Rheological and textural characteristics of low-lipid meat emulsions with hydrocolloids as binders

MARCHETTI LUCAS; ANDRÉS S. C.; CALIFANO A N

Rheology: Theory, Properties and Practical Applications

Nova Science Publisher

Año: 2012;

Changes in meat fat composition, mainly reducing saturated fatty acids (FA) and increasing mono and polyunsaturated FA, have been persistently recommended by nutritionists, thus, reduction of fat content in frankfurters and substitution of animal fat with vegetable or marine oils should result in a healthier product.  When low lipid sausages are formulated, fat is mostly replaced by water, consequently, additives have to be incorporated to improve not only texture but water holding capacity of the matrix as well.  In this chapter we compare the effect of a 1% addition of several binders (hydroxypropylmethylcellulose, HPMC, methylcellulose, MC, a mixture of 2k:1i  carrageenans, C, and a mixture of 2:1 xanthan-locust bean gums, XL) to meat emulsions formulated with 5% fish oil as lipid source. Two control formulations with beef tallow fat (FC) or fish oil without any binder added are included. The replacement of fat with fish oil had a strong impact on sausages texture. A reduction of 40.2% of hardness, measured by  Texture Profile Analysis (TPA) occurred when solid fat was replaced by fish oil.  Addition of XL or C gums gave the highest hardness, similar to fat control while adhesiveness was higher for OC, MC, and HPMC formulations. Temperature sweep curves showed a typical behaviour of thermal gelation of meat systems where the main component corresponds to the denaturation of myosin. As temperature increased bond-making led to structural changes that affected rheological properties increasing elastic moduli and decreasing loss tangent. Cooked batters behaved as viscoelastic solids at 25°C. G´ >> G´´ in the tested frequency range, with a minimum of the latter at intermediate frequencies and a plateau region in G´. Formulations containing mixtures of C or XL gums showed the highest elastic moduli, reflecting the formation of an important three-dimensional network with even more solid-like characteristics than FC; OC always had the less elastic behavior of all the formulations. The viscoelastic behaviour of the cooked systems was modelled according to the broadned Baumgaertel-Schausberger-Winter equation, to predict the mechanical relaxation spectra. An empirical superposition method was applied, using the inverse of the plateau moduli GN0 as normalization factors to obtain a single master-curve. It is interesting to mention that small strain results could be linked to the textural properties of the samples measured by TPA; a good correlation between GN0 and hardness was found.