Carob pod powder, an excellent source of health-promoting substances, has found its use in a wide range of food products. Grinding conditions affect the physical and chemical properties of the ...powder, but their influence on the bioaccessibility of phenolic compounds in carob pod powder has not yet been determined. The carob pods were ground for 30-180 s in a vibratory grinder. The median values (D
) of particle size decreased after 60 s of grinding (87.9 μm), then increased to 135.1 μm. Lightness showed a negative correlation with D
and a
, while the values of redness and yellowness decreased with the reduction in particle size and water activity. The smaller the value of D
, the higher the equilibrium moisture content of carob powder. Phenolic acids (vanillic, ferulic, cinnamic) and flavonoids (luteolin, naringenin, apigenin) were found in all samples of carob powder. The grinding time influenced their content in carob powder, with maximum values at 180 s. Similar observations were made when assessing antioxidant capacity. The in vitro digestion process only improved the bioaccessibility of catechin content in all samples. However, the bioaccessibility of the phenolic compounds and the total phenolic and flavonoid contents decreased with the increase in grinding time. Our findings revealed that the grinding of carob pods for 180 s improved the extractability of phenolics; however, their bioaccessibility was reduced. It is sufficient to ground the carob pod for 30 s, ensuring good availability of nutraceuticals and lower energy cost for grinding.
•Cryogenically ground carob pulp had a higher phenolic content.•More phenolics were released from the cryogenically ground sample after digestion.•The phenolic compounds of vibratory ground samples ...were more bioaccessible.
Carob pod powder prepared by cryogenic (CG) and vibratory grinding for 4 min (VG-4) and 8 min (VG-8) was evaluated for its antioxidant properties, and phenolic content. The bioaccessibility of phenolics was determined after the oral, gastric, and intestinal digestion phases in vitro. CG carob powder had a higher total phenolic content (6.46 mg gallic acid/g) and antioxidant capacities in terms of DPPH (15.60 mg Trolox/g) and ABTS (28.58 mg Trolox/g) assays. Quercitrin (44.54–64.68 μg/g) and cinnamic acid (27.48–31.40 μg/g) were the most abundant phenolics in all carob powder samples determined by liquid chromatography. The bioaccessibility of only ferulic acid (108%) had increased after digestion of the CG carob powder. Vibratory grinding (VG-4 and VG-8) improved the bioaccessibility of cinnamic acid (86–87%), vanillic acid (87–95%), quercitrin (33–34%), and naringenin (19–22%). A better bioaccessibility of phenolic constituents was observed for vibratory ground carob powder.
Carbon paste electrode was used for evaluation of oxidative stability of rapeseed oil samples using cyclic voltammetry in 0.1 mol.L-1 HCl as a supporting electrolyte. Rapeseed oil samples were ...exposed to daylight and oxygen in open glass baker at the laboratory condition in order to obtain oils with accelerated primary and secondary products of oxidation. The oxidation status was determinated by peroxide value and p-anisidine value. Total oxidative stability was expressed as TOTOX index. The edible oils were used for preparation (modification) of the carbon paste composite material followed by the cyclic voltammetric measurement. Peroxide values significantly increased whereas p-anisinde value rather fluctuated during 40 days of storage in all the samples. Cyclic voltammograms showed anodic current peaks at 575 - 600 mV and cathodic current peaks at 400 - 425 mV. The oxidation and reduction waves diminished at pH ≥3.0 suggesting not only phenolic compounds contributed to the electrochemical characteristic of oil samples. The peroxide value or p-anisidine value did not correlate with oxidation or reduction peak currents at the potential 575 - 600 mV and 400 - 425 mV, respectively. Both cathodic and anodic currents increased with increasing TOTOX index exhibiting positive correlation with high Spearman correlation coefficient (r = 0.894 and r = 0.914 for anodic and cathodic current, respectively). Linear relationship was found for each sample individually. A caution has to be done when interpreting results since the correlation seems to be of oil sample specific. Nevertheless, the modified carbon paste electrode with rapeseed oil represents a suitable and alternative tool for determination of the oxidative state of edible oils without use of organic solvents.
•GAB isotherms successfully described the experimental moisture content data.•Strongly bound water molecules in unroasted carob powder were observed.•Different integral thermodynamic properties were ...determined.•Roasted carob powder exhibited better stability.
Mycotoxins have been widely studied by many research groups but further multidisciplinary research is needed to better understand and clarify many issues. This study describes the use of ...high-performance liquid chromatography coupled with ion trap mass spectrometry (HPLC-MS) to measure T-2 toxin and its metabolites, such as HT-2 toxin, neosolaniol (NEO) and diacetoxyscirpenol (DAS), as well as masked glucosylated mycotoxins in Fusarium-infected Czech spring barley. In total, 152 spring barley samples from the 2018 harvest were analyzed by the ELISA screening method for the presence of T-2 toxin. The most contaminated samples (15), which exceeded the recommended maximum level set by the EU for the sum of T-2 and HT-2 toxin in unprocessed cereals (200 μg/kg), were analyzed by HPLC-MS/MS and microbiological testing. Isolated fungi were evaluated microscopically and identified by polymerase chain reaction (PCR) assays. The prevalence of Fusarium species in spring barley across the Czech Republic in 2018 showed a predominance of F. poae (12 barley samples) and F. tricinctum (9 barley samples). Other strains (F. sporotrichioides and F. langsethiae) were present at a lower frequency, in 1 and 2 samples, respectively. The average concentration of T-2 plus HT-2 toxin was 107.7 μg/kg, while NEO and DAS were found in a few samples at values close to their limit of quantification. HT-2 glucoside was identified in all samples.
•In total 152 barley samples were analyzed by ELISA for the presence of T2 toxin.•Fifteen of them exceeded the recommended maximum level set by the EU for the sum of T-2 and HT-2 toxin.•T-2 toxin and its metabolites including masked forms were identified and quantified by HPLC-MS/MS.•Cross-reactivity and overestimation of ELISA results compared to HPLC-MS/MS was confirmed.•In the most contaminated samples Fusarium tricinctum and Fusarium poae were predominant.
The oxidation mechanism of all-
-retinol (vitamin A
) and its several esters in non-aqueous, aqueous organic mixture, and pure aqueous media was investigated by cyclic voltammetry. The oxidation ...occurred in several irreversible steps. The calculated highest density of electrons in retinoid molecules which are delocalized over carbon atoms of the five conjugated double bonds (C5-C14) was found in the part of the molecule involved in oxidation processes. The most sensitive oxidation peak (at +0.8 V
. Ag/AgCl) was used for development of new direct voltammetric method based on differential pulse voltammetry for the determination of retinol at carbon paste electrode modified with surfactant sodium dodecyl sulfate (CPE/SDS). The results show that 30% (by mass) of modifier SDS exhibited optimal sensitivity and shape of voltammograms. Compared to commonly used glassy carbon electrode (GCE), the CPE/SDS showed significant progress in the retinol electroanalysis. The linear ranges for retinol determination were 1.5·10
-1.8·10
M for CPE/SDS and 4.4·10
-7.0·10
M for GCE with the detection limits of 1.3·10
and 4.6·10
M, respectively.
This study aims to determine the effect of ultrasound on the oxidation process of starch, molecular structure, and its functional properties. Corn starch is oxidized by hydrogen peroxide (with Cu(II) ...or Fe(II) ions as catalysts) in the ultrasound field. Changes in starch structure are identified based on determinations of the carboxyl, carbonyl groups, copper, iron content, molecular characterization by GPC, crystallinity, gelatinization characteristics, and surface area. Functional properties are determined based on analysis of color parameters, water binding capacity, solubility in water, and pasting characteristics. It is found that the effectiveness of the starch oxidation under ultrasound is affected by the presence and type of catalysts. The content of metal incorporated into starch during oxidation is approximately 15% lower when an ultrasound treatment is applied. When starch oxidation is assisted with ultrasound, the metal incorporation preferentially occurs in the pores and holes of the grain. Starches oxidized in the presence of Fe(II) and Cu(II) catalysts can be successfully used not only as thickeners in food industry but also as metal carriers in many industries.
The ultrasonic field influences on effectiveness oxidation starch. The ultrasonic influences on catalysts mobility during oxidation of starch. Structural and functional properties of oxidized starch are related with ultrasonic. Oxidized starch can be used in industries as thickeners and as carriers of metal ions.
Research background. The objective of this paper is to introduce an instrumentally simple analytical tool for determination of cocoa solids content in chocolates. This electroanalytical method is ...based on amperometric oxidation of all present antioxidants in chocolates at boron-doped diamond electrode (BDDE) that is integrated in a flow injection analysis (FIA) wall-jet electrode system.
Experimental approach. As part of optimisation, thirteen commonly occurring antioxidants were investigated using cyclic voltammetry at BDDE in 0.1 mol/L phosphate buffer with different methanol (MEOH) content. Working parameters, such as of MeOH content, flow rate, and detection potential, were optimised. Principally, the height of the oxidation peak (current response) representing the oxidation of the sum of antioxidants (Total Antioxidant Content; TAC) was expressed as Trolox content.
Results and conclusions. For analytical purpose, a linear range from 5.0 to 100 mg/L Trolox described by regression equation and characterized by correlation of determination 0.9994 was found. Obtained high positive correlation between determined values of Trolox equivalent antioxidant capacity (TEAC) and cocoa contents characterised by correlation coefficient of 0.9187 for eight randomly selected samples (one white, two milk, and five dark chocolates) confirmed the fact that cocoa solids represent the main source of antioxidants (reducing agents).
Novelty and scientific contribution. The research demonstrates that TEAC values could be probably considered as additional marker of cocoa content in the chocolate analysis to commonly used theobromine (authenticity of food products). The developed FIA method could therefore serve as simple analytical tools in the food quality control.
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