Evaluation of Rigor and Aging Process of Mutton Stored at Ice-temperature Based on Bio-impedance

Author:Wang Zheng Gang

Supervisor:jin zuo

Database:Doctor

Degree Year:2019

Download:23

Pages:93

Size:7068K

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The electrical impedance and quality of mutton stored at ice-temperature(-1±0.6℃)were determined including color,drip loss rate,shear force value,pH value,Cole-Cole plots,intracellular resistance(Ri),extracellular resistance(Re),cytomembrane capacitive(Cm),the tangent of dielectric loss angle tan(δ),polarization coeffecient(k)relaxation factor(a)form 0.3 to 14 day after slaughter.The correlation of meat quality characteristics and electrical impedance properties and trends of impedance were analyzed.Also,the effect of ice-temperature on bio-impedance of mutton was invested.A new rapid method were established for evaluating rigor and aging process of mutton in order to present the theoretical and data support of evaluating aging process of mutton for industrial production on line.The results showed that:The color a*,water holding capacity and tenderness of mutton of positive direction set were significantly better than those of negative direction set(P<0.05).pH value of positive direction set were lower than negative direction set(P<0.05)throughout the storage time.It was indicated that the quality of mutton of positive direction set were better than those of negative direction set.For the positive and negative direction set stored at ice-temperature,maximization of rigor was achieved at 48 h and continued until 72 h after slaughter;The process was resolution phase from 72 h to 7 day post-mortem;Mutton entered the aging process after 7 days of slaughter.The rigor and aging process of mutton stored at ice-temperature were prolonged.As the storage time increased,Ri and Rc of samples increased firstly then decreased greatly,and then decreased slightly as the storage time continued.The Cm,a,tanδand k of the samples exhibited a decreased trend throughout the ripening time.Cole-Cole models of mutton presented the semicircles with different diameters,which represented the characteristics of typical muscle tissue.The diameter decreased obviously from 0.3 to 14 day.The impedance of positive direction set were higher than negative direction group(P<0.05)at the same storage time.Analysis of variance results showed rigor and ageing process had significant influence on the electrical impedance propcrties(Ru,Re,Cm,tanδ,k)(P<0.05).It was also confirmed that electrical impedance properties of muscle can reflect rigor and ageing process including in the rapid phase,post-rigor phase,resolution,aging phase.It was indicated that there were high correlations(P<0.05)between impedance properties(Ri,Rc,Cm,tan6,k)and quality of mutton(the color a*,water holding capacity,tenderness,pH value)for the two sets at specific storage time,while the linear correlations were not significant at the rest of storage time.The mechanism regulation of electrical impedance properties during stored process at ice-temperature were invested.The results showed that mobility and distribution of three kinds of moisture(bound water,immobilized water and free water)and metabolism of energy had influences on intracellular resistance(Ri),extracellular resistance(Re).Hydrophobicity of myofibrillar surface,solubility of myofibrillar protein,secondary structure of myofibrillar protein had influences on intracellular resistance(Ri),extracellular resistance(Re)also.Degradation of muscles proteins had influences on intracellular resistance(Ri),extracellular resistance(Re),relaxation factor(a).Cytomembrane capacitive(Cm),the tangent of dielectric loss angle tan(δ),polarization coeffecient(k)affected by degradation of integrinβ1.Activation of the apoptotic enzyme caspase-3 indicated that both death and necrosis forms were involved in the changes of physiology and biochemistry in muscle tissue after slaughter,leading to changes in electrical impedance properties.Two kinds of weighting mathematies model(over satandard with weight method,coefficient of variation method)was used to evaluate rigor process of mutton utilizing the electrical impedance parameter,and fuzzy comprehensive evaluation model is founded.Two kinds of model can evaluate rigor and aging process by validation.Compared with fuzzy matrix model founded by the method of coefficient of variation,the fuzzy matrix model founded by the method of over standard with weight was higher in accuracy.These results reflect that electrical impedance properties measurement combined with fuzzy matrix model is a rapid and innocuous way for evaluating rigor and aging process of mutton stored at ice-temperature.