Submitted to: Journal of Texture Studies
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/1/2007
Publication Date: 8/1/2007
Publication URL: naldc.nal.usda.gov/download/2368/PDF
Citation: Cheng, E.M., Alavi, S., Pearson, T.C., Agbisit, R. 2007. Mechanical-Acoustic and Sensory Evaluations of Corn Starch-Whey Protein Isolate Extrudates. Journal of Texture Studies. Vol. 38(4):473-498. Interpretive Summary: The textural perception of foods during product development has traditionally been evaluated by sensory panels who are trained to develop descriptive attributes specific to the food products and rate them on those attributes. Although sensory panels can never be replaced, the product evaluation cycle can be shortened and some of the time and costs involved can be reduced by the use of appropriate instrumental measurements. Moreover, the sharing of data on product quality derived from standard instruments between different geographical regions can be more easily accomplished if sensory terms do not have to be translated. This study utilized mechanical properties and acoustic properties of expanded corn starch as they were crushed. Using signal and data processing schemes similar to those used in voice recognition technologies, the combination of mechanical and acoustic testing could distinguish crisp products with different sensory perception at high accuracy (93 to 97%).
Technical Abstract: To study the mechanism that relates sensory perception of brittle food foams to their mechanical and acoustic properties during crushing, corn starch was extruded with four levels (0, 6, 12, and 18%) of whey protein isolate (WPI) and two levels of in-barrel moisture (23 and 27%). Texture of the expanded extrudates was characterized by sensory panelists, and the corresponding force-deformation and acoustic signals were recorded using instrumental testing. The microstructure of the extrudates was measured non-invasively using X-ray microtomography. The microstructure and texture of the extrudates could be adjusted by changing the in-barrel moisture or WPI level. High correlations (R2 ranging from 0.708 to 0.996) were identified between sensory perception and mechanical properties. The combination of mechanical and acoustic testing could distinguish crisp cellular extrudates with different sensory perception at high accuracy (93 to 97%).