Definitions of Free and Bound Water in Plants and a Comparative Analysis of the Drying Method over a Dewatering Agent and Differential Scanning Calorimetry

2021 ◽  
Vol 11 (6) ◽  
pp. 640-646
Author(s):  
R. V. Malyshev
2021 ◽  
pp. 50-53
Author(s):  
Варужан Амбарцумович Саркисян ◽  
Юлия Владимировна Фролова ◽  
Роман Владимирович Соболев ◽  
Алла Алексеевна Кочеткова

Полисахариды являются многофункциональными пищевыми ингредиентами, применяемыми в различных типах пищевых продуктов. Особый интерес вызывает изучение роли полисахаридов в качестве потенциальных про- или антиоксидантов в составе пищевых эмульсий. Основным недостатком традиционных способов оценки развития окислительных процессов в эмульсиях является необходимость предварительной экстракции жировой фазы, что может сопровождаться искажением реальных значений показателей окисления. В данной работе влияние полисахаридов на окислительную стабильность эмульсий изучено при помощи реактора окислительной устойчивости Oxitest, который позволяет проводить прямое измерение потребления кислорода в процессе окисления липидов, тем самым исключая необходимость экстракции и повышая достоверность полученных данных. Проведен сравнительный анализ 6 различных полисахаридов (альгинат натрия, i-каррагинан, камедь рожкового дерева, пектин амидированный, пектин высокоэтерифицированный, картофельный крахмал) в составе пищевых эмульсий. Методами ИК-Фурье спектроскопии и дифференциально-сканирующей калориметрии охарактеризованы состав и свойства исходных полисахаридов. Изучена вязкость 0,5%-ных растворов полисахаридов при помощи метода ротационной вискозиметрии. В результате проведенного анализа полисахаридов выявлены и охарактеризованы основные отличия в колебательных спектрах поглощения функциональных групп. Методом дифференциально-сканирующей калориметрии определены энтальпии теплового эффекта отделения влаги и начала термической деградации полисахаридов. Проведен многомерный статистический анализ полученных данных, выявивший основные закономерности между структурой и свойствами полисахаридов в составе эмульсий. Наибольшую окислительную стабильность проявили эмульсии на основе камеди рожкового дерева и амидированного пектина. Polysaccharides are multifunctional food ingredients used in various types of food products. The role of polysaccharides as potential pro- or antioxidants in food emulsions is of particular interest is. The main drawback of traditional methods for assessing the development of oxidative processes in emulsions is the need for preliminary extraction of the fat phase, which may be accompanied by a distortion of the real values of oxidation indices. In this work, the effect of polysaccharides on the oxidative stability of emulsions was studied using the Oxitest oxidative stability reactor, which allows the direct measurement of oxygen consumption during lipid oxidation, thereby eliminating the need for extraction and increasing the reliability of the obtained data. Comparative analysis of 6 different polysaccharides (sodium alginate, i-carrageenan, locust bean gum, amidated pectin, highly esterified pectin, potato starch) in food emulsions was performed. The composition and properties of the initial polysaccharides were characterized by FTIR spectroscopy and differential scanning calorimetry methods. The viscosity of 0.5% solutions of polysaccharides was studied using the rotary viscometry method. The analysis of polysaccharides revealed and characterized the main differences in the vibrational absorption spectra of functional groups. The enthalpies of the thermal effect of moisture separation and the beginning of thermal degradation of polysaccharides were determined by differential scanning calorimetry. A multivariate statistical analysis of the obtained data revealed the main relations between the structure and properties of polysaccharides in emulsions. Emulsions based on locust bean gum and amidized pectin exhibited the highest oxidative stability.


1981 ◽  
Vol 51 (9) ◽  
pp. 607-613 ◽  
Author(s):  
Kunio Nakamura ◽  
Tatsuko Hatakeyama ◽  
Hyoe Hatakeyama

2012 ◽  
Vol 38 (3) ◽  
pp. 197-200
Author(s):  
Khee-Hwan Choi ◽  
Myung-Jin Ann ◽  
Hong-Ha Son ◽  
Kyong-Seub Kim ◽  
Sang-Min Lee ◽  
...  

1971 ◽  
Vol 36 (1) ◽  
pp. 84-86 ◽  
Author(s):  
P. J. BECHTEL ◽  
M. P. PALNITKAR ◽  
D. R. HELDMAN ◽  
A. M. PEARSON

2021 ◽  
Vol 2021 ◽  
pp. 148-154
Author(s):  
G. Erkan ◽  
G.C. Türkoğlu ◽  
S.Y. Karavana ◽  
A.M. Sariişik ◽  
B. Ütebay ◽  
...  

Microencapsulation technology has been increasingly used in textile industry due to give some peculiarities such as controlled released etc. In this study we aim to make aromatherapy sportswear using lavender oil. Lavender oil is encapsulated by different wall materials. Microcapsules were obtained by spray drying method. Differential scanning calorimetry, thermal gravimetric analysis, Fourier Transform infrared spectroscopy, morphological analyses were applied to microcapsules. Optimum microcapsules were applied to different fabrics. Fastness to washing and rubbing, SEM and antibacterial tests were carried out.


Author(s):  
Maria Marudova ◽  
Stanko Stankov ◽  
Marianna Baeva

AbstractThe effect of three types of emulsifiers (polyglycerol monostearate ester – E475, sucrose stearate ester – E473 and modified inulin palmitate ester – HP-25) on the starch retrogradation in sponge cake (SC) during storage was investigated. The method of differential scanning calorimetry (DSC) was applied to determine the changes in the starch retrogradation during the staling process. The retrogradation temperature and the enthalpy of the endothermic transition decreased when emulsifiers were added. The lowest values of the enthalpy for the whole storage period were found for SC with 1% HP-25. The methods of differential thermal analysis (DTA) and thermogravimetry analysis (TGA) showed significantly bigger (1.43 times) amount of strongly bound water in the crumb of the SC with E475 and HP-25 in comparison to the control sample on the sixth day of storage. Based on our results, emulsifiers possessed retarding effect on the starch retrogradation and extend the shelf-life of the SC.


2018 ◽  
Vol 97 (9) ◽  
pp. 1017-1022 ◽  
Author(s):  
A.K. Lauritsen ◽  
J.E.M. Pereira ◽  
F. Juranyi ◽  
H.N. Bordallo ◽  
L. Larsen ◽  
...  

The aim of this study was to investigate hydrogen mobility within innate and demineralized human dentine. Dentine sections from extracted human molars, demineralized or not, were analyzed by combining neutron spectroscopy with thermal analysis. For the thermal analysis of the samples, differential scanning calorimetry and thermal gravimetric analysis, coupled with Fourier transform infrared spectroscopy, were performed. The hydrogen dynamics of water, collagen, and hydroxyl groups present in the samples were investigated via neutron spectroscopy. From the mass loss observed from the thermogravimetric analysis curves up to 600 °C, the same amount of organic content is identified in the samples. From the differential scanning calorimetry curves, a higher change in enthalpy associated with the denaturation of collagen is registered in the demineralized dentine; that is, a structural change occurs in the collagen subsequent to demineralization. Since the intensity measured by neutron spectroscopy is dominated by the signal from hydrogen, in our samples—coming mostly from the bulk-like and loosely bound water as well as from the collagen itself—higher proton mobility within the demineralized dentine was detected when compared with innate dentine. In the demineralized dentine, this proton mobility amounts to 80%, while the remaining hydrogen accounts for a combination of 1) structural hydroxyls, as a result of the incomplete dissolution of the mineral phase by acid etching, and 2) hydrogen tightly bound in the collagen structure. By combining neutron spectroscopy with the calorimetry data, our findings support the idea that hydroxyapatite protects the collagen in innate dentine. Demineralized dentine, however, acts as a sponge where free bulk-like water is trapped.


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