Cambios microestructurales del almidón de Canavalia ensiformis modificado por métodos térmicos / Microstructural changes of Canavalia ensiformis starch modified by thermal methods

1999 ◽  
Vol 5 (1) ◽  
pp. 31-40 ◽  
Author(s):  
A.M. Rincón Carlés ◽  
E.E. Pérez Sira ◽  
Z.M. González Parada ◽  
P.J. Rodríguez González

The aim of this study was to evaluate the structural changes of Canavalia ensiformis starch, which was gelatinized in limited and excess water model systems and modified by dry heat, extrusion-cooking and pregelatinization, as well as to relate the changes caused by extrusion cooking and pregelatinization with some functional properties of this starch. The microscopical observation performed in the model systems showed granular swelling, solubility and lixiviation of intragranular material, while dry heat did not affect the starch microstructure. The extrusion-cooking partially changed the starch mor phology, with some granules affected, while others remained intact; the pregelatinization totally al tered the granular structure and the starch granules showed a coarse and flaky appearance. These changes could be associated with the functional properties of canavalia starch, although the most evident variations were produced by the pregelatinization process.

2007 ◽  
Vol 60 (10) ◽  
pp. 706 ◽  
Author(s):  
Alain Buléon ◽  
Gabrielle Véronèse ◽  
Jean-Luc Putaux

Amylose, the linear constituent of starch, consists of α(1,4)-linked glucose monomers. Although weakly involved in the crystalline structure of starch, it can be recrystallized in a variety of allomorphic types, including those encountered in native starch (A- and B-types). Amylose can either be extracted from starch or produced in vitro by enzymatic synthesis using amylosucrase or phosphorylase. Recrystallization and self-association of amylose in aqueous solutions have been widely studied to understand both the crystallization of starch during biosynthesis and the structural changes that occur during starch processing. Depending on the chain length, concentration, and temperature, gels, spherulites, or lamellar crystals can be formed with A or B allomorphic type. Other ligand-dependent allomorphs (the various V-types) are obtained when amylose is complexed with molecules such as alcohols, lipids, or flavours. Amylose also self-associates into networks, spherulites, or axialites during in-vitro enzymatic synthesis by amylosucrase. When a highly branched acceptor like glycogen is used, dendritic nanoparticles are formed by elongation of the external chains. The recrystallization of amylose extracted from starch and the self-association of amylose during its in-vitro synthesis are described. The amylose properties are discussed in terms of polymer behaviour and model systems to investigate the structure and formation of starch granules.


2018 ◽  
Vol 22 (4) ◽  
pp. 660-665
Author(s):  
O.V. Astakhova ◽  
O.B. Malinina ◽  
A.M. Grigorenko

The problem of reproductive health in Ukraine over the last decade has become very important. The greatest clinical interest is infertility, which is accompanied by a violation of the ovulatory function of the ovaries due to hypothalamic-pituitary-ovarian failure. Sustained anovulation for a long time, as well as the lack of adequate correction of menstrual disorders, lead to the development of endocrine-dependent gynecological diseases, the manifestation of which is primary or secondary infertility. Increased flow of venous blood through the ovarian veins is accompanied by phlebostasis and phlebohypertension in the venous sector of the internal genital organs. Increasing the viscosity and rheological properties of blood that occurs at the same time leads to a deterioration of transcapillary metabolism and transport of oxygen to tissues. In the ischemic ovary, degenerative changes in the follicular apparatus, yellow bodies, followed by spreading to all the ovarian structural elements, which leads to its atrophy and reduced functional properties. Considering the importance of venous blood flow in the development of hormonal imbalance as a result of a violation of the endocrine function of the ovaries, the purpose of our study was to assess the menstrual and reproductive function of infertile women against the background of varicose veins. The reproductive function of women with infertility and varicose changes in ovarian veins is represented by a significant percentage of unauthorized miscarriages (41.9%) in the period of pregnancy after 6 weeks (30.6%). In patients with varicose veins in the ovaries, there was a tendency to increase the duration of infertility compared with patients without varicose dilatation of ovarian veins, which may indirectly indicate more significant functional and structural changes in the reproductive organs. In women, both the primary and the comparator groups are predominantly the late and early menarche, but the rates in groups differ slightly in their direction in women with infertility and varicose veins in the ovaries, although they do not reach statistically significant values. The menstrual function of women in the main group is characterized by a regular menstrual cycle (77.5%), regular duration (43.6%) with excessive blood loss during menstruation (54.8%) and a duration of more than 6 days (50.1%) with acyclic uterine bleeding (37.1%), dysmenorrhea (56.4%) and premenstrual disorders (51.6%), which significantly impairs the quality of life of women. At the same time, the violation of the menstrual cycle in the form of its shortening of 16,1% and acyclic uterine bleeding — 6,5%, was gradually increasing with age and was statistically significant against women from the comparison group. Conclusion in the analysis of clinical characteristics, the more significant percentage of changes in the menstrual cycle, reproductive function in women with functional infertility and varicose veins of the ovary compared with patients with infertility without structural changes in ovarian veins indicates the significant importance of venous hemodynamics in the functional properties of the ovary.


2021 ◽  
Vol 27 (2) ◽  
pp. 293-300
Author(s):  
Shota Koyama ◽  
Yuko Nemoto ◽  
Masahiro Ichikawa ◽  
Daiki Oka ◽  
Yoshimasa Tsujii ◽  
...  

2020 ◽  
Vol 13 (12) ◽  
pp. 2145-2155
Author(s):  
Sofia Melchior ◽  
Sonia Calligaris ◽  
Giulia Bisson ◽  
Lara Manzocco

Abstract Aim The effect of moderate-intensity pulsed electric fields (MIPEF) was evaluated on vegetable protein concentrates from pea, rice, and gluten. Methods Five percent (w/w) suspensions of protein concentrates (pH 5 and 6) were exposed to up to 60,000 MIPEF pulses at 1.65 kV/cm. Both structural modifications (absorbance at 280 nm, free sulfhydryl groups, FT-IR-spectra) and functional properties (solubility, water and oil holding capacity, foamability) were analyzed. Results MIPEF was able to modify protein structure by inducing unfolding, intramolecular rearrangement, and formation of aggregates. However, these effects were strongly dependent on protein nature and pH. In the case of rice and pea samples, structural changes were associated with negligible modifications in functional properties. By contrast, noticeable changes in these properties were observed for gluten samples, especially after exposure to 20,000 pulses. In particular, at pH 6, an increase in water and oil holding capacity of gluten was detected, while at pH 5, its solubility almost doubled. Conclusion These results suggest the potential of MIPEF to steer structure of proteins and enhance their technological functionality.


2020 ◽  
Vol 22 (9) ◽  
pp. 5024-5032
Author(s):  
Junhua Chen ◽  
Yang Zheng ◽  
Alessio Melli ◽  
Lorenzo Spada ◽  
Tao Lu ◽  
...  

A joint experimental-theoretical spectroscopic investigation has focused on a better understanding of the nature of weak, non-covalent interactions in amine-water model systems.


2011 ◽  
Vol 85 (1) ◽  
pp. 272-275 ◽  
Author(s):  
Youshuang Chen ◽  
Shirong Huang ◽  
Zhongfeng Tang ◽  
Xiaowei Chen ◽  
Zengfang Zhang

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