Proteolysis Process in Fermented Sausage Model Systems As Studied by NMR Relaxometry

Abstract

Proton NMR relaxation analyses were performed in sausage model systems (SMS) at different manufacturing times (0, 1, 3, 5, 7, and 9 days) to evaluate changes in water distribution and mobility. Three different water populations were identified, T2b (5-10 ms), T21 (30-70 ms), and T22 (100-300 ms), and the progress of ripening could be followed as a shift toward shorter relaxation times. In addition, the combined effect of adding commercial proteases (Pronase E and aspartyl proteinase) on protein breakdown and structural integrity of sausage models (SMS+P) was investigated, resulting in the formation of a more fluid and less organized meat matrix that led to changes in water populations T2b2 and T22 compared with SMS. A very different protein degradation pattern between SMS and SMS+P was observed by means of SDS-PAGE and fluorescamine assay, supporting that some degree of protein aggregation is needed for the presence of the T22 population in fermented sausages.

Improvement of quality and flavor of salted egg yolks by ultrasonic assisted cooking

“…It was obvious that the overall trend of T 2 (T 2b , T 21 , T 22 ) significantly decreased (or left shift) ( Fig. 5 a & Table S3 ), which indicated that the protons derived from water or lipid in cooked SEYs bound more close with the matrix (proteins and lipids) in it [59] . The mobility of water (lipids) decreased might be explained by the gelation of SEYs, water fixed in gel network, promoted by heat (or ultrasonic) treatment, such as the gradual reduction of T 2b (A 2b ) ( Fig.…”

Influence of Rice Flour, Glutinous Rice Flour, and Tapioca Starch on the Functional Properties and Quality of an Emulsion-Type Cooked Sausage

“…The first water component (T 2 b 1 ) detected was associated with the lack of a strong and well-organized composite system gel structure, as suggested by García García et al [22]. Other authors [23] have indicated that the shortest T2 relaxation time could be associated with water within the cell wall of the samples.…”

“…Low filed NMR T2 relaxation time measurements demonstrated that the addition of these ingredients could induce the transference of water molecules from a loosely bound to tightly bound water fraction. Consequently, the presence of longer T 22 and shorter relaxation times (T 2b1 , T 2b2, T 21 ) suggests that the binding properties are stronger between water molecules and muscle tissue. The cooked sausage samples, with or without RF, GRF, or TS, showed similar trends in T2 relaxation times (Figures 1 and 2A).…”

“…The four proton populations detected in the emulsion-type sausages formulated with or without plant-based starch were designated as P 2b1 , P 2b2 , P 21 , and P 22 , as shown in Figure 2B. T2 relaxometry proportion measurements showed that the sausage samples with the highest P 21 had the lowest P 22 proportion. In general, T2 relaxation times demonstrated the possibility of water protons to interact with the surrounding surfaces of RF, GRF, or TS, which consequently caused some alterations in the structural space of the emulsion-type cooked sausage.…”

Benchtop NMR for the monitoring of bioprocesses

“…The following recent examples highlight the diversity of the processes that can be studied in this field. Garcìa et al studied the ripening step of fermented sausages. Several fermented sausages were prepared and analyzed after different ripening times.…”