Cottonseed Protein Isolates Research Articles

Protein profiling of water and alkali soluble cottonseed protein isolates

Currently, there is only limited knowledge on the protein types and structures of the cottonseed proteins. In this work, water-soluble cottonseed proteins (CSPw) and alkali-soluble cottonseed proteins (CSPa) were sequentially extracted from defatted cottonseed meal. Proteins of the two fractions were separated by 4–20% gradient polyacrylamide gel electrophoresis (SDS-PAGE); There were 7 and 12 polypeptide bands on SDS-PAGE of CSPa and CSPw, respectively. These individual bands were then excised from the gel and subjected to mass spectrometric analysis. There were total 70 polypeptides identified from the proteins of the two cottonseed preparations, with molecular weights ranging from 10 to 381 kDa. While many proteins or their fragments were found in multiple bands, 18 proteins appeared only in one SDS-PAGE band (6 in CSPa, 12 in CSPw). Putative functions of these proteins include storage, transcription/translation, synthesis, energy metabolism, antimicrobial activity, and embryogenesis. Among the most abundant are legumin A (58 kDa), legumin B (59 kDa), vicilin C72 (70 kDa), vicilin GC72-A (71 kDa), and vicilin-like antimicrobial peptides (62 kDa). This work enriched the fundamental knowledge on cottonseed protein composition, and would help in better understanding of the functional and physicochemical properties of cottonseed protein and for enhancing its biotechnological utilization.

Sequential Fractionation of Cottonseed Meal to Improve Its Wood Adhesive Properties

AbstractFor better understanding of the adhesive properties of different fractions of cottonseed protein, cottonseed meals from both glanded and glandless cotton varieties were separated into several fractions. Each meal was sequentially extracted with water and 1 M NaCl solution, or with phosphate buffer and NaCl solution. Adhesives were prepared from the recovered fractions and hot‐pressed onto maple veneer strips and tested for their properties. The adhesive strength of the water‐ and buffer‐washed solid fractions (i.e., the un‐extractable residues of the meals) from the glanded seed ranged from 1.32 to 1.62 MPa and were unchanged or increased compared with the adhesive strength of the original meal that varied from 0.98 and 1.49 MPa. Soaking the wood specimens bonded at 80 °C revealed that the water resistance of these water‐ and buffer‐washed adhesives was significantly improved in that they exhibited no delamination during soaking compared with the meal adhesive that showed some delamination (20–30 % of the samples). Furthermore, the water resistance of these fractions with wet shear strength around 1.5 MPa was comparable to that of cottonseed protein isolate (>90 % protein) when the joints were bonded at 100 °C. The preparations from glandless cottonseed meals showed similar adhesive performances. Additional extraction of the meals with NaCl solution reduced adhesive performance. The results suggest that water‐ or buffer‐washed cottonseed meal fractions can be used as wood adhesives and would be less costly to prepare than cottonseed protein isolates.

Investigation of modified cottonseed protein adhesives for wood composites

Several modified cottonseed protein isolates were studied and compared to corresponding soy protein isolates for their adhesive properties when bonded to wood composites. Modifications included treatments with alkali, guanidine hydrochloride, sodium dodecyl sulfate (SDS), and urea. Wood composites bonded with cottonseed protein exhibited higher shear strength relative to modified or unmodified soy proteins. Cottonseed protein with SDS treatment gave comparable or better shear strength than unmodified cottonseed protein. Wood composites bonded with unmodified or SDS-modified cottonseed protein also showed superior retained strengths on a hot water test. Thus, a cottonseed protein adhesive (with or without SDS modification) seems to be a viable alternative to soy protein adhesives for wood composites.

Angiotensin I-converting enzyme inhibitor derived from cottonseed protein hydrolysate

Six proteolytic enzymes, including alcalase, flavourzyme, trypsin, neutrase, papain and pepsin, were employed to hydrolyze cottonseed protein to produce the hydrolysates of Angiotensin I-converting enzyme (ACE) inhibitory activity. The result indicated that the cottonseed protein hydrolysate (CPH) produced by papain had the highest ACE inhibitory activity. Therefore, papain was selected for enzymatic production of ACE inhibitor from cottonseed protein isolates (CPI). CPI was hydrolyzed with papain for 1 - 8 h, and the 6 h hydrolysate had the strongest ACE inhibitory ability. The product was separated into four ranges of molecular weight (UF-I, > 30 kDa; UF-II, 30 – 10 kDa; UF - III, 10 - 5 kDa; UF - IV, 2.43 kDa, 2.43 - 0.82 kDa, 0.82 - 0.35 kDa and <0.35 kDa, respectively. Fra II exhibited the strongest ACE inhibitory ability (IC 50 = 0.159 mg/ml) with the yield of 41.63%. It was suggested that Fra II with good ACE inhibitory activity can be a potential source of natural ACE inhibitor. Keywords: Cottonseed protein hydrolysate, peptide fractions, angiotensin I-converting enzyme inhibitory ability, ultrafiltration

Evaluation of the emulsifying properties of cottonseed protein isolates

Cotton is mainly cultivated for fiber production, but its seed is also very important as a source of proteins for human and animal consumption. In the present work cottonseed protein isolates (CPI) produced either by isoelectric precipitation (at different pH values) or dialysis through membranes, were evaluated for their emulsifying properties. The respective emulsion stability of the emulsions produced at pH 7.0 and 6.0, as well as the effect of polysaccharides (xanthan and pullulan) and different concentration of NaCl, on these properties, were evaluated. Emulsion stability was greater at continuous phase pH 7.0 than at 6.0. The addition of xanthan gum 0.1% w/v had a positive effect on emulsion stability while pullulan had a smaller positive effect. Addition of NaCl enhances emulsion stability at pH 7.0 and pH 6.0 until the concentration of 0.2M by increasing the solubility of proteins, which declined at higher concentrations. The physicochemical parameters used in the model systems (e.g. methods for CPI preparation, pHs of the continuous phase, values of the interfacial pressure, etc.) and viscoelastic parameters give us a picture (not always clear) for the conditions which should be used in order to increase the stability, against coalescence of the emulsion systems. A close parallelism was observed between emulsifying properties and the rheological characteristics of the absorbed films.

Evaluation of the foaming properties of cottonseed protein isolates

Cotton is cultivated mainly for fiber production, but it also produces seed which is an important source of proteins for human and animal consumption. In the present work cottonseed protein isolates (CPI) produced either by isoelectric precipitation or dialysis with membranes, where evaluated for their foaming properties. The respective foam ability and stability of the foams produced at pH 6.0 and 7.0, as well as the effect of polysaccharides (xanthan and pollulan) and different concentrations of NaCl, on these properties, were measured. Foam ability was greater at pH 7.0 than at pH 6.0. The addition of xanthan gum 0.1% had a positive effect on foam properties while pollulan had a negative effect. Addition of NaCl increased foam ability and stability at pH 6.0 until the concentration of 0.5 M by increasing the solubility of proteins, while both properties declined at higher concentrations. Surface tension and viscoelastic parameters of absorbed films greatly effected by the CPI production, pHs and concentrations. A close parallelism was observed between foaming properties and the rheological characteristics of the absorbed films.

A COMPARATIVE STUDY OF IRON BIOAVAILABILITY IN RATS FROM SOYBEAN AND COTTONSEED PROTEIN ISOLATE DIETS

ABSTRACTThe purpose of this research was to determine the relative iron bioavailability from soybean and cottonseed protein isolates by using an iron depletion/repletion method. Iron stores of rats were depleted so that any iron introduced in the diet would be utilized at a maximum and linear rate for hemoglobin regeneration. A comparison of iron utilization from cottonseed and soy to the reference standard could then be made. Between 40 and 47% of the iron consumed from the soy diet was converted to hemoglobin iron. The cottonseed diets had a significantly lower (29 to 34%) conversion efficiency (P &lt; 0.05) in comparison to casein but were not significantly different from the soy diets.

Preparation, evaluation and functional properties of gossypol-poor cottonseed protein isolates

The glanded cottonseed ( Gossypol barbadense, variety Ashmouni) was used in the present study. The location, distribution and properties of the most important constituents of the seeds, namely protein, oil and gossypol were examined. Four treatments were used to prepare gossypol-poor flour from the cottonseed. Treatment I depended on differential settling using fresh hexane in all different steps. The process was repeated to prepare different fractions of gossypol-poor flour. Treatment II was similar to I except that fresh hexane was used only in the first step and the produced oil-hexane miscella was used in the subsequent steps. Treatments III and IV depended on a combination of sieving (200 mesh sieve) and the differential settling process. For treatment III the residual flour was ground, sieved and used to prepare fractions of gossypol-poor flour using fresh hexane. The oil-hexane miscella was used in treatment IV. The four treatments can be arranged in the following decreasing order according to the amount of edible protein obtained from 100g of dehulled cottonseed: III > I > IV > II. Three protein isolates, namely A, B and D' were obtained from treatment III giving a recovery of 21.2% of edible flour from dehulled cottonseed, i.e. 66% of the original protein present in the Ashmouni cottonseed variety. The protein isolates obtained were evaluated for nitrogen extractability as well as some chemical, nutritional and physicochemical properties. The results illustrate the possibility of using the prepared protein isolates as thickening and whipping agents, emulsifiers and extenders in different food products.

Formulation of nondairy coffee whiteners with cottonseed protein isolates

AbstractNondairy coffee whiteners were prepared on a pilot scale using four different glandless cottonseed protein isolates prepared by different processes. Bulk density, whitening capacity, cream separation and oil retention capacity of the whiteners were compared to those formulated with sodium caseinate and a commercial whitener. Glandless cottonseed protein isolates, prepared by conventional and aqueous extraction processes, are poor ingredients for coffee whitener production, showing poor whitening capacity, separation of proteins through sedimentation and separation of fat as a cream layer in a mixture with aqueous coffee. Succinylated cottonseed proteins showed many markedly improved characteristics as coffee whiteners. Ca. 50% replacement of sodium caseinate with succinylated cottonseed protein isolate did not affect the quality of whiteners compared to that of 100% sodium caseinate‐based whitener.

Succinylation of Cottonseed Flour: Effect on the Functional Properties of Protein Isolates Prepared from Modified Flour

ABSTRACTSuccinylated cottonseed protein isolates (40% and 54% modification of amino groups of control isolate) were prepared under pilot scale processing conditions. Partial succinylation of cottonseed flour increased the yield of protein isolate in isoelectric precipitation (pH 4.5). The succinylated isolates were more water soluble, less heat‐coagulable in water, and lighter in color as compared to conventional isolates. They also showed improved functional properties including higher oil absorption, emulsion capacity, gel strength, water hydration, water retention, and viscosity. Bulk density was decreased and resulted in fluffy isolates.

TEXTURAL PROPERTIES OF COTTONSEED PROTEINS

ABSTRACTMethods of texturing and gelling cottonseed protein isolates without extrusion were investigated as a means of extending the use of cottonseed derivatives as food ingredients. Water suspensions of storage protein isolates with a pH of 4.5–9.0 heated to 90°C while being stirred had the mouthfeel and chewiness of cooked meat; suspensions at pH values above and below this range formed self‐sustaining gels. Isolates containing both nonstorage and storage proteins required suspension in 0.3% NaCl solutions between pH 4.0 and 9.0 for texturing. The textured products can be dehydrated for storage and rehydrated as needed. Meat products containing 10–20% textured cottonseed proteins had acceptable texture, color, flavor, and chemical properties; blandness was a problem with 30% products. Gel electrophoretic techniques elucidated some of the interactions of meat and cottonseed proteins during processing and also showed the usefulness of these procedures in identifying vegetable proteins in food systems.

COPRECIPITATION OF CHEESE WHEY WITH SOYBEAN AND COTTONSEED PROTEINS USING ACID AND HEAT TREATMENT

ABSTRACTSoybean‐ and cottonseed‐whey protein coprecipitate isolates (SIW and CIW) and coprecipitate concentrates (SCW and CCW) were all prepared using heat treatment (95°C, 15 min) at acidic pH (4.6). Soybean and cottonseed protein isolates (SI and CI) and concentrates (SC and CC) and whey protein concentrate (WC) were also prepared under similar conditions for comparison with the coprecipitates. In general, the coprecipitation resulted in acidulant savings (7–9% for SIW and CIW, 51–68% for SCW and CCW), higher nitrogen yields (24–29% for SIW and SCW, 10–17% for CIW and CCW), higher protein scores, lighter color, slightly higher solubility, lower water and fat absorption and emulsifying capacities compared with separate precipitation of the oil‐seed proteins. The whipping properties decreased in the coprecipitate isolate but increased in the coprecipitate concentrate of soybean and cottonseed. Compared with a commercial soy isolate, all coprecipitates had lower solubility, emulsifying and whipping capacities but equivalent water and fat absorption capacities.