Protective effect of fresh and processed Jalapeño and Serrano peppers against food lipid and human LDL cholesterol oxidation

The potential of fresh and processed Jalapeño and Serrano pepper extracts for the control of lipid oxidation in several systems was investigated. The assays used included β-carotene/linoleate model system, striped corn oil, ground pork meat and Cu(II)-induced oxidation of human low-density lipoprotein (LDL). The results showed that all extracts were effective in at least one system, although their potency varied. Extracts of smoked Jalapeño were particularly effective. The lipid-protective effect of the extracts was mainly due to the presence of phenolic compounds, but other phytochemicals, such as chlorophylls were also involved.     

Chromium determination in food by slurry sampling graphite furnace atomic absorption spectrometry using classical and permanent modifiers

A simple method, using permanent modifiers, has been developed for chromium (Cr) determination in food of plant origin by the slurry sampling graphite furnace atomic absorption spectrometry. In particular comparison of the action of Mg(NO₃)₂, iridium (Ir)/niobium (Nb) and iridium (Ir)/tungsten (W) was examined. Finally, for chromium determination in food, the mixture of 2 μg of Ir with 10 μg of Nb was used as permanent modifier. The analytical procedure was optimised carefully on the basis of the data from pyrolysis and atomisation temperature curves studies. The results obtained for four certified reference materials using external calibration with aqueous standards were in good agreement with the certified values. The precision and accuracy of Cr determination by the described method were also acceptable: the RSD were lower than 10% and recoveries for CRMs were in the range of 95-103%. The characteristic mass for chromium was determined to be 3.9 pg and the detection limit for the optimised procedure at the 0.75% (w/v) slurry concentration - 86.6 ng g⁻¹.     

Partial characterization of natural antioxidants in canola meal

Defatted canola meal was extracted with 95% (v/v) ethanol at 80 °C. The extract was fractionated on a Sephadex LH-20 column using methanol as eluate. Seven major fractions were isolated according to UV absorption, content of phenolics and sugars. Antioxidant activity of these fractions was evaluated in a β-carotenelinoleate model system. Fraction IV showed the best antioxidant effect by exhibiting the highest preventive activity against the bleaching of β-carotene. Further separation of this fraction on TLC indicated that it contains several compounds including phenolic acids and trihydroxy phenolic compounds such as flavones and flavonols.     

Evolution of soluble carbohydrates during the development of pea, faba bean and lupin seeds

Seeds of pea (Pisum sativum L. cv. Ergo), faba bean (Vicia faba ssp. minor Harz., cv. Tibo) and yellow pea lupin (Lupinus luteus L. cv. Juno) were sampled at different days after flowering (DAF) and their content of soluble carbohydrates was determined: Analysis of samples showed thatmyo-inositol, fructose, glucose, galactose and sucrose were found in high abundance early in development and their content decreased gradually during maturation. -Galactosides, which includes the content of raffinose, stachyose and verbascose, started to appear later in seed development, at 37 DAF in peas, 40 DAF in faba beans and 45 DAF in lupins. Their accumulation increased considerably during seed growth, and the maximum content was obtained in mature seeds; 3.8% in peas, 4.5% in faba beans and 10.4% in lupins. Results obtained for these sugars during seed development were fitted to modelling curves in order to predict sugar content at different development stages.     

A method of concentration estimation of trienes,tetraenes, and pentaenes in evening primrose oil

There is no simple method available to estimate the concentration of conjugated fatty acids (CFA) with more than two double bonds in plant oils, because there are no commercially available complete sets of CFAs standards needed for such analysis. This paper presents such a method based on the absorption and fluorescence spectra of available CFAs standards and a computer program calculation. Using this method, the concentrations of the α‐eleostearic acid (conjugated trienoic acid (ELA) 8.8 × 10^?4 mol/L) and cis‐parinaric acid (conjugated tetraenoic acid (PnA) 3.5 × 10^?5 mol/L) in evening primrose oil were estimated. The accuracy of the calculation method is around 10%. Practical applications: This is the first report about the existence of CFAs in evening primrose oil. The described method estimates the total concentration of trienes, tetraenes, and pentaenes in evening primrose oils without using HPLC or other analytical methods. These CFAs are important from a health point of view. They are not synthesized by the human body. Therefore, plant oils containing these fatty acids (FA) are very valuable. Knowledge about the concentrations can be utilized to prepare a mixture of the plant oils with a favourable n‐3 to n‐6 FAs ratio and in addition containing CFAs.     

Influence of Variety,Moisture Content,Kernel Size and Applied Current Frequency on the Electric Properties of Wheat Grain

The work aimed at determination of electric properties of wheat grain in dependence on its variety, moisture, geometrical features of kernels and applied current frequency. Wheat grain of 4 Polish winter varieties: Korweta, Juma, Mikon and Kobra from harvest 2001 were used as the material for study. Grain was sized into 3 fractions: (1) > 2,8mm, (2) 2,5–2,8mm, and (3) 2,2–2,5mm. Basic geometrical features were determined for not sorted grain (control sample) and its three fractions by the use of digital image analysis. Electric properties of grain (at 11% and 15% moisture content) have been performed with the Hewlett Packard 4263B meter. Measurements of impedance, resistance, admittance, conductance, as well as equivalent parallel capacitance and equivalent series capacitance were made. Obtained results were subjected to statistical analysis with the use of Statistica? programme. Changes in electric properties of grain significantly depended on all of studied factors. Most of all significant correlations appeared between geometrical features and studied electric properties of grain of 15% moisture. Statistical analysis of the results proved significant linear correlations between electric properties of kernels and their length, perimeter and circularity coefficient R_C2 at higher measurement frequencies.     

Protein-precipitating capacity of crude condensed tannins of canola and rapeseed hulls

The protein-precipitating potentials (PPP) of soluble condensed tannins (SCT) were determined in hulls from several samples of canola and rapeseed varieties. The PPP were expressed as slopes of lines (titration curves) reflecting the amount of SCT-protein precipitated vs. the amount of SCT added to the reaction mixture. The slopes (S _p ) of titration curves obtained using the protein-precipitation assay ranged from 2.96 to 10.91 (absorbance units at 510 nm per mg SCT), and those of titration curves, obtained using the dye-labeled bovine serum albumin (BSA) assay (S _d ), ranged from 28.1 to 267 (% precipitated BSA per mg SCT). For both assays, a statistically significant (P≤0.001) semilogarithmic linear correlation existed between the slopes and the SCT contents in the canola and rapeseed hulls. Higher amounts of SCT-protein complexes were precipitated at 40°C than at room temperature. Determination of titration curves under standardized conditions (type and concentration of protein, pH and temperature) afforded meaningful differences in the slopes among the range of SCT extracts from canola and rapeseed hulls used in this study.     

Shear Stress-Dependent Viscosity Master Curves for Practical Applications

It was shown using several examples that the ratio of apparent viscosity and Newtonian viscosity at the same temperature as function of shear stress is independent of temperature. It means that viscosity curves for different homogeneous polymer systems measured in various temperatures create a common master curve, which is very convenient for practical calculations of many technically important flows. It was also shown that for such systems, the stress dependence can be often very well described by simple function of Kohlrausch type. Moreover, it was found that for small-amplitude oscillatory shear, similar master curves can be created by representing the absolute value of complex viscosity or its components as functions of absolute value of complex modulus. For nonhomogeneous systems, second-order temperature effects may appear. They were taken into account by additional rule based on the so-called no-flow temperature. It was also shown that the first normal stress difference as function of shear stress is temperature independent. POLYM. ENG. SCI., 60:44–54, 2020. © 2019 Society of Plastics Engineers