Sunflower Protein Concentrates and Isolates Prepared from Oil Cakes Have High Water Solubility and Antioxidant Capacity

Abstract

Increasing the applications of industrial byproducts is of great interest. Therefore, in the present study, sunflower oil cake from a local oil manufacturing company was used to obtain soluble protein concentrates and isolates with different content of phenolic compounds. All the extraction procedures evaluated resulted in concentrates and isolates with water solubility higher than 75% but with different chemical composition, color and physicochemical properties (i.e. surface hydrophobicity, thermal stability, and polypeptide composition). Since no extraction process led to a complete extraction of phenolic compounds, all the products exhibited antioxidant activity, which depended on the concentration of such compounds. Phenolic compounds give a dark color to sunflower protein concentrates and isolates; nevertheless their final color tone was more dependent on the conditions used in the preparation process than on the amount of phenolic compounds in the product. The results demonstrate the value of sunflower industrial oil cake as a source of proteins with high water solubility, good physicochemical properties and antioxidant activity.

The net contribution of dairy production to human food supply: The case of Austrian dairy farms

“…Possible protein (and fat) extraction rate c Aider and Barbana, 2011;DLG, 1997;Fischer et al, 2001;Salgado et al, 2011;Salgado et al, 2012;Shallo et al, 2001;Tan et al, 2011;Villanueva et al, 1999;Wang et al, 2005 Maize silage Potential starch extraction at different maturity stages b,c or harvested as maize grains a Baldwin et al, 1992;DLG, 1997;Stolp, 2004 a Identical factor for the human-edible fraction for protein and energy due to presumed usage of whole grain. b Two different factors for the human-edible fractions for protein and energy: human-edible fractions for protein are derived from the potential extraction rates for protein, whereas the human-edible fractions for energy are the sum of the amount of gross energy in the extractable starch and protein divided by the gross energy content of the feedstuff.…”

Effect of removal of phenolic compounds on structural and thermal properties of sunflower protein isolate

“…Thermal properties of sunflower protein isolates were determined using Differential Scanning Calorimetry (DSC Q100 V9.8 Build 296 New Castle, Del., USA) following the method adopted by Salgado et al (2011). Hermetically sealed aluminium pans containing 10-15 mg sunflower protein solution (20 % w/v) were scanned over a range of 20-120°C at a rate of 10°C/min.…”

Comparison of biological value and technological properties of oil seed proteins

“…Determination of protein products solubility were performed according to [30] using solutions with pH values from 2 to 10, adjusted with 1 N HCl or 1 N NaOH, and protein concentration 1 mg/1 ml. Prepared protein suspensions were mixed by shaker during 1 h. Suspensions were centrifuged for 30 min at 3,500g.…”

“…At the same time it was shown that protein isolates, prepared from sunflower oil cake, had very high solubility (above 80% at pH 8) [30]. For this purpose authors had suspended isoelectric protein pellet in water at pH 9 and suspension was dried lyophilization.…”

“…Salgado et al [30] had proposed that protein aggregation had resulted in decrease of surface hydrophobicity. On the contrary, it is possible, that high solubility and surface hydrophobicity of isolated rape proteins were associated with their disaggregation.…”