Influence of lard-based diacylglycerol on rheological and physicochemical properties of thermally induced gels of porcine myofibrillar protein at different NaCl concentrations
Graphical abstract
Introduction
Myofibrillar protein (MP) is an important functional protein in muscle which is responsible for the thermally induced gelation properties of meat products. MP plays a critical role in producing the three-dimensional viscoelastic gel network via interactions among the proteins by hydrogen bonds, disulfide bonds, and hydrophobic interactions during thermal processing. For comminuted meat products, MP can provide a cohesive force to stabilize fat droplets and water in the three-dimensional network structure and bring meat particles together during thermal processing (Guo et al., 2019). The formed protein gels are notably important for their ability to bind water, stabilize fat, and form cohesive membranes on the surface of fat globules in emulsion systems (Wu, Xiong, Chen, Tang, & Zhou, 2009). The gel formation of MP is influenced by many factors, and one of the most important factors is salt concentration. Myosin accounts for nearly 43% of MP in muscle tissue, and the molecule is highly sensitive to the ionic strength (Yates, Greaser, & Huxley, 1983). At low ionic strength (<0.3 M), myosin molecules aggregate and produce a filament, whereas at high ionic strength (>0.3 M), myosin molecules disperse individually and occur as monomers (Sano, Noguchi, Matsumoto, & Tsuchiya, 1990). Moreover, high salt concentration is the pre-condition for the solubilization which is followed by the gelation of MP. Hegg (1982), revealing that the proper concentration of salt plays a positive role in protein-protein interactions and enhanced quality of the heat-induced gels. NaCl as the most important brine ingredient plays an important role in providing desirable flavour and texture characteristics in comminuted meat products (Gordon & Barbut, 1992). Addition of NaCl to meat products not only influences MP gel behaviour and gel formation but also influences flavour release (Feng, Cao et al., 2018). The perceived saltiness was owing to the Na+ and Cl-, and the flavor intensity depended on salt concentration in meat products (Feng, Cao et al., 2018). However, overconsumption of salt has been shown to lead to degenerative diseases such as hypertension, stroke, cerebrovascular, and cardiovascular diseases (He et al., 2011, Kloss et al., 2015).
Fat is an important ingredient in meat products. Addition of animal fat to meat products can provide good textural characteristics, attractive flavour, and high sensory acceptability (Yoo, Kook, Park, Shim, & Chin, 2007). However, excessive animal fat intake could bring about lifestyle-related diseases, particularly obesity, hypertension, and coronary heart disease (Yoo et al., 2007). Triacylglycerol (TG) is a major component, while diacylglycerol (DG) is a minor component in various plant oils and animal fats. Cheong, Zhang, Xu, and Xu (2009) showed that lard is comprised of 97.90% TG and 2.10% DG. In our previous study, the acylglycerol profile of lard, unpurified DG (UDG), and purified DG (PDG) was analysed by HPLC (Diao, Guan, Kong, & Zhao, 2017). The results revealed that lard was composed of 100% TG; UDG was comprised of 14.50% monoacylglycerol (MG), 61.76% DG, and 23.74% TG; and PDG was comprised of 8.85% MG, 82.03% DG, and 9.12% TG. Compared with TG, DG can reduce postprandial serum TG elevation and suppress fat accumulation in the body (Yasukawa & Katsuragi, 2004). The differences in metabolic characteristics between DG and TG result from differences in metabolic pathways in the small intestinal cells (Yasukawa & Katsuragi, 2004). Moreover, numerous studies in animal and human clinical trials have revealed that DG exerted no adverse effects on health (Morita & Soni, 2009). In addition, compared with TG, DG exerts unique physicochemical properties related to hydrogen bonding due to the presence of a hydrophilic group (hydroxyl group) in DG (Zhao, Sun, Qin, Liu, & Kong, 2018). DG can also improve product texture due to its higher melting point (Yasukawa & Katsuragi, 2004). Meanwhile, the taste, flavour, and texture of DG are similar to those of TG (Nishide, Shimizu, Tiffany, & Ogawa, 2004). Therefore, total or partial substitution of porcine fatback with lard-based DG in meat products may represent an alternative method to improve functional and nutritional properties. Miklos et al. (2014) reported that partial substitution of pork back fat with lard-based DG in fermented sausages could improve the quality of meat products.
Our previous experiments studied the preparation of DG from lard by lipase-catalysed glycerolysis (Diao et al., 2017). Furthermore, we evaluated the influence of ultrasonic pretreatment on DG preparation by enzymatic glycerolysis of lard (Zhao, Sun, Liu, & Kong, 2018). The results revealed that the lard samples, after 4 h of glycerolysis reactions with ultrasonic pretreatment, had similar DG contents to 11 h of glycerolysis reactions without ultrasonic pretreatment, which showed that ultrasonic pretreatment promotes DG preparation from lard. The UDG was prepared by a ultrasonic pretreatment method. The UDG was purified by molecular distillation and labelled as PDG. The melting point of UDP was between 29 °C and 42 °C, and melting point of PDG was between 30 °C and 44 °C (Diao, Guan, Kong, Han, & Zhao, 2016). In addition, lard, UDG, and PDG had very similar fatty acid compositions with C14:0 (myristoleic, 1.10–1.20%), C16:1 (palmitoleic, 1.79–1.92%), C16:0 (palmitic, 23.97–24.60%), C18:2 (linoleic, 7.75–8.03%), C18:1 (oleic, 47.64–48.09%), and C18:0 (stearic, 12.95–13.05%) (Diao et al., 2017). However, there were limited reports about the influence of DG on gelation and processing properties of MP. The aim of this work was to investigate rheological and physicochemical properties of porcine MP as influenced by the addition of lard-based DG at different NaCl concentrations, and the changes in gel microstructure, water distribution, and protein secondary structure were also analysed.
Section snippets
Materials
Fresh pork backfat and fresh pork loin muscle were purchased from the Beidahuang Meat Corporation (Harbin, Heilongjiang, China). Piperazine-1, 4 bisethanesulfonic acid (PIPES) was obtained from the Shanghai Yuanye Chemical Technology Co. Ltd. (Shanghai, China). All reagents in this work were of analytical grades.
Preparation of lard-based diacylglycerol
Lard was obtained by heating fatback at 120 °C with constant agitation. Lard-based diacylglycerol (DG) was synthesized according to the procedure of Zhao et al. (2018). Before the
Gel strength and water-holding capacity
Gel strength was examined by gel compression force testing. As shown in Fig. 1A. as the concentration of NaCl increased from 0 M to 0.6 M, the compression forces significantly increased (P < 0.05) and the maximum gel strength appeared at 0.6 M. The compression forces increased from 0.06, 0.11, 0.14 and 0.16 N (0 M NaCl) to 0.38, 0.45, 0.59 and 0.72 N (0.6 M NaCl) for control (MP alone), lard-, UDG- and PDG-composite gels (P < 0.05), respectively. These results likely occurred because protein
Conclusion
Incorporation of lard-based DG and change of NaCl concentrations had a profound effect on rheological and physicochemical gelation properties of porcine MP. The incorporation of UDG or PDG, the gel compression force and gel WHC were enhanced and the rheological properties (G′ and G″) and gel microstructure were improved with the increase in NaCl concentration. LF-NMR analysis revealed that the incorporation of UDG or PDG and the increase in NaCl concentration increased the entrapped water
Declaration of interest statement
The authors declare no competing financial interest.
Acknowledgements
This study was funded by the National Natural Science Foundation of China (31771990) and National Key Research and Development Program during the 13th Five-year Plan in China (2016YFD0401504).
References (60)
- et al.
Functionality of myofibrillar proteins as affected by pH, ionic strength and heat treatment-a low-field NMR study
Meat Science
(2004) Reducing salt: A challenge for the meat industry
Meat Science
(2006)- et al.
Properties and oxidative stability of emulsions prepared with myofibrillar protein and lard diacylglycerols
Meat Science
(2016) - et al.
Physicochemical and structural properties of composite gels prepared with myofibrillar protein and lard diacylglycerols
Meat Science
(2016) - et al.
Effects of partial substitution of NaCl on gel properties of fish myofibrillar protein during heating treatment mediated by microbial transglutaminase
LWT-Food Science and Technology
(2018) - et al.
Thermal gelling properties and mechanism of porcine myofibrillprotein containing flaxseed gum at different NaCl concentrations
LWT-Food Science and Technology
(2018) - et al.
Effect of operating conditions on the concentration of monoglycerides using molecular distillation
Chemical Engineering Research & Design
(2007) - et al.
Effect of low-frequency magnetic field on the gel properties of pork myofibrillar proteins
Food Chemistry
(2019) - et al.
Sodium intake and its reduction by food reformulation in the European Union-a review
NFS Journal
(2015) - et al.
Authentication of extra virgin olive oils by Fourier-transform infrared spectroscopy
Food Chemistry
(2010)
Structural changes of the myofibrillar proteins in common carp (Cyprinus carpio) muscle exposed to a hydroxyl radical-generating system
Process Biochemistry
Role of secondary structures in the gelation of porcine myosin at different pH values
Meat Science
Influence of lipid type on water and fat mobility in fermented sausages studied by low-field NMR
Meat Science
Application of pork fat diacylglycerols in meat emulsions
Meat Science
Safety assessment of diacylglycerol oil as an edible oil: A review of the published literature
Food and Chemical Toxicology
On the mechanism of water holding in meat: The swelling and shrinking of myofibrils
Meat Science
Deciphering the characteristics of soybean oleosome-associated protein in maintaining the stability of oleosomes as affected by pH
Food Research International
Physicochemical and structural properties of composite gels prepared with myofibrillar protein and lecithin at various ionic strengths
Food Hydrocolloids
Physicochemical change and protein oxidation in porcine longissimus dorsi as influenced by different freeze-thaw cycles
Meat Science
Evaluation of protein structural changes and water mobility in chicken liver paste batters prepared with plant oil substituting pork back-fat combined with pre-emulsification
Food Chemistry
Muscle proteins
Effect of pH on the interaction of volatile compounds with the myofibrillar proteins of duck meat
Poultry Science
Quatitative determination of myosin and actin in rabbit skeletal muscle
Journal of Molecular Biology
Effects of protein level and fat/oil type on emulsion stability, texture, microstructure and color of meat batters
Meat Science
Ultrasonic pretreatment promotes diacylglycerol production from lard by lipase-catalysed glycerolysis and its physicochemical properties
Ultrasonics Sonochemistry
Partial substitution of NaCl with chloride salt mixtures: Impact on oxidative characteristics of meat myofibrillar protein and their rheological properties
Food Hydrocolloids
Effect of low fat addition on chicken myofibrillar protein gelation properties
Food Hydrocolloids
Physicochemical properties and microstructure of fish myofibrillar protein-lipid composite gels: Effects of fat type and concentration
Food Hydrocolloids
The effect of insoluble dietary fiber on myofibrillar protein emulsion gels: Oil particle size and protein network microstructure
LWT-Food Science and Technology
Water distribution and microstructure in enhanced pork
Journal of Agricultural and Food Chemistry
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