FTIR Imaging for Structural Analysis of Frankfurter Sausages Subjected to Salt Reduction and Salt Substitution

Abstract

In this study, the effects of NaCl, KCl, and MgSO4 in various concentrations on structural and sensory properties of frankfurter sausages were investigated. FTIR was used to analyze the overall homogeneousness of the sausages by simultaneously following the distribution of main sausage ingredients, i.e., proteins, fats, and starch. A more homogeneous distribution of the main ingredients was observed with higher concentration of added salts, while it was most pronounced for the MgSO4 recipe. Furthermore, FTIR imaging was used in order to follow the distribution of protein secondary structure motifs throughout the sausage matrix. It was confirmed that KCl inhibited the partial denaturation of proteins, unlike that observed for MgSO4 recipes, where an additional increase in protein hydration was detected. These findings were unequivocally supported by WHC measurements. However, the sensory analysis clearly distinguished the sausages prepared with MgSO4 due to undesired sensory attributes, which underlines the necessity for using taste masking agents.

Model‐based pre‐processing in Raman spectroscopy of biological samples

“…Multiplicative scatter correction (MSC), and later extended MSC (EMSC), was developed in the 80s for applications in near‐infrared (NIR) spectroscopy in food science, and today, EMSC is one of the major frameworks for model‐based pre‐processing in vibrational spectroscopy. In the last years, EMSC has particularly attracted attention within IR spectroscopy for selective correction of features like sample thickness and temperature, water vapour, carbon dioxide and salt concentration . An EMSC‐based algorithm for estimating and correcting the contribution of Mie scattering effects in Fourier‐transform (FT) IR microspectroscopy of cells has also recently gained attention …”

Effects of NaCl on water characteristics of heat-induced gels made from chicken breast proteins treated by isoelectric solubilization/precipitation

“…The comprehensive disruption of muscle structure by ISP may also be important in aligning proteins for gel formation during heating, thus reducing NaCl demand to induce the same effect (Chang, Feng, & Hultin, 2001;Wright & Lanier, 2005). Additionally, the increase of potassium content in the ISPCgels (Figure 1) might result in more β-sheets that was conducive to obtain the good texture at 1% NaCl (Choi & Ma, 2007;Perisic, Afseth, Ofstad, Scheel, & Kohler, 2013). Our results did demonstrate that the gel-type meat products created by the ISP process with low sodium content had good textural properties that were equal to those produced by the conventional process with high sodium content.…”

“…However, another work concluded that the addition of NaCl to myosin from catfish treated by the ISP process reduced the content of α-helix to 15% and this occurrence corresponded to an increase in β-sheet content (Raghavan & Kristinsson, 2008). In addition, the increase of potassium content in the ISP-recovered proteins also enhanced the signal intensity of the β-sheets (Perisic et al, 2013). The reduced α-helix and increased β-sheet levels prior to heating is conducive to the formation of a three-dimensional gel network and increase hardness, but decreases the binding strength of water to protein molecules and the capacity of the gels to trap water in the matrix (Choi & Ma, 2007;Liu et al, 2008).…”

“…Thus, NaCl is essential to obtain a high cook yield. Perisic et al (2013) suggested that the intensity of the β-sheets signal in Frankfurters increased and the α-helical bands decreased with the increase of salt addition, and the cooking loss decreased concomitantly. Hence, we speculated that more β-sheets in the ISPCgels resulted in the decrease of cooking loss when NaCl addition increased from 0% to 1%.…”

“…Besides, the ISPrecovered proteins contained more potassium ions (Figure 1). This resulted in more β-sheets (Perisic et al, 2013), which existed in the ISPC-gels with 1% NaCl and might be sufficient to form gel network and reduce the mobility of free water. Hence, the cooking loss remained stable at 1-2% NaCl.…”