title: Stability of hydroperoxide lyase activity from Amaranthus tricolor (Amaranthus mangostanus L.) leaves: influence of selected additives.
abstract: BACKGROUND
  Hydroperoxide lyase (HPL) has potential value for the flavour additive industry. Currently, the production and application of HPL suffer from stability problems. The objective of this study was to investigate the stabilisation of HPL preparation from Amaranthus tricolor leaves by the addition of selected chemical additives.
  
  
  RESULTS
  Amaranthus tricolor leaves were identified as a particularly rich source of 13-HPL activity. The addition of 100 g L(-1) sucrose and trehalose to microsomal HPL prior to lyophilisation could retain nearly 100% enzymatic activity, compared to only 20% for the lyophilised control. The lyophilised microsomal HPL containing sucrose maintained full activity for even 40 days storage at -20 degrees C. For HPL solution, glycerol was effective for long-term stability at -20 degrees C. Moreover, poyols (sucrose and trehalose) and amino acid (glycine) enhanced the thermostability of HPL, while KCl and polyol mannitol decreased the thermostability of HPL.
  
  
  CONCLUSIONS
  The flavour-producing enzyme HPL, found in the leaves of Amaranthus tricolor, was stabilised by the addition of chemical additives.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu Province, People's Republic of China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Long
authors.forename: Xiangzhen
authors.initials: X
authors.lastname: Kong
authors.forename: Caimeng
authors.initials: C
authors.lastname: Zhang
authors.forename: Yufei
authors.initials: Y
authors.lastname: Hua
mesh_terms: D000446:Aldehyde-Lyases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D027721:Amaranthus / Q000201:enzymology*; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004795:Enzyme Stability; D005421:Flavoring Agents / Q000378:metabolism; D005524:Food Technology / Q000379:methods; D005612:Freeze Drying; D005990:Glycerol / Q000737:chemistry; D005998:Glycine / Q000737:chemistry; D008861:Microsomes / Q000201:enzymology; D009994:Osmolar Concentration; D018515:Plant Leaves / Q000201:enzymology*; D010940:Plant Proteins; D013395:Sucrose / Q000737:chemistry; D013696:Temperature; D014199:Trehalose / Q000737:chemistry; D014675:Vegetables / Q000201:enzymology
chemical_list: D005421:Flavoring Agents; D010940:Plant Proteins; D013395:Sucrose; D003577:Cytochrome P-450 Enzyme System; D014199:Trehalose; D000446:Aldehyde-Lyases; C054540:hydroperoxide lyase; D005990:Glycerol; D005998:Glycine