不同复合磷酸盐添加量下牛肉糜理化特性研究

Effect of Compound Phosphate on Hydration,Structure and Rheological Properties of Beef Minced Meat

利用核磁共振仪(NMR)、扫描电子显微镜(SEM)、傅里叶变换红外(FITR)、旋转流变仪(DHR)等研究复合磷酸盐添加量(质量分数0~0.5%)对牛肉糜的水分分布、结构、流变学特性的影响。结果表明,随着复合磷酸盐添加量的增加,牛肉糜含水率增加、蒸煮损失减少、pH值增加,添加量在0.2%之后各指标基本保持稳定。添加量为0.2%时,与空白对照组相比,含水率增加了5.87个百分点,蒸煮损失率减少了8.58个百分点,pH值从5.7上升到6.4;复合磷酸盐可以缩短肉糜体系与结合水、不易流动水的横向弛豫时间T21、T22(p<0.05),说明复合磷酸盐的添加提高了对水的束缚能力。随着复合磷酸盐添加量的增加,蛋白网络孔洞更加密集,孔径更加细小。与热处理前相比,热处理后的牛肉糜α-螺旋、β-折叠相对含量上升,β-转角相对含量下降;热诱导凝胶形成后,随着复合磷酸盐添加量的增加,α-螺旋相对含量由34.34%降至26.76%、β-转角相对含量由17.41%增加至29.41%。添加复合磷酸盐会降低牛肉糜的储能模量、损耗模量和损耗角正切值,添加量为0.2%的处理组损耗角正切值在升温过程中变化最为剧烈。因此,复合磷酸盐使牛肉糜体系结构疏松,与结合水、不易流动水的结合程度增强,保水性提高,蛋白质二级结构趋于无序化。复合磷酸盐添加量为0.5%时,结构最为疏松;添加量为0.2%时,保水效果最显著。

Using nuclear magnetic resonance(NMR),scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FITR),rotational rheometer(DHR)and other methods to study the effects of different phosphate additions(mass fraction was 0~0.5%)on the hydration,structure and rheological properties of beef minced meat.The results showed that with the increase of compound phosphate content,the moisture content of beef minced meat was increased gradually by 5.87 percentage points,the cooking loss was decreased by 8.58 percentage points,and the pH value was increased from 5.7 to 6.4.The compound phosphate shortened the meat emulsion system T21 and T22(p<0.05),indicating that the binding ability to water was enhanced.As the amount of complex phosphate added was increased,the protein network pores were denser and the pore size was finer.After heat treatment,the relative content ofα-helix andβ-sheet was increased and the relative content ofβ-turn was decreased compared with beef minced meat before heat treatment.After the formation of heat-induced gel,the relative content ofα-helix was gradually decreased from 34.34%to 26.76%,and the relative content ofβ-turn was gradually increased from 17.41%to 29.41%,indicating that the complex phosphate made the beef prion protein system tend to be unstable.The addition of complex phosphate reduced the storage modulus(G′),loss modulus(G″)and loss tangent(tanδ)of beef minced meat.The tanδvalue of the treatment group with 0.2%addition of phosphate was the most intense during the heating process.It can be concluded that the composite phosphate can loosen the structure of beef minced meat,strengthen the combination with the combined water and the non-flowable water,improve the water retention,and the secondary structure of the protein tended to be disordered.When the addition amount of the composite phosphate was 0.5%,the structure was the most loose;when the addition amount was 0.2%,the water retention effect was most remarkable.