Certain functional properties including water absorption, fat absorption, emulsification, whippability and foam stability were determined on the sunflower flour, protein concentrates and isolate. The results were also compared to those obtained on soy products. Data on water and fat absorption studies suggest that soy products are more hydrophilic in nature while sunflower material exhibited greater lipophilic properties than the soy products. Emulsification tests showed that sunflower flour was superior to all other soy and sunflower products. In general, whipping properties of soy and sunflower isolates were similar, while less whippability was observed for the soy flour and protein concentrates. Whipped foams produced by soy and sunflower protein isolates and sunflower flour were more stable than soy flour, soy and sunflower protein concentrates.

Certain functional properties of sunflower meal products

There is increasing worldwide demand for proteins of both animal and plant origin However, animal proteins are expensive in terms of both market price and environmental impact Among alternative plant proteins, sunflower seeds are particularly interesting in view of their widespread availability in areas where soy is not or only sparsely produced Compared with other sources of vegetable proteins, sunflower seeds have been reported to have a low content of antinutritional factors Although the absence of these factors is important, the functionality of the protein preparations will mainly determine their applicability This review provides detailed information about sunflower seed composition and processing, including processes to remove phenolic compounds from meals The main part of the review concerns the structure and functionality of the two major protein fractions, helianthinin and 2S albumins Regarding functionality, emphasis is on solubility, thermal behaviour and surface activity Protein structure and functionality are discussed as a function of extrinsic factors such as pH, ionic strength, temperature and the presence of other seed components, particularly chlorogenic acid In addition, sunflower proteins are compared from a structural and functional point of view with other plant proteins, particularly soy proteins

Sunflower proteins: overview of their physicochemical, structural and functional properties

The functional properties of rapeseed meal, flours, protein concentrates and isolate were evaluated in comparison with those of soybean. Generally, rapeseed products were lower in protein but higher in crude fiber and ash contents than the corresponding soybean flour, concentrate or isolate, Rapeseed flours were comparable to soybean flour in water absorption but showed much higher nitrogen solubility, fat absorption, oil emulsification, whippability and foam stability. The viscoamylograph curves for rapeseed flours were characterized by intermediate peak and high cold viscosities, but their gelation properties were poor. Unfortunately, flour from the low glucosinolate cultivar, Tower, contained 1.2 mg/g of glucosinolates, primarily oxazolidinethione, and only the detoxified concentrates and isolate would be safe for human consumption. Rapeseed concentrates and isolate showed excellent water-and fat-holding capacity and the isolate was high in oil emulsification and whipping characteristics. While superior to soybean products in most functional tests, the utilization of rapeseed products may be limited by green or brown colors in the aqueous slurries.

Functional propreties of rapeseed flours, concentrates and isolate

Flaxseed (Linum usitatissimum L.) is an oilseed used in industrial and natural health products. Flaxseed accumulates many biologically active compounds and elements including linolenic acid, linoleic acid, lignans, cyclic peptides, polysaccharides, alkaloids, cyanogenic glycosides, and cadmium. Most biological and clinical studies of flaxseed have focused on extracts containing α-linolenic acid or lignan. Other flaxseed compounds have received less attention and their activity is not well described. The benefits of consumption of whole flaxseed fractions such as oil, mucilage and protein indicate that consideration of the entire portfolio of bioactives present is required to associate biological activity with specific compounds.

A. Bakal

Papers

Isolated Proteins from Rapeseed, Flax and Sunflower Meals