Laccase-catalyzed conjugation of potato protein (PPT) with selected pectic polysaccharides (PPS): Conjugation efficiency and emulsification properties

•Laccase-catalyzed conjugation of PPT and 5 PPS was studied for the first time.•The conjugation was dependent on the ferulic ester content of PPS and their structure.•Heteroconjugation can be promoted by modulating the reactivity and the ratio of biopolymers.•Developed predictive models for conjugation extent and emulsification performance.•Importance in controlling conjugation extent towards good emulsification performance. The current study focused on the investigation of laccase-catalyzed conjugation of potato protein (PPT) with selected pectic polysaccharides (PPS) and modulation of the conjugation in order to obtain desired functional ingredients. PPS, including sugar beet pectin/arabinan, apple/citrus pectin and potato galactan, were evaluated as substrates in the conjugation reaction-catalyzed by laccases (Trametes versicolor-LacTv, Coriolus hirsutus-LacCh). LacCh exhibited a higher catalytic efficiency than LacTv. The reactivity of PPT/PPS and their ratio were determinants for their heteroconjugation. Both laccases exhibited the highest specificity towards the conjugation of PPT/sugar beet pectin. Predictive models were developed for conjugation efficiency and emulsification performance. The conjugation extent was negatively affected by the protein proportion and the protein proportion/enzyme concentration interaction; while the emulsification performance was positively correlated with the protein proportion and the protein proportion/reaction time interaction. This study contributed to the understanding of laccase-catalyzed conjugation reaction for the controlled synthesis of conjugated-PTT as functional ingredients.