Effect of Salt and Liver/Fat Ratio on Viscoelastic Properties of Liver Paste and Its Intermediates

• Published in: Food and bioprocess technology Vol. 7; no. 2; pp. 496 - 505
• Main Authors: Steen, Liselot, Fraeye, Ilse, De Mey, Eveline, Goemaere, Olivier, Paelinck, Hubert, Foubert, Imogen
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-02-2014; Springer Nature B.V
• Subjects: Agriculture; Biotechnology; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Crystallization; Emulsions; Food Science; Intermediates; Liver; Original Paper; Pasteurization; Properties (attributes); Proteins; Salts; Viscoelasticity; Liver pâté; Salt; Meat emulsion; Liver/fat ratio; Structure; Rheological properties
• ISSN: 1935-5130; 1935-5149
• DOI: 10.1007/s11947-012-1038-8

The effect of salt and liver/fat ratio on the viscoelastic characteristics of liver paste and its intermediates (liver batter and liver paste batter) were evaluated by applying dynamic oscillatory tests in order to obtain detailed insight into the structural organisation of those products and how the characteristics of the intermediates are related to those of the end product. Liver paste batters were prepared at liver/fat ratios of 35/35 (
w
/
w
) and 20/50 (
w
/
w
). Salt was added at 0 and 1.8 % at each ratio. Stress sweeps and frequency sweeps were executed to characterise the viscoelastic properties of liver batter, liver paste batter and liver paste. Both intermediates and liver paste were characterised as weak gel-like emulsions with
G
′ greater than
G
″.
G
′ and
G
″ of liver paste were higher in magnitude compared with both intermediates due to structure building during pasteurisation and cooling. Generally, the values of the viscoelastic parameters of liver paste batter and liver paste increased with the addition of salt. With salt, a stronger and more stable liver paste was obtained. This effect may be attributed to solubilisation of salt soluble proteins, making more liver proteins available to act as emulsifier. However, salt affected the viscoelastic properties of liver batter in the opposite way: a weaker structure was formed with salt. A higher liver/fat ratio (35/35 versus 20/50) only increased the viscoelastic properties of liver paste batter while liver paste was not affected. This is probably due to the crystallisation of the fat in the liver paste with a high fat/liver ratio, which besides the liver proteins, also aid to structure building of liver paste. However, a higher liver/fat ratio did increase the critical stress (
σ
c
) in both liver paste batter and liver paste with the formation of a more stable structure.