On the viscosity behaviour of field bean protein isolates in dependence on their degree of acetylation

✍ Scribed by Schmidt, G. ;Schmandke, H.

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 342 KB
• Volume: 31
• Category: Article
• ISSN: 0027-769X
• DOI: 10.1002/food.19870310813

✦ Synopsis

The increase of apparent viscosity when protein concentration is raised becomes more and more distinctly pronounced with an increasing degree of acetylation and is displaced at lower protein concentrations. Investigations of the influence oftemperature on viscosity behaviour are therefore carried out on the basis ofcomparable initial viscosity. 20 min heat treatment at different temperatures shows that above 40 -C the order of magnitude of the temperature-induced increase in viscosity depends decisively on the degree of acetylation. With an increasing degree of acetylation there is a comparably stronger increase in viscosity. An increase of viscosity is also linked to increasing duration of the heat treatment. The higher the degree of acetylation, the greaterrelated to a defined duration of heat treatmentis the growth of viscosity. During the heating phase in cyclical temperature tests a viscosity maximum is formed at 60 C, which becomes more and more distinctly pronounced with an increasing degree of acetylation. From computerised evaluation of flow curves it is generally established that the complexity of flow properties increases with increasing degree of acetylation, increasing concentration of protein and the effect of heat.

' Delivered as a lecture on 11.--12. December 1984 at the 3rd Colloquium on 'Rheology and Texture of Foodstuffs' in Dresden, GDR