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

Occurrence and Characteristics of Oils and Fats

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 influence of temperature on the oil content and composition of sunflower was studied on plants grown under field conditions and in a range of controlled environments. Traces of oil were detectable in cypsela (seed) almost immediately after pollination. Much of this appeared to be present in the hull (pericarp), which is well developed at this stage. Significant production of oil commenced with the development of the embryo about 150 day-degrees after pollination, and the oil content reached a maximum value just prior to physiological maturity of the seed. Linoleic acid constituted the major component of the oil at all stages of seed development, and under favourable temperature conditions increased from c. 50% soon after pollination to over 70% at physiological maturity. High temperature during the development of the seed was associated with a reduction in total oil yield. However, under field conditions this effect was variable owing to confounding with other environmental factors such as moisture stress, which also influence the yield of oil through their effects on growth and development of seed. Elevated temperatures, and in particularly high night temperatures, caused a marked reduction in the percentage of linoleic acid, apparently due to the effect of temperature on the activity of the desaturase enzymes which are responsible for the conversion of oleic to linoleic acid. These results support the hypothesis that reduced yields and altered composition of sunflower oil from crops matured under high temperature conditions in midsummer are due to the effects of heat stress on the biosynthesis of fatty acids.

Influence of temperature on oil content and composition of sunflower seed

Based on production volume and value and on per capita consumption, shellfish are an important food group in the United States. The nutrient composition of shellfish indicates that this food group is low in fat and relatively high in protein. Tabulated data on fatty acids in the different edible portions of seven species of crustaceans and over twenty species of mollusks are presented. The proportionately high level of polyunsaturated fatty acids is shown by the polyunsaturation index calculated for some important species of shellfish.

Comprehensive evaluation of fatty acids in foods.

Comparative data are provided on the composition of achenes from sunflower varieties Armavirec, Peredovik, VNIIMK 8931, Smena, Krasnodarets, Arrowhead and Mingren. Handseparated achene components were analyzed. Kernel oil from seed raised in northern United States or southern Canada typically contains about 70% of linoleic acid. In addition to other common acids, traces of C17, C20, C22, C24 acids and linolenic acid are present. The amino acid composition of sunflower kernel protein suggests that the meal may be a valuable ingredient of high-quality feed or food materials. The hull is primarily cellulose, lignin and pentosans; hull lipid and protein differ in composition from the corresponding kernel constituents.

T. F. Clark

Papers

Compositional data on sunflower seed