Effect of Subcritical Water on the Extraction of Bioactive Compounds from Carrot Leaves

Carrot leaves, which are generally considered as agricultural residue, are rich in bioactive compounds, such as polyphenols. This study investigates the extraction of polyphenols and luteolin (flavonoid) from freeze-dried and ground carrot leaves (d?<?100 μm) using subcritical water (SCW). Water at elevated temperatures and at high pressure (40 bar) could behave as low-polar solvent to enhance extraction of organic compounds. SCW was investigated at different temperatures (110–230 °C), time (0–114 min), and solid-liquid ratio (15 and 35 g/L). Accordingly, it was revealed that total phenolic content (TPC) from carrot leaves using SCW has an increasing trend with temperature and resulted in 42.83 ± 1.85 mg per g of dry weight in gallic acid equivalent at 210 °C/113.5 min. However, luteolin content using SCW extraction behaved differently, where increase of temperature adversely affected its content. Hot water extraction studies revealed the presence of optimum luteolin content (0.768 ± 0.009-mg/g dry weight) at 120 °C for 10 min. In conclusion, it was shown that carrot leaves are a promising feedstock to extract polyphenols that has high content of luteolin.     

A critical evaluation on the reliability of two aluminum chloride chelation methods for quantification of flavonoids

Flavonols kaempferol, quercetin, myricetin and gossypetin, and flavones apigenin, acacetin, luteolin, orientin and tricin, are subjected to two AlCl(3) spectrophotometric methods used for determination of total flavonoid content. The method developed by Woisky and Salatino involves addition of AlCl(3) solution to the flavonoid solution and recording of optical density at 420nm. All flavonols except kaempferol have absorption maxima above 440nm and so readings at 420nm are erroneous. Among flavones, all except for luteolin and orientin, have absorption maxima below 400nm. Further, addition of CH(3)COOK and recording the absorbance at 415nm, as modified by Chang et al., works well for flavonols kaempferol, quercetin and myricetin, but not for gossypetin. The flavones luteolin and orientin absorbed above 400nm, whereas all others absorbed below 400nm. Examination of the results of both methods indicates they are inadequate, and should not to be considered as universal and standard methods for total flavonoid determination.     

Fast Automated Determination of Total Tocopherol Content in Virgin Olive Oil Using a Single Multicommuted Luminescent Flow Method

Tocopherols are natural fluorophores of great importance for the characterization and authentication of virgin olive oil. Herein, a single automatic multicommuted flow method has been developed for the determination of total tocopherol content as well as the semi-quantitative estimation of α-tocopherol in extra virgin olive oil (EVOO) samples. Only appropriate dilution of samples with 2-propanol was necessary for their direct analysis by a multicommuted flow injection (MCFIA) manifold based on three solenoid valves with fluorescence detection. The peak height at λ _em = 330 nm (emission) with λ _exc at 296 nm was used as analytical signal. Linear response was observed within the range from 50 to 350 mg of tocopherols (expressed as α-tocopherol kg^?1 olive oil), suitable to cover the usual range for tocopherols in (extra) virgin olive oil ((E)VOO)). The results were consistent with those obtained by reversed-phase HPLC reference method, whereas the analysis time was significantly reduced. The sample frequency of the proposed automatic method was close to 40 samples h^?1, in contrast to typically 15–30 min required by HPLC. The method is fast, straightforward, cost-effective, and easy to implement in routine laboratories for screening purposes.     

Physicochemical,Phytochemical and Mycological Characteristics of Italia Muscat Raisins Obtained Using Different Pre-treatments and Drying Techniques

Raisins represent an economically important grapevine by-product. However, their quality is largely dependent on drying techniques and processing conditions. In this context, two drying processes were monitored: hot air drying in a convective oven and greenhouse drying. Grape berries were previously subjected to two chemical pre-treatments (olive oil and K₂CO₃ emulsion dipping (I) and NaOH solution bleaching (II)). Pre-treated grapes processed using both methods were compared with sun-dried samples. The results show that oven drying was more efficient and rapid (5 days) as compared with greenhouse drying (13 days). The end moisture content of grapes varied from 16.12% to 22.25% on a wet basis in dried samples, respectively. Significant differences in the pH value (3.85–4), acidity (1172.5–2730 mg TA/100 g DW) and total sugars (31.5–49.7%) were also observed, between raisin samples subjected to both treatments and drying methods, whereas protein levels (1–1.25%) were not affected. The analysis of minerals indicates that greenhouse-dried raisins had high amounts of calcium (Ca), magnesium (Mg) and sodium (Na). The highest polyphenol (417.70 mg GAE/100 g DW), flavonoid (115.87 mg CE/100 g DW) and tannin (368.13 mg CE/100 g DW) contents were recorded in sun-dried samples, respectively. The distribution of fungal flora shows a noteworthy variability among raisin samples, with a marked abundance of ochratoxinogenic species such as Aspergillus ochraceus and Aspergillus carbonarius (15.56% and 10.41%, respectively). Italia Muscat raisins processed using oven drying could be an economically interesting alternative to manage the excessive grapes production and consequently solve related marketing issues.     

Phenolic Profiles and Antioxidant Capacities of Chinese Unifloral Honeys from Different Botanical and Geographical Sources

Honey has been acknowledged worldwide as a good source of natural antioxidants. Chemical properties of total phenolics and flavonoids of 33 Chinese unifloral honeys from nine different floral sources were investigated. Antioxidant activities including 1, 1-diphenyl-2- picrylhydrazyl radical (DPPH·) scavenging, superoxide anion radical (O₂ ^?·) scavenging, hydroxyl radical (·OH)-scavenging activities, and reducing powers were evaluated. The results indicated that total phenolic content (TPC) ranged from 10.43 to 149.6 mg of PCE/100 g, while total flavonoid content (TFC) ranged from 9.41 to 102.1 mg QE/100 g. Positive correlations between radical-scavenging activities and, respectively, TPC values and TFC values were found. Remarkable variations in antioxidant properties, TPC, and TFC values were demonstrated in hydrophilic extracts of honeys from different botanic and/or geographic sources. The current findings will provide useful information for evaluating the food quality of Chinese honey and for educating consumers to choose specific honey lines for their specific health-promoting effects.     

Determination of Arsenic Species in Edible Mushrooms by High-Performance Liquid Chromatography Coupled to Inductively Coupled Plasma Mass Spectrometry

The content of total arsenic was determined by inductively coupled plasma mass spectrometry after microwave digestion. The results showed that the content of total arsenic was ranged from 0.04 to 212.3 mg kg^?1 in the test edible mushrooms. The content of total arsenic in eight test samples was greater than 0.5 mg kg^?1. However, the toxicity of arsenic is closely related to the chemical form. Therefore, the determination of arsenobetaine, arsenocholine, dimethylarsinic acid, monomethylarsonic acid, arsenite, and arsenate in edible mushrooms was performed on an ion exchange chromatography column (Dionex IonPac AS19) with inductively coupled plasma mass spectrometry as a detector. When water and 50 mM (NH₄)₂CO₃ (pH = 9.7) were worked as a mobile phase, the six arsenic species could be well separated in 20 min. Ultrapure water was selected as extraction solvent for the validation of ultrasound-assisted extraction method due to its advantage of simple, cheap, and high extraction efficiency. Under optimum conditions, the limits of detection were <2.5 μg kg^?1 of the test arsenic species for arsenic, and the recoveries of all six arsenic species were >91.0 % with the relative standard deviation of <5.5 %. The method was applied to 19 different mushroom samples. The results indicated that the total content of arsenic species was basically identical with the content of total arsenic. And arsenobetaine was proved to be the main arsenic species in the test Lentinus edodes-2 sample.     

Effect of Carbonic Maceration Pre-treatment on Drying Kinetics of Chilli (Capsicum annuum L.) Flesh and Quality of Dried Product

A new pre-treatment — carbonic maceration (CM) pre-treatment — was presented in this paper. To study the effect of CM on microwave drying (MD) kinetics of Chilli flesh and quality of dried product, the fresh (control group, CK) and CM pre-treated samples were dried through MD at 100, 150 and 200 W, respectively. CM conditions were optimized by orthogonal test. The drying results indicated that, the average drying rate for CM samples were as much as 150–185 % of these for CK samples. For both CK and CM samples, the drying rate increased at the initial time (a warming-up period) and then decreased at the end time (a falling rate period) after reaching a plateau (a constant rate period). And the effective diffusivity, D _eff, increased gradually at the initial period and then rapidly at the final period with the diminishing moisture content. Elevated microwave power levels could lead to a linear increase in values of D _eff at the same moisture content. The activation energy, E _a, increased rapidly when moisture content was below about 1 g water/g dry mass, which was lower for CM samples than for CK samples, and can be well described with a logistic model. Scavenging free radical capability (DPPH), ferric reducing antioxidant power (FRAP), total phenol contents and vitamin C retention contents of the dried products for CM samples were as much as 170.1–190.9 %, 140.2–147.8 %, 140.1–160.0 % and 212.7–682.4 % of these for CK samples, respectively. The CM dried products were also better in terms of colour differences than CK.     

Characterization of phenolics in different parts of selected <Emphasis Type="Italic">Capparis</Emphasis> species harvested in low and high rainfall season

The stem bark, shoot, fruit, flower and root from Capparis spinosa and Capparis decidua, harvested in April and September (corresponding to low and high rainfall season, respectively), were investigated for variations in the contents of total phenols, flavonoids and individual phenolics. Aqueous methanol (80%) soluble extracts from different parts of the selected species, were evaluated colorimetrically for total phenolic contents (TPC), total flavonoid contents (TFC) and inhibition of linoleic acid peroxidation. Relatively, a higher extract yield (5.57–42.43%), TPC (157.3–348.6 GAE mg/100 g), TFC (229.2–584.9 CE mg/100 g) for both the species were recorded for September samples. Among the parts tested of both the species, fruits offered higher content of total phenolics (235.1–455.3 GAE mg/100 g) whereas flowers contained greater amount of flavonoids (96.7–269.9 CE mg/100 g). A notably variable content of phenolic compounds (0.24–94.22 mg/100 g) such as gallic acid, p-coumaric acid, caffeic acid, p-hydroxybenzoic acid and sinapic acid were detected by RP-HPLC in different parts of the selected species; however, sinapic acid was not detected in the flowers of both the species. It can be concluded from the findings of the present study that season has significant effect on the phenolics profiling of Capparis plants and thus collection of different parts of the selected species in an appropriate season can be beneficial towards maximizing their functional food and nutraceutical benefits.     

Antitumor,Antioxidant, and Nitrite Scavenging Effects of Chinese Water Chestnut (Eleocharis dulcis) Peel Flavonoids

The preparation, quantification, and characterization of flavonoid compounds from Chinese water chestnut peel (CWCP) flavonoid extract and ethyl acetate fraction (EF), n‐butanol fraction, and water fraction were studied. Among these, EF showed the maximum free radical levels (IC₅₀ values of 0.36, 0.40, and 0.37 mg/mL for DPPH?, ABTS? ⁺ , and ?OH, respectively), nitrite scavenging effects (IC₅₀ = 1.89 mg/mL), and A549 cell inhibitory activities (IC₅₀ = 776.12 μg/mL) with the highest value of total flavonoid content (TFC, 421.32 mg/g). Moreover, the contents of 8 flavonoids in this fraction were quantified using high‐performance liquid chromatography, and fisetin, diosmetin, luteolin, and tectorigenin were the 4 major flavonoids with levels of 31.66, 29.91, 13.69, and 12.41 mg/g, respectively. Luteolin produced a greater inhibition of human lung cancer A549 cells (IC₅₀ = 59.60 μg/mL) than did fisetin, diosmetin, and tectorigenin. Flow cytometry revealed that the cellular mechanisms of luteolin inhibition of A549 cells were achieved via the induction of cell proliferation arrest at G₁ phase and apoptosis/necrosis. Our findings suggest that flavonoids are closely associated with antitumor, antioxidant, and nitrite scavenging effects of CWCP.     

Oil content,phenolic profiling and antioxidant potential of Tunisian olive drupes

BACKGROUND: The aim of this work was to investigate the effect of the maturation process of the olive fruit on oil content, phenolic profile and antioxidant activity of four Tunisian cultivars (Zelmati, Chemchali, Chemlali and Chétoui). RESULTS: The average oil content of the studied varieties ranged between 17.50% and 20.25% at the first stage of maturation and from 30.20% to 35% in the last harvest. Qualitative and quantitative analysis of phenolic compounds were carried out using HPLC and LC‐MS/MS. Twenty‐six biophenolic compounds were identified. In all samples, hydroxytyrosol and oleuropein were the major compounds identified while rutin and luteolin 7‐O‐glucoside were the two main flavonoids. The total phenolic content varied from 3.46 to 4.30 g kg^?1 at the first stage of maturation and from 8.71 to 11.52 g kg^?1 of fruit fresh weight at the last maturation phase. Total flavonoid content reached 432.80 mg kg^?1. The antioxidant activity of the extract was evaluated by DPPH and ABTS assays. The IC₅₀ values of the olive extracts ranged from 2.69 to 10.96 µg L^?1 and from 2.15 to 3.03 mmol L^?1 trolox equivalent at the last stage of maturation. CONCLUSION: A relationship between the changes in phenolic content and the physicochemical changes in Tunisian olive fruit during maturation was established. These findings could be used for controlling the production processes and correlating the oil sensorial characteristics to the polyphenolic pattern. Copyright © 2010 Society of Chemical Industry     

Spectral evaluation of total phenolic components in Vitis vinifera: Grapes and wines

Whereas high levels of flavonoid extractives are responsible for the characteristic λ_Dmax at about 280 nm in the ultra-violet spectra of red wines, there is wide variability in the spectral features of natural white wines, in which the phenolic content is often minimal. For the latter, λ_Dmax may occur anywhere within the range 265–285nm, with relatively strong absorbance at 320 nm arising from the presence of hydroxycinnamate esters. Massive fining of many white wines and juices with polyvinylpyrrolidone (10% w/v) has shown residual non-phenolic u.v. absorbing constituents to be sufficiently uniform to enable direct spectral measurement of total hydroxycinnamates in white juices, white wines and rosés as (E₃₂₀-1.4) absorbance units. For white grape juices and white wines, total hydroxycinnamates are directly quantitated as mg litre^?1 ‘caffeic acid equivalents’ and total flavonoid extractives may also be estimated. Total phenolic components of red wines are accounted as (E₂₈₀-4) absorbance units. The spectral interpretations enable comparative estimation of flavonoid extractives in all natural wine types.     

Ultraviolet Light-Assisted Photocatalytic Disinfection of <Emphasis Type="Italic">Escherichia coli</Emphasis> and Its Effects on the Quality Attributes of White Grape Juice

Ultraviolet (UV) light-assisted titanium dioxide (TiO₂) photocatalysis is an emerging technology in food safety that utilizes TiO₂ photocatalysts to accelerate the generation of reactive oxygen species during UV illumination. In this work, we studied the use of immobilized TiO₂-SiO₂ photocatalysts illuminated with UVA radiation (350 nm; 14.8 mW/cm²) for the inactivation of Escherichia coli ATCC 25922 in white grape juice, and compared the effectiveness of the photocatalytic disinfection with respect to the quality attributes of white grape juice against those of thermal and UVC (254 nm; 19.7 mW/cm²) treated samples. To obtain a 5-log reduction of the target microorganism, treatment durations of UVA in the absence and presence of the photocatalyst were 60 and 40 min, respectively. A 5-log reduction with UVC radiation led to the loss of health-related compounds such as vitamin C, total phenolic content, and total antioxidant capacity at 92.0?±?1.1%, 19.4?±?5.6%, and 54.3?±?10.0%, respectively. However, the same level of reduction with UVA led to a loss of 74.2?±?2.3%, 7.1?±?3.6%, and 39.7?±?2.5%, and with UVA-assisted photocatalytic method resulted in a loss of 75.8?±?6.1%, 13.6?±?5.8%, and 45.6?±?4.4% of vitamin C, total phenolic content, and total anti-oxidant capacity, respectively. Given its efficacy in deactivating E. coli while retaining a relatively higher level of health-related constituents in the fruit juice compared to other common pasteurization techniques, the photocatalyst developed in this study provides a promising technology for food disinfection.     

Changes in Chemical and Microbial Qualities of Dried Apricots Containing Sulphur Dioxide at Different Levels During Storage

Effects of different sulphur dioxide (SO₂) concentrations (188, 452, 791, 1,034, 1,236, 2,899 and 3,864 mg SO₂ kg^?1) and storage temperatures (5, 10, 20 and 30 °C) on the physical, chemical and microbial qualities of sulphited-dried apricots (SDAs) were evaluated. Analysis of kinetic data suggested first-order models for losses of moisture and SO₂ and formation of brown colour. Strong correlations were found between SO₂ concentrations and moisture loss constants (r?=??0.943), and brown colour values (r?=?0.949). β-carotene contents in SDA samples ranged from 26.6 to 36.2 mg 100 g^?1 dry weight, depending on SO₂ content of dried apricots. The SO₂ concentration over 791 mg per kg of dried apricots effectively protected carotenoids in dried apricots during drying. While storage times had significant effect on β-carotene contents, storage temperatures did not have such effects. The number of total mesophilic aerobic bacteria in all SDA samples ranged from 8.20?×?10¹ to 1.84?×?10² CFU g^?1. The number of total psychrophilic aerobic bacteria, lactic acid bacteria, yeast and mould, xerophilic mould, Staphylococcus spp. and total Enterobacteriaceae were below the detection limits (<4 CFU g^?1) in samples containing SO₂ even at the lowest level (188 mg SO₂ kg^–1) throughout the storage. Regardless of SO₂ concentration in dried apricots, low storage temperatures (below 20 °C) should be preferred to prevent the characteristic golden yellow colours of dried apricots.     

Calibration Transfer from Micro NIR Spectrometer to Hyperspectral Imaging: a Case Study on Predicting Soluble Solids Content of Bananito Fruit (<Emphasis Type="Italic">Musa acuminata</Emphasis>)

Calibration transfer from a handheld micro NIR spectrometer (NIR-point, 939–1602 nm, 6.2 nm) to a desktop hyperspectral imaging (NIR-HSI) for predicting soluble solids content (SSC) of bananito flesh was investigated in the study. Different spectral pre-processing and standardization methods were employed for correcting spectra so as to minimise spectral differences between NIR-point and NIR-HSI. Results show that application of standard normal variate (SNV) reduced spectral differences from 31.49 to 8.96%. The best standardization method was developed based on piecewise direct standardization (PDS) algorithm using ten transfer samples. The developed PLS model yielded a high prediction performance (R ² _p = 0.922 and RMSEP = 1.451%) for predicting SSC of validation samples using the NIR-point spectra. After SNV and standardization, the model was successfully transferred to NIR-HSI data, giving a comparable prediction accuracy of R ² _p = 0.925 and RMSEP = 1.592%. The results illustrated the potential of transferring calibration models from a simple and easy-available micro NIR spectrometer to a more expensive and sophisticated hyperspectral imaging system, when the spatial distribution of quality information is required.     

Bioactive compounds and antioxidant activities of sprout soybean fermented with <Emphasis Type="Italic">Irpex lacteus</Emphasis> mycelia

To enhance the biological activities of sprout soybean, beans were treated with steaming (SS), germinating (GS), or roasting (RS) prior to fermentation with Irpex lacteus mycelia for 20 days. The total phenolic, flavonoid, isoflavone, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of each fermented bean preparation were examined every 5 days for 20 days. The total phenolic content of SS, GS, and RS preparations was 9.61, 10.23, and 10.46 mg/g, respectively, after 15 days of fermentation. These concentrations were approximately 4–5 folds higher compared to initial levels. The total flavonoid content was 8–9 folds higher than initial levels. The isoflavone content was highest in the RS sample (6.84 mg/g). The DPPH radical scavenging activity of beans fermented with I. lacteus mycelia was increased 2–8 folds after 20 days of fermentation. These results indicate that antioxidant activity components were increased by fermentation of I. lacteus mycelia irrespective of soybean treatments.     

Quantitation of aflatoxins in walnut kernels by high-performance liquid chromatography with fluorescence detection

A total of 85 walnut samples collected between October 2012 and April 2013 in different provinces of Turkey were analysed for the presence of aflatoxins (AFs). The method involved methanol–water extraction, clean-up with immunoaffinity columns and a sensitive high-performance liquid chromatography coupled with fluorescence detection after post-column derivatisation. The method was validated for selectivity, linearity, trueness, precision, limit of detection and limit of quantification (LOQ), which met the performance criteria as set by EC regulation No. 401/2006. LOQs were 0.07, 0.04, 0.09 and 0.05 µg kg^–1 for AFB₁, AFB₂, AFG₁ and AFG₂, respectively. AFs were present in 9.4% of walnut samples (8/85) at total AFs levels ranging from 0.09 to 15.4 µg kg^–1. Only one of eight walnut samples exceeded the European Union limit of 2 and 4 µg kg^–1 for AFB₁ and total AFs, respectively.     

Effect of Controlled Atmosphere Storage and Chitosan Coating on Quality of Fresh-Cut Jackfruit Bulbs

Fresh-cut jackfruit bulbs were evaluated for quality changes as effect of an additive pretreatment with CaCl₂, ascorbic acid, citric acid, and sodium benzoate followed by chitosan coating. Different types of samples such as pretreated and coated, only pretreated, only coated, and untreated were subjected to controlled atmosphere (CA) storage (3 kPa O₂?+?6 or 3 kPa CO₂; N2 balance) or normal air at 6 °C. CA conditions, pretreatment, as well as chitosan coating in synergy with each other, could significantly minimize the loss in total phenolics and ascorbic acid content of the samples to the levels of around 5% and 17%, respectively, during extended storage up to 50 days. Chitosan coating could also restrict the changes in microbial load. The CA condition of 3 kPa O₂?+?6 kPa CO₂ was found to render higher efficacy in retaining quality attributes of the samples.     

Investigation of Sensitivity Against Different Flavonoid Derivatives of Aminophenyl-Modified Glassy Carbon Sensor Electrode and Antioxidant Activities

The electrochemical behaviors of 10 structurally different flavonoids (quercetin, galangin, chrysin, 3-hydroxyflavone, naringenin, luteolin, apigenin, flavone, kaempferol, and naringin) on a glassy carbon electrode were studied by cyclic voltammetry. In the current study, nitrophenyl diazonium salt has been synthesized from p-nitrophenylamine. One millimolar prepared nitrophenyl diazonium salt (in 100 mM tetrabutylammonium tetrafluoroborate) in acetonitrile was used to modify the glassy carbon electrode. Nitro groups have been reduced to amine groups in 100 mM HCl medium on the nitrophenyl-modified glassy carbon electrode surface. Although nitrophenyl-modified glassy carbon electrode surface was electro-inactive, it is activated by reducing the nitro group into amine group. And then, aminophenyl-modified glassy carbon electrode surface has been used for the determination of antioxidant activities of 10 flavonoid derivatives with cyclic voltammetry technique. The activity sequence of the investigated, structurally different, flavonoids follows the sequence: quercetin > galangin > chrysin > 3-hydroxyflavone > naringenin > luteolin > apigenin > flavone > kaempferol > naringin.     

Phytochemicals and antioxidant activity of different fruit fractions (peel,pulp, aril and seed) of Thai gac (Momordica cochinchinensis Spreng)

Three fractions (peel, pulp and aril) of gac fruit (Momordica cochinchinensis Spreng) were investigated for their phytochemicals (lycopene, beta-carotene, lutein and phenolic compounds) and their antioxidant activity. The results showed that the aril had the highest contents for both lycopene and beta-carotene, whilst peel (yellow) contained the highest amount of lutein. Two major phenolic acid groups: hydroxybenzoic acids and hydroxycinnamic were identified and quantified. Gallic acid and p-hydroxybenzoic acid were found in all fractions. Ferulic acid and p-hydroxybenzoic acid were most evident in pulp. Myricetin was the only flavonoid found in all fractions. Apigenin was the most predominant flavonoid in pulp (red), whereas rutin and luteolin gave the highest content in aril. The extracts of different fractions exhibited different levels of antioxidant activity in the systems tested. The aril extract showed the highest FRAP value. The greatest antioxidant activities of peel and pulp extracts were at immature stage, whereas those in the seed extracts increased from mature stage to ripe stage. The contents of total phenolic and total flavonoid in peel and pulp decreased during the fruit development stage (immature > ripe fruit) and subsequently displayed lower antioxidant capacity, except for the seed.     

Detection and characterisation of aluminium-containing nanoparticles in Chinese noodles by single particle ICP-MS

This study investigated Chinese noodles for the presence of aluminium-containing nanoparticles by using inductively coupled plasma mass spectrometry in single particle mode (spICP-MS) after enzymatic digestion by α-amylase. The aluminium concentrations in the noodle samples, determined by conventional ICP-MS without or with the use of hydrofluoric acid for digestion, were 5.4 ± 1.9 µg/g and 10.1 ± 2.2 µg/g (N = 21), respectively. Aluminium-containing nanoparticles were detected by spICP-MS in all 21 samples. Depending on the assumed particle composition, Al₂O₃ or Al₂O₃?2SiO₂?2H₂O, the median particle diameters were either below or above 100 nm, respectively. The minimum detectable particle diameter by spICP-MS was between 54 and 83 nm. The mass recovery of aluminium in the form of particles was between 5% and 18%. The presented work reports for the first time the detection of Al-containing particles in food by spICP-MS.