Simultaneous Determination of Alpha-Tocopherol and Alpha-Tocopheryl Acetate in Dairy Products,Plant Milks and Health Supplements by Using SPE and HPLC Method

A solid phase extraction technique for sample cleanup and extraction of α-tocopherol and α-tocopheryl acetate is described and applied to their simultaneous HPLC analysis in dairy products, plant-based milks, infant formulas, and pharmaceutical colostrum. The proposed method includes sample pretreatment by using ethanol, followed by solid-phase extraction of the organic supernatant on C18 cartridges. The identification and quantification were done by reversed-phase HPLC with fluorescence detection (ex 295 nm, em 330 nm) for tocopherol and with UV detector set at 220 nm for tocopheryl acetate. The mobile phase consisted of 100% acetonitrile. The linear ranges were from 0.02–0.40 μg/mL (dairy products) and 0.50–5.00 μg/mL (plant milks, infant formulas, powdered products) for α-tocopherol and those of α-tocopheryl acetate were from 0.20–2.00 μg/mL (dairy products) and 1.00–10.0 μg/mL (plant milks, infant formulas, powdered products). The LOD and LOQ of α-tocopherol were 0.1 and 0.4 μg/mL, while those of the α-tocopheryl acetate were 2.0 μg/mL for LOD and 6.0 μg/mL for LOQ. The method gave extraction recoveries from 73–94% with RSDs values being 5–10%. This method is simple, SPE procedure is fast and HPLC analysis time is less than 10 min. The total time of performing analysis per sample is less than 1 h. The important advantage of the proposed method is the capability of determining and reporting α-tocopherol and α-tocopheryl acetate separately. Moreover, the developed method is suitable for fast screening of the synthetic form of vitamin E in dairy products, plant-based milks, infant formulas, and pharmaceutical colostrum.     

Antioxidant and cell growth activities of beet root pomace extracts

Beetroot (Beta vulgaris) pomace, processing by-product from food industry, was investigated in this work as a starting raw material. The contents of phenolics (1.87–11.98 mg GAE/g of dry weight) and betalains (0.75–3.75 mg betalains/g of dry weight) in the extracts were determinated spectrophotometrically. Some individual phenolic compounds, including ferulic, vanillic, p-hydroxybenzoic, caffeic and protocatehuic acids, were identified and quantified by HPLC. The antioxidative activity of beetroot extracts was tested using DPPH, hydroxyl and superoxide anion radicals by ESR spectroscopy. ${\text{IC}}_{50}^{{}^{\text{<mglyph src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/rad"></mglyph>}}\text{OH}}$ (0.05–0.108 mg/ml), $\text{IC}{50}^{{\text{DPPH}}^{\text{<mglyph src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/rad"></mglyph>}}}$ (0.183–0.333 mg/ml), and ${\text{IC}}_{50}^{{\text{O}}_2^{\text{<mglyph src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/rad"></mglyph>}-}}$ (0.198–1.000 mg/ml) were calculated. The regression analysis produced moderate to high correlation coefficients between the scavenging activities and phenolics, and some individual phenolic compounds which indicated that beetroot pomace may be used as functional food ingredient. Cell growth effects were determined in MCF7 and MRC-5 cell lines, using SRB assay. IC₅₀ values were in the range of 362.478–503.525 and 383–587.880 μg/ml in MRC-5 and MCF7, respectively.     

Characterization of lactic acid bacteria isolated from Bukuljac, a homemade goat's milk cheese

The Bukuljac cheese is traditionally homemade cheese, produced from heat-treated goat's milk without the addition of any bacterial starter culture. The presence of lactic acid bacteria (LAB) in Bukuljac cheese has been analyzed by using a polyphasic approach including microbiological and molecular methods such as rep-PCR with (GTG)5 primer. Lactobacillus paracasei subsp. paracasei represents a dominant strain in the microflora of analyzed cheese. Out of 55 Gram-positive and catalase-negative isolates, 48 belonged to L. paracasei subsp. paracasei species. Besides lactobacilli, five Lactococcus lactis subsp. lactis and two Enterococcus faecalis were found. Results of PCR-denaturing gradient gel electrophoresis (DGGE) of DNA extracted directly from the fresh cheese revealed the presence of Leuconostoc mesenteroides. Only lactobacilli showed a high proteolytic activity and hydrolyzed alpha(s1)- and beta-caseins. They are also producers of diacetyl. In addition, 34 out of 55 isolates, all determined as lactobacilli, showed the ability of auto-aggregation. Among 55 isolates, 50 also exhibited antimicrobial activity.     

Effect of supercritical CO2 extraction process parameters on oil yield and pigment content from by‐product hemp cake

This research gives an insight into the possibility of exploiting the one of the food industry's by‐products – pressed hemp cake. The complete recovery of oil from pressed hemp cake was achieved. Residual oil that remained in cake after pressing was extracted with supercritical CO₂ by applying different process parameters. Optimal extraction conditions were determined using response surface methodology. Total pigment contents of the oils obtained were determined. Extraction pressure had the most significant influence on yield and pigment content of extracted hemp cake oil. Depending on the pressure, the chlorophyll a content ranged from 101.11 to 378.28 mg kg^?1 and chlorophyll b from 65.14 to 189.78 mg kg^?1, while total carotene content was in the range from 33.58 to 132.67 mg kg^?1. The remaining oil in pressed hemp cake after supercritical CO₂ extraction was determined to be 0.56 ± 0.08% and the defatted cake was rich in proteins and fibre.     

POLYCYCLIC AROMATIC HYDROCARBONS IN PRODUCTS OF A BEET SUGAR FACTORY IN VOJVODINA: LEVELS AND INTAKES

The levels of 16 EPA polycyclic aromatic hydrocarbons (PAHs) were investigated in samples of sugar beets and their products representative for a beet sugar factory located in the central part of Vojvodina, the main agricultural region in Serbia. The sum of the detected PAHs ranged from 51 pg g ^?1 ww for molasses to 391 pg g ^?1 ww for dried sugar beet pulp. The concentration of benzo(a)pyrene (BaP) for all sample types was about or less than 100 pg g ^?1 ww, which is far less than the existing Serbian and EU tolerances set for some foodstuffs. The Serbian intake of BaP via total sugar consumption that ranged from 70–85 g per capita day ^?1 , was assessed to be from 0.029 to 0.035 ng kg ^?1 b.w. day ^?1 . Furthermore, the toxic equivalency factor (TEF) approach was used to estimate the carcinogenicity of PAH mixture found in analyzed samples.     

Motional heterogeneity of polystyrene-block-polybutadiene: a spin probe study

Polystyrene-block-polybutadiene copolymers (SB) with 0.5 mass fraction of styrene were studied by electron spin resonance (ESR) of nitroxide spin probes. The influence of the block length ( and ) and the solvation power of casting solvents on the motional dynamics of spin probe were measured over a wide temperature range. Two nitroxide radicals as spin probes were selected: 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl benzoate (BzONO) and 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (Tempol). Irrespective of the spin probe used two ESR spectral components differing in their motional properties above the phase transition of polybutadiene blocks (PB) were observed. The fast component was assigned to spin probes located in polybutadiene-rich domains and the slow component to spin probes in polystyrene-rich domains. The range of two spectral components and the phase transition of the slow ESR component, T_5mT, depend on the block length. The influence of the interphase and accumulation of free volume in the interphase on the Tempol probe motion was investigated by changing copolymer morphology in the films casted from selective and nonselective solvents. The analysis of the motional heterogeneity from the ratio of the fast and slow motional component presents evidence that in the selective solvent for polystyrene (PS) blocks (2-butanone) the most irregular structure with a large interphase is formed. The difference in fast motion of spin probes indicates that the motional dynamic is related to the change of domain structure.     

Spray-dried nanoparticle-loaded pectin microspheres for dexamethasone nasal delivery

Abstract

In this study, we present the development of an innovative dry powder dexamethasone (Dex) nasal delivery system comprising Dex-loaded lipid/alginate nanoparticles incorporated within pectin microspheres (Dex/NPs-loaded pectin microspheres; DNM). DNM microspheres were characterized by the mean diameter of 2.76?±?0.10?µm, zeta-potential of –36.2?±?1.1?mV, and drug loading of 3.3?±?0.3%. The morphology study revealed irregular microsphere surface forming external voids. In contact with simulated nasal fluid, DNM microspheres demonstrated desirable property of moderate swelling and ensured stronger mucoadhesion compared with conventional Dex-loaded pectin microspheres. The strategy of Dex incorporation within the lipid/alginate NPs resulted in prolonged Dex release in relation to Dex being directly entrapped within the conventional pectin microspheres. DNM microspheres showed excellent biocompatibility and rendered Dex permeation across the selected epithelial cell model similar to that of Dex solution. In conclusion, balanced biopharmaceutical properties of the proposed nasal Dex delivery system provides the potential for prolonged contact time with nasal mucosa, prolonged therapeutic effect, and improved patient compliance.