Food Analytical Methods最新文献

In this work, Design of Experiments and the Derringer’s desirability function were used to optimize the chromatographic conditions and an ultrasound-extraction procedure for the simultaneous determination of caffeine, theobromine, theophylline, catechin, and epicatechin in guarana seeds by HPLC-UV/Vis. The composition of the mobile phase was optimized using a mixture design, where an adequate chromatographic separation was obtained with 92.4% of an aqueous solution of acetic acid (0.1% v v^− 1), 5.2% methanol, and 2.4% isopropanol. A mixture design using water, acetone, and ethanol was used to optimize the composition of the extractor solution for ultrasound-assisted extraction. The best conditions for simultaneous extraction of the target compounds were 1.45, 0.45, and 0.1 mL of water, ethanol, and acetone, respectively. After defining the extractor solution, we applied a Doehlert matrix to study the instrumental conditions of the ultrasonic bath. Instrumental parameters were optimized at 35 °C, 30% and 10.5 min for temperature, power, and extraction time, respectively. The proposed procedure was validated and applied for analysis of guarana seeds samples dried by different techniques. Our results indicated that post-harvest management can significantly change the catechin and epicatechin contents in guarana samples.

The physicochemical properties of dabai kernel oil as well as the morphology of dabai samples are affected by the optimal extraction method and process configurations. Subcritical water treatment prior to dabai kernel oil extraction was optimized through the utilization of response surface methodology based on central composite design. The subcritical water treatment was carried out within the following temperature ranges of 100 to 150 °C, 10- to 20-min reaction times, and 10:1 to 20:1 solvent to solid ratios. Results showed that temperature of 100 °C, reaction time of 10 min, and solvent to solid ratio of 10:1 were optimal parameters for dabai kernel oil by subcritical water treatment prior to Soxhlet extraction. Dabai kernel oil yields via subcritical water treatment were 96.53% on average, compared to 42.85% for Soxhlet extraction sample. Gas chromatography mass spectrometry analysis found for subcritical water treatment samples revealed value-added compounds, including oxalic acid and 9-octadecenoic acid, which can be utilized for cleaning and pharmaceutical applications. Scanning electron microscope images provided evidence that rapid extraction was driven by the degradation and aggregation of dabai kernel powder structure. The Brunauer–Emmett–Teller analysis indicated that the dabai kernel of subcritical water treatment displayed a greater surface area (14.813 m²/g) than the raw (2.804 m²/g) or Soxhlet extraction (13.452 m²/g) dabai kernel. Subcritical water treatment could be considered a promising method in combination with Soxhlet extraction in order to improve the oil yield from dabai kernels.

Black cumin (Nigella sativa) and coriander (Coriandrum sativum L.) are common culinary spices that are used singly or combined in the diet of many populations of Ethiopia, and there is a long-held belief of their health-enhancing properties. The present study was designed to investigate the antioxidant properties, phenolic and flavonoid contents of aqueous methanolic extracts from Nigella sativa and Coriandrum sativum L. seed samples. The contents of polyphenols and flavonoids were evaluated by colorimetric method, and antioxidant activity was determined based on the ability to scavenge free radicals by using DPPH assay. An aqueous methanol extract of Coriandrum sativum L. resulted in the highest phenolic content from West Dembia (1.799 ± 0.0011 mg GAE/g), followed by Nigella sativa from East and West Dembia (1.737 ± 0.0014 & 1.734 ± 0.0013 mg gallic acid equivalent per gram (mg GAE/g) respectively) and Coriandrum sativum L. from West Dembia (1.678 ± 0.0018 mg GAE/g) measured by the Folin–Ciocalteu reagent method. The greatest flavonoid content was observed with extracts of Coriandrum sativum L. (1.114 ± 0.0005 mg quercetin equivalents per gram samples (mg QE/g)) from East Dembia district followed by Nigella sativa (1.002 ± 0.0007 (mg QE/g)) as measured by an aluminum chloride colorimetric method, while the least was recorded for Coriandrum sativum L. (0.926 ± 0.0013 mg QE/g) and Nigella sativa (0.764 ± 0.0010 mg QE/g) from West Dembia district. Among the two selected spice extracts, Nigella sativa from East Dembia district displayed the highest DPPH radical scavenging activity with an IC₅₀ value 432-mg ascorbic acid equivalent per gram sample (AAE/g), while Nigella sativa and Coriandrum sativum L. from West Dembia and Coriandrum sativum L. (East Dembia) showed lower antioxidant activities having 372, 320, and 366 mg AAE/g of sample respectively. These results confirmed that Nigella sativa and Coriandrum sativum L. extracts possess appreciable natural antioxidant potentials, thereby providing good justification for their increased domestication and combined food consumption.

In recent years, the Mexican government has implemented several economic sanctions on producers and marketers of milk bovine cheese due to food fraud such as mislabeling or addition of vegetable fats. However, there have been no official reports on the authenticity of goat cheese. This research aimed to detect adulteration in goat cheese by terms of food substitution with bovine milk or soy protein. For which, bovine cytochrome b genes (274 bp) and lectin genes (118 bp) were amplified in 12 commercial brands of goat cheese by real-time PCR (qPCR) where the detection limit for each species was assigned to the lowest concentration detected with a confidence level ≥ 95% being 0.01 ng/µL for bovine milk, and 0.1 ng/µL for soy DNA. Research findings indicate the absence of soy protein; however, a high degree of adulteration with bovine milk (92.3%) was found. The above evidence suggests the need for regulatory agencies to improve verification and traceability mechanisms to ensure the authenticity of these products and protect consumers by providing reliable information.

A better quality of life comes with a healthy diet without adulteration or contamination. As much as the demand for purity in diet increases, the risk of adulteration also increases in daily edibles. The present study proposed Raman spectroscopy for the identification of used cooking oils to overcome adulteration. Unused cooking oil with different concentrations of used oil (waste oil) as an adulterant was examined by Raman spectroscopy along with principal component analysis (PCA). Increasing the concentration of used oil causes changes in Raman spectral features. The changes can be observed at 1413 cm⁻¹, 1521 cm⁻¹, and 1745 cm⁻¹ in Raman mean spectra of unused oil with the addition of different concentrations of the adulterant. Raman spectroscopy with PCA gives qualitative analysis and helps to monitor the quality of the cooking oil. PCA is a statistical tool that is used to examine variations in the given Raman spectral dataset. PC-1 shows more variability about 93.8% for the differentiation of the Raman spectral groups of the used and unused oil, while for unused oil and its different concentrations with adulterant, it shows a variability of 88.8%. These results demonstrate that Raman spectroscopy can be applied for the identification of adulterated oil. In the future, this spectroscopic technique can be used in the field of food chemistry because of its non-invasiveness and non-destructive analysis.

This study presents a comprehensive exploration of an antenna system designed for tomographic image reconstruction, with a particular focus on the application to various fruits. The antenna, simulated using CST software and physically manufactured, operates in two frequency bands (0.915 GHz and 2.45 GHz) and is arranged in a circular configuration for signal reception. The experimental setup incorporates a microwave source generator, an 8-element antenna array, a vector network analyzer (VNA), and probes. Employing the “Dielectric Anomaly Detection Approach,” the system achieves detailed tomographic reconstructions, emphasizing dielectric anomalies in defective fruit regions. Additionally, Fourier transform infrared (FTIR) spectroscopy is employed to examine the molecular composition of fruit specimens, providing insights into their chemical properties. The non-invasive nature of the experimental setup is highlighted in contrast to the invasive FTIR method, offering advantages in assessing fruit quality without altering specimens.

Peanuts are taken through routine postharvest procedures to assess quality, establish the grade, and determine the amount of revenue that the farmer will be allotted. Moisture content and meat content are examples of parameters determined to assess the grade of the peanuts. Such parameters are assessed for bulk samples usually with mass > 1 kg, and the resulting values are averages of peanuts within the bulk sample. Such processes are destructive and lack provision for assessment of single, in-shell peanuts. Thus, the characterization of single, in-shell peanuts was investigated by measuring the shift in resonant frequency and the change in cavity transmission characteristics caused by each peanut once inserted into a resonant cavity connected to a vector network analyzer (VNA). Such microwave measurements were taken for over 300 in-shell peanuts at 22 °C. The peanuts were divided into seven categories based on custom fillings to simulate diseased and damaged peanuts. One category, serving as the control, consisted of intact peanuts, while the other categories consisted of peanuts filled with coffee, cornstarch, and/or a single kernel. The measured resonant-cavity parameters and the calculated dielectric properties provided a means to characterize each in-shell peanut. Statistical analysis was performed to assess differentiation between the seven categories using those parameters. Kruskal–Wallis One-Way ANOVA on Ranks, Tukey test, and Dunn’s Method were used to determine which categories were statistically significantly different from each other for each parameter at the 95% confidence interval. Lastly, artificial intelligence was used to investigate the creation of models to accurately classify the peanuts.

Minocycline is a broad-spectrum antibiotic widely used in clinical and veterinary medicine and its adverse effects are as prominent as its potent efficacy. To avoid its abuse and accumulation, it is very important to detect minocycline in medical science, food industry, and aquaculture industry. Here, a conjugated polymer probe for minocycline is prepared and its optical properties and fluorescence response to minocycline is studied. The quenching efficiency is linear relevant with the amount of minocycline at the concentration range of 0–12 µM in PBS and 0–28 µM in ethanol with the limit of detection of 0.0151 µM. Moreover, the standard addition recoveries of minocycline in skim milk samples are between 92.22 and 104.43%, and the relative standard deviation values are less than 3%. These results imply that the probe has a great potential for detecting minocycline in actual samples with simplify, rapidity, and sensitivity.

A method for the determination of 106 pesticides, 74 veterinary drugs, 10 mycotoxins, and 18 persistent organic pollutants in livestock and poultry meat was developed and validated in the present study. The meat was extracted with acetonitrile under citric acid caching and purified using the multi-plug filtration clean-up (m-PFC) column. The components were separated using liquid chromatography on a C₁₈ column and then eluted using a gradient of the aqueous solutions of acetonitrile and 0.1% formic acid (containing 2 mmol/L ammonium acetate) as the mobile phase. The mass spectrometry analysis was performed next using two electrospraying scan modes—the positive ion mode and the negative ion mode, and multiple reaction monitoring (MRM) modes. The results revealed that all 208 target analytes exhibited good linearity in their respective linear ranges, with the correlation coefficient of each analyte above 0.9953 and the corresponding limits of quantification (LOQs) in the range of 0.1–9.8 µg/kg. The average recovery values of 189 targets at three different spiked levels of low, medium, and high ranged from 70.1 to 120.0%, and the corresponding values of relative standard deviation (RSD) ranged from 1.3 to 15.0%, respectively. The remaining 19 targets exhibited the average recovery values [at three different spiked levels of low, medium, and high] ranging from 18.6 to 58.9%, with the corresponding RSD values ranging from 1.5 to 11.3%. The developed method was applied to 132 batches of livestock and poultry meat, and nine pesticides and seven veterinary drugs were detected in the concentration range of 0.1–24.8 µg/kg. These results suggested that the developed method is simple, reliable, reproducible, and suitable for the determination of pesticides, veterinary drugs, mycotoxins, and persistent organic pollutants in livestock and poultry meat.