Food Analytical Methods最新文献

The standard method for determining seed moisture uses the low constant temperature oven method. Although moisture meters allow rapid determination of seed moisture content, it is necessary first to calibrate and validate them using standard methods. Calibration and validation of the LDS-1G grain moisture meter were conducted on seven tropical vegetable seeds (chickpeas, chili, cucumber, water spinach, long beans, tomatoes, and spinach) using the oven method. The paired t-test results revealed no significant difference between the moisture content measurements of cucumber, water spinach, long beans, and tomato obtained using the oven method and LDS-1G grain moisture meter. However, the prediction of seed moisture content by the LDS-1G grain moisture meter differs significantly from the oven method for chickpea, chili, and spinach seeds. The recommended codes for measuring the moisture content of tropical vegetable seeds using LSD-1G grain moisture meter are as follows: P6 and P7 for cucumber codes; P5, P6, P10, P11, and P12 for water spinach; P6, P7, P10, P11, and P12 for long beans; and P3, P6, P10, P11, and P12 for tomatoes.

Yerba mate (Ilex paraguariensis A. St.-Hil.) is a legacy of the Guarani tradition that the peoples of Uruguay, Paraguay, Argentina, and Brazil have shared for centuries. It is usually consumed as a mildly stimulating drink called mate. However, numerous other applications exist, such as in the composition of pharmaceutical products, dyes, cosmetics, food, and beverages. It’s industrialization for producing yerba mate relies on relatively simple processes, of which little information is available related to sustainability. This work proposes evaluating the yerba mate processing industry’s environmental, social, and economic aspects. Thus, industries from southern Brazil—Rio Grande do Sul state—were interviewed and answered a questionnaire with indicators associated with the tripod of sustainability. The responses were applied to a mathematical model to calculate the sustainability index. As a result, it was found that the maximum degree of sustainability for the environmental scope was obtained in 40% of the industries interviewed. In contrast, in the economic scope, it was 25%, and in the social scope, 35% of the interviewed sectors. The global sustainability index was identified with a maximum degree for only 20% of the industries interviewed. These results show that there is still room for improvement and the need for interventions so that more industries achieve excellence. The results based on this system provide subsidies for adapting processes and certifying that production follows guidelines and other standardization aspects associated with sustainability, contributing to the UN Sustainable Development Goals (SDGs) and emphasizing the search for sustainable food production.

In this study, a new sample preparation methodology was applied to facilitate the accurate and precise determination of 12 selected elements in vegan food samples. Vegan foods (soy granules, egg substitute, puffed rice chocolate, oat nut chocolate, meatball mix, cheese, meat, chocolate vegan wafer, chips, sausage, butter, almond milk, soy milk, coconut milk, oat milk) were digested in a closed-vessel microwave system using various HNO₃ and H₂O₂ combinations. The arsenic, barium, cadmium, cobalt, chromium, copper, iron, manganese, lead, nickel, vanadium, and zinc in vegan foods were determined by inductively coupled plasma mass spectrometry. The NIST 1515 (apple leaves) and NIST 1573A (tomato leaves) certified reference materials were used as test samples to optimize the digestion, and validate the trueness of the procedure using the certified values. The limits of detection calculated for the 12 elements were in the range of 0.010–0.042 ng mL⁻¹, and the corresponding limits of quantification were in the range of 0.030–0.140 ng mL⁻¹. Nine out of the twelve selected elements were detected in vegan samples digested with 14 mol L⁻¹ HNO₃ + H₂O₂ with the mass fractions ranging between 0.03 and 43 µg g⁻¹. Toxic elements such as As, Cd, and Pb were detected below the detection limits in all vegan samples. The aim of this study is to investigate by using ICP-MS the effect of different HNO₃ + H₂O₂ combinations on the amounts of trace elements in such a number of such diverse vegan foods.

A new pre-treatment and determination methodology has been developed including magnetic solid phase extraction (MSPE) combined with high-performance liquid chromatography with diode array detector (HPLC–DAD) for the determination of trace sibutramine and fluoxetine molecules in herbal slimming products. In the proposed method, fluoxetine and sibutramine molecules were extracted with the help of newly synthesized magnetic-Fe₃O₄-based nanoparticles in the presence of a pH 10.0 medium. The analytical performance criteria of the developed method such as linear range, enrichment factor, and detection limit were studied and calculated according to official guidelines after optimization of the experimental variables of MSPE such as pH, adsorption, and desorption conditions. Fluoxetine and sibutramine molecules were determined by a HPLC–DAD system at 225 and 265 nm for fluoxetine and sibutramine using a mobile phase composed of pH 5.0 acetate buffer and methanol (30:70). The obtained detection limits from experimental results were calculated as 3.41 ng mL⁻¹ and 3.83 ng mL⁻¹ for fluoxetine and sibutramine, respectively. The accuracy of the method was evaluated by means of recovery tests in model solutions and real samples for two concentration levels. As a result of recovery experiments, the values were found in the range of 94.8–104.5% while relative standard deviation (RSD %) values were below 6.0%.

The present work investigates the adulteration of extra virgin olive oil (EVOO) using highly surface-sensitive SPR-enhanced ellipsometry (SPRE) technique, aiming to ensure food quality and consumer safety. Due to the elevated cost of EVOO, adulteration with cheaper, poor-quality refined or edible oils has become a common practice for economic profit. The EVOO is purposely adulterated by blending four different edible oils with transparent or similar colors and similar refractive indices to replicate realistic adulteration scenarios. An in-house-built SPRE setup was used to conduct the experiments using a reusable bimetallic Ag-Au SPR sensor chip. The quantification limit for EVOO adulteration was successfully obtained at a low level of 5% (v/v) at room temperature. This optical technique has strength in its convenience, simple instrumentation, ease of sample preparation, minimal solvent usage, non-destructive nature, and rapid real-time analysis. We believe that our experimental outcomes make a valuable contribution to the field, addressing the critical need for reliable methods to ensure the authenticity and quality of EVOO.

Anthocyanins have gained significant attention for their potent colorant capacity and multifaceted biological activities. As a result, the quantification of anthocyanin content in wild berries and the identification of anthocyanin profiles have become increasingly important, as well as the optimization of methods for these determinations. The present study shows a rapid UHPLC-DAD method for identifying and quantifying individual anthocyanins in selected wild berries and fruit samples of Mediterranean origin, namely, Prunus avium, Fragaria vesca, and Vaccinium myrtillus. Moreover, the applicability of the developed method to different food matrices was verified in cultivated berries, specifically, Punica granatum, Fragaria x ananassa, Rubus spp., and Vaccinium corymbosum. The developed method showed great sensitivity (LOD of 23.92 ng/g, LOQ of 79.73 ng/g), precision (RSD below 2.599%), and accuracy (recovery percentages of 97.97 and 98.88%). It successfully quantified individual anthocyanins (delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, petunidin-3-O-glucoside, pelargodinin-3-O-glucoside, malvidin-3-O-glucoside) across different berries and fruit samples. The developed methodology allows to conduct routine analysis without the need for mass spectrometry. The range of total anthocyanins quantified in wild berries and fruit samples was 0.03 to 7.66 mg/g of powdered extract corresponding to Prunus avium L. and Vaccinium corymbosum L., respectively.

A magnetic solid-phase extraction (MSPE) approach is developed as an efficient and simple method on the basis of the modification of magnetic nanoparticles using an ionic liquid in order to preconcentrate and extract catechin from grape juice samples. A narrow-bore tube (NBT) containing the sample was used to carry out the extraction in a simple and efficient manner. Using scanning electron microscopy (SEM), Fourier transfer infrared (FT-IR) spectroscopy, and X-ray spectroscopy (EDX), the specifications of the synthesized nanoparticles modified with 2-hydroxyethyl ammonium chloride ionic liquid were scrutinized. The impact of various parameters on catechin extraction was assessed. Under optimized conditions (i.e., sample volume of 10 mL, pH 3, 14 mg of sorbent, 20-min desorption time, and elution with 3.0 mL of 0.15 mol L^–1 phosphate buffer at pH 10), the relative standard deviation and limit of detection (LOD) were found to be 1.63% and 0.141 µg mL⁻¹, respectively, for seven replicate determinations using HPLC–UV. Based on the obtained experimental results, the maximum adsorption capacity of the sorbent for catechin was 61 mg g⁻¹. Eventually, to determine the applicability of the developed technique, the method was a success when utilized to analyze the catechin content of the samples of grape juice, indicating a recovery range of 93.4–99.5%.

Milk powder is a common food in most families. It is of great significance to accurately detect the quality and safety of milk powder to mitigate food safety problems. This paper presents a method for the determination of vanillin and ethyl vanillin in milk powder based on terahertz (THz) spectroscopy. Samples with varying concentration gradients of these two additives were prepared, and a terahertz time-domain spectrometer was used to collect spectral data from the samples in the 0.2 to 1.5 THz range. Seven spectral preprocessing algorithms were evaluated using the partial least squares (PLS) method, and it was found that the combination of multivariate scattering correction (MSC) and Savitzky-Golay (SG) smoothing preprocessing yielded the best results, significantly improving the accuracy of the test sets for both additives. Subsequently, nine quantitative detection methods were constructed by combining three dimensionality reduction algorithms (ant colony algorithm (ACO), competitive adaptive reweighted sampling (CARS), and successive projection algorithm (SPA)) with three regression models (support vector regression (SVR), long short-term memory (LSTM), and particle swarm optimization-back propagation (PSO-BP)). The results showed that the LSTM regression model, with dimensionality reduction performed by the CARS algorithm, performed best for detecting vanillin in milk powder, achieving a recognition rate of 94.49%. Compared to the other eight methods, this increased the recognition rate by 7.69%. Similarly, the LSTM regression model, combined with the SPA algorithm for dimensionality reduction, performed best for detecting ethyl vanillin in milk powder, reaching a recognition rate of 98.37%. This represented a 6.59% increase in recognition rate over the other eight methods, providing a novel technical approach for non-destructive testing and analysis of milk powder quality and safety.

The objective of this study was to determine the total glucosinolate (GLS) content in Camelina sativa, using a simple and sensitive method, based on the colorimetric reaction of sodium tetrachloropalladate (II) with GLSs, and to quantify them by spectrophotometry without the use of HPLC. Glucosinolates from defatted meal, seeds, animal feeds and sprouts were extracted and isolated using a weak anion exchange column. Sodium tetrachloropalladate (II) solution was added to the extract and the absorbance measured at 420 nm. The repeatability (intra-assay) of the sodium tetrachloropalladate (II)—assay (Pd-assay) was very high, with CVs ranging from 2.07 to 0.90% for the single experiments. The inter-assay was also very high, displayed by a CV of 1.65% across all of the experiments. The Pd-assay is therefore able to quantify GLS amounts with good accuracy in all the tested matrices, which cover a very wide range from 0.50 µmol g⁻¹ DW in animal feed to about 40 µmol g⁻¹ DW in defatted meal. The good agreement between the Pd-assay and HPLC was testified by a significant correlation R² = 0.9937. These results indicate that the accuracy and repeatability of the Pd-assay are suitable for measuring total GLS in all camelina tissues tested.