Properites of malva nut scaphium scaphigerum mucilage and its effects on properties and microstructures of normal and low fat meat emulsions

Abstract

The alkaline extracted gum from malva nut (Scaphium scaphigerum) contained 83.1% carbohydrate, 8.4% ash, and 8.3% protein. The monosaccharide compositions of the gum were 17.1% arabinose, 15.1% galactose, 15.0% rhamnose with the molar ratio of 1.00 : 0.21 : 1.24 and small amounts of glucose, xylose and mannose. The gum also contained 6.4% uronic acid. The average molecular weight (Mw) and intrinsic viscosity (eta) of the gum were 6.65 x 10[superscript 6] Da and 10.0 dl/g, respectively. Dialysis or dialysis plus decoloring with 30% H[subscript 2]O[subscript 2] at pH 9 reduced Mw and eta of the gum. The FT-IR spectrum of the alkaline extracted gum revealed the loss of methyl esterifed carboxyl group. The 0.1 to 4.0% purified malya nut gum (PMG) solutions had the shear thinning behavior over a range shear rates of 0.01 to 1000 s[superscript -1]. The 0.5 to 4.0% PMG solutions exhibited a weak gel structure with G' (storage modulus) being higher than G'' (loss molulus) over the entire frequency ranges from 0.01 to 10.00 Hz. However, both G' and G'' showed appreciable frequency dependence, especially for the 0.5% PMG. The addition of 5 to 15 mM CaCl[subscript 2] to 1.5% PMG solutions did not change the values of G' and G''. All 1.5% PMG gels with 5 to 15 mM CaCl[subscript 2] did not melt within the temperature range studied (10-60 ํC). Furthermore, effects of crude malva nut gum (CMG) and PMG on qualities of lean meat batters and meat emulsions were studied. In the lean poultry meat batters, increasing the salt level resulted in an overall increase of cook yield, and the addition of 0.2% CMG further improved yields at all salt levels. However cohesiveness and chewiness were reduced. Addition of CMG and STPP resulted in more stable batters. Furthermore, increasing salt level, along with the addition of 0.1% PMG, was beneficial in reducing the cook loss of lean chicken meat batter. At all salt levels, batters with PMG showed lower springiness comparing to batters without PMG. Batter with 2% salt, 0.5% STPP and 0.1% PMG showed lower fracture force, fracture distance, springiness and chewiness comparing to batter with only 2% salt and 0.5% STPP. In addition, the effects of CMG and PMG on qualities of the meat emulsions were in vestigated. Firstly, for the mechanically deboned chicken meat (MDCM) emulsions, the emulsions with 0.2% CMG or 0.6% CMG and 0.5% STPP had the lower cook loss when compared with the emulsions containing only CMG and the emulsion without CMG and STPP. Addition of 0.5% STPP decreased fat loss and improved stability of the MDCM emulsions. Secondly, for the emulsions from chicken breast meat, the addition of PMG or CMG reduced cook losses of the emulsions. The emulsions with PMG and STPP had lower fat losses when compared with the emulsion without malva nut gums and STPP. The addition of PMG and STPP resulted in more stable emulsions. The emulsions with 0.1% PMG or 0.3% PMG and 0.4% STPP showed higher values of hardness, springiness, cohesiveness and chewiness comparing to the emulsions wht only PMG. Furthermore, G' of the emulsions during cooking between 30 ํC to 70 ํC and cooling from 70 ํC to 30 ํC increased by the addition of PMG, CMG or STPP. For the chicken frankfurters, the frankfurters with 0.2% CMG had lower cook loss and better textural properties than the frankfurters without CMG. Sensory analysis results indicated that the frankfurters with 0.2% CMG were the most acceptable. Addition of CMG or PMG resulted in darker color of all poultry meat samples. Overall, this study indicated the potential use of malva nut gums for improving yield and stability of the lean meat batters and meat emulsions.