SCIENTISTS have pinned down some of the possible reasons for a large number of oilseed rape samples last year failing to meet standards required for for human consumption.
As a result, the Home Grown Cereals Authority (HGCA) has advised growers to look at the timing of harvest, drying temperature and seed handling as all those factors appear to influence the free fatty acid (FFA) content in rapeseed oil.
The survey followed extensive problems with particularly high FFA levels recorded in Scotland last year with growers being penalised if their samples exceeded 2 per cent of FFAs.
FFAs are a concern for end users because they can make the oil unsuitable for human consumption and can also cause “foaming” in biofuels.
“Although this was a small, self-selecting survey, it indicates that harvesting too early or too late after desiccation can both increase the amount of free fatty acids,” said Dr Simon Oxley, HGCA senior research manager.
With most of the reported problems last year coming from Scottish grown crops, HGCA also looked at whether other factors such as variety or region had an effect on FFA levels but there was no conclusive evidence of this.
Earlier this year, the trade body representing oilseed rape buyers indicated they would be increasing their testing procedures before taking samples into store.