Stability of a-Linolenic Acid and Secoisolariciresinol Diglucoside in Flaxseed-Fortified Macaroni

Research was conducted to determine the stability of secoisolariciresinol diglucoside (SDG) and a-linolenic acid (ALA) in flaxseed-fortified macaroni. Macaroni was fortified with whole ground flaxseed (GWF) at levels of 10% to 20% and then dried under low temperature (LT, 40 °C), high temperature (HT, 70 °C), or ultrahigh temperature (UHT, 90 °C). Macaroni was also fortified with 15% ground hull (GHF) or steam-treated whole ground flaxseed (GSWF) and dried under UHT. The dried macaroni was stored for 32 wk under ambient conditions. Approximately 80% to 95% of the SDG was recovered, indicating that SDG was stable during the 32-wk storage period. Total lipid and ALA levels in all flaxseed macaroni treatments remained unchanged throughout the 32-wk storage. This observation was consistent across the drying conditions and flaxseed addition levels. Conjugated diene (CD) values indicated that macaroni fortified with GWF did not oxidize significantly during the 32-wk storage for the macaroni dried under HT or UHT. However, a significant increase (P < 0.05) in CD values for macaroni containing 10% and 20% flaxseed and dried using LT was observed at the 32-wk storage period. Headspace volatile concentrations did increase over the storage period for macaroni containing GWF, but the increase was not significant. Significant increases (P < 0.05) in oxidation were found by 24 wk in GHF- and GSWF-fortified macaroni. GWF macaroni dried at UHT, HT, or LT could be used as a way to improve our dietary consumption of ALA and SDG. However, use of steam as a method to inactivate unwanted enzyme activity is not recommended. Author's Abstract.