Texture Perception Determined by Soy Protein Isolate and Inulin Addition in Potato Puree: Links With Mechanical and Microstructural Features

Abstract

KEYWORDSFlow behavior, long-chain inulin, microstructure, soy protein isolate, texture perception, trained and untrained panel 4 Corresponding ABSTRACTThis study evaluated the effect of adding soy protein isolate (SPI) and long-chain inulin (INL) blends with 10 different SPI : INL ratios on the textural, rheological and microstructural properties of freshly made and frozen/thawed potato puree. All the potato puree samples were subjected to a sensory texture profile analysis and a trained panel rated the intensity of six descriptors, while an untrained panel did the same on six selected frozen/thawed products. The main SPI : INL ratio effect remained significant for all the descriptors evaluated, when the analysis of variance was applied considering the untrained assessors as random effects. However, only trained panel scores for creaminess corresponded well with untrained assessor ratings. Rheological flow index values were linked with variations in perceived consistency, and geometric and surface textural attributes were explained by structural features such as the presence of INL crystallites and SPI coarse strands. PRACTICAL APPLICATIONSA potato puree (PP) serving of 200 g with added soy protein isolate (SPI) and/or inulin (INL) concentrations of 1.5-6% provides from 3 to12 g of SPI and/or INL, respectively. The presence of SPI strands is a dominant factor in texture perception of PP with regard to mouthfeel geometric attributes (visual graininess and fibrousness) and the after-feel attribute (mouth coating), while INL crystallites are the most important feature influencing creaminess. By adding small amounts of SPI (1.5%) together with INL at >3% increases the intensity of perceived creaminess, which was the most important descriptor in practical terms. In view of the foregoing, PP with ada'ed SPI and INL is a promising foodstuff for incorporating into a diet and in addition, even improves product structure.understanding texture perception would depend on a multidisciplinary approach considering sensory research, physiology and research into food structure.Basically, potato puree (PP) is formulated with native potato starch (Alvarez et al. 2009), and this starch-based food can be considered as a semisolid or soft-solid, viscoelastic material (Foegeding et al. 2011). Changing their composition by adding new ingredients would result in texture changes of the final product. Soy protein isolate (SPI) is an ingredient bs_bs_banner A journal to advance the fundamental understanding of food texture and sensory perception Journal of Texture Studies

Sensory Description of Potato Puree Enriched with Individual Functional Ingredients and Their Blends

“…The amount of each ingredient, either alone or in blends, that could be added to the PP control was based in previous studies (Alvarez et al . ,b, ). Code samples and composition of the seven PPs studied are presented in Table .…”

“…In each methodology, the seven PPs were served in white plastic vessels, coded with a three‐digit number, at a temperature of 55 ± 1C, as previous studies showed that this is the preferred temperature for PP consumption (Alvarez et al . ,b, ). After thawing, samples were brought up to 55C and kept at this temperature by placing them in a Hetofrig CB60VS water bath (Heto Lab Equipment A/S, BirkerØd, Denmark) prior to tasting, where water and product temperatures were monitored by T‐type thermocouples.…”

“…Potato purees (PPs) themselves make up a combined system of native potato starch, denatured milk protein, water and salt, plus added cryoprotectants (kappa‐carrageenan [ κ ‐C] and xanthan gum [XG]) as the product is intended to be frozen (Alvarez et al . ). Variations in the composition of PPs by adding new ingredients would produce noticeable differences in the physical and sensory properties of the final product (Bayarri et al .…”

“…In turn, assessors found that soy protein isolate (SPI) conferred excessive thickness and gave the PPs an unfamiliar taste and odor (Alvarez et al . ).…”

“…Previous sensory analyses showed that the preferred temperature for PP consumption was 55C (Alvarez et al . , ). Therefore, a problem for the assessment of these products is the preparation and heating processes and the necessity of serving the samples hot at homogeneous temperature for the whole panel in a sensory test.…”