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To study the effects of an ultrasound (0, 30, and 60 min) and sodium bicarbonate (0% and 0.2%) combination on the reduced-salt pork myofibrillar protein, the changes in pH, turbidity, aggregation, and conformation were investigated. After the ultrasound-assisted sodium bicarbonate treatment, the pH increased by 0.80 units, the absolute value of Zeta potential, hydrophobic force, and active sulfhydryl group significantly increased (p < 0.05), and the turbidity and particle size significantly decreased (p < 0.05). Meanwhile, the fluorescence intensity decreased from 894 to 623, and the fluorescence peak showed a significant redshift, which indicated that the ultrasound-assisted sodium bicarbonate treatment exposed the non-polarity of the microenvironment in which the fluorescence emission group was located, leading to the microenvironment and protein structure of myofibrillar tryptophan being changed. Overall, an ultrasound-assisted sodium bicarbonate treatment could significantly improve pork myofibrillar protein solubility and change the protein structure under a reduced-salt environment. [ABSTRACT FROM AUTHOR]

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In this study, the changes of protein structure, proximate composition and physico-chemical attributes of frankfurters (1% NaCl) with pre-emulsified soy oil used in the beating processing were investigated. Three samples were prepared: C, with pork backfat; T1, with pre-emulsified soy oil (soy protein isolate (SPI): soy: water was 1:10:10); T2, with pre-emulsified soy oil (SPI: soy: water was 1:5:5). The energy and fat content decreased while the protein content, L ∗ value, cooking yield and textural properties of frankfurters increased when substituting backfat with pre-emulsified soy oils. The microstructure of C showed a spongy appearance with numerous cavities, then T1 and T2 showed more cavity formation and SPI dispersed around the oil globules. There were significantly (p < 0.05) affected the secondary and tertiary structures of protein, an increase of β-sheet, β-turn and random coil content accompanied by a decrease of α-helices content, and formed more hydrophobic interactions were found. However, there was no significantly (p > 0.05) changes for the secondary structures of protein in T1 and T2. The results showed that replaced pork backfat with pre-emulsified soy oil enabled to produce low-salt and low-fat frankfurters. [ABSTRACT FROM AUTHOR]

To study the impact of ultrasonic duration (0, 30, and 60 min) and sodium bicarbonate concentration (0% and 0.2%) on the gel properties of reduced-salt pork myofibrillar protein, the changes in cooking yield, colour, water retention, texture properties, and dynamic rheology were investigated. The findings revealed that added sodium bicarbonate significantly increased (P < 0.05) cooking yield, hardness, springiness, and strength of myofibrillar protein while reducing centrifugal loss. Furthermore, the incorporation of sodium bicarbonate led to a significant decrease in L ⁎, a⁎, b⁎, and white values of cooked myofibrillar protein; these effects were further amplified with increasing ultrasonic duration (P < 0.05). Additionally, storage modulus (G') significantly increased for myofibrillar protein treated with ultrasonic-assisted sodium bicarbonate treatment resulting in a more compact gel structure post-cooking. In summary, the results demonstrated that ultrasonic-assisted sodium bicarbonate treatment could enhance the tightness of reduced-salt myofibrillar protein gel structure while improving the water retention and texture properties. [Display omitted] • Adding sodium bicarbonate increased cooking yield, texture properties of myofibrillar protein. • Decreased L ⁎, a⁎, b⁎, and white values with increasing ultrasound duration. • G' increased and a more compact gel structure formed treated with ultrasonic-assisted sodium bicarbonate. • Utrasonic-assisted sodium bicarbonate enhanced the tightness and water retention. [ABSTRACT FROM AUTHOR]

In order to study the potential of replacing pork back-fat by sodium alginate solution (sodium alginate/water = 1/29, W /W), the physico-chemical, protein conformation and sensory of frankfurters made with various amounts of pork back-fat and sodium alginate were evaluated. With the increase of sodium alginate solute, the fat and energy was decreased significantly (P <.05). Compared with the control, the cooking yield, emulsion stability, L⁎ and ΔE values were not different significantly (P >.05) when pork back-fat was replaced by 25% and 50%, meanwhile, a decrease of α-helix content accompanied by an increase of β-sheet, β-turn and random coil content, more hydrophobic and tyrosine residues became exposed, those implied the hardness was increased. The texture, juiciness and overall acceptance scores were decreased significantly (P <.05) when pork back-fat was replaced beyond 50%. From the above, the use of sodium alginate solution instead of pork back-fat could transform protein structure and lowered fat and energy of frankfurters. • Fat content and energy were decreased when replaced pork back-fat by sodium alginate solution. • The physico-chemical and protein structure were affected by sodium alginate solution. • Added sodium alginate solution, increased β-sheet, β-turn and random coil content. • Sodium alginate solution can be utilized to reduce the fat content of frankfurters. [ABSTRACT FROM AUTHOR]