The Chemical Basis of Green Pigment Formation ('Greening') in Crushed Garlic (Allium sativum L.) Cloves

  • Lee, Eun-Jin (National Horticultural Research Institute, Rural Development Administration) ;
  • Cho, Jung-Eun (Department of Plant Science, College of Agriculture and Life Sciences, Seoul National University) ;
  • Lee, Seung-Koo (Department of Plant Science, College of Agriculture and Life Sciences, Seoul National University)
  • Published : 2006.12.31

Abstract

The chemical processes involved in the formation of green pigment in crushed garlic cloves were investigated based on the principle of pink pigmentation in macerated onions. Intact greening and non-greening garlic cloves were either left untreated or heated at $90^{\circ}C$ for 3 min to inactivate enzyme activities. First, a colorless ether soluble compound referred to as color developer reacted with glycine (among all free amino acids) in garlic to form a second compound insoluble in ether. The latter compound then reacted with formaldehyde to yield the green colored pigment. Alliinase activity was necessary for the production of color developer and for the development of green pigment. In greening garlic that had been heat treated, green pigmentation did not proceed due to the heat-inactivation of alliinase, but the addition of alliinase solution into the garlic homogenates restored the pigmentation. However, this phenomenon was not observed in non-greening garlic with or without heat treatment. Finally, the mechanism of green pigment formation in crushed garlicis similar to that of pink pigment formation in macerated onions.

Keywords

References

  1. Hong SI, Kim DM. Storage quality of chopped garlic as influenced by organic acids and high-pressure treatment. J. Sci. Food Agric. 81: 397-403 (2001) https://doi.org/10.1002/1097-0010(200103)81:4<397::AID-JSFA831>3.0.CO;2-R
  2. Bai B, Chen F, Wang Z, Liao X, Zhao G, Hu X. Mechanism of the greening color formation of 'Laba' garlic, a traditional homemade Chinese food product. J. Agr. Food Chem. 53: 7103-7107 (2005) https://doi.org/10.1021/jf051211w
  3. Kubec R, Hrbacova M, Musah RA, Velisek J. Allium discoloration: Precursors involved in onion pinking and garlic greening. J. Agr. Food Chem. 52: 5089-5094 (2004) https://doi.org/10.1021/jf0497455
  4. Lukes TM. Factors governing the greening of garlic puree. J. Food Sci. 51: 1577, 1582 (1986)
  5. Shannon S, Yamaguchi M, Howard FD. Precursors involved in the formation of pink pigments in onion purees. J. Agr. Food Chem. 15: 423-426 (1967a) https://doi.org/10.1021/jf60151a027
  6. Shannon S, Yamaguchi M, Howard FD. Reactions involved in formation of a pink pigment in onion purees. J. Agr. Food Chem. 15: 417-422 (1967b) https://doi.org/10.1021/jf60151a026
  7. Lukes TM. Pinking of onions during dehydration. Food Technol.-Chicago 13: 391-393 (1959)
  8. Bandyopadhyay C, Tewari GM. Thin-layer chromatographic investigation of color developer involved in pinking of white onion purees. J. Agr. Food Chem. 21: 952-954 (1973) https://doi.org/10.1021/jf60190a031
  9. Ahmed J, Pawanpreet, Shivhare US. Physico-chemical and storage characteristics of garlic paste. J. Food Process Pres. 25: 15-23 (2001) https://doi.org/10.1111/j.1745-4549.2001.tb00440.x
  10. Cho JS, Ku KH, Kim WJ. Effects of heating, pH, salts, and organic acids on color changes of ground garlic. Korean J. Food Sci. Technol. 31: 399-403 (1999)
  11. Krest I, Glodek I, Keusgen M. Cysteine sulfoxides and alliinase activity of some Allium species. J. Agr, Food Chem. 48: 3753-3760 (2000) https://doi.org/10.1021/jf990521+
  12. Imai S, Akita S, Tomatake M, Swada H. Identification of two novel pigment precursors and a reddish-purple pigment involved in the blue-green discoloration of onion and garlic. J. Agr, Food Chem. 54: 843-847 (2006) https://doi.org/10.1021/jf0519818
  13. Imai S, Akita S, Tomatake M, Swada H. Model studies on precursor system generating blue pigment in onion and garlic. J. Agr. Food Chem. 54: 848-852 (2006) https://doi.org/10.1021/jf051980f