'Laba' garlic processed by dense phase carbon dioxide: the relation between green colour generation and cellular structure, alliin consumption and alliinase activity.
BACKGROUND
'Laba' garlic is usually processed by soaking garlic in vinegar for more than 1 week during winter. It is popular for its unique green colour and tasty flavour. Greening is desirable and required for this product as its characteristic. Dense phase carbon dioxide (DPCD) had a significant effect on the greening of intact garlic (Allium sativum L.) cloves. The relation between green colour generation and alliin consumption, alliinase activity and the cellular structure of garlic, respectively, were investigated in this work. The effects of treatment time, pressure and temperature of DPCD were also analysed and discussed.


RESULTS
DPCD had a significant effect on the cellular structure of garlic cells. Garlic protoplast underwent greater morphological change after DPCD treatments at higher temperatures while the amount of precipitate increased with greater treatment time and temperature. Common trends on garlic greening and alliin consumption were observed except for DPCD treatment at 10 MPa and 65 °C. The alliinase activity decreased with increasing treatment time, pressure and temperature. It reached the lowest level at 13 MPa and 55 °C.


CONCLUSION
The formation of the green colour was a comprehensive result of DPCD on changing cellular structure, alliin consumption and alliinase activity. DPCD treatment at 10 MPa and 55 °C was the optimum condition for the greening of 'Laba' garlic. This work further facilitated the application of DPCD in the industrial production of 'Laba' garlic. © 2015 Society of Chemical Industry.
['Tao|Dandan|D|', 'Zhou|Bing|B|', 'Zhang|Luyao|L|', 'Hu|Xiaosong|X|', 'Liao|Xiaojun|X|', 'Zhang|Yan|Y|']
D002245:Carbon Dioxide D013437:Carbon-Sulfur Lyases D011232:Chemical Precipitation D002681:China D018556:Crops, Agricultural D003545:Cysteine D005520:Food Preservatives D063427:Food Quality D061353:Food Storage D057141:Food, Preserved D005737:Garlic D006358:Hot Temperature D008855:Microscopy, Electron, Scanning D010860:Pigments, Biological D010940:Plant Proteins D018517:Plant Roots D011312:Pressure D011523:Protoplasts D012034:Refrigeration D013997:Time Factors
alliin consumption alliinase activity DPCD garlic greening SEM analysis