Study On Effect Of Polyphosphates On Processing Characteristics Of Beef

Phosphates have been used as food additives in meat processing. Phosphates possess versatile functionality:increasing pH and ionic strength, chelating metal ions, promoting dissociation of actomyosin to actin and myosin. However, disintegrating actomyosin is generally considered to be the role of pyrophosphate (PP). Dimer form when tripolyphosphate (TPP) added into meat is hydrolyzed to be by endogenous enzyme has also this efficacy. But, whether trimer form of phosphate alone is effective or not has not been proved conclusively. The influence of dynamic hydrolysis of phosphates in meat on functional characteristics of muscle proteins has not received concern. In our studies, firstly, actomyosin was purified from bovine longissimus dorsi, its tripolyphosphatase (TPPase) activity was completely inhibited by polyphosphatase inhibitor. It is to research that effect of sodium tripolyphosphate (STPP) hydrolysis or not on dissociation, gel characteristics, and rheological characteristics of actomyosin, in contrast to sodium pyrophosphate (TSPP). Secondly, the influence of hydrolysis of TSPP, STPP and polyphosphates blends with time on solubility, gel characteristics, rheological characteristics and emulsifying properties was studied. Finally, the effect of phosphate and muscle type on quality characteristics of beef emulsion-type sausage was researched. Following are the results.1Trimer form of phosphate has not the role of dissociating the actomyosinAfter actomyosin was purified, and the EDTA-Na2optional concentration of2.5mmol/L can inhibit fully TPPase activity was determined, we found that TSPP and TSPP from STPP enzymolysis all can dissociate actomyosin, and improve water holding capacity (WHC), gel strength and the final G’(storage modulus) value during thermal gelation. Whereas, STPP neither dissociated the actomyosin, nor improved WHC and gel strength and final G’ value, after TPPase activity was inhibited fully. Therefore, trimer form of phosphate has not the role of dissociating the actomyosin, and only when STPP is hydrolyzed to TSPP can play this role.2Effect of polyphosphates hydrolysis on processing characteristics of salt-soluble proteins from beefTSPP, STPP, polyphosphate blends A (TSPP/STPP/HMP=2:5:2) and polyphosphate blends B (TSPP/STPP/HMP=5:2:2) improved protein solubility, WHC, gel strength, emulsifying capacity and emulsifying stability, and weakened or disappeared the phenomenon of G’ concave change. The TPPase in protein solution hydrolyzed STPP constantly. With the continuous hydrolysis of STPP, protein solubility, WHC, gel strength improved continuously, and the rising degree of G’ value during the whole heating was increasing. The molecular shape of TSPP in protein solution with time didn’t change, thus, the function of TSPP was always stronger than STPP. The effect of polyphosphate blends A and polyphosphate blends B on solubility, gel characteristics and emulsifying properties of beef salt-soluble proteins is similar.3Effect of polyphosphates on quality characteristics of beef emulsion-type sausagePhosphate can increase WHC of meat, and improve the texture of meat processing products. Muscle type is also an important factor to affect the quality of gels meat products. The study found that: the gel strength and elasticity of sausage formed by white muscle were higher than red muscle, and color L*value was bigger than the red muscle, but the color a*value was lower than the red muscle. The process yield of sausage combined white muscle and polyphosphate blends B was the biggest. The total expressible fluid of the combination of white muscle and polyphosphate blends A was the least, and sensory characteristics of the sausage were the best. The mutual promotion between polyphosphates mixture and white muscle gave emulsion-type sausage the best water retention and the perfect sensory characteristics.