Functional Properties of Acylated Flax Protein Isolates (original) (raw)
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Functional properties of deamidated oat protein isolates
Journal of Food Science, 1987
Flaxseed protein isolates were prepared by sodium hexametaphosphate complexation and acylated with acetic or succinic anhydride to improve their functional properties. The degree of acylation of free amino groups was lower when succinic anhydride was used in place of acetic anhydride. The color of the acylated proteins became lighter as the degree of acylation was increased. Emulsification properties of protein preparations were improved due to acylation, particularly for succinylated products. While foaming properties of flax protein isolates were not improved by acylation, their solubility was markedly improved. Low degrees of acetylation improved fat binding capacity of flax protein isolates, but succinylation did not exhibit such an effect. Acylation also increased aromatic or surface hydrophobicity of the products, and the highest value was observed at the lowest degree of acetylation. The in-vitro enzymic hydrolysis of the isolated proteins was reduced due to the acylation process.
Functional properties of acylated oat protein
Journal of Food Science, 1984
Protein extracted from defatted oat (Auena sativa L., variety Sentinel) was acylated with acetic or succinic anhydride at levels of 0.05 and 0.20 g/g protein. Acetic anhydride was more reactive than succinic anhydride in modifying lysine groups. Total essential amino acid content was slightly lowered by acetylation but unaffected by succinylation. Gel filtration chromatography showed some dissociation of oat polypeptides by succinylation. Solubility, emulsifying properties and fat finding capacity were all markedly improved by acylation, and the effect was more pronounced with succinylation. Emulsifying capacity of meat was enhanced by blending with acylated oat protein. Water hydration capacity and foam stability were adversely affected by acylation. Results suggest that acylated oat protein may be a valuable functional ingredient in meat and other emulsion food products.
Effects of succinylation and deamidation on functional properties of oat protein isolate
Food Chemistry, 2009
The effects of two different modification methods (deamidation and succinylation) on the functional properties (solubility, water-and oil-binding capacity, foaming capacity and stability, emulsion activity and stability) of oat protein isolates were evaluated. Protein isolates extracted from defatted oat flour at alkaline pH were acylated by 0.20 g/g of succinic anhydride. The protein isolate was also modified using a mild acidic treatment (HCl, 0.5 N). Succinylation and deamidation improved solubility and emulsifying activity of the native protein isolate. Foaming capacity of oat protein isolate increased after deamidation, whereas succinylation decreased it. The deamidated and succinylated proteins had lower foam and emulsion stabilities than had their native counterpart. Water-and oil-binding capacity, in both modified oat proteins, was higher than those of the native oat protein isolate.
LWT - Food Science and Technology, 2006
Protein concentrate was prepared from jack bean (JNP) and it was modified by acylation using acetic (JAP) and succinic anhydrides (JSP). Proximate analyses revealed that moisture and ash content increased following acetylation and succinylation, while both acetylation and succinylation reduced percentage crude fat and protein. Acetylation and succinylation reduced protein solubility in the acidic pH range below the isoelectric point (4.5) of the protein concentrate but improved the solubility of the unmodified protein concentrate at the isoelectric point and pH range alkaline to the isoelectric point. Both acetylation and succinylation increased the water absorption capacity of unmodified protein concentrates at all levels of ionic strength investigated (0.1-1.0 mol/l). Acetylation improved oil absorption capacity whereas the tendency to absorb oil reduced after succinylation. Maximal emulsifying activity of native and modified proteins were obtained at pH 10. Emulsion stability of acylated proteins was higher than those of native proteins in the range of pH 4-10 but lower when the pH was 2. Foam capacity and stability of both native and modified proteins increased with increase in protein concentration. Foam capacity of modified proteins increased progressively with increase in pH from 2 to 10. Also, acylated protein derivatives had improved foam capacity over the native protein except at pH 2. Gelation capacity of both native and modified proteins was maximal at the region of isoelectric point.
Improved emulsifying properties of soy proteins by acylation with saturated fatty acids
Effects of acylation on emulsifying properties of soy proteins were investigated using a variety of saturated fatty acids. Beta conglycinin (7S), glycinin (11S), and acid-precipitated protein (APP) were acylated with activated fatty acid esters (6C-18C) to form covalent linkage between the carboxyl group of the fatty acid and the free amino groups of the protein. Reduction in the free amino groups of acylated 7S, 11S and APP resulted into the dissociation of the protein, indicating a structural change, as evidenced by the fluorescence spectra and the degree of modification. It was shown that the emulsifying activity (EAI) and emulsion stability (ES) of 7S and 11S were significantly improved (p < 0.05) upon acylation with all saturated fatty acids, whereas no change in EAI and ES for the acylated APP was observed upon attachment of short and long chain fatty acids. The fluorescence intensity was also remarkably affected by acylation showing significant changes in protein structure. Covalent attachment of fatty acids resulted into 1.4-2.2 and 1.1-1.8-fold increase in the oil binding capacity (OBC) of 7S and 11S respectively, however no changes in acylated APP. Acylated 7S showed 3.0-9.4-fold increase in the water binding capacity (WBC), with no change in acylated 11S, while acylated APP with longest chains showed low WBC. The surface hydrophobicity of 7S was significantly improved (p < 0.05) by acylation; no changes were observed in the acylated 11S. Furthermore, acylation decreased the surface hydrophobicity of APP. Thus, it was demonstrated that saturated fatty acids with adequate chain length are suitable candidates for the preparation of functional lipoproteins from soy proteins.
Food Chemistry, 2000
Mung bean protein isolate was acylated to various degrees by acetic and succinic anhydrides. Changes in functional properties (protein solubility index in dierent solutions, water and oil absorption capacities, emulsi®cation properties, foam capacity and stability), antinutritional factors (tannins, phytic acid and trypsin inhibitor) and in-vitro protein digestibility of acylated protein isolate were determined. The modi®cation rate with acetic anhydride was greater than with succinic anhydride. Succinylation sig-ni®cantly increased the protein solubility index in water and 1 M NaCl whereas acetylation decreased it in water. Acetylation and succinylation caused signi®cant increases in water and oil absorption capacities. Foam capacity and foam stability (up to 0.4 g anhydrides/g protein) were signi®cantly increased due to acylation. Signi®cant increase was observed in emulsi®cation capacity and emulsi®cation stability (up to 0.8 g acetic and 0.6 g succinic anhydrides/g protein) by acylation; however, emulsi®cation activity was signi®cantly decreased over 0.6 g anhydrides/g protein. Acetylation is more eective for reduction of antinutritional factors than succinylation. Also, acetylation is more eective in improving the in-vitro protein digestibility than is succinylation.
Food Chemistry, 1988
Protein extract from oat groats was acylated to various degrees with acetic and succinic anhydrides to produce acetyl protein concentrate ( APC ), and succinyl protein concentrate ( SPC ), respectively. With both the acylating agents, approximately 36% ( APC-37, SPC-35) and 76% of the e-amino groups of lysine were acylated, and changes in functional properties were monitored. Size exclusion-HPLC showed some dissociation of oat proteins with acylation. Nitrogen solubility, emulsifying properties, water hydration and fat binding capacities were improved by acylation, and the effect was more pronounced with succinylation. Although the nitrogen solubility of the blend (SPC-76 and whey protein concentrate, 1:1 ratio on protein basis) was slightly lower than that of the whey protein concentrate (WPC), the other functional properties such as emulsifying properties, water hydration, and fat binding capacities were improved in comparison with that of the WPC. The results suggest that a~Tlated oat protein and the blend may serve as a valuable.functional ingredient in emulsion food products.
Journal of The American Oil Chemists Society, 2008
A study was conducted to determine bioactivities of flaxseed (Linum usitatissimum L.; variety: Valour) proteins and their hydrolysates. Isolated flaxseed proteins were treated with Flavourzyme® at different levels of enzyme to substrate ratio (E/S) and hydrolysis time. The unhydrolysed proteins and hydrolysates were studied for angiotensin I-converting enzyme inhibiting (ACEI) activity, hydroxyl radical (OH·) scavenging activity and bile acid binding ability. Flavourzyme catalysed hydrolysis generated hydrolysates with a 11.94–70.62% degree of hydrolysis (DH). The hydrolysates (0.67 mg/ml) had strong ACEI activity (71.59–88.29%). The maximum ACEI activity containing hydrolysate exhibited an IC50 of 0.07 mg/ml (E/S: 1.5; Time: 12 h; DH: 11.94%). The OH· scavenging activity of the hydrolysates (0.5 mg/ml) was 12.48–22.08% with an IC50 of 1.56 mg/ml in the sample possessing maximum activity (E/S: 47.5; Time 0.7 h; DH: 24.63%). Both these activities were greater in hydrolysates with lower DH and higher peptide chain length (PCL) than those with higher DH and lower PCL. Hydrolysed flaxseed proteins (0.67 mg/ml) had no bile acid binding ability. The unhydrolysed proteins had no ACEI or OH· scavenging activity but demonstrated bile acid binding ability.
Food Science and Biotechnology, 2013
The effects of glycosylation of African yam bean (AYB) protein on its nutritional and physico-functional properties were investigated and compared with those of acylated species. Both glycosylated and acylated AYB protein had reduced amino acid content, but retained their nutritional viability. The UV-visible absorption spectra of modified AYB proteins showed that glycosylation did not affect the exposure of its aromatic residue to the hydrophilic environment, but the reverse was the case with acylation. Glycosylation reduced AYB protein thermal stability compared to acylation. Glycosylation of AYB protein enhanced its solubility and emulsifying activity index significantly (p<0.05) more than acylation in various aqueous ionic media but the reverse was the case with their foaming attribute in both ionic and pH media. Both modifications maintained the good gelling attribute of AYB protein. These physico-functional attributes on acylated or glycosylated AYB protein could serve as useful guide into their plausible application in food products development.