In situ 13C solid‐state polarization transfer NMR to follow starch transformations in food. (8th February 2022)

• Record Type: Journal Article
• Authors: Nowacka‐Perrin, Agnieszka; Steglich, Thomas; Topgaard, Daniel; Bernin, Diana
• Other Names: Bertram Hanne Christine guestEditor.; van Duynhoven John guestEditor.
• Is Part Of: Magnetic resonance in chemistry. Volume 60:Number 7(2022)
• Page Start: 671
• Page End: 677
• Publication Date: 2022-02-08
• Subjects: 1H -- 13C -- convenience food -- CP -- gelatinization -- INEPT -- MAS -- solid‐state NMR -- starch‐rich food products; Nuclear magnetic resonance spectroscopy -- Periodicals; Chemistry, Organic -- Periodicals; Magnetic resonance -- Periodicals; 538.36
• DOI: 10.1002/mrc.5253
• Languages: English
• ISSNs: 0749-1581

Abstract

Abstract: Convenience food products tend to alter their quality and texture while stored. Texture‐giving food components are often starch‐rich ingredients, such as pasta or rice. Starch transforms depending on time, temperature and water content, which alters the properties of products. Monitoring these transformations, which are associated with a change in mobility of the starch chain segments, could optimize the quality of food products containing multiple ingredients. In order to do so, we applied a simple and efficient in situ 13 C solid‐state magic angle spinning (MAS) NMR approach, based on two different polarization transfer schemes, cross polarization (CP) and insensitive nuclei enhanced by polarization transfer (INEPT). The efficiency of the CP and INEPT transfer depends strongly on the mobility of chain segments—the time scale of reorientation of the CH‐bond and the order parameter. Rigid crystalline or amorphous starch chains give rise to CP peaks, whereas mobile gelatinized starch chains appear as INEPT peaks. Comparing 13 C solid‐state MAS NMR experiments based on CP and INEPT allows insight into the progress of gelatinization, and other starch transformations, by reporting on both rigid and mobile starch chains simultaneously with atomic resolution by the 13 C chemical shift. In conjunction with 1 H solid‐state MAS NMR, complementary information about other food components present at low concentration, such as lipids and protein, can be obtained. We demonstrate our approach on starch‐based products and commercial pasta as a function of temperature and storage. Abstract : The comparison of 13 C solid‐state magic angle spinning (MAS) NMR experiments based on two different polarization transfers—CP and INEPT—can be used to investigate the state of starch and other molecules in starch‐based food products. Line shapes and peak positions, as well as the interplay between the CP and INEPT intensities, provide information concerning crystallinity, mobility and simultaneous presence of rigid and mobile fractions of molecules. Here, we present this approach to monitor the gelatinization of starch in a pasta strand in situ.