Viscoelasticity and microstructure of inulin-enriched mashed potatoes: Influence of freezing and cryoprotectants

The effect of the addition of inulin (0%, 1.5%, 3%, 4.5% and 6%) on viscoelastic properties and microstructure of fresh and frozen/thawed mashed potatoes (FMP and F/TMP, respectively) formulated without and with added cryoprotectants (kappa-carrageenan (κ-C) and xanthan gum (XG)) was investigated. Results showed that inulin concentration was the factor that set the minor difference among most of rheological properties, firmness and overall acceptability (OA) of the samples, whereas addition of κ-C and XG resulted in main differences between samples. Inulin effect on the thickening of the product was limited, which is mainly ascribed to a high heating temperature reached by the product during manufacture process inducing inulin hydrolysis. FMP samples presented more rigid structure than their F/TMP counterparts, although either inulin concentration or processing had much less significant effect on the viscoelasticity of the mashed potatoes containing cryoprotectants, evidencing the ability of this biopolymer blend to impart freeze/thaw stability.