Defatted Flaxseed Flour as a New Ingredient for Foodstuffs: Comparative Analysis with Whole Flaxseeds and Updated...

Flaxseeds are functional foods popular in current diets. Cold-pressing is a solvent-free method to extract flaxseed oil, resulting in a by-product-defatted flour.

This study compared whole flaxseeds and defatted flour (proximate composition, fatty acids, vitamin E, total phenolics and flavonoids, antioxidant activity, amino acids, and protein quality) and updated the composition of cold-pressed oil (oxidative stability, peroxide value, UV absorbance, colour, fatty acids, vitamin E, total phenolics and flavonoids, and antioxidant activity) to assess the nutritional relevance and potential for food applications of these samples.

The flour had higher ash (6% vs. 4%), fibre (36% vs. 34%), protein (28% vs. 16%), phenolics (205 vs. 143 mg gallic acid equivalents/100 g), and antioxidant activity than seeds (p < 0.05), so it should be valued as a novel high-fibre food ingredient with high-quality plant-based protein, as it contains all essential amino acids (106 mg/g) and a high essential amino acids index (112%), with L-tryptophan as the limiting amino acid. The oil, while low in oxidative stability (1.3 h), due to its high polyunsaturated fatty acids sum (75%), mostly α-linolenic acid (57%), contains a significant amount of vitamin E (444 mg/kg), making it a specialty oil best consumed raw.

The exploration of the flour as a minimally processed food ingredient highlights its role in supporting food security, circular economy, and sustainability goals, aligning with consumer preferences for natural, low-fat foods. Future research should investigate the bioactivity and shelf-life of the samples, as well as the bioavailability of compounds after digestion.