Enrichment of stirred yogurt with soluble dietary fiber from Pachyrhizus erosus L. Urban: Effect on syneresis, microstructure and rheological properties

摘要

Yam soluble fiber (YSF) extracted from Pachyrhizus erosus was added (1 g per 100 mL) to a stirred yogurt (SY_(ysf)). Its syneresis and microstructure properties were evaluated and compared to those of a stirred yogurt (SY_C) without added YSF. The SY_C yogurt exhibited a more compact casein micelle aggregates network than that of the SY_(Ysf) yogurt which was more open, relaxed and covered with fibrous structures attributed to the YSF components. The Theological analysis showed that the SY_(Ysf) yogurt had lower storage modulus (G') and loss modulus (G") values in the linear viscoelastic region than the SY_C yogurt, but its flow behavior was characterized by a lower flow index (n), higher consistency index (k), and higher yield stress (τ_0) than the SY_C yogurt. Incorporation of the YSF reduced significantly the syneresis and produced a more acceptable mouthfeel in the SYysf yogurt in comparison to the SY_C yogurt, indicating the viability of the process to obtain a commercial product.