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

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.

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.