title: Prediction of essential oil content of oregano by hand-held and Fourier transform NIR spectroscopy.
abstract: BACKGROUND
  In the framework of a breeding programme, the analysis of hundreds of oregano samples to determine their essential oil content (EOC) is time-consuming and expensive in terms of labour. Therefore developing a new method that is rapid, accurate and less expensive to use would be an asset to breeders. The aim of the present study was to develop a method based on near-inrared (NIR) spectroscopy to determine the EOC of oregano dried powder. Two spectroscopic approaches were compared, the first using a hand-held NIR device and the second a Fourier transform (FT) NIR spectrometer.
  
  
  RESULTS
  Hand-held NIR (1000-1800 nm) measurements and partial least squares regression allowed the determination of EOC with R² and SEP values of 0.58 and 0.81 mL per 100 g dry matter (DM) respectively. Measurements with FT-NIR (1000-2500 nm) allowed the determination of EOC with R² and SEP values of 0.91 and 0.68 mL per 100 g DM respectively. RPD, RER and RPIQ values for the model implemented with FT-NIR data were satisfactory for screening application, while those obtained with hand-held NIR data were below the level required to consider the model as enough accurate for screening application.
  
  
  CONCLUSIONS
  The FT-NIR approach allowed the development of an accurate model for EOC prediction. Although the hand-held NIR approach is promising, it needs additional development before it can be used in practice.
authors.affiliation: Agroscope Research Station, Research Department of Production and Plant Protection of Crops in Alpine Areas/Greenhouse Crops, Route des Vergers 18, CH-1964, Conthey, Switzerland.
authors.forename: Cédric
authors.initials: C
authors.lastname: Camps
authors.forename: Marianne
authors.initials: M
authors.lastname: Gérard
authors.forename: Mélanie
authors.initials: M
authors.lastname: Quennoz
authors.forename: Cécile
authors.initials: C
authors.lastname: Brabant
authors.forename: Carine
authors.initials: C
authors.lastname: Oberson
authors.forename: Xavier
authors.initials: X
authors.lastname: Simonnet
mesh_terms: D002138:Calibration; D017598:Efficiency, Organizational; D005513:Food Inspection / Q000295:instrumentation / Q000379:methods*; D057141:Food, Preserved / Q000032:analysis*; D016018:Least-Squares Analysis; D008954:Models, Biological; D009822:Oils, Volatile / Q000032:analysis* / Q000378:metabolism; D031341:Origanum / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D015203:Reproducibility of Results; D013045:Species Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000295:instrumentation; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation; D013557:Switzerland
chemical_list: D009822:Oils, Volatile
keywords: FT-NIR; PLS; essential oil content (EOC); hand-held NIR; oregano