The heat-induced gelation of egg albumen involves the unfolding and aggregation of denatured proteins to form a three-dimensional gel structure. The phenomenon is affected by several factors including protein concentration, pH and ionic strength, whose variations cause modifications in the rheological properties of the gels. The aim of the present study was to investigate the main and combined effects of protein concentration and pH on the gelation temperature, the colour and the mechanical characteristics of gels formed by thermal treatment of albumen-powder water dispersions. A two-factors experimental central composite design was used, processing to gels 13 albumen dispersions having different concentrations (from 7.9 to 12.1%) and pH values (from 2.76 to 11.24). A commercial high-gel albumen powder was used for experiments. Significant quadratic models were obtained for the Young modulus (p<0.001), the load at 20% strain (p<0.001), the colour components L* and a* (p<0.05), and the gelation temperature (p<0.05). The two factors affected in opposite ways both Young modulus and load of gels, having the concentration a major positive effect on the load. No quadratic effects were observed for the concentration. The pH, instead, showed significant quadratic coefficients (p<0.01) for the mechanical characteristics, the colour component a* and the gelation temperature, causing a neat curvature of the response surfaces. No linear interaction effects between pH and concentration were observed for any response. Unfortunately, the calculated models suffered from a significant lack of fit, indicating that the shape of the response surfaces did not fit enough the experimental points. This impairs the use of the models for an accurate prediction of gel characteristics. Anyhow the developed models give actual and useful indications about the effects of albumen pH and concentration on gel properties.
Application of a response surface methodology to study the gelling properties of egg albumen powder / M. Rossi, C. Alamprese - In: Egg : Bioactive Treasure / [a cura di] M. Korzeniowska, T. Trziszka. - Wroclaw : Wydawnictwo Uniwersytetu Przyrodniczego we Wroclawiu, 2014. - ISBN 978-83-7717-185-1. - pp. 35-35 (( convegno Wroclaw Banff Egg Forum tenutosi a Wroclaw nel 2014.
|Titolo:||Application of a response surface methodology to study the gelling properties of egg albumen powder|
ROSSI, MARGHERITA (Primo)
ALAMPRESE, CRISTINA (Ultimo)
|Parole Chiave:||Albumen powder ; gelling property ; response surface methodology|
|Settore Scientifico Disciplinare:||Settore AGR/15 - Scienze e Tecnologie Alimentari|
|Data di pubblicazione:||2014|
|Enti collegati al convegno:||Wroclaw University of Environmental and Life Science|
University of Alberta
|Tipologia:||Book Part (author)|
|Appare nelle tipologie:||03 - Contributo in volume|