Production and characterization of sunflower (Helianthus annuus L.) protein-enriched products obtained at pilot plant scale (original) (raw)
Related papers
Journal of The American Oil Chemists Society, 2011
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.
Composition and properties of partially hydrolyzed sunflower protein isolates
Ukrainian Food Journal, 2016
Partial enzyme hydrolysis of proteins is common method of modification of their functional properties. The characteristics of partially hydrolyzed proteins obtained from sunflower meal are presented in this work. Materials and methods. Proteins of sunflower meal were extracted in the presence of two proteases viz. neutral protease and Alkalase during 40 min. Partially hydrolyzed protein samples were prepared by isoelectric precipitation and next drying. The polypeptide composition of protein isolates were studied by polyacrylamide gel electrophoresis, degree of protein hydrolysis, amino acid composition, surface activity and functional properties were estimated. Results and discussion. The polypeptides of higher molecular weight (45-54 and about 32-35 kDa) were absent in polypeptide profile of partially hydrolyzed proteins either of proteases. At the same time they were abounded with 14-16 kDa polypeptides and polypeptides with molecular weight lower 14 kDa. Partially hydrolyzed protein samples had higher protein content, lower content of ash and carbohydrates as compared with the control sample. The biological value of sunflower protein isolates were limited by three amino acids-sulfur containing amino acids (methionine and cysteine) and lysine. The content of methionine, cysteine and lysine has been increased in protein samples obtained with neutral protease, relative to protein isolate. Differential scanning calorimetric analyze of protein samples have demonstrated that partially hydrolyzed samples contained undenaturated proteins, but their denaturation degree was higher compared with control samples. Partial hydrolysis of sunflower seed proteins have improved their solubility in pH range from 2 to 8, water holding, oil binding, foaming, emulsifying capacities and surface activity. Conclusions. Partially hydrolyzed protein samples had higher protein content, lighter color, lower degree of denaturation and better functional properties compared to the traditional protein isolates.
European Food Research and Technology, 2011
Sunflower protein extraction using sodium chloride solutions allows high extraction yields at pH ~6 while preventing oxidation and covalent binding of phenolic compounds to the proteins, which usually occurs under alkaline conditions. Since protein solubility is enhanced at high NaCl concentrations, isoelectric precipitation had to be adapted in the present study besides developing subsequent desalting steps. Precipitation losses decreased from 62 to 31% with increasing NaCl (0.6–2.0 mol/L) and protein concentrations of the solution (6–14 mg/mL) and decreasing pH of precipitation (pH 4.5–3.0). Maximum yields were achieved at low temperature (8 °C) and upon instant acid addition. After adsorptive removal of co-extracted phenolics from the protein extracts, overall protein yields were considerably higher after precipitation at pH 3.5 compared with 4.5, but only slightly higher after washing of the precipitates. The physico-chemical properties of the protein isolates did not differ significantly except for the marked protein denaturation upon precipitation at pH 3.5. From the proposed process, light-coloured protein isolates of high purity (>98%) are obtained, which are suitable for food use.
The functional properties of three sunflower protein concentrates having different content of phenolic compounds (mainly chlorogenic and caffeic acids) obtained from sunflower oil cake, a by-product of the oil industry, were evaluated. Sunflower protein concentrates exhibited high water solubility and moderate water-imbibing and water-holding capacities. It was possible to obtain foams and emulsions of different stability at different pH and ionic strength from these protein concentrates, as well as self-supporting gels produced by thermal induction. The presence of phenolic compounds not only conferred antioxidant activity and changed the color of protein products, but also reduced the water imbibing capacity of sunflower protein concentrates, the stability of the emulsions obtained, and the hardness of protein gels. In contrast, phenolic compounds did not modify the water holding capacity, their water solubility or their foaming properties. These results suggest that these protein...
LWT, 2018
The present study was carried out to enhance the functional properties of sunflower protein isolates near isoelectric point. Protein isolates were subjected to heat treatment at 80 °C for 5, 15 and min at three pH values (3.5, 4.5 and 5.5) and were evaluated for physicochemical and functional properties. It was observed that surface hydrophobicity and sulfhydryl content of sunflower protein isolate were lower near isoelectric point and increased with heat treatment. Highest hydrophobicity value of 123.27 was observed at pH 5.5 and heating time of 25 min. Higher particle size of 102.56 nm was observed at pH 4.5 due to aggregation of proteins and was further increased to 108.29 nm with heat treatment. SDS-PAGE analysis showed that heat treatment near isoelectric point did not cause hydrolysis of protein molecules. Heat treatment decreased the available lysine content of protein isolates at all the pH values studied. Functional properties like solubility, emulsification and foaming properties were lower near isoelectric point and showed increasing trend with heat treatment. Water binding capacity decreased with heat treatment near isoelectric point, while oil binding capacity increased with heat treatment near isoelectric point.
Food Hydrocolloids, 2017
The present work was aimed to investigate the effect of polyphenols on functional and rheological properties of protein isolates obtained from sunflower seed and kernel. Protein isolates were obtained from both dephenolized and undephenolized meals of seed and kernel by isoelectric precipitation. Protein isolates from dephenolized meals had higher percentage of proteins than protein isolates from undephenolized meals. Concentration of proteins in kernel protein isolates was higher as compared to seed protein isolates. The colour of kernel protein isolates improved considerably after removal of polyphenols, however, colour of seed protein isolates did not improve to a larger extent. Higher solubility, emulsion activity, emulsion stability, dispersibility, foaming activity and foaming stability were found in protein isolates obtained from dephenolized meal. Lowest values of these properties were obtained at isoelectric point and highest at alkaline pH. Water binding capacity was higher for protein isolates with higher phenolic content and further increased toward alkaline pH. Least gelation concentration was lower for protein isolates with higher percentage of protein and lower phenolic content. Polyphenols in protein isolates decreased their available lysine content and reduced both the storage modulus and loss modulus of protein dispersions and formed more viscous and less elastic gels.
Food Hydrocolloids, 2012
The aim of this study was to assess the potential activation of sunflower protein films with antioxidant and antimicrobial properties conferred by the phenolic compounds of sunflower seeds, which remain associated to the proteins used as starting material for film preparation. Two sunflower protein concentrates obtained from the residual pellet of oil industry were used, which had different content of phenolic compounds, mainly chlorogenic and caffeic acids. The film-forming dispersions and the films obtained were analyzed regarding their antioxidant properties (using ABTS, FRAP and PCL assays) and their antimicrobial properties (by agar disk diffusion tests). Phenolic compounds conferred important antioxidant properties to both dispersions and films, this activity being dependent on their content and their free or protein-bound nature. These compounds, however, did not confer their characteristic antimicrobial properties reported in previous studies, possibly due to their interaction with proteins and the pH of the film-dispersions. Since the antioxidant activity of phenolic compounds was preserved during the protein concentration process (inherent to the film formation), these protein matrices may be considered useful for protecting these bioactive compounds.
Characterization of enzymic sunflower protein hydrolyzates
Journal of Agricultural and Food Chemistry, 1993
Sunflower meal (SFM) proteins are denatured during the process of oil extraction, which greatly limits their functional and nutritional properties. Protein hydrolysates were prepared from defatted undehulled SFM by enzymatic hydrolysis using Kerase-a microbial neutral protease-as hydrolytic agent. The resulting protein hydrolysates contained 78.9-84.8% protein and were highly soluble over a wide pH range (2-10). Their chemical composition, molecular weight distribution, and biological protein quality (protein efficiency ratio) were also studied. The properties of the resulting hydrolysates make them potentially useful in the food industry for dietetic purposes or as special food ingredients.
Processes
The influence of freeze and convection (at 40 and 50 °C) drying on the physical, functional, and rheological attributes of sunflower protein (SP) and its hydrolysate (SPH) was investigated. Compared with convectively-dried samples, the lightness, turbidity, bulk density, and particle size values of the freeze-dried SP and SPH were substantially higher, but the browning index was lower (p < 0.05). Additionally, freeze-dried samples exhibited good solubility and foaming characteristics, whereas lower emulsion properties with the most pH values were observed. Furthermore, SPHs possessed higher solubility as well as foamability over SPs under varying pH values (2.0–10.0), whilst reduction in the emulsion activity index was clearly observed (p < 0.05). Convectively-dried powders exhibited greater viscosity and consistency coefficient; and significantly lower flow behavior index of dispersions, relative to the respective freeze-dried preparations, indicating that dehydration methods...