Development of Near-Infrared Reflectance Spectroscopy to Estimate Oil Content in Safflower

Summary

The oil of safflower (Carthamus tinctorius L.) is a valuable oil for human nutrition. It contains a high amount of unsaturated fatty acids, in particular linoleic acid (up to 90 %).
There is a great demand for ecologically produced oil in Germany, though oil crops are cultivated on 2 % of the ecological acreage.
In Germany, hardly any variety test exists, moreover there has been no breeding efforts so far, although genetic variation in safflower is large. The aim of this study was the development of a rapid and non-destructive method to determine oil content in safflower seed using NIRS (Near-Infrared Reflectance Spectroscopy).
A total of 203 seed samples were scanned with NIRS to estimate the oil content. Intact seeds as well as milled seeds were tested. The reference values for calibration were obtained with the Soxhlet extraction technique.
The oil content analysed by Soxhlet ranged from 10% to 29.6%. NIRS-scanning of milled seed showed better values of calibration compared to intact seed (milled seed: coefficient of determination of calibration: RSQ=0.96, coefficient of determination of cross validation: 1-VR=0.93; intact seed RSQ=0.90, 1-VR=0.82).
These results show that NIRS appears to be a suitable, rapid method to estimate oil content in safflower.