NMR and X-Ray Studies of Starches Derived from Tropical Fruit Seed Gelatinization Process

Abstract

Gelatinization of the starch obtained from fruit seed such as mango and cumbaru was investigated applying an analytic methodology developed in the polymer nuclear magnetic resonance (NMR) laboratory at IMA=UFRJ, employing high resolution nuclear magnetic resonance spectroscopy in the solid state for hydrogen nucleus, using 1 H HR-MAS pulse sequence. The results showed that NMR can be used instead of some techniques normally applied to study the gelatinization process, because 1 H HR-MAS and relaxation time allow the evaluation of this process at the molecular level. NMR was also able to indicate the best gelatinization conditions. To start this study the glass transition (Tg) determination was a first step, because the Tg of seed starches are different than the Tg of starches derived from cereal, for example. The 1 H HR-MAS NMR showed some useful information on the fruit seed starches gelatinization process. X-ray measurements were also used to support the data obtained from NMR technique. It was verified, 1135 from X-ray, that mango starch exhibits crystallinity in the A form and cumbaru showed a predominant amorphous phase. The use of 1 H HR-MAS was shown to be a new, powerful method to follow the gelatinization process, because this process can be understood at the molecular level.

The NMR Study of the Latex Extracted from Brosimum Parinarioides

“…The 13 C NMR signals located from 10 to 60 ppm and 1 H NMR signals from 1 to 2 ppm, belonged to saturated region and were associated with acylglycerols of long chains. The double region was assigned from 100 to 130 ppm, in respect to 13 C NMR and from 4.5 to 5.5 ppm in relation to 1 H NMR signals, which were attributed to cis-isoprene and triacylglycerols and therpenes. The carbonyl region was located at around 170 ppm that is associated with the ester group.…”

“…It is known that nuclear magnetic resonance is very much used to characterize a chemical structure and a molecular dynamic of samples [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. This spectroscopy has many techniques, which differ in pulse sequence that permits us to evaluate both chemical constituents and molecular dynamic, because NMR analyzes the sample in different physical states [2][3][4][10][11][12][13][14][15]. According to the context, this work has a purpose to map the principal components that are responsible for the pharmacological and toxic effects and determine the stability degree of this latex after being kept at environment conditions.…”

NMR Relaxometry to Evaluate the Bauhinia Forficata Tea Infusion and Decoction

“…The spinlattice relaxation time is the time needs to the spins return to the equilibrium after being disturbed from the radiofrequency (is a thermal process) and the spin-spin relaxation time is required to the spins returns to its magnitude after being excited from the radiofrequency, this process does not involves energy changes, is more entropic. The determination of these parameters, through low field NMR, is rapid and precise, and the values determined are representative of the whole sample, because they are influenced by all the compounds, proportion of them as well as the molecular organization and intermolecular interaction (COSTA et al, 2007;NASCIMENTO;TAVARES, 2007). Generally speaking an increase in the proton spin-lattice relaxation time means that the samples become more rigid due to the new intermolecular interactions, causing a long time to the components relaxing.…”

The Use of Solid State NMR to Evaluate EVA/Silica FILMs

“…The best 13 C CPMAS NMR spectrum is obtained from a series of 13 C CPMAS NMR spectrum with the increase of contact times, which generates successive decays controlled by the protons' spatial proximity on the 13 C spectra during the variable contact time (VCT) experiment. From these decays the values of proton spin-lattice relaxation time in the rotating frame (T 1 ρH) is determined [21][22][23][24][25][26][27][28] and it informs on local molecular motions. The VCT experiment provides details about sample heterogeneity, molecular mobility and intermolecular interactions of domains, formed.…”