Questions of authentication and standardization of white varieties of Ceylon tea imported to Russia

The article raises questions concerning the reasons for the falsification of white tea varieties in Russia, the possibility of determining its authenticity by instrumental and sensory methods. The technological process and parameters of brewing leaves of white tea varieties, for example, silver tea, are considered. The criteria for the organoleptic evaluation of the silver tea infusion are developed with repeated brewing by "spillage" metho

Morphology of Camellia Sinensis L. leaves as marker of white tea authenticity

Received: February 1st, 2021 ; Accepted: April 24th, 2021 ; Published: August 18th, 2021 ; Correspondence: [email protected] is one of the most common drinks in the world. Classic tea is obtained by brewing the leaves of the Camellia sinensis L plant in hot water. However, even the leaves collected from the same branch of the same tea bush can have completely different anatomical, biochemical and taste characteristics. White tea is the youngest, immature apical leaves of the tea bush (fleshes) together with leaf buds (tips) which are is considered the most valuable parts of teaplant. The chemical composition of tea is studied in sufficient detail, however, there are still no uniform criteria for determining the authenticity of white tea leaves, which creates great preconditions for falsifying this most valuable type of raw material. The aim of this study was to study the macroand microstructure of white tea leaves from different manufacturers and to determine the morphological markers of the authenticity of white tea leaves. The objects of research were white tea from the Nandana Tea Factory (Sri Lanka) and white tea from an unknown manufacturer, purchased from a local tea shop. The study of raw materials was carried out in accordance with the requirements of GF XIV OFS 1.5.1.0003.15 ‘Leaves’ and OFS 1.5.3.0003.15 ‘Technique of microscopic and microchemical examination of medicinal plants and herbal medicinal products.’ The work was carried out on the basis of the laboratories of the Department of Food Technologies of FGBOU VO Saratov GAU named after N.I. Vavilov, and the Department of General Biology, Pharmacognosy and Botany, Saratov State Medical University named after V.I. Razumovsky Ministry of Health of Russia. Studies of the structure of white tea leaves from various manufacturers have shown that the structure and presence of morphological elements of leaves, such as hairs, stomata, leaf edge, druses, sclereids, differ markedly and can serve as reliable markers for identifying the variety of tea

Chromosome analysis of chironomids (Diptera: Chironomidae) – obligatory miners of freshwater sponges (Porifera)

Karyotypic characteristics of the chironomids Demeijerea rufipes (Linnaeus, 1761) and Xenochironomus sp., obligatory miners of freshwater sponges, are considered. The karyotype of Xenochironomus sp. is described for the first time. It is assumed that the ordered spatial organization of chromosomes of these species, expressed in terms of the presence of chromocentres of different degrees of stability and an almost complete absence of polymorphism for chromosome rearrangements, represents an adaptation to inhabiting host tissues, i.e. to habitat relative constancy

Chromosome analysis of chironomids (Diptera: Chironomidae) – obligatory miners of freshwater sponges (Porifera)

Karyotypic characteristics of the chironomids Demeijerea rufipes (Linnaeus, 1761) and Xenochironomus sp., obligatory miners of freshwater sponges, are considered. The karyotype of Xenochironomus sp. is described for the first time. It is assumed that the ordered spatial organization of chromosomes of these species, expressed in terms of the presence of chromocentres of different degrees of stability and an almost complete absence of polymorphism for chromosome rearrangements, represents an adaptation to inhabiting host tissues, i.e. to habitat relative constancy

Chromosome analysis of Endochironomus albipennis Meigen, 1830 and morphologically similar Endochironomus sp. (Diptera, Chironomidae) from water bodies of the Volga region, Russia

Based upon the detailed chromosome map of polytene chromosomes of the eurybiont species Endochironomus albipennis Meigen, 1830, the localization of the centromere regions using a C-banding technique is defined. Chromosomal polymorphism in populations from two water bodies in the Volga region has been studied, 17 sequences are described. Polytene chromosomes of Endochironomus sp. (2n=6), having larvae morphologically similar to those of E. albipennis Meigen, 1830 (2n=6) are described for the first time

Assessment of repolarization heterogeneity in myocardial infarction patients by QT interval time variability (dispersion) and dynamics of the first electrocardiogram derivative

Aim. To assess the parameters of QT interval variability and time dynamics of T wave velocity characteristics in patients with ST segment elevation myocardial infarction (STEMI). Material and methods. In total, 116 patients with acute MI (mean age 54,9±8,5 years), who underwent urgent thrombolytic therapy (TLT) with alteplase and were admitted to the emergent cardiology department, were followed up. MI diagnosis was verified according to the recommendations by the Society of Cardiology of the Russian Federation (2007) and the criteria of the universal MI definition (2007). In all patients, an electrocardiogram (ECG) was recorded for 5 minutes, with the assessment of the QT interval time variability, data processing, and creation of the first ECG derivative. Results. The first ECG derivative demonstrates two positive waves in the T wave area of the initial ECG. Waves T1 and T2 reflect smoothed modules of the initial T wave increase and decrease velocity, respectively. Therefore, in STEMI patients, the parameters of the time dynamics of T wave velocity could be assessed by the markers of time heterogeneity of myocardial repolarization. In anterior MI, compared to posterior MI, a significant increase in heart-rate adjusted QT interval dispersion (DQTec/VRV) was registered. In patients with effective vs. ineffective TLT, such parameters as variability range (VR (T2/T1)) and DQTec/VRV were significantly different. The first parameter reflects the time dynamics of wave T morphology, while the second characteristic denotes QT interval variability, adjusted for heart rate and the extent of sinus arrhythmia. Conclusion. The proposed parameters of QT interval time variability and time dynamics of wave T velocity characteristics could be used for the risk stratification in MI patients. This method is faster and less expensive than coronary angiography, as a standard visualization procedure