title: 'Laba' garlic processed by dense phase carbon dioxide: the relation between green colour generation and cellular structure, alliin consumption and alliinase activity.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Tao
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhou
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Luyao
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Hu
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Liao
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D013437:Carbon-Sulfur Lyases / Q000378:metabolism*; D011232:Chemical Precipitation; D002681:China; D018556:Crops, Agricultural / Q000737:chemistry / Q000201:enzymology / Q000648:ultrastructure; D003545:Cysteine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D005520:Food Preservatives / Q000737:chemistry*; D063427:Food Quality; D061353:Food Storage; D057141:Food, Preserved / Q000032:analysis; D005737:Garlic / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D006358:Hot Temperature / Q000009:adverse effects; D008855:Microscopy, Electron, Scanning; D010860:Pigments, Biological / Q000032:analysis*; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D011312:Pressure / Q000009:adverse effects; D011523:Protoplasts / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D012034:Refrigeration; D013997:Time Factors
chemical_list: D005520:Food Preservatives; D010860:Pigments, Biological; D010940:Plant Proteins; D002245:Carbon Dioxide; C006453:alliin; D013437:Carbon-Sulfur Lyases; C019243:alliin lyase; D003545:Cysteine
keywords: DPCD; SEM analysis; alliin consumption; alliinase activity; garlic greening