Stability of bioactives in flaxseed and flaxseed-fortified foods.

Key Findings

Bioactive ingredients in food have long been known to have cardioprotective properties. Dietary flaxseed possesses an abundance of several bioactive ingredients, including alpha-linolenic acid (ALA), the lignan secoisolariciresinol diglucoside (SDG) and dietary fiber. The aim of this review was firstly to identify the most abundant flaxseed bioactives with observed roles in CVD prevention and secondly, to define optimal processing and storage conditions that preserves the content of flaxseed bioactives in both its natural form and when it is fortified in food products. The investigators report that preservation of ALA and SDG, depends upon processing and storage conditions of the natural or functional food products. Bioactives in whole flaxseed are stable under a variety of preparation and storage conditions, however, the tissue bioavailability of ALA and SDG is reduced because of the hard intact seed coat. Milling, grinding or crushing flaxseed enhances plasma bioavailability of ALA and SDG. Grinding, however, increases the susceptibility of ALA to oxidation and incorporation into food products may offer a protective strategy. Thermal processing does not appear to alter the ALA or SDG content. Cooler temperatures appear optimal for longer storage times and more important, is how they are packaged.

ABSTRACT

Dietary flaxseed is being studied as an alternative or complementary therapy tomedications for reducing risk factors related to cardiovascular disease progression. The suggested benefits of alpha-linolenic acid (ALA) as an antihypertensive agent, of secoisolariciresinol diglucoside (SDG) derived enterolignans as antioxidants and estradiol mimetics and dietary fiber for its role in cholesterol lowering are just some of the potential benefits of consuming flaxseed. These studies have progressed from dietary studies involving animal models to largescale clinical trials with the ultimate goal of adopting its consumption by the general public. To promote adherence in long-term clinical trials and encourage its consumption by the general public, flaxseed in one of its various forms or as its isolated bioactive ingredients is either incorporated into food products, called functional foods, or sprinkled onto foods before consumption. The stability of these bioactives in any of these forms becomes crucial for its acceptance by these populations and in order to optimize its biological actions. The effects of the food matrix, food preparation processes and storage conditions are all factors that can influence bioactive stability and are discussed here.