15E-17 |
Mechanical fractionation and storage of flaxseed |
K. TOSTENSON1, N. Kangas1, D. Wiesenborn1, and C. Hall, III2. (1) Agricultural & Biosystems Engineering Dept., North Dakota State Univ., Pilot Plant, 1533 17th St. N., Fargo, ND 58105, (2) Cereal Science Dept., North Dakota State Univ., 324 IACC, Fargo, ND 58105 Recently, flaxseed has gained recognition as a food ingredient due to potential health benefits associated with flaxseed consumption. The hull is rich in fiber and the lignan, secoisolariciresinol diglucoside (SDG); and the embryo contains oil high in alpha-linolenic acid, an omega-3 fatty acid. Previous bench-scale trials demonstrated that an abrasive method of dehulling flaxseed gave favorable results. Our objectives in recent studies were 1) to increase the yield and purity of hull and embryo fractions and also process capacity, and 2) to examine storage effects on the fractions produced. A continuous abrasive process was utilized to separate Omega flaxseed. Percent oil of the fractions was measured and used as a guideline for degree of separation. Whole flaxseed; whole, ground flaxseed; hull and embryo fractions; and steam-cooked/ ground flaxseed were subjected to a six-month storage study, which included a comparison at room temperature in closed containers versus an elevated temperature (40°C) in open containers. Oxidation products were quantified using peroxide value, conjugated dienoic acid content, and free fatty acid content. Our highest fractionation results gave hull and embryo fraction yields with nearly 30 and 32%, respectively at 3.8 kg/h. Increased capacity lowered embryo and hull fraction yields. Storage study results showed a significant increase in peroxide value and conjugated dienoic acid but relatively little change in the free fatty acid content of the steam-cooked flaxseed. The oil in the hull fraction was slightly less stable than the oil from the embryo, whole intact flaxseed, or the whole, ground flaxseed in accelerated storage. These results suggest that abrasive mechanical fractionation is an effective method for separating flaxseed into hull and embryo portions. However, the methods of storage and handling are critical for preventing oxidation and loss of the potential benefit as a food ingredient.
Session 15E, Nutraceuticals & Functional Foods I
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