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Survey of current agronomic practices influencing free fatty acid content in oilseed rape during the 2012-2012 season


HGCA PROJECT REPORT 514

Survey of current agronomic practices influencing free fatty acid content in oilseed rape during the 2012-2012 season


by

Eleanor Marshall

 

HGCA, Agriculture and Horticulture Development Board, Stoneleigh Park, Kenilworth, Warwickshire CV8 2TL



Month 2004

Abstract

Introduction

  • High levels of free fatty acids (FFAs) in rapeseed oil were a problem in 2012, particularly in Scotland. HGCA and oilseed merchants and processors have worked in partnership to conduct a grower survey and review crop quality.
  • High levels of FFAs make oil unsuitable for human consumption and can also cause foaming in biofuels. Removing FFAs is a significant cost for processors and this is reflected in a lower price for growers.
  • This research looks at how region, variety, cultivation method, harvest method, drying method and storage method affected free fatty acid levels in oilseed rape during harvest 2012.

Conclusions and recommendations

  • Although weather was a major factor in the increase of FFA in 2012, there are practical steps growers can take to minimise the risk.

  • Attention to detail should be paid, and oilseed rape should be handled after harvest in a similar way to malting barley or any seed crop
  • Timeliness of harvest - this research has indicated that the time the oilseed rape crop is harvested can impact FFA content. Attention to detail regarding the interval between desiccation and harvest is required.
  • If the crop is harvested too early, it is at risk of immature seeds~

  • If the crop is harvested too late, it is at risk of pre-germination
    (Immature and pre-germinated seeds have been identified in the scientific literature as contributing to increased FFA content (Uppström et al., 1995))
  • Drying temperature
  • Care should be taken in selecting the temperature of the dryer

  • FFA content increases with an increase in dryer temperature
  • Ventilation of the rapeseed has a significant impact on FFA content
  • Rapeseed which was not ventilated recorded a higher FFA content

  • It is important that the crop is ventilated prior to drying, as any build-up of heat in the crop may significantly increase the risk of FFAs.
  • Varietal differences within the 2011/12 season have not been significant but ultimately more research is needed.

Further steps

  • HGCA and the industry agree that it is important to invest further in FFA research

    • Potential varietal differences could be tested by analysis of Recommended Lists material at harvest.

It is proposed the survey is continued for a further two years to confirm findings. The survey must be extended to the whole of the UK and, where possible, include samples where FFA hotspots have been identified.

 



 

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