Underlying mechanisms and effects of ultrasound treatment on the gelling properties, sensory attributes and in vitro digestibility of κ-carrageenan contained frankfurters

Abstract

The study aimed to investigate the combined effect of κ-carrageenan (KC, 0.2 %, w/w) coupled with different ultrasound (US) treatment duration times (10, 20, 30, 40 and 50 min) on the gelling properties, sensory attributes and in vitro digestibility of frankfurters. The results indicated that the combination of US and KC exhibited effective outcomes in diminishing cooking loss and enhancing emulsion stability of frankfurters (P < 0.05). Meanwhile, the 20-min US treatment combined with KC demonstrated optimal enhancement of the textural characteristics of frankfurters, accompanied by the development of a denser meat protein gel network as compared to the incorporation of KC alone. Furthermore, US treatment for 10–30 min significantly improved the interior colour, springiness and flavour intensity of frankfurters compared to control. Moreover, the primary molecular forces in frankfurters treated with US treatment and KC were hydrogen bonds and disulfide bonds. In addition, US combined with KC compensated for the reduced in vitro digestibility of frankfurters caused by the addition of KC alone, mainly because the cavitation and mechanical oscillation effects induced by US promote the occurrence of hydrophobic groups of meat proteins and contribute to the binding of proteins to digestive enzymes. In conclusion, moderate US treatment (20 min) was identified as optimal, with extended treatment durations (40 and 50 min) leading to protein aggregation, which was detrimental to the quality of frankfurters.