Studies On The Reactivity Of Green Tea Polyphenol As Formaldehyde Capture Agent And Application In Squid Products

The great attention has been paid to volatile toxic aldehydes in the aquatic products,and formaldehyde problem in squid has became serious in China recently.There are few researches about control of formaldehyde in the aquatic products at home and abroad,so it is necessary to study the safety processing technology for controlling the formaldehyde content of squid products.Based on above reasons,the reactivity of green tea polyphenol as formaldehyde capture agent was studied,and then acute toxicity of green tea polyphenol-formaldehyde reaction products in mice was studied to provide safety guarantee for application of green tea polyphenol as formaldehyde capture agent in food.Finally,application of green tea polyphonel in the processing of squid products was studied to control the formaldehyde content.The reaction of green tea polyphenol with formaldehyde was studied under various pH value,reaction temperature and reaction time.The results suggested that the activity was the lowest at pH 3-4 and higher at strong acidic and alkaline conditions.Prolonging the time facilitated the reaction under the higher temperature.Three-level,three-variable Box-Behnken Combination experiment showed that pH was the most effect on reaction, followed by temperature.So the optimum condition for application is higher pH(＞7),higher temperature(＞60℃)and more time in permission scope.To further understand the reactivity of tea polyphenol with formaldehyde,the reactivity of various kinds of simple phenolic compounds and green tea caechins was examined,the results suggested that factor for reactivity with formaldehyde may be the presence of a phloroglucinolic A-ring structure,and the number of hydroxyl groups in the B-ring hardly affected the reactivity with formaldehyde.In contrast, (-)-epigallocatechin gatlate and(-)-epicatechin gallate,which have a galloyl moiety at the C-3 position,showed much higher reactivity than did the nongalloylated catechins.Acute toxicity of green tea polyphenol-formaldehyde reaction products in mice was studied,the results suggested that acute peroral LD₅₀ was 5.01g/kg body weight in female mice,the confidence limit was 3.44-7.30g/kg body weight,LD₅₀was 6.81g/kg body weight in male mice, the confidence limit was 4.41-10.5g/kg body weight,so it belonged to practically non-toxic class.Preliminary application of green tea polyphenol as formaldehyde capture agent in squid thread was studied.Various treatments such as immersion and cooking processing mode,immersion time,pH value of green tea polyphenol solution,concentration of green tea polyphenol solution,rehydration mode were researched.The results suggested that the optimum processing mode of squid product was immersion and cooking with green tea polyphenol solution,immersion time was 12 hours or so; concentration of immersion solution was 0.05%-0.15%,and then, rehydration of squid semifinished product with 0.05%green tea polyphenol solution could further reduce the formaldehyde content.But pH value had insignificant effect on formaldehyde content of squid product.Application of green tea polyphenol as formaldehyde capture agent in the processing of dried quid thread,sootiness squid ring,cooking squid strip.After application,formaldehyde content of jumbo dried quid thread, North Pacific Ommastrephes dried squid Shred,sootiness squid ring and cooking squid strip were 5.32mg/kg,5.81mg/kg,6.74mg/kg and 2.65mg/kg, there were all significant less than control sample and met the requirement of NY5172-2002.Green tea polyphenol had a little effect on the colour of jumbo dried quid thread which required further study,Green tea polyphenol had no significant effect on the colour or taste of N.P.Ommastrephes dried squid Shred,sootiness squid ring and cooking squid strip.