Storage stability of milled flaxseed

Two samples of flaxseed, Linott and a mixture of several varieties, were mi lled and stored at 23 +/- 2 degrees C for 128 d in paper bags with plastic liners. Samples were evaluated at 0, 33, 66, 96, and 128 d for chemical, se nsory, and volatile indicators of quality. Neither the mixed variety nor Li nott samples showed a significant increase in peroxide values or conjugated double bonds throughout the 128-d storage period. Only the Linott sample s howed a significant increase in free fatty acids, which was likely due to t he presence of immature seed in the sample. Total volatiles increased with storage in the mixed variety sample but showed minimal change in the Linott sample. Overall, the levels of total volatiles in the milled flaxseed samp les were much lower than levels reported in stored vegetable oils containin g significantly lower levels of linolenic acid. Dienals, formed during poly unsaturated fatty acid oxidation, and hexanal, a compound used as an indica tor of oxidative deterioration, were found at very low levels in both sampl es and did not reach high levels throughout the 128-d storage period. A tra ined sensory panel could not detect any differences in the odor properties of fresh or stored milled samples. No differences in flavor could be detect ed between bread made with 0- and 128-d milled flaxseed. This study showed that milled flaxseed can be stored up to 4 mon at ambient temperatures with out noticeable changes in quality. The presence of endogenous antioxidants in the milled flaxseed may account for the stability observed.