our analysis, the variety from Sichuan, Dechang is a high-quality plant source for mulberry fruit cultivation. This research provides a basis for the rational development and utilization of mulberry fruit resources in China.

Chemical Fingerprint of Non-aged Artisanal Sugarcane Spirits Using Kohonen Artificial Neural Network

This study focuses on the determination of the chemical profile of 24 non-aged Brazilian artisanal sugarcane spirits (cachaça) samples through chromatographic quantification and chemometric treatment via principal component analysis (PCA) and Kohonen’s neural network. In total, forty-seven (47) chemical compounds were identified in the samples of non-aged artisanal cachaça, in addition to determining alcohol content, volatile acidity, and copper. For the PCA of the chemical compounds’ profile, it could be observed that the samples were grouped into seven groups. On the other hand, the variables’ bearings were grouped together, making it difficult to separate the components in relation to the sample groups and reducing the chances of obtaining all the necessary information. However, by using a Kohonen’s neural network, samples were grouped into eight groups. This tool proved to be more accurate in the groups’ formation. Among the chemical classes of the compounds observed, esters stood out, followed by alcohols, acids, aldehydes, ketones, phenol, and copper. The abundance of esters in these samples may suggest that these compounds would be part of the regional standard for cachaças produced in the region of Salinas, Minas Gerais.

Chemometric tools in the optimization of a microwave-assisted digestion procedure for guarana-based drink samples and data analysis from elemental, caffeine, and epicatechin contents

In this work, a method was developed for the determination of Na, K, Ca, Mg, P, S, Fe, Zn, Mn, and Cu by ICP OES and caffeine and epicatechin by HPLC-DAD in industrialized guarana-based beverages. The acid digestion in microwave oven was optimized by constrained mixture design. The optimum volumes found for the reagents were 2.60 mL (HNO₃), 1.80 mL (H₂O₂), and 0.60 mL (HCl) for a final volume of 10 mL, resulting in a final digestate with residual acidity of 0.8 mol L^-1 and 9% for residual carbon content. The detection limits found for the studied elements were between 0.0010 and 0.050 mg L^-1. Precision (%RSD) was always below 6%. Accuracy was assessed by analyzing a certified reference material and addition and recovery tests. PCA and HCA were applied to caffeine, epicatechin and elemental concentrations aiming to evidence latent information.

Self-organizing map applied to the choice of internal standards for the determination of Cd, Pb, Sn, and platinum group elements by inductively coupled plasma mass spectrometry

The behaviors of internal standards, according to different flow rates of the cell collision gas (He), were studied for the determination of Cd, Pb, Pd, Pt, Rh, and Sn in samples of fish and mollusks by inductively coupled plasma mass spectrometry (ICP-MS). The elements Bi, Ge, In, Sc, and Y were selected as internal standards, considering their masses and first ionization energies. Addition and recovery experiments were carried out at three concentration levels to evaluate the accuracy of the method applied for the analysis of two samples with different matrices. The results were evaluated using a self-organizing map (SOM). The best analyte/IS pairs were as follows: ¹¹⁴Cd⁺/⁷⁴Ge⁺, ¹⁹⁵Pt⁺/⁷⁴Ge⁺, and ²⁰⁸Pb⁺/⁷⁴Ge⁺. For ¹⁰³Rh⁺, ¹⁰⁶Pd⁺, and ¹²⁰Sn⁺, greater accuracy was achieved without use of an internal standard. Helium gas (2.8 mL min^-1) was used in the collision cell for the analytes, except for Sn, and recoveries ranged from 98 to 101% under optimal conditions. The use of SOM as an exploratory analysis tool was an effective approach for selection of the most appropriate internal standards.

Determination of Mn(II) and Mn(VII) in beverage samples using magnetic dispersive micro-solid phase extraction coupled with solidified floating organic drop microextraction followed by graphite furnace atomic absorption spectrometry

Magnetic dispersive micro-solid phase extraction (MDMSPE) was coupled with solidified floating organic drop microextraction (SFODME) for direct separation and preconcentration of Mn(II) and Mn(VII) before graphite furnace atomic absorption spectrometry determination. MDMSPE involved use of magnetic ZnFe₂O₄ nanotubes for adsorbing Mn(VII). Sorbent was isolated from aqueous phase by an external magnet. Mn(II) in upper solution from MDMSPE was further enriched by SFODME. This method avoids tedious pre-oxidation/pre-reduction operation and time-consuming centrifugation/filtration step. An enrichment factor of 200-fold was obtained. Detection limits of this method were 0.005 and 0.007 ng mL^-1 for Mn(II) and Mn(VII) with relative standard deviations of 4.0% and 4.8% (n = 9), respectively. This method was successfully used for detection of Mn(II) and Mn(VII) in tap water, ice tea, energy drink, mineral water, sprite drink and carbonated drink. A certified reference material of water sample was analyzed with satisfactory results. Recoveries of spike experiments ranged from 92.5 to 106%.

Recent Techniques in Nutrient Analysis for Food Composition Database

Food composition database (FCD) provides the nutritional composition of foods. Reliable and up-to date FCD is important in many aspects of nutrition, dietetics, health, food science, biodiversity, plant breeding, food industry, trade and food regulation. FCD has been used extensively in nutrition labelling, nutritional analysis, research, regulation, national food and nutrition policy. The choice of method for the analysis of samples for FCD often depends on detection capability, along with ease of use, speed of analysis and low cost. Sample preparation is the most critical stage in analytical method development. Samples can be prepared using numerous techniques; however it should be applicable for a wide range of analytes and sample matrices. There are quite a number of significant improvements on sample preparation techniques in various food matrices for specific analytes highlighted in the literatures. Improvements on the technology used for the analysis of samples by specific instrumentation could provide an alternative to the analyst to choose for their laboratory requirement. This review provides the reader with an overview of recent techniques that can be used for sample preparation and instrumentation for food analysis which can provide wide options to the analysts in providing data to their FCD.

Total Versus Inorganic and Organic Species of As, Cr, and Sb in Flavored and Functional Drinking Waters: Analysis and Risk Assessment

Packing material can release certain elements such as As, Cr, or Sb into its content and, thus, contaminate the drinking water. The effect of As, Cr, and Sb on human health depends highly on the chemical species in which these elements are introduced into the body. For the above reasons quantification and speciation of As, Cr, and Sb in flavored and functional drinking water samples is an important issue. Total, inorganic, and organic species of As, Cr, and Sb including As(III), As(V), Cr(VI), Sb(III), and Sb(V) were studied in flavored and functional drinking waters. Analyses of total As, Cr, and Sb were conducted using inductively coupled plasma mass spectrometry (ICP-MS) according to ISO 17294-2:2016. The speciation analysis of arsenic, chromium, and antimony in bottled flavored and functional drinking waters was conducted with the use of the elemental (HPLC/ICP dynamic reaction cell (DRC) MS) and molecular (electrospray ionization MS/MS) mass spectrometry. Concentrations of total As, Cr, and Sb (µg∙L⁻¹) in waters studied were in the ranges 0.0922 ± 0.0067 to 8.37 ± 0.52, 0.0474 ± 0.0014 to 1.310 ± 0.045, and 0.0797 ± 0.0026 to 1.145 ± 0.019, respectively. Speciation analysis showed that, apart from the toxic ionic species, known and unknown organic species were present in test samples. The risk assessment results proved that there is no risk associated with consumption of these tested beverages in terms of the non-carcinogenic effect of total and inorganic or organic species of As, Cr, and Sb.

Anti‑gouty arthritis and anti‑hyperuricemia properties of celery seed extracts in rodent models

Gout is a type of serious arthritis that is caused by hyperuricemia. Celery is an umbelliferous plant that was shown to exhibit anti‑inflammatory activity in rodent. The present study aimed to investigate the effects and potential preliminary mechanisms of celery seed aqueous extract (CSAE) and celery seed oil extract (CSOL) for gout treatment. The components of CSAE and CSOL were systematically analyzed. In mice with hyperuricemia induced by potassium oxonate and yeast extract, CSAE and CSOL treatment reduced the serum levels of uric acid and xanthine oxidase. In addition, CSAE and CSOL reduced the levels of reactive oxygen species and increased the serum levels of superoxide dismutase and glutathione peroxidase in mouse serum. In rats with acute gouty arthritis induced by intra‑articular injection of monosodium urate crystals, CSAE and CSOL treatment alleviated the swelling of the ankle joints and reduced inflammatory cell infiltration around the ankle joints. In addition, CSAE and CSOL reduced the levels of interleukin (IL)‑1β and tumor necrosis factor α and increased the levels of IL‑10. The results of the present study suggested that celery seed extracts may have anti‑gout properties, partially through anti‑inflammatory and antioxidative effects.