Preparation Of Ozonated-ice And Its Application In The Fresh-Keeping For Squid

Ozone becomes widely used in the food industry due to its goodbroad-spectrum germicidal efficacy, non-toxicity, non-residual. But the ozonated-icepreparation was proved to be very difficult due to rather low solubility and stability ofozone in ozonated water. At the present, the reports on the preparation and stability ofozonated-ice are few yet. Therefore, in this thesis, the major preparation technics andthe stability theory of ozonated-ice was studied. Furthermore, the effects of ozonated-ice on the aquatic qualities was tested during storage.The main contents and results of this study are as follows:1Preparation of ozonated-ice with low-temperature alcoholThe effects of freezing medium, freezing temperature and acidity regulator onthe retention rate of ozone in ozonated-ice (the content of retention ozone inozonated-ice/the initial content of ozone in water) were studied. The results showedthat, by comparison to air freezing, freezing with low-temperature alcohol couldsignificantly(p≤0.01) improve the retention rate of ozone in ozonated ice. Acidityregulators improved the retention rate of ozone vs the blank control group, andphosphoric acid was the best selection. Using alcohol as freezing medium,0.1mol/Lphosphoric acid addition, freezing at-30℃, the retention rate of ozone reached up to51%.2Study on the stability and decomposition kinetics of ozone in ozonated-ice(1) The effects of acidity regulators on the stability of ozone in ozonated-ice at3℃were studied by monitoring the remained rate of ozone in ozonated-ice prepared withdifferent acidity regulators. The results showed that acidity regulator improved thestability of ozone vs the blank control group, and phosphoric acid is the bestcandidate.(2) The effects of pH on the stability of ozone in ozonated-ice at3℃were studiedby monitoring the remained rate of ozone in ozonated-ice. The results showed that inthe range of pH3~pH7, there was a positive correlation between the decomposition rate of ozone and pH. And the equation of decomposition kinetic of ozone inozonated-ice at3℃was given as A(t)=exp[-(0.0236pH+0.0183) t].(3) The effects of temperature on the stability of ozone in ozonated-ice at pH3werestudied by monitoring the remained rate of ozone in ozonated-ice. The results showedthat in the range of0℃~10℃, there was a positive correlation between thedecomposition rate of ozone and temperature. And the equation of decompositionkinetic at pH3was given as A(t)=exp[-(0.0085T+0.0706) t].3Study on the application of ozonated-ice in fresh-keeping of squidIn this study, the fresh-keeping effects of ozonated-ice on the qualities of squidwere tested at0℃~2℃storage. The results showed that compared to the blank controlgroup, the self-life of squid preserved with the ozonated-ice whose concentration is3.53mg/kg was lengthened up to4~5days, the total bacteria count, TVB-N and pHwere reduced significantly(p≤0.01), and the initial sensory quality was consequentlymaintained.