The Research Of Change Rule About The Phenolics Of Litchi Pulp In Browning And Microbial Transformation

Litchi is known as the south characteristic fruit with its bright color, good taste, good nutrition. Litchi is highly resistant to storage, due to the effect of its own material. In recent years, Chinese rapid economic development puts in motion many industries, including litchi industry. But litchi industry appeared the problems of excess production, and lagging processing under the economic model. In order to solve the problems above, litchi can be made the litchi juice. But the polyphenol may make the juice browning; the production may also bring large number of by-product. This study is about the polyphenols in litchi fruit pulp, litchi juice Browning in storage and microbial transformation of polyphenols in litchi slag. The main conclusions are as follows:Litchi pulp contains a variety of classified material. This study has identified free phenol and combined phenol of litchi fruit pulp by the HPLC- MS and found that: Seven kinds of free phenol, kaempferol-3-O-rutinoside, quercetin-3-rutinoside-7-rhamnoside,kaempferol-3-O-rutinoside- rhamnoside, narcissoside, rutin, quercetin, kaempferol. The quercetin- 3-rutinoside- 7- rhamnoside is the highest polyphenol in. Now, this study just determined the 9 structural formula of combined phenol C15H14O7, C15H20O9, C15H20O9,C11H16O2(caffeic acid), C17H24O3, C14H20O2, C11H14 O, C11H22O3, C19H32O4.The degree of browning of the group of DMDC joint Nisin processing is higher than the group of heat treatment. Comparing the change rule of the main phenols during storage,the study shows that the polyphenols oxidative degradation is the main factor of Browning.Because the content of polyphenols of Feizixiao is higher than Huaizhi, so the juice of Feizixiao is easier to brown.The litchi cloudy juice of ultrahigh pressure processing had the minimum color change and Browning. The degree of combined phenols change was higher than the free phenols. The degree of cloudy juice browning was higher than the group of clear juice,which shows that the suspended solids in litchi juice played a delay effect in browning of litchi juice.Researched 8 kinds of microorganisms(Actinomucor elegans, Aspergillus oryzae,Rhizopus, Trichoderma lignorum, Candida lipolytica, Bacillus subtilis, Bacillus subtilis subspecies, Bacillus cereus), the result showed that the transformation capacity of Actinomucor elegans is biggest, and it could make the content of litchi slag combined phenols down 11.12%. Bacillus subtilis could degrade 8.46% combined phenols. Candida lipolytica could not transformate the combined phenols or the transformation ability was not significant. The rest of the microorganisms showed weaker transformation ability.