[Influence of technological processing on various nutritional characteristics of sunflower protein isolates]

The composition and nutritional value of sunflower meals and protein isolates were determined. One of the meals was an ordinary industrial one (HI) and the other (HL) was prepared at the laboratory from the same batch of sunflower seeds. The protein isolates were obtained from both meals (AHI and AHL, respectively) and from the original seeds (AS), by means of a process employing water extraction and precipitation at pH 4.3. Chemical analysis of both meals showed that their moisture, protein crude fiber and fat contents had no significant difference. Sulphur amino acids (g/16 g N) were higher in the isolates than in the flours. The HL flour, and the AHL and AS isolates had a higher proportion of available lysine (96.9%, 93.0%, and 92.4% respectively) than the HI flour and AHI isolate. This improvement of protein quality was attained by the employment of less drastic thermal treatments in their preparation, as compared with the treatments to which other materials were submitted.