| Spanish mackerel was the object of study.Firstly,we investigated the effect of different concentrations of ozone water rinsing on the color and aroma characteristics of Spanish mackerel surimi.Then the effect of ozone oxidation on the oxidative modification of myofibrillar protein and its effect on the gel properties and water holding capacity of the surimi were studied.Finally,we researched the changes of gel properties,water-holding capacity and the oxidation of myofibrillar protein in the surimi rinsed by ozone water during low temperature freezing storage.1.Spanish mackerel surimi was rinsed by different concentrations(0,2,4,6,8,and 10mg/L)of ozone water,to investigate its influences on the color and aroma characteristics of surimi.The results showed that the lightness and whiteness of surimi increased and the electronic nose responses of fishy smell obviously reduced with the increasing concentrations of ozone water after rinsing.The lightness and whiteness of the surimi rinsed with 6 mg/L ozone water(68.64 and 67.48)were significantly improved compared with the blank group(66.43 and 65.41).The electronic nose responses of fishy smell in surimi,including aromatic,ammonia,short-chain alkane,methyl and organic sulfur compounds,obviously reduced after rinsing by ozone water.The electronic tongue responses of bitterness obviously reduced that the bitter post-taste value decreased to 0.13 compared with the control group(0.84).Thirty-six kinds of volatile compounds were identified from the different surimi samples.The number of volatile compounds detected in Spanish mackerel surimi after rinsing in 0,2,4,6,8 and 10 mg/L ozone water were 27,12,10,11,18 and 14,respectively.The result of GC-MS demonstrated that the contents of volatile compounds in surimi rinsed by ozone water,such as aldehydes,alcohols,olefins,thioethers,alkanes compounds,decreased significantly.In conclusion,the color and aroma characteristics of the surimi improved by ozone water.2.Ozone water treatment could cause the protein oxidation modification of Spanish mackerel surimi.The results showed that the carbonyl contents of myofibrillar proteins in rinsed surimi increased by 25.63%,54.12%,62.03%(P<0.05),while the contents of total sulfhydryl groups decreased by 11.69%,21.81%,21.36%(P<0.05),with the increasing concentrations 6,8,10 mg/L of ozone water.The Raman spectroscopy indicated that the structure and conformation of myofibrillar proteins suffered changes after rinsing,including the decrease of a-helical relative content,the increase of β-turn,β-sheet,random coil content,and the exposure of tryptophan and tyrosine amino acid residues to the polar environment.SDS-PAGE plot showed that the cross-link and aggregation of myofibrillar proteins occurred in the rinsed surimi.The above results indicated that ozone water rinsing caused oxidation of the myofibrillar protein,which led to the changes of protein structural and conformational properties.3.After being chopped in a vacuum,Spanish mackerel surimi was heated in two stages(40℃/30 min,90℃/30 min)to form a gel.Effect of ozone water rinsing on the surimi gel quality was analyzed by the centrifuge loss,solubility,gel strength,texture,moisture distribution,micro-structure and protein electrophoresis.The results showed that the breaking force,gel strength,hardness and adhesive degree of the surimi gel increased gradually with the increase of ozone water concentration.The breaking power of the ozone water treatment of 2,4,6,8 and 10 mg/L increased significantly by 18.67%,21.92%,28.46%,24.42% and33.09%(P<0.05)compared with the blank group(69.71 g).The gel centrifugation loss with 6mg/L ozone rinsing decreased by 21.43%(P<0.05)compared group(P<0.05).As the concentration of ozone water increases,surimi gel can bind more water.The free water of surimi gel with 10 mg/L of ozone rinsing decreased by 52.94%(P<0.05)compared to the control group.At the same time,the gels treated with ozone water had more continuous,smooth and denser network structures than that of control group according to scanning electron microscope.In conclusion,the gel properties and water holding capacity of Spanish mackerel surimi were improved by ozone water.4.The effect of chlorogenic acid or propygallate on the protein oxidation and gel degradation of Spanish mackerel surimi rinsed with 8 mg/L ozone water during low temperature freezing storage(after pre-freezing at-80℃ storage at-18℃ for 0,30,60 and 90days).The results showed that the addition of CA and PG resulted in a slight decrease in surimi gel properties and water holding capacity.The surimi storage for 0 day in each group(0 mg/L OW(ozone water),8mg/L OW,8mg/L OW+CA,8mg/L OW+PG)of the gel breaking forces(g)was 223.13,252.04,185.15,208.91;the gel strength(g.mm)was 1223.82,1362.50,986.83,1119.83;the centrifugal loss(%)was 7.83,7.38,8.90,7.22,respectively.With the increase of storage time,the gelation properties of the surimi gradually decreased but the addition of antioxidants could inhibit the quality deterioration rate of surimi.Compared with the experimental group after 0 days of storage,the surimi(0 mg/L OW,8mg/L OW,8mg/L OW+CA,8mg/L OW+PG)in each group after 90 days of storage that the breaking power of decreased by 11.03%,21.42%,11.19% and 14.19%(P <0.05);the gel strength decreased by 13.81%,19.85%,11.46%,14.08%(P <0.05),and hardness decreased by 14.95%,22.69%,22.29%,11.58%(P <0.05).Moreover,CA and PG reduced the brightness and whiteness values of surimi gels.During storage,the addition of antioxidants can inhibit the protein oxidation of surimi.The surimi(0 mg/L OW,8mg/L OW,8mg/L OW+CA,8mg/L OW+PG)in each group after 90 days of storage that the carbonyl content of myofibrillar protein increased by 52.82%,36.10%,31.30%,28.60%(P <0.05).The whiteness value and aroma characteristics of Spanish mackerel surimi improved by rinsed ozone water.Ozone water rinsing caused oxidation of the myofibrillar protein,which led to the changes of protein structural and conformational properties.This slight oxidation did not change the rheological properties,but increased the gel properties and water holding capacity of the surimi gel.As the storage time increases,the gel properties,water holding capacity and protein oxidation of Spanish mackerel surimi decreased during the freezing storage.The chlorogenic acid or propygallate inhibited the carbonyl contents of myofibrillar proteins increased,but reduced the lightness and whiteness values of surimi gel during the freezing storage. |
PDF Full Text Request