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Effect of pigskin-originated gelatin on dough properties and bread characteristics, especially on bread staling was investigated in terms of starch retrogradation and water migration in the present study. Results showed that gelatin significantly improved bread qualities during storage. Compared with the control, 7-day staling rate of bread containing 0.5% and 1.0% gelatin decreased by 6.56% and 20.83% respectively, indicating gelatin retarded the staling process of bread. This retardation effect was related to starch retrogradation and water migration. The relative crystallinity decreased from 15.12%, 11.60% to 10.75%, which demonstrated the alleviation effect of amylopectin crystallization. Bread samples containing 1.0% gelatin had the lowest retrogradation enthalpy of 2.93 ± 0.24 J/g followed by 0.5% gelatin bread and the control group, further indicating that gelatin may induce less water available to form crystal lattice and restrict the migration of starch molecules. The 5-day moisture loss rate for the control group was highest with the values of 12.39%, which was 1.43% and 1.83% higher than that of bread with 0.5% gelatin and 1.0% gelatin, respectively. Water activity and T 2 relaxation results provided the information that gelatin inhibited water migration upon storage and gelatin interacted with bread components. However, the effect of gelatin on improving bread quality and retarding staling could not be reflected by the dough properties measured through farinograph, extensograph and rheometer. This study suggested gelatin from pigskin had great potential to be served as an effective bread improver. Image 1 • Gelatin enhanced the bread qualities significantly, especially retarding the staling process. • Gelatin hindered the chain reassociation of starch molecules during storage. • Gelatin interacted with bread components and restricted water transfer. • Dough properties showed gelatin might to some extent weaken the gluten network. [ABSTRACT FROM AUTHOR]

Effect of pigskin gelatin and its hydrolysates on overall changes that frozen dough underwent during storage was investigated. The results showed that gelatin from pigskin could fortified the frozen dough bread quality, embodying in larger bread volume, softer and more uniform bread crumb. Impact of pigskin gelatin on changes in the structure of gluten network in frozen dough was evaluated by different techniques. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed gelatin may inhibit the crosslinking of HMW macromolecules and entangle with SDS-soluble LMW proteins. The increased SDS-soluble proteins suggested a lower aggregation extent of glutenin macropolymer (GMP) caused by pigskin gelatin. However, the significant reduction in GMP depolymerization degree and thiol groups (-SH) content after 60-day frozen storage in presence of gelatin indicated the formation of a more resistant gluten structure against the distortion of ice crystals. There were no significant differences in the alteration of secondary structure and high-temperature stability between gelatin-depleted and gelatin-fortified groups. Nevertheless, the effect of pigskin gelatin on qualities of frozen dough was independent on its hydrolysis degree. Image 1 • Gelatin from pigskin fortified the frozen dough bread quality. • Effect of pigskin gelatin on qualities of frozen dough was independent on its hydrolysis degree. • Pigskin gelatin resulted in a lower aggregation extent of glutenin macropolymer. • Gelatin inhibited the crosslinking of HMW macromolecules and entangle with SDS-soluble LMW proteins. [ABSTRACT FROM AUTHOR]