Gelling properties of myosin as affected by L-lysine and L-arginine by changing the main molecular forces and microstructure

Abstract

This paper investigated the effects of L-lysine (Lys) and L-arginine (Arg) on the water-holding capacity (WHC) and hardness of myosin gel as well as the mechanism of these effects. The results showed that Lys, Arg, and KOH increased the WHC but decreased the hardness in all cases. At pH 6.32, the WHC increased in the order control < KOH < Lys ≈ Arg, while the hardness decreased in the order control > KOH > Lys > Arg. Lys shortened low field nuclear magnetic resonance spin-spin relaxation times (T 2 ), while Arg and KOH slightly affected T 2 . Lys, Arg, and KOH had different influences on the molecular forces in myosin gels and the distribution of myosin size. Lys formed a gel with porous clusters, while Arg generated a gel with fine caves. Therefore, both Lys and Arg changed the microstructure of myosin gel by changing the distribution of the myosin size as well as the molecular forces that form and/or maintain myosin gel, ultimately contributing to the differences in the WHC, hardness, and T 2 .ARTICLE HISTORY

Modification of heat-induced whey protein gels by basic amino acids

“…The addition of basic amino acids increased the WHC at all pHs except for pH 5.2, at which only 0.5% lysine resulted in a significantly higher WHC (P < 0.05). Histidine, lysine, and arginine have been reported to improve WHC of chicken salt soluble protein gel (Qin et al, 2015), chicken myosin gel (Fu et al, 2017), surimi gel (Cando et al, 2016), porcine myosin gel (Zhang et al, 2017), and pork sausage Zhou, Li, Tan, & Sun, 2014). Some of the studies attributed the enhanced WHC to basic amino acid-induced pH deviation away from pI (Fu et al, 2017;Qin et al, 2015;Zhou, Li, Tan, & Sun, 2014).…”

“…However, since the pH of the samples were controlled in the current investigation, factors other than pH shifting must have also contributed to the increased WHC. Basic amino acid-induced increase in protein solubility and hydration capacity (Li et al, 2019;Li et al, 2018), suppression of protein aggregation (Qin et al, 2015), reduction in water mobility (Fu et al, 2017;Zhang et al, 2017), and formation of a fine gel structure (Fu et al, 2017;Qin et al, 2015) have been suggested as possible mechanisms.…”

“…Adding basic amino acids resulted in gels with improved water holding capacity, viscoelasticity and texture profile, and sensory attributes (Cando et al, 2016;Hayakawa et al, 2012;Lei, Fu, Xu, Zheng, & Zhou, 2016;Qin, Xu, Zhou, & Wang, 2015;Zhang et al, 2017;Zhou, Li, Tan, & Sun, 2014;Zhu et al, 2018). The underlying mechanisms include pH modulation, reduced water mobility, increased protein solubility, suppressed protein aggregation, altered protein thermal stability, facilitated protein unfolding and exposure of buried hydrophobic groups and sulfhydryls, and formation of a fine gel network (Cando et al, 2016;Chen et al, 2016;Fu et al, 2017;Gao, Wang, Mu, Shi, & Yuan, 2018;Guo, Peng, Zhang, Liu, & Cui, 2015;Hayakawa et al, 2012;Lei et al, 2016;Lei et al, 2017;Li et al, 2019;Qin et al, 2015;Zhang et al, 2017;Zhou, Li, Tan, & Sun, 2014). In addition, basic amino acids can improve emulsion stability Zhu et al, 2018), inhibit lipid and protein oxidation , and stabilize heme color Zhou, Li, Tan, & Sun, 2014;Zhou, Ye, Nishiumi, Qin, & Chen, 2014;Zhou, Ye, Wang, Qin, & Li, 2015), and are particularly useful in emulsified gel systems such as sausages.…”

“…Although extensive evidence has demonstrated that basic amino acids are effective in improving quality of muscle protein gels (Fu et al, 2017;Hayakawa et al, 2012;Lei et al, 2016;Lei et al, 2017;Qin et al, 2015;Zhang et al, 2017), egg yolk gel (Primacella et al, 2018), and complex gel systems such as sausages Zhou, Li, Tan, & Sun, 2014;Zhu et al, 2018), surimi (Cando et al, 2016), and cheese (Felicio et al, 2016), to the best of our knowledge, no study has investigated the effect of basic amino acids on gelling properties of whey protein isolate (WPI) gels. WPI is a widely used gelling and thickening agent in a variety of foods such as processed meat, bakery products, and dairy products (Havea, Watkinson, & Kuhn-Sherlock, 2009).…”

“…This could serve as an alternative method to pH-based manipulation of gel properties, which are particularly advantageous for foods produced at a given pH. Several studies attributed part of the gelation promoting effects of the basic amino acids to their ability to increase the pH (Fu et al, 2017;Qin et al, 2015;Zhou, Li, Tan, & Sun, 2014). Since there are more effective and economic ways to adjust pH, we controlled the pH in the current investigation and examined the effectiveness of other mechanisms.…”