scholarly journals STUDY OF THE ENZYMATIC STAGE OF MILK GELATION: CHANGES IN VISCOSITY AND MICROSTRUCTURE

Food systems ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 4-8
Author(s):  
I. T. Smykov
Keyword(s):  
Phase Transition ◽  
Statistical Processing ◽  
Middle Part ◽  
Gel Point ◽  
Casein Micelles ◽  
Viscosity Change ◽  
Research Results ◽  
Milk Coagulation ◽  
Milk Gelation ◽  
The Moment

The article presents the results of experimental joint studies of changes in the viscosity and microstructure of milk at the enzymatic stage of gelation. Based on the statistical processing of the array of research results, it was determined that the viscosity change at this stage is not monotonic, as it is usually stated, but two-stage in the middle part and S-shaped, preceding the gel point, at its end. It was found that the S-shaped change in viscosity at the end of the enzymatic stage of milk coagulation coincides with changes in the microstructure of casein micelles and reflects the existence of a cooperative conformational phase transition in casein molecules of micelle clusters. A description of the possible mechanism of this phase transition is proposed. It was noted that the moment of the S-shaped change in the milk viscosity at the enzymatic gelation stage and the corresponding cooperative phase transition in casein micelles are a physical reflection of the gel point. The research results provide a better understanding of the mechanism of enzymatic coagulation of milk in a cheesemaking tank.

scholarly journals The influence of environment forming factors on the productivity of winter wheat

2021 ◽  
Vol 207 (04) ◽  
pp. 9-16
Author(s):  
Valeriy Burluckiy ◽  
Polina Semeshkina ◽  
Vladimir Mazurov
Keyword(s):  
Winter Wheat ◽  
Statistical Processing ◽  
Mineral Fertilizers ◽  
First Year ◽  
Wheat Grain ◽  
Significance Level ◽  
Research Results ◽  
Yield And Quality ◽  
Close Relationship

Abstract. The goal is to study the influence of the predecessor and fertilizers on the yield and quality of winter wheat grain. Methods. The studies were carried out in a long-term stationary field experiment on a gray forest medium loamy soil. Field experience, observations, accounting and generalization of research results were carried out in accordance with the methodological recommendations of B.A. Dospekhov. Statistical processing of the research results was performed using Microsoft Excel 2007 with a 95 % significance level of the results. Results. As a result of the studies, it was noted that the studied predecessors had an insignificant effect on the development of winter wheat plants in the initial phases of growth. The density of winter wheat plants during the germination period varied within the range of 314–323 psc/m2 without the use of fertilizers and 317–328 psc/m2 against the background of their application. Further growth and development of plants took place in close relationship with the studied factors. At the end of the growing season, the number of productive stems was higher on the plots, where the clover of the first year of use was used as a predecessor, both in the control (without fertilizers) and when applying mineral fertilizers. Accordingly, the yield of winter wheat grain was higher for this predecessor, averaging 35.7 c/ha for 2014–2019. Without fertilization, depending on the predecessor, 25.2–32.8 c/ha were obtained, against the background of fertilization – 34.2–39.6 c/ha of winter wheat grain. On average, over the years of research, winter wheat grain contained 10.7–14.0 % protein. Depending on the year, this indicator varied from 8.8 % to 16.8 %. At the same time, the lowest values for the protein content were obtained for the variants without the use of fertilizers. In general, the content of protein and gluten in winter wheat grain largely depended on the application of mineral fertilizers and to a small extent on the predecessor. The weight of 1000 grains, depending on these factors, changed insignificantly.

Gelation of casein-whey mixtures: effects of heating whey proteins alone or in the presence of casein micelles

2001 ◽  
Vol 68 (3) ◽  
pp. 471-481 ◽  
Author(s):  
CATHERINE SCHORSCH ◽  
DEBORAH K. WILKINS ◽  
MALCOLM G. JONES ◽  
IAN T. NORTON
Keyword(s):  
Heat Treatment ◽  
Whey Protein ◽  
Protein Denaturation ◽  
Whey Proteins ◽  
Treatment Sequence ◽  
Gel Properties ◽  
Casein Micelles ◽  
Gelation Kinetics ◽  
Milk Gelation

The aim of the present work was to investigate the role of whey protein denaturation on the acid induced gelation of casein. This was studied by determining the effect of whey protein denaturation both in the presence and absence of casein micelles. The study showed that milk gelation kinetics and gel properties are greatly influenced by the heat treatment sequence. When the whey proteins are denatured separately and subsequently added to casein micelles, acid-induced gelation occurs more rapidly and leads to gels with a more particulated microstructure than gels made from co-heated systems. The gels resulting from heat-treatment of a mixture of pre-denatured whey protein with casein micelles are heterogeneous in nature due to particulates formed from casein micelles which are complexed with denatured whey proteins and also from separate whey protein aggregates. Whey proteins thus offer an opportunity not only to control casein gelation but also to control the level of syneresis, which can occur.

scholarly journals Rheology and Microstructures of Rennet Gels from Differently Heated Goat Milk

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 283
Author(s):  
Zorana Miloradovic ◽  
Nemanja Kljajevic ◽  
Jelena Miocinovic ◽  
Steva Levic ◽  
Vladimir B. Pavlovic ◽  
...  
Keyword(s):  
Heating Temperature ◽  
Goat Milk ◽  
High Heat ◽  
Yield Efficiency ◽  
Rennet Coagulation ◽  
Heat Treated ◽  
Cross Links ◽  
Milk Coagulation ◽  
C 30 ◽  
The Moment

Rennet coagulation of goat milk heated to 65 °C/30 min (Gc), 80 °C/5 min (G8) and 90 °C/5 min (G9) was studied. A rheometer equipped with a vane geometry tool was used to measure milk coagulation parameters and viscoelastic properties of rennet gels. Yield parameters: curd yield, laboratory curd yield and curd yield efficiency were measured and calculated. Scanning electron microscopy of rennet gels was conducted. Storage moduli (G’) of gels at the moment of cutting were 19.9 ± 1.71 Pa (Gc), 11.9 ± 1.96 Pa (G8) and 7.3 ± 1.46 Pa (G9). Aggregation rate and curd firmness decreased with the increase of milk heating temperature, while coagulation time did not change significantly. High heat treatment of goat milk had a significant effect on both laboratory curd yield and curd yield. However, laboratory curd yield (27.7 ± 1.84%) of the G9 treatment was unreasonably high compared to curd yield (15.4 ± 0.60%). The microstructure of G9 was notably different compared to Gc and G8, with a denser and more compact microstructure, smaller paracasein micelles and void spaces in a form of cracks indicating weaker cross links. The findings of this study might serve as the bases for the development of different cheese types produced from high-heat-treated goat milk.

Mode of binding of ionic materials to casein micelles

1982 ◽  
Vol 49 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Margaret L Green
Keyword(s):  
Calcium Phosphate ◽  
Binding Sites ◽  
Hydrophobic Interactions ◽  
Casein Micelles ◽  
Phosphate Moiety ◽  
Colloidal Calcium Phosphate ◽  
Ionic Materials ◽  
Milk Coagulation

SUMMARYThe proportion of materials which adsorb to casein micelles and accelerate milk coagulation, and remain bound on dilution of the micelle suspension with milk dialysate was determined. This was higher than expected from the postulate that equilibration took place between the solution and many equivalent binding sites on the micelle. This suggests that binding involved either or both hydrophobic interactions and multipoint attachment to charged groups. The location of the additive binding sites in the micelle was investigated using models Na caseinate and hydroxyapatite at pH 6·6. Materials which accelerated coagulation bound to either or both models. Those with the greatest effect on milk coagulation probably bound primarily to the casein rather than to the colloidal calcium phosphate moiety of casein micelles.

scholarly journals PSYCHOSOCIAL NANISM AS A RESULT OF ATTACHMENT DEFORMATION IN CHILDREN LEFT WITHOUT PARENTAL CARE

2020 ◽  
Vol 13 (1) ◽  
pp. 70-78
Author(s):  
Anastasiya Valerevna Butyakova ◽  
Zhaniya Serikpaevna Tasbulatova
Keyword(s):  
Parental Care ◽  
Residential Care ◽  
Statistical Processing ◽  
Foster Family ◽  
Foster Families ◽  
Residential Care Facilities ◽  
Research Results ◽  
Completion Task ◽  
Care Facilities ◽  
Story Completion

Background. An important feature of psychosocial nanism is its openness to corrective influences. However, in residential care facilities, it is possible to provide only external conditions that guarantee physical security but do not form a feeling of social attachment. A way to solve the problem can be sending a child to a foster family. Aim. The article deals with considering the phenomenon of psychosocial nanism in the context of social attachment in children left without parental care (hereinafter, LWPC children) and brought up in different conditions (in foster families and residential care facilities). Materials and methods. The study was conducted on the following premises: Sandyktau Orphanage (village of Sandyktau, Akmola Region, Kazakhstan), Esil Orphanage (Esil, Akmola Region, Kazakhstan), foster families of the villages of Baitus and Kenashchi (North Kazakhstan Region, Kazakhstan). The sample consisted of the LWPC children of preschool age brought up in an orphanage (25 people) and in foster families (25 people). Results. In LWPC children from an orphanage, the type of attachment relationship in the final diagnosis has insignificant changes in comparison with the initial diagnosis. In LWPC children from a foster family, the type of attachment has a significant difference in comparison with the initial diagnosis. There are statistically significant differences in the growth rate of LWPC  children brought up in foster families and in orphanages. Anthropometric development in children raised in a foster family is faster than in children raised in an orphanage. The type of attachment was determined using a story-completion task. Statistical processing of the research results was carried out by calculating using a story-completion task. Statistical processing of the research results was carried out by calculating the criteria for the significance of the ᵡ² differences and Mann-Whitney using the Statistica v. 15.0 software. Conclusion. Psychosocial nanism as a functional feature of the body manifested in reduced body length compared with peers and being the result of adverse conditions of the external and internal environment is leveled into normal physical developmentprovided that there is an object of attachment, who will act as a stabilizer of emotional, psychological and physical safety of a child.

scholarly journals Biodiversity of the flora of vascular plants of the Makarovsky Nature Reserve on Sakhalin Island

2021 ◽  
Vol 946 (1) ◽  
pp. 012045
Author(s):  
N D Sabirova ◽  
R N Sabirov
Keyword(s):  
Vascular Plants ◽  
Nature Reserve ◽  
Life Forms ◽  
Middle Part ◽  
Rare Plants ◽  
Sakhalin Island ◽  
Research Results ◽  
Red Data Book ◽  
Data Book ◽  
Geographical Elements

Abstract The article is devoted to the research results concerning the flora of vascular plants of the Makarovsky Nature Reserve situated in the middle part of Sakhalin Island. Nowadays, 407 species of vascular plants have been identified on its territory, and 26.8 % of the total number of taxa known on the island. Among them, 13 species of rare plants included in the Red Data Book of the Sakhalin Region have been identified. The structure of the leading families and genera is indicated, the flora is analyzed by life forms, geographical elements and ecological-cenotic groups.

scholarly journals The program of social and educational training for athletes to form personal positive motivation to maintain health under the conditions of the COVID-19 coronavirus pandemic

2020 ◽  
pp. 185-190
Author(s):  
O.I. Tsyhanenko ◽  
Ya.V. Pershehuba ◽  
N. A. Sklyarova
Keyword(s):  
Theoretical Analysis ◽  
Field Experiment ◽  
Research Methods ◽  
Questionnaire Survey ◽  
Statistical Processing ◽  
Educational Training ◽  
Research Results ◽  
Sports Industry ◽  
Positive Motivation

The purpose of the study: is to develop a program of social and educational training for the formation of personal positive motivation for maintaining health in athletes under the conditions of the COVID-19 coronavirus pandemic. Research methods: theoretical analysis of scientific and scientific - methodical literature: generalization, synthesis, formalization, abstraction, the method of questionnaire survey and the method of statistical processing of information from the assessment of two different series of observations on the same group of subjects. Research results and coclusions: a program for the formation of athletes' personal positive motivation to maintain health under the conditions of the COVID-19 coronavirus pandemic was developed and tested in a field experiment. It was concluded that the developed program can be used in practice with respect to athletes by sports doctors and other specialists in the sports industry during a coronavirus pandemic COVID - 19.

The nestling – waiting for adulthood?

2014 ◽  
Vol 12 (3) ◽  
pp. 65-83
Author(s):  
Bogna Bartosz ◽  
Agata Lewandowska ◽  
Iga Antczak
Keyword(s):  
Young Adults ◽  
Adult Child ◽  
Developmental Tasks ◽  
Cultural Economic ◽  
Research Results ◽  
Global Problem ◽  
Child Perspective ◽  
The Moment

Abstract Our article deals with the problem of ‘nestlings’ - young adults who postpone the moment of entering adulthood. A brief review of data and research results indicates that delays in undertaking developmental tasks typical of adulthood refer to a professional job, starting a family or a relationship, and gaining independence (not only financially). We discuss cultural, economic and psychological contexts of nestling, and attempt to answer the question whether waiting for adulthood is a global problem or a problem specific to only certain countries or just to Poland. It seems necessary to undertake research on this phenomenon. Nestling ought to be explored not only from the adult child’ perspective but from the parental perspective as well.

An Experimental Study on Synchronizing Process of Synchronizer

2013 ◽  
Vol 336-338 ◽  
pp. 1532-1539
Author(s):  
Zai Min Zhong ◽  
Qiang Lv ◽  
Xue Ping Chen
Keyword(s):  
Phase Transition ◽  
Phase Angle ◽  
Rotation Speed ◽  
Complex Impedance ◽  
Transition Process ◽  
Electrical Vehicle ◽  
Severe Mutation ◽  
Transition Criteria ◽  
Equivalent Complex ◽  
The Moment

Based on the establishment of each independent phase theoretical model during synchronizing process of synchronizer used in HEV (hybrid electrical vehicle), an experimental means to analyze that synchronizing process is put forward in this article. Firstly, alternative current impedance analyzer is adopted to obtain amplitude and phase angle information of equivalent complex impedance between engaged gear ring and synchronizing ring. There are significant changes between the obtained results when the phase transition happens. Therefore, the moment of each phase transition can be determined through the experimental data. Then, to verify the consistency of the experiment mentioned above, a series of experiments are conducted under different rotation speed differences between the driving and driven cone. The experimental results show that different rotation speed differences lead to different moments when the severe mutation of amplitude and phase angle of the equivalent complex impedance occurs. It demonstrates the validity of the experiment that the rotation speed difference which belongs to phase transition criteria has a certain influence on the phase transition process. Furthermore, it is quite consistent with the actual situation, which also verifies that the experimental method put forward in this article has certain reliability.

scholarly journals Reply to Kroll and Schmid-Beurmann's comment on “Water decreases displacive phase transition temperature in alkali feldspar” by Liu et al. (2018)

2020 ◽  
Vol 32 (3) ◽  
pp. 305-310
Author(s):  
Wendi Liu ◽  
Yan Yang ◽  
Qunke Xia
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Alkali Feldspar ◽  
Spectroscopic Studies ◽  
Chemical Compositions ◽  
Factors Affecting ◽  
Displacive Phase Transition ◽  
Redistribution Of Hydrogen ◽  
The Moment

Abstract. It has long been known that hydrogen impurities can be incorporated in the structure of nominally anhydrous minerals (NAMs) and substantially influence their physical properties. One of the geologically most prominent NAMs is feldspar. The hydrogen concentration in NAMs is usually expressed in parts per million of water by weight (ppm H2O wt.) In this paper, we use the term “hydrogen” for uniformity, except when we use “water” for describing its amount expressed as parts per million of H2O by weight. In our article (Liu et al., 2018), we carried out in situ high-temperature X-ray powder diffraction and Raman spectroscopic studies on three natural anorthoclase samples with similar Or (K-feldspar) contents (Ab67Or31An2, Ab66Or31An2, and Ab65Or33An3) and Al–Si disordering but contrasting water contents. The spectroscopic results suggested that the displacive phase transition temperature is higher for the nearly anhydrous anorthoclase sample than the anorthoclase samples with about 200 ppm water, and we thus concluded that hydrogen is another factor impacting the displacive phase transition temperature. We thank Kroll and Schmid-Beurmann for pointing out the weakness in our interpretation that hydrogen is a possible important factor (Kroll and Schmid-Beurmann, 2020). To clarify this issue, we conducted transmission electron microscopy (TEM) experiments on the three samples to check texture effects. The TEM studies indicated that the nearly anhydrous anorthoclase sample consists of two feldspar phases, a K-poor and a K-rich one, and that the K-poor area may be responsible for the higher displacive phase transition temperature. According to the observation that the temperature of redistribution of hydrogen is accordant with the displacive phase transition temperature, the effect of hydrogen could not be ruled out. Based on these results, it can be concluded that hydrogen may not be the sole possible factor, and it was a proposition more than a definitive proof for the moment. Natural feldspars are complex, and factors affecting displacive phase transitions are multiple (e.g., Salje et al., 1991; Harrison and Salje, 1994; Hayward and Salje, 1996; Dobrovolsky et al., 2017). Therefore, to further investigate hydrogen effects on displacive phase transition in feldspar, synthetic samples with pure chemical compositions and hydrogen species are necessary. In the following, we address each issue in the same order as in the comment by Kroll and Schmidt-Beurmann (2020).

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