Applications of Vibrational Spectroscopy to the Analysis of Polysaccharide and Hydrocolloid Ingredients

Abstract

The applications of vibrational spectroscopy to study the structure of polysaccharide and hydrocolloid ingredients are presented. Vibrational spectroscopy, including infrared (IR) and Raman spectroscopies, has been used for both qualitative and quantitative analysis of starches and other polysaccharide ingredients. Some structural characteristics of starch and nonstarch polysaccharides have been studied using various vibrational spectroscopic techniques. The degree of substitution (DS) in modified polysaccharides can also be determined by IR and Raman spectroscopy, replacing the traditional wet chemistry procedure. Vibrational spectroscopy has also been used to determine protein structural characteristics and to monitor conformational changes under different buffer conditions. Conformation is an important parameter affecting the functional properties of protein hydrocolloids, and extensive conformational changes may occur during food processing and interactions with other food ingredients. Fourier transform (FT)–mid‐IR spectroscopy has been used to obtain information on protein structure and protein–protein and protein–lipid interactions. The extent of modification in modified food proteins and the effect of these modifications on protein conformation have been monitored by Raman spectroscopy. These modified polysaccharide and protein hydrocolloids, with enhanced gelling, thickening, and emulsifying properties, are important hydrocolloid ingredients for a wide variety of food products.

Edible Oils Differentiation Based on the Determination of Fatty Acids Profile and Raman Spectroscopy—A Case Study

“…The same percentage was achieved for the separation of hemp oil from the rest of the samples; this time the discrimination signals are 1775 and 1780 cm −1 , which could be attributed to the C=O vibrations from the amino acid residue found in the hempseeds and, also as minor constituents, in oil [19,20].…”

“…Figure 3 presents the representative Raman spectra for the six types of the investigated oils and the markers which allowed their classification; these signals are: 1443, 1523, 1649, 1666, and 1780 cm −1 . The bands observed for the simultaneous classification can be tentatively assigned as follows: 1443 cm −1 to the CH deformation (CH 2 group) from the saturated part of oils [15], 1523 cm −1 to the C=C stretching vibration from carotenoids [16], 1649 and 1666 cm −1 to the C=C stretching vibration from cis conjugated systems and trans-CH=CHgroups [17,18], while 1780 cm −1 could be assigned to the C=O stretching vibration from some minor constituents-e.g., aspartic/glutamic acid residue [19] that exist in significant amounts in the appropriate seeds (e.g., hempseeds) [20]. Considering these data, we observed that the oils discrimination is mainly based on the peaks associated to the saturated part, to cis or trans configurations, to a characteristic band from carotenoids, or to a specific band (C=O) from different minor ingredients found in some oils.…”

Facile residue analysis of recent and prehistoric cook stones using handheld Raman spectrometry

“…Previous literature reports on carbohydrates confirm the ability of Raman spectroscopy to distinguish different chemicals. Raman spectroscopy was shown to be a valuable tool for the studies of carbohydrates . For example, distinct Raman spectra were measured for 13 different sugars including glucose, fructose, starch and cellulose .…”