Current IssueEditorial BoardOnline First ArticlesArchive
Current IssueEditorial BoardOnline First ArticlesArchive

Full Research Article

Functional, Structural and Thermal Properties of Protein Fractions from Cottonseed Meal

K
Kavita Ware1
0009-0009-4508-1549
O
Onkar Lonsane1
P
Piyush Kashyap1,*
0000-0003-1650-082X
1Department of Food Technology and Nutrition, School of Agriculture, Lovely Professional University, Phagwara-144 411, Punjab, India.

ABSTRACT

Background: The increasing global demand for sustainable protein sources has focused interest on plant-derived alternatives, one of which is cottonseed meal (CSM), largely underutilized until now. Though, it possesses high-quality protein, but its’ potential remains unexplored due to limited characterization of its constituent protein fractions.

Methods: In our study, CSM was fractionated using Osborne’s sequential extraction method into albumin, globulin, prolamin and glutelin. Protein fraction yield, protein concentration and the functional properties of each fraction were evaluated. Additionally, the structural and thermal characteristics of the fractions were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA).

Result: Study findings revealed that CSM had a protein content of 46.16%. At the fraction level, globulin was detected with the highest yield (74.58%) and protein concentration (52.37%) among all four protein components. Albumin showed higher water-holding and emulsifying capacities as compared to ?? and glutelin had better foaming ability. FTIR and SEM analyses represented distinct structural and morphologicalstructures for all the fractioned proteins with each exhibiting unique secondary-structure features and surface microstructures reflective of their varying conformations, aggregation levels and functional behaviour,  Maximum thermal stability was recorded in globulin. Overall, proteins fromCSM, especially globulin and albumin fractions, presented good functional and structural properties, thus making them potential ingredients for food formulations and protein-based value added food products.

INTRODUCTION

The global population is expected to reach a level between 8.5 and 10 billion in 2050, with increased living standards and a shift in dietary preferences. This rapid population growth will intensify the need for affordable, nutritious and sustainable high-protein foods to meet global dietary requirements. Therefore, demand for sustainable and more reasonably priced protein sources than traditional animal origin proteins will continue to surge upwards (Ware et al., 2025). Within this context, plant-derived proteins have recently attracted interest worldwide because of their nutritive value, functional diversity, lower environmental footprint and economic viability. Among the plant sources, cotton holds a unique position as one of the most extensively cultivated plants in the world. The production of cotton generates large amounts of cottonseed as a by-product during fiber production, accounting for approximately 50% of the seed weight. Regardless of its abundance and nutritional richness, cottonseed remains largely underutilized. According Xie et al., (2023) during the year 2021-2022, global cotton production reached to a significant figure (43.8 million tonnes), highlighting its potential as an abundant protein feedstock. Cottonseed meal (CSM), the major by-product after oil extraction, contains about 23% protein, is a promising feedstock to meet increasing global protein demand (Sunilkumar et al., 2006).
               
CSM proteins have a balanced amino acid profile; and their functional properties of solubility, emulsification, foaming and gelation are desirable in many food systems (Hinze et al., 2015; Rigney, 2025). Such characteristics position cottonseed protein as an excellent player among established plant proteins viz. soy, pea and wheat gluten. Functional properties of CSM play a pivotal role for its’ diverse applications in baked products, beverages, dairy alternatives and plant-based meat formulations, for obtaining desirable textural, stability and sensory qualities of the prepared product. The increasing consumer demand for protein-enriched foods, such as powders, bars and ready-to-drink formulations, has increased research into finding new and sustainable plant protein sources. More recently, proteins from unconventional sources, such as quinoa, jackfruit seeds and prickly pear seed cake have been studied (Mir et al., 2018; Ulloa et al., 2017; Borchani et al., 2021; Verma et al., 2022). In this context, valorization of cottonseed protein also presents an opportunity to convert an agricultural bye-product into a sustainable protein ingredient for value addition. Regardless of its nutritional potential, the value of cottonseed proteins has not been fully explored. Most literature has focused on general composition or oil extraction and specific information on physicochemical, structural and functional properties of these proteins is limited. The present study focuses on the systematic extraction and fractionation of proteins from CSM and comparative evaluation of their yield, functional, structural and thermal properties to ascertain the food applications of CSM as a low-cost, sustainable plant protein source.

MATERIALS AND METHODS

Raw material
 
The CSM was obtained from Kapeesh Industries, Khanna, Ludhiana, Punjab, India. All the chemicals and reagents were of analytical grade (Sigma-Aldrich) (Mention brand name).
 
Preparation of defatted CSM powder
 
The CSM was ground to a fine powder, then the obtained powder was defatted using hexane as the Soxhlet solvent for 8 hours at 60°C. The resulting defatted CSM powderwas dried at 40°C and stored in airtight pouches for further analysis.
 
Proximate analysis
 
The proximate composition of defatted CSM powder was determined using standard AOAC (2009) methods to detect moisture, crude protein, crude lipid, crude fiber  and ash contents. Carbohydrate content was calculated by difference, subtracting the sum of moisture, protein, fat, fiber and ash from 100. All results were expressed on a dry-weight basis (g/100 g).
 
Osborne fractionation technique for CSM
 
Protein fractions were extracted from defatted CSM powder based on the modified Osborne and Voorhees (1894) sequential extraction procedure (albumin, globulin, prolamin and glutelin). For albumin, the defatted CSM powder was mixed with deionized water in a 1:10 w/v ratio and stirred overnight, after adjusting the pH to 7.0,. Then, the suspension was centrifuged at 8000 rpm for 15 minutes and the supernatant was collected (Albumin-1). The extraction was repeated twice to ensure maximum recovery. Then globulin, prolamin and glutelin were sequentially extracted with 0.5 N NaCl, 70% aqueous ethanol and 0.2% NaOH, respectively, under the same conditions of extraction and centrifugation. Supernatants were freeze-dried and kept in airtight containers at 4°C until use.
 
Estimation of protein yield and concentration
 
Protein yield was determined based as:


Where,
P= Weight of particular protein fraction (g).
S= Dry weight of CSM powder taken for protein extraction (g).

Protein concentration was estimated by using the Kjeldahl method.
 
Functional properties of CSM protein fractions
 
Water and oil holding capacity
 
Water and oil holding capacities were determined according to the procedure described by Tounkara et al., (2013). For water-holding capacity, 0.5 g protein sample was mixed with 10 mL of deionized water, vortexed for 30 seconds and then left at room temperature for 30 min prior to centrifugation (3000 rpm, 25 min). The supernatant was filtered and weight of the residue recorded. For oil-holding capacity, 1 g of protein was mixed in 10 g of refined soybean oil, vortexed for 5 minutes, incubated for 30 minutes and then centrifuged at 3000 rpm for 20 minutes.


Where,
W1= Weight of centrifuged tube (g).
W2= Weight of centrifuged tube after draining the supernatant (g).
Ws= Sample weight (g, db).
 
Emulsifying capacity
 
Emulsifying capacity was determined by the method of Kashyap et al., (2023). One gram of protein sample was dissolved in 50 mL of 0.5 N NaCl and mixed with 50 mL refined soybean oil. The emulsion was homogenized and heated at 90°C for 10 min, then centrifuged at 3000 rpm for 20 min.


Where,
V1= Volume of oil mixed to prepare emulsion (mL).
V2= Volume of oil released after centrifugation (mL).
Ws= Sample weight (g,db).
 
Foaming capacity and foaming stability
 
The foaming properties were determined by the method described by Kashyap et al., (2023). One gram of protein was dissolved in 100 mL deionized water at pH 7.4 and stirred for 3 minutes. The mixture was transferred to a 250 mL graduated cylinder and the foam volume was recorded.                          

                                 

Where,
V1= Volume of protein sample solution (mL).
V2= Volume of foam (mL).
       
The foam stability was measured at 10 min intervals over a period of 1 h under static conditions.
 
Wettability
 
Wettability was determined according to Akpossan et al., (2015). One gram of protein sample was put in a 10 mL graduated cylinder, inverted 10 cm above deionized water and released gently. The time taken for complete wetting of the sample was recorded as wettability time.

Structural properties of CSM protein fractions
 
Fourier transform infrared (FTIR) spectroscopy
 
According to Kashyap et al., (2023) Fourier transform infrared spectra were recorded on Perkin Elmer Spectrum (RX-I, FTIR, USA). The sample was scanned in the spectral range of 4000 to 600 cm- 1 at a resolution of 4 cm- 1.
 
Scanning electron microscopy (SEM)
 
Surface morphology was analyzed in each protein fraction by a Scanning Electron Microscope (Hitachi SE 300H, Tokyo, Japan) according to the method of Kashyap et al., (2023). Samples were mounted on conductive adhesive stubs, sputter-coated with gold and observed at 2500× magnification with an accelerating voltage of 25 kV.
 
Thermal Property of CSM protein fractions
 
Thermo-gravimetric analysis (TGA)
 
The thermostability of the protein fractions was measured according to Kashyap et al., (2023) by using a Perkin Elmer TGA 4000 (USA). About 5 mg of protein powder was heated from 40°C to 600°C at 10°C/min with a nitrogen flow of 20 mL/min.
 
Statistical analysis
 
All analyses were performed in triplicate and the results were presented as mean ± standard deviation. Significant differences among the samples were tested by one-way ANOVA. Homogeneity among means was compared by the Duncan’s multiple range test (p<0.05) using SPSS software (version 16.0, IBM, USA).

RESULTS AND DISCUSSION

Proximate composition of CSM
 
The proximate analysis of CSM showed that the major constituents in order of magnitude were protein (46.16±0.35%), carbohydrates (26.89±0.04%), crude fat (1.8±0.35%), ash (7.60±0.46%) and crude fiber (8.00±0.81%). This agrees with earlier works where 35-45% protein and 0.8-1.0% fat in CSM have been reported (Cheng et al., 2020; Kumar et al., 2021; Srinath et al., 2025). A high protein value indicates a promising plant protein source, while high ash values suggest the presence of essential minerals in foods.
 
Yield and concentration of different protein fractions
 
Fractionation of CSM proteins yielded four major classes globulin, albumin, glutelin and prolamin accounting for 94.55±1.05% of the total protein and 9.12±0.24 g/100 g total yield, representing 89.76% recovery of crude protein (16.21±0.14 g/100 g) (Table 1). The minor unextracted fraction (8-10%) eflects variations in solvent polarity, extraction pH, ionic strength, or particle size affecting solubility and diffusivity (Deb et al., 2022; Patel et al., 2025). Globulin was predominant (12.09±0.25 g/100 g; 55.37±1.32% protein), followed by albumin, glutelin and prolamin, a distribution consistent with oilseed protein profiles. The dominance of globulin and albumin aligns with previous findings (Gandhi et al., 2017), emphasizing their nutritional relevance as they are rich in essential amino acids and contribute to structural and enzymatic functions. Their high solubility and interfacial activity suggest strong potential for emulsified or protein-enriched food systems (Singh, 2019). Conversely, the lower glutelin and prolamin contents typically abundant in cereals indicate that CSM proteins are primarily salt and water-soluble, highlighting their distinct biochemical nature and superior functional adaptability compared to cereal storage proteins.

Table 1: Protein content of fractions and protein fraction yield.


 
Functional properties of CSM protein fractions
 
Water holding capacity (WHC) and oil holding capacity (OHC)
 
The significant difference was seen among various CSM protein fractions for water and oil-holding capacities (Table 2). Albumin showed the highest WHC, which was followed by globulin, glutelin and prolamin. Higher WHC for albumin can be ascribed to its relatively flexible structure, higher surface polarity and exposure of hydrophilic groups, facilitating water–protein interactions and network formation during hydration (Kamani et al., 2024). The variability among the fractions arises due to the difference in molecular conformation, surface charge distribution and extent of protein denaturation during extraction (Dabbour et al., 2023).

Table 2: Functional properties of cotton seed meal protein fractions.


       
The OHC values ranged from 1.71±0.01 to 2.51±0.01 g/g of albumin. The superior OHC of albumin indicates a greater availability of hydrophobic residues capable of binding nonpolar lipid chains, whereas the compact quaternary structure restricts such interactions in globulin. In contrast, the moderate OHC values of prolamin and glutelin indicate intermediate surface hydrophobicity (Borchani et al., 2021). Both WHC and OHC illustrate that albumin is an effective contributor to viscosity and texture enhancement both in aqueous systems and in lipid-based formulations, suggesting its potential use in bakery, confectionery and emulsified food applications.
 
Emulsifying capacity
 
Table 2 presented the emulsifying capacity of the respective protein fractions from CSM. Interestingly enough, albumin exhibited highest emulsifying capacity followed in efficiency by glutelin, globulin and prolamin. Of significance here is that the difference in emulsifying capacity between albumin and glutelin was not quite significant (p<0.05). These protein fractions stabilize emulsions during homogenization by lowering interfacial tension to produce smaller droplets and by increasing repulsive forces to prevent aggregation (Rudra et al., 2016). The relatively greater emulsion capacities of these two fractions could be due to the higher proportion of small, soluble protein particles, based on their particle size distribution. Smaller particle-sized proteins have been shown to have greater emulsifying activity based on their better ability to quickly adsorb at the oil-water interface, thus stabilizing emulsions (Chen et al., 2022).
 
Foaming capacity and foaming stability
 
The CSM protein fractions exhibited significant differences in foaming properties, indicating structural and interfacial heterogeneity among the extracted proteins. FC values ranged from 16.00±0.01% for prolamin to 26.62±0.03% for glutelin (Table 2). A higher FC value for glutelin indicates a balanced composition of hydrophobic and hydrophilic domains that favor rapid diffusion and adsorption at the air-water interface, enhancing foam generation. Globulin had a moderate FC of 20.98±0.03%, while albumin had a relatively lower FC of 19.50± 0.01% but with relatively good stability due to its flexible and compact molecular structure in general (Chen et al., 2022). Globulin exhibited the highest foam stability, showing the capability to form cohesive and viscoelastic interfacial films by resisting coalescence and liquid drainage (Fig 1). On the contrary, despite the higher FC of glutelin, it showed rapid foam collapse, possibly due to insufficient interfacial rigidity or weak intermolecular crosslinking. Prolamin exhibited poor FC and stability, consistent with its limited solubility and tendency toward aggregation in aqueous environments. These observations suggest that globulin and albumin stabilize foam while glutelin enhances foam formation, implying complementary functionality for fractions of CSM in both aerated and whipped food products.

Fig 1: Foaming stability of CSM protein fractions.


 
Wettability
 
Wettability of CSM protein fractions reflected their hydration and dispersibility characteristics, influenced by particle size, surface polarity and hydrophobicity. Significant differences (p<0.05) occurred among the fractions, where globulin exhibited the shortest wetting time (9.65±0.14 s), reflecting rapid hydration and superior dispersibility. Albumin and glutelin exhibited intermediate levels of wettability at 13.27±0.07 s and 10.60±0.01 s, respectively, while prolamin demonstrated the longest wetting time of 15.31±0.04 s, attributed to an aggregated structure and high hydrophobic amino acid content that restrict water entrance. These observations are in good agreement with those made in the case of some plant proteins, in which higher surface polarity and increased porosity enhance the dynamics of hydration (Akpossan et al., 2015). In general, globulin and glutelin showed rapid wettability and, hence, a greater potential for instant or dispersible food applications.
 
Fourier transform infrared spectroscopy
 
The FTIR spectra of albumin, globulin, glutelin and prolamin fractions of CSM proteins showed different absorption bands, thus confirming their intact secondary structures (Fig 2). The broad peak at 3300-3400 cm-1 was assigned to O-H and N-H stretching, showing the presence of hydrogen bonding and typical protein groups such as hydroxyls and amines. The Amide I band, around 1650 cm-1, which represents C=O stretching of peptide linkages, suggested the presence of α-helix and β-sheet, while Amide II (~1540 cm-1) was due to N-H bending and C-N stretching, further confirming the protein nature of the samples (Kong and Yu, 2007). The additional peaks between 1000-1200 cm-1 due to C-N and C-O stretching have formed the fingerprint region that differentiated fractions. Albumin exhibited broader and less defined peaks, indicating a more heterogenous structure, whereas globulin had a lower intensity band, suggesting a compact conformation. These show successful extraction and different secondary structures which influence functional behavior in food matrices (Zeng et al., 2011). These are important because they influence how each protein behaves functionally, which has direct implications for their use in food applications and other industrial products.

Fig 2: FTIR spectroscopy of cottonseed meal protein fractions.


 
Scanning electron microscopy
 
SEM micrographs of CSM protein fractions are presented in Fig 3 and have shown different morphologies related to their functional properties. Albumin had a dense smooth surface, indicating an aggregated or denatured protein, matching its low solubility. Globulin had a rough and irregular granular appearance with apparent porosity that favored hydration and oil-binding potential. Glutelin presented spherical, moderately aggregated particles with uniform packing and is associated with improved dispersion and emulsification capability (Wu et al., 2022). Prolamin displayed porous, flaky and loosely aggregated structures, reflecting weak intermolecular interaction but high water absorption upon hydration. These morphological differences are consistent with previous reports on plant proteins (Sun and Arntfield, 2010) and directly impact the solubility, emulsification and foaming properties of interest in food applications.

Fig 3: SEM images of the cotton seed meal protein fraction Albumin (A), globulin (B), glutelin (C), Prolamin (D).


 
Thermogravimetric analysis
 
TGA profiles of CSM protein fractions over the temperature range of 0-600°C showed distinct thermal degradation characteristics (Fig 4). An initial weight loss below 200°C corresponded to the evaporation of moisture. Relatively higher weight losses were observed in prolamin and glutelin, which may be attributed to a higher moisture content or higher water retention in their structures. The major decomposition took place between 200-400°C, reflecting peptide bond cleavage and protein denaturation as stated by Kumar et al., (2021). Accordingly, albumin showed the fastest degradation, marking low thermal stability, while globulin degraded more gradually and developed a secondary peak in degradation near 400°C, confirming superior thermostability as explained by Taarji et al., (2024). Glutelin and prolamin developed intermediate profiles with greater initial moisture losses but moderate structural resistance. Residual mass at 600°C was highest for globulin, perhaps due to mineral and non-volatile residues as stated by Ortega et al., (2024). Globally, thermal behavior suggests that globulin is most suitable for high-temperature applications, while albumin does better under mild conditions.

Fig 4: Thermogravimetric analysis of CSM protein fractions.

CONCLUSION

The extraction, fractionation and characterization of cottonseed meal protein isolates (CSMPI) demonstrated that CSM is an excellent source of high-quality plant proteins with functional and nutritional potential. Conventional extraction yielded substantial protein recovery, suggesting that advanced methods could further enhance the yield. Thermal analysis revealed moderate denaturation temperatures, desirable for nutritional applications. FTIR spectra confirmed typical amide I, II and III protein bands, with β-sheet as the predominant secondary structure. Functional assessments showed favorable foaming and emulsifying capacities comparable to other plant proteins. SEM micrographs exhibited distinct microstructural variations among fractions, explaining their functional differences. Notably, the high albumin content underscores CSM’s potential to reduce reliance on animal-derived albumin. Overall, cottonseed meal protein fractions exhibit desirable functional and structural properties suitable for food, nutraceutical and pharmaceutical applications, though further optimization of extraction and evaluation under varied processing conditions remain necessary.

CONFLICT OF INTEREST

The authors have no conflicts of interest to declare.

REFERENCES


  1. AOAC. (2009). Official Methods of Analysis of AOAC International (18th ed., Rev. 2). AOAC International, Gaithersburg, MD, USA.

  2. Akpossan, R.A., Digbeu, Y.D., Koffi, M.D., Kouadio, J.P.E.N.G., Dué, E.A. and Kouamé, P.L. (2015). Protein fractions and functional properties of dried imbrasia oyemensis larvae full-fat and defatted flours. International Journal of Biochemistry Research and Review. 5(2): 116.

  3. Borchani, M., Yaich, H., Abbès, F., Blecker, C., Besbes, S., Attia, H. and Masmoudi, M. (2021). Physicochemical, functional and antioxidant properties of the major protein fractions extracted from prickly pear (Opuntia ficus indica L.) seed cake. Waste and Biomass Valorization. 12(4): 1749-1760.

  4. Chen, M., Xu, F., Nsor-Atindana, J., Chen, X., Liu, F., Wu, J. and Zhong, F. (2022). High protein and high oil emulsions: Phase diagram, stability and interfacial adsorption. Lwt.  153: 112464.

  5. Cheng, H. N., He, Z., Ford, C., Wyckoff, W. and Wu, Q. (2020). A review of cottonseed protein chemistry and non-food applications. Sustainable Chemistry. 1(3): 256-274.

  6. Dabbour, M., Hamoda, A., Mintah, B.K., Wahia, H., Betchem, G., Xu, H. and Ma, H. (2023). Ultrasonic-aided extraction and degossypolization of cottonseed meal protein: Optimization  and characterization of functional traits and molecular structure. Industrial Crops and Products. 204: 117261.

  7. Deb, S., Kumar, Y. and Saxena, D.C. (2022). Functional, thermal and structural properties of fractionated protein from waste banana peel. Food Chemistry: X. 13: 100205.

  8. Gandhi, K., Litoriya, N., Shah, A. and Talati, J.G. (2017). Extraction, fractionation and characterization of cotton (Gossypium herbaceum L.) seed proteins. Indian Journal of Agricultural Biochemistry. 30(1): 21-26.

  9. Hinze, L.L., Horn, P.J., Kothari, N., Dever, J.K., Frelichowski, J., Chapman, K.D. and Percy, R.G. (2015). Nondestructive measurements of cottonseed nutritional trait diversity in the US national cotton germplasm collection. Crop Science.  55(2): 770-782.

  10. Kamani, M.H., Liu, J., Fitzsimons, S.M., Fenelon, M.A. and Murphy, E.G. (2024). Determining the influence of fava bean pre- processing on extractability and functional quality of protein isolates. Food Chemistry: X. 21: 101200.

  11. Kashyap, P., Riar, C.S. and Jindal, N. (2023). Detoxification of Meghalayan cherry (Prunus nepalensis) kernel and its effect on structural and thermal properties of proteins.  Food Research International. 164: 112437.

  12. Kong, J. and Yu, S. (2007). Fourier transform infrared spectroscopic analysis of protein secondary structures. Acta Biochimica  et Biophysica Sinica. 39(8): 549-559.

  13. Kumar, M., Potkule, J., Patil, S., Saxena, S., Patil, P.G., Mageshwaran, V. and Kennedy, J.F. (2021). Extraction of ultra-low gossypol protein from cottonseed: Characterization based on antioxidant activity, structural morphology and functional group analysis. Lwt. 140: 110692.

  14. Mir, N. A., Riar, C.S. and Singh, S. (2018). Nutritional constituents of pseudo cereals and their potential use in food systems: A review. Trends in Food Science and Technology. 75: 170-180.

  15. Ortega, M.L.S., Orellana-Palacios, J.C., Garcia, S.R., Rabanal-Ruiz, Y., Moreno, A. and Hadidi, M. (2024). Olive leaf protein: Extraction optimization, in vitro digestibility, structural and techno-functional properties. International Journal of Biological Macromolecules. 256: 128273.

  16. Osborne, T.B. and Voorhees, C.L. (1894). Proteids of the wheat kernel. Journal of the American Chemical Society. 16(8): 524-535.

  17. Patel, P., Pang, Y.L.J., Choi, W.J. and Wong, A. (2025). Protein extraction and isolation from legumes and algae: An industry primer. Food and Bioprocess Technology. pp 1-29.

  18. Rigney, D. (2025). Investigating Genetic Influences on Nutritive Value of Whole Cottonseed (Master’s thesis).

  19. Rudra, S.G., Sethi, S., Jha, S.K. and Kumar, R. (2016). Physico- chemical and functional properties of cowpea protein isolate as affected by the dehydration technique. Legume  Research-An International Journal. 39(3): 370-378. doi: 10.18805/lr.v0iOF.9441.

  20. Srinath, S., Kaur, J. and Hundal, J.S. (2025). Chemical composition, in vitro gas production and ruminal fermentation of cottonseed meal and certain conventional protein sources in buffalo inoculum. Asian Journal of Dairy and Food Research. 44(5): 850-855. doi: 10.18805/ajdfr.DR-1918.

  21. Singh, A., and Kaur, A. (2019). Comparative studies on seed protein characteristics in eight lines of two Gossypium species.  Journal of Cotton Research. 2(1): 6.

  22. Sun, X.D. and Arntfield, S.D. (2010). Gelation properties of salt- extracted pea protein induced by heat treatment. Food Research International. 43(2): 509-515.

  23. Sunilkumar, G., Campbell, L.M., Puckhaber, L., Stipanovic, R.D. and Rathore, K.S. (2006). Engineering cottonseed for use in human nutrition by tissue-specific reduction of toxic gossypol. Proceedings of the National Academy of Sciences. 103(48): 18054-18059.

  24. Taarji, N., Lyamlouli, K., Barakat, A., Tominaga, K., Isoda, H. and Nakajima, M. (2024). Biochemical and techno-functional investigation of argan press-cake proteins foreseeing food application. LWT-Food Science and Technology.  192: 115734.

  25. Tounkara, F., Amza, T., Lagnika, C., Le, G.W. and Shi, Y.H. (2013). Extraction, characterization, nutritional and functional properties of Roselle (Hibiscus sabdariffa Linn) seed proteins. Songklanakarin. Journal of Science and Technology. 35(2): 159-166.

  26. Ulloa, J.A., Barbosa, M.C.V., Vazquez, J.A.R., Ulloa, P.R., Ramirez, J.C.R., Carrillo, Y.S. and Torres, L.G.  (2017). Production, physico-chemical and functional characterization of a protein isolate from jackfruit (Artocarpus heterophyllus) seeds. CyTA-Journal of Food. 15(4): 497-507.

  27. Verma, P., Kumar, V., Das, K. and Parashar, M. (2022). Biochemical compositions of milling by product of mungbean and its fractions. Asian Journal of Dairy and Food Research.  41(4): 417-423. doi: 10.18805/ajdfr.DR-1840.

  28. Wu, J., Zhou, X., Zhou, L., Liu, W., Zhong, J., Zhang, Y. and Liu, C. (2022). Physicochemical, structural and functional properties of protein fractions and protein isolate from jackfruit seeds. Journal of Food Science. 87(4): 1540- 1551.

  29. Ware, K., Kashyap, P., Gorde, P. M., Yadav, R. and Sharma, V. (2025). Comparative analysis of RSM and ANN-GA based modeling for protein extraction from cotton seed meal: Effect of extraction parameters on amino acid profile and nutritional characteristics. Food and Bioproducts Processing. 150: 63-77.

  30. Xie, X., Liang, X., Wang, H., Zhu, Q., Wang, J., Chang, Y. and Wang, J. (2023). Effects of paraprobiotics on bile acid metabolism and liver health in largemouth bass (Micropterus salmoides) fed a cottonseed protein concentrate-based diet. Animal Nutrition. 13: 302-312.

  31. Zeng, H.Y., Cai, L.H., Cai, X.L., Wang, Y.J. and Li, Y.Q. (2011). Structure characterization of protein fractions from lotus (Nelumbo nucifera) seed. Journal of Molecular Structure.  1001(1-3): 139-144.
Published In
Asian Journal of Dairy and Food Research
Article Metrics
Metrics Icon
0
Views
0
Citations
Reviewed By
Share Article
Download Article
In this Article
    Contact us
    Follow us

    Full Research Article

    Functional, Structural and Thermal Properties of Protein Fractions from Cottonseed Meal

    K
    Kavita Ware1
    0009-0009-4508-1549
    O
    Onkar Lonsane1
    P
    Piyush Kashyap1,*
    0000-0003-1650-082X
    1Department of Food Technology and Nutrition, School of Agriculture, Lovely Professional University, Phagwara-144 411, Punjab, India.

    ABSTRACT

    Background: The increasing global demand for sustainable protein sources has focused interest on plant-derived alternatives, one of which is cottonseed meal (CSM), largely underutilized until now. Though, it possesses high-quality protein, but its’ potential remains unexplored due to limited characterization of its constituent protein fractions.

    Methods: In our study, CSM was fractionated using Osborne’s sequential extraction method into albumin, globulin, prolamin and glutelin. Protein fraction yield, protein concentration and the functional properties of each fraction were evaluated. Additionally, the structural and thermal characteristics of the fractions were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA).

    Result: Study findings revealed that CSM had a protein content of 46.16%. At the fraction level, globulin was detected with the highest yield (74.58%) and protein concentration (52.37%) among all four protein components. Albumin showed higher water-holding and emulsifying capacities as compared to ?? and glutelin had better foaming ability. FTIR and SEM analyses represented distinct structural and morphologicalstructures for all the fractioned proteins with each exhibiting unique secondary-structure features and surface microstructures reflective of their varying conformations, aggregation levels and functional behaviour,  Maximum thermal stability was recorded in globulin. Overall, proteins fromCSM, especially globulin and albumin fractions, presented good functional and structural properties, thus making them potential ingredients for food formulations and protein-based value added food products.

    INTRODUCTION

    The global population is expected to reach a level between 8.5 and 10 billion in 2050, with increased living standards and a shift in dietary preferences. This rapid population growth will intensify the need for affordable, nutritious and sustainable high-protein foods to meet global dietary requirements. Therefore, demand for sustainable and more reasonably priced protein sources than traditional animal origin proteins will continue to surge upwards (Ware et al., 2025). Within this context, plant-derived proteins have recently attracted interest worldwide because of their nutritive value, functional diversity, lower environmental footprint and economic viability. Among the plant sources, cotton holds a unique position as one of the most extensively cultivated plants in the world. The production of cotton generates large amounts of cottonseed as a by-product during fiber production, accounting for approximately 50% of the seed weight. Regardless of its abundance and nutritional richness, cottonseed remains largely underutilized. According Xie et al., (2023) during the year 2021-2022, global cotton production reached to a significant figure (43.8 million tonnes), highlighting its potential as an abundant protein feedstock. Cottonseed meal (CSM), the major by-product after oil extraction, contains about 23% protein, is a promising feedstock to meet increasing global protein demand (Sunilkumar et al., 2006).
                   
    CSM proteins have a balanced amino acid profile; and their functional properties of solubility, emulsification, foaming and gelation are desirable in many food systems (Hinze et al., 2015; Rigney, 2025). Such characteristics position cottonseed protein as an excellent player among established plant proteins viz. soy, pea and wheat gluten. Functional properties of CSM play a pivotal role for its’ diverse applications in baked products, beverages, dairy alternatives and plant-based meat formulations, for obtaining desirable textural, stability and sensory qualities of the prepared product. The increasing consumer demand for protein-enriched foods, such as powders, bars and ready-to-drink formulations, has increased research into finding new and sustainable plant protein sources. More recently, proteins from unconventional sources, such as quinoa, jackfruit seeds and prickly pear seed cake have been studied (Mir et al., 2018; Ulloa et al., 2017; Borchani et al., 2021; Verma et al., 2022). In this context, valorization of cottonseed protein also presents an opportunity to convert an agricultural bye-product into a sustainable protein ingredient for value addition. Regardless of its nutritional potential, the value of cottonseed proteins has not been fully explored. Most literature has focused on general composition or oil extraction and specific information on physicochemical, structural and functional properties of these proteins is limited. The present study focuses on the systematic extraction and fractionation of proteins from CSM and comparative evaluation of their yield, functional, structural and thermal properties to ascertain the food applications of CSM as a low-cost, sustainable plant protein source.

    MATERIALS AND METHODS

    Raw material
     
    The CSM was obtained from Kapeesh Industries, Khanna, Ludhiana, Punjab, India. All the chemicals and reagents were of analytical grade (Sigma-Aldrich) (Mention brand name).
     
    Preparation of defatted CSM powder
     
    The CSM was ground to a fine powder, then the obtained powder was defatted using hexane as the Soxhlet solvent for 8 hours at 60°C. The resulting defatted CSM powderwas dried at 40°C and stored in airtight pouches for further analysis.
     
    Proximate analysis
     
    The proximate composition of defatted CSM powder was determined using standard AOAC (2009) methods to detect moisture, crude protein, crude lipid, crude fiber  and ash contents. Carbohydrate content was calculated by difference, subtracting the sum of moisture, protein, fat, fiber and ash from 100. All results were expressed on a dry-weight basis (g/100 g).
     
    Osborne fractionation technique for CSM
     
    Protein fractions were extracted from defatted CSM powder based on the modified Osborne and Voorhees (1894) sequential extraction procedure (albumin, globulin, prolamin and glutelin). For albumin, the defatted CSM powder was mixed with deionized water in a 1:10 w/v ratio and stirred overnight, after adjusting the pH to 7.0,. Then, the suspension was centrifuged at 8000 rpm for 15 minutes and the supernatant was collected (Albumin-1). The extraction was repeated twice to ensure maximum recovery. Then globulin, prolamin and glutelin were sequentially extracted with 0.5 N NaCl, 70% aqueous ethanol and 0.2% NaOH, respectively, under the same conditions of extraction and centrifugation. Supernatants were freeze-dried and kept in airtight containers at 4°C until use.
     
    Estimation of protein yield and concentration
     
    Protein yield was determined based as:


    Where,
    P= Weight of particular protein fraction (g).
    S= Dry weight of CSM powder taken for protein extraction (g).

    Protein concentration was estimated by using the Kjeldahl method.
     
    Functional properties of CSM protein fractions
     
    Water and oil holding capacity
     
    Water and oil holding capacities were determined according to the procedure described by Tounkara et al., (2013). For water-holding capacity, 0.5 g protein sample was mixed with 10 mL of deionized water, vortexed for 30 seconds and then left at room temperature for 30 min prior to centrifugation (3000 rpm, 25 min). The supernatant was filtered and weight of the residue recorded. For oil-holding capacity, 1 g of protein was mixed in 10 g of refined soybean oil, vortexed for 5 minutes, incubated for 30 minutes and then centrifuged at 3000 rpm for 20 minutes.


    Where,
    W1= Weight of centrifuged tube (g).
    W2= Weight of centrifuged tube after draining the supernatant (g).
    Ws= Sample weight (g, db).
     
    Emulsifying capacity
     
    Emulsifying capacity was determined by the method of Kashyap et al., (2023). One gram of protein sample was dissolved in 50 mL of 0.5 N NaCl and mixed with 50 mL refined soybean oil. The emulsion was homogenized and heated at 90°C for 10 min, then centrifuged at 3000 rpm for 20 min.


    Where,
    V1= Volume of oil mixed to prepare emulsion (mL).
    V2= Volume of oil released after centrifugation (mL).
    Ws= Sample weight (g,db).
     
    Foaming capacity and foaming stability
     
    The foaming properties were determined by the method described by Kashyap et al., (2023). One gram of protein was dissolved in 100 mL deionized water at pH 7.4 and stirred for 3 minutes. The mixture was transferred to a 250 mL graduated cylinder and the foam volume was recorded.                          

                                     

    Where,
    V1= Volume of protein sample solution (mL).
    V2= Volume of foam (mL).
           
    The foam stability was measured at 10 min intervals over a period of 1 h under static conditions.
     
    Wettability
     
    Wettability was determined according to Akpossan et al., (2015). One gram of protein sample was put in a 10 mL graduated cylinder, inverted 10 cm above deionized water and released gently. The time taken for complete wetting of the sample was recorded as wettability time.

    Structural properties of CSM protein fractions
     
    Fourier transform infrared (FTIR) spectroscopy
     
    According to Kashyap et al., (2023) Fourier transform infrared spectra were recorded on Perkin Elmer Spectrum (RX-I, FTIR, USA). The sample was scanned in the spectral range of 4000 to 600 cm- 1 at a resolution of 4 cm- 1.
     
    Scanning electron microscopy (SEM)
     
    Surface morphology was analyzed in each protein fraction by a Scanning Electron Microscope (Hitachi SE 300H, Tokyo, Japan) according to the method of Kashyap et al., (2023). Samples were mounted on conductive adhesive stubs, sputter-coated with gold and observed at 2500× magnification with an accelerating voltage of 25 kV.
     
    Thermal Property of CSM protein fractions
     
    Thermo-gravimetric analysis (TGA)
     
    The thermostability of the protein fractions was measured according to Kashyap et al., (2023) by using a Perkin Elmer TGA 4000 (USA). About 5 mg of protein powder was heated from 40°C to 600°C at 10°C/min with a nitrogen flow of 20 mL/min.
     
    Statistical analysis
     
    All analyses were performed in triplicate and the results were presented as mean ± standard deviation. Significant differences among the samples were tested by one-way ANOVA. Homogeneity among means was compared by the Duncan’s multiple range test (p<0.05) using SPSS software (version 16.0, IBM, USA).

    RESULTS AND DISCUSSION

    Proximate composition of CSM
     
    The proximate analysis of CSM showed that the major constituents in order of magnitude were protein (46.16±0.35%), carbohydrates (26.89±0.04%), crude fat (1.8±0.35%), ash (7.60±0.46%) and crude fiber (8.00±0.81%). This agrees with earlier works where 35-45% protein and 0.8-1.0% fat in CSM have been reported (Cheng et al., 2020; Kumar et al., 2021; Srinath et al., 2025). A high protein value indicates a promising plant protein source, while high ash values suggest the presence of essential minerals in foods.
     
    Yield and concentration of different protein fractions
     
    Fractionation of CSM proteins yielded four major classes globulin, albumin, glutelin and prolamin accounting for 94.55±1.05% of the total protein and 9.12±0.24 g/100 g total yield, representing 89.76% recovery of crude protein (16.21±0.14 g/100 g) (Table 1). The minor unextracted fraction (8-10%) eflects variations in solvent polarity, extraction pH, ionic strength, or particle size affecting solubility and diffusivity (Deb et al., 2022; Patel et al., 2025). Globulin was predominant (12.09±0.25 g/100 g; 55.37±1.32% protein), followed by albumin, glutelin and prolamin, a distribution consistent with oilseed protein profiles. The dominance of globulin and albumin aligns with previous findings (Gandhi et al., 2017), emphasizing their nutritional relevance as they are rich in essential amino acids and contribute to structural and enzymatic functions. Their high solubility and interfacial activity suggest strong potential for emulsified or protein-enriched food systems (Singh, 2019). Conversely, the lower glutelin and prolamin contents typically abundant in cereals indicate that CSM proteins are primarily salt and water-soluble, highlighting their distinct biochemical nature and superior functional adaptability compared to cereal storage proteins.

    Table 1: Protein content of fractions and protein fraction yield.


     
    Functional properties of CSM protein fractions
     
    Water holding capacity (WHC) and oil holding capacity (OHC)
     
    The significant difference was seen among various CSM protein fractions for water and oil-holding capacities (Table 2). Albumin showed the highest WHC, which was followed by globulin, glutelin and prolamin. Higher WHC for albumin can be ascribed to its relatively flexible structure, higher surface polarity and exposure of hydrophilic groups, facilitating water–protein interactions and network formation during hydration (Kamani et al., 2024). The variability among the fractions arises due to the difference in molecular conformation, surface charge distribution and extent of protein denaturation during extraction (Dabbour et al., 2023).

    Table 2: Functional properties of cotton seed meal protein fractions.


           
    The OHC values ranged from 1.71±0.01 to 2.51±0.01 g/g of albumin. The superior OHC of albumin indicates a greater availability of hydrophobic residues capable of binding nonpolar lipid chains, whereas the compact quaternary structure restricts such interactions in globulin. In contrast, the moderate OHC values of prolamin and glutelin indicate intermediate surface hydrophobicity (Borchani et al., 2021). Both WHC and OHC illustrate that albumin is an effective contributor to viscosity and texture enhancement both in aqueous systems and in lipid-based formulations, suggesting its potential use in bakery, confectionery and emulsified food applications.
     
    Emulsifying capacity
     
    Table 2 presented the emulsifying capacity of the respective protein fractions from CSM. Interestingly enough, albumin exhibited highest emulsifying capacity followed in efficiency by glutelin, globulin and prolamin. Of significance here is that the difference in emulsifying capacity between albumin and glutelin was not quite significant (p<0.05). These protein fractions stabilize emulsions during homogenization by lowering interfacial tension to produce smaller droplets and by increasing repulsive forces to prevent aggregation (Rudra et al., 2016). The relatively greater emulsion capacities of these two fractions could be due to the higher proportion of small, soluble protein particles, based on their particle size distribution. Smaller particle-sized proteins have been shown to have greater emulsifying activity based on their better ability to quickly adsorb at the oil-water interface, thus stabilizing emulsions (Chen et al., 2022).
     
    Foaming capacity and foaming stability
     
    The CSM protein fractions exhibited significant differences in foaming properties, indicating structural and interfacial heterogeneity among the extracted proteins. FC values ranged from 16.00±0.01% for prolamin to 26.62±0.03% for glutelin (Table 2). A higher FC value for glutelin indicates a balanced composition of hydrophobic and hydrophilic domains that favor rapid diffusion and adsorption at the air-water interface, enhancing foam generation. Globulin had a moderate FC of 20.98±0.03%, while albumin had a relatively lower FC of 19.50± 0.01% but with relatively good stability due to its flexible and compact molecular structure in general (Chen et al., 2022). Globulin exhibited the highest foam stability, showing the capability to form cohesive and viscoelastic interfacial films by resisting coalescence and liquid drainage (Fig 1). On the contrary, despite the higher FC of glutelin, it showed rapid foam collapse, possibly due to insufficient interfacial rigidity or weak intermolecular crosslinking. Prolamin exhibited poor FC and stability, consistent with its limited solubility and tendency toward aggregation in aqueous environments. These observations suggest that globulin and albumin stabilize foam while glutelin enhances foam formation, implying complementary functionality for fractions of CSM in both aerated and whipped food products.

    Fig 1: Foaming stability of CSM protein fractions.


     
    Wettability
     
    Wettability of CSM protein fractions reflected their hydration and dispersibility characteristics, influenced by particle size, surface polarity and hydrophobicity. Significant differences (p<0.05) occurred among the fractions, where globulin exhibited the shortest wetting time (9.65±0.14 s), reflecting rapid hydration and superior dispersibility. Albumin and glutelin exhibited intermediate levels of wettability at 13.27±0.07 s and 10.60±0.01 s, respectively, while prolamin demonstrated the longest wetting time of 15.31±0.04 s, attributed to an aggregated structure and high hydrophobic amino acid content that restrict water entrance. These observations are in good agreement with those made in the case of some plant proteins, in which higher surface polarity and increased porosity enhance the dynamics of hydration (Akpossan et al., 2015). In general, globulin and glutelin showed rapid wettability and, hence, a greater potential for instant or dispersible food applications.
     
    Fourier transform infrared spectroscopy
     
    The FTIR spectra of albumin, globulin, glutelin and prolamin fractions of CSM proteins showed different absorption bands, thus confirming their intact secondary structures (Fig 2). The broad peak at 3300-3400 cm-1 was assigned to O-H and N-H stretching, showing the presence of hydrogen bonding and typical protein groups such as hydroxyls and amines. The Amide I band, around 1650 cm-1, which represents C=O stretching of peptide linkages, suggested the presence of α-helix and β-sheet, while Amide II (~1540 cm-1) was due to N-H bending and C-N stretching, further confirming the protein nature of the samples (Kong and Yu, 2007). The additional peaks between 1000-1200 cm-1 due to C-N and C-O stretching have formed the fingerprint region that differentiated fractions. Albumin exhibited broader and less defined peaks, indicating a more heterogenous structure, whereas globulin had a lower intensity band, suggesting a compact conformation. These show successful extraction and different secondary structures which influence functional behavior in food matrices (Zeng et al., 2011). These are important because they influence how each protein behaves functionally, which has direct implications for their use in food applications and other industrial products.

    Fig 2: FTIR spectroscopy of cottonseed meal protein fractions.


     
    Scanning electron microscopy
     
    SEM micrographs of CSM protein fractions are presented in Fig 3 and have shown different morphologies related to their functional properties. Albumin had a dense smooth surface, indicating an aggregated or denatured protein, matching its low solubility. Globulin had a rough and irregular granular appearance with apparent porosity that favored hydration and oil-binding potential. Glutelin presented spherical, moderately aggregated particles with uniform packing and is associated with improved dispersion and emulsification capability (Wu et al., 2022). Prolamin displayed porous, flaky and loosely aggregated structures, reflecting weak intermolecular interaction but high water absorption upon hydration. These morphological differences are consistent with previous reports on plant proteins (Sun and Arntfield, 2010) and directly impact the solubility, emulsification and foaming properties of interest in food applications.

    Fig 3: SEM images of the cotton seed meal protein fraction Albumin (A), globulin (B), glutelin (C), Prolamin (D).


     
    Thermogravimetric analysis
     
    TGA profiles of CSM protein fractions over the temperature range of 0-600°C showed distinct thermal degradation characteristics (Fig 4). An initial weight loss below 200°C corresponded to the evaporation of moisture. Relatively higher weight losses were observed in prolamin and glutelin, which may be attributed to a higher moisture content or higher water retention in their structures. The major decomposition took place between 200-400°C, reflecting peptide bond cleavage and protein denaturation as stated by Kumar et al., (2021). Accordingly, albumin showed the fastest degradation, marking low thermal stability, while globulin degraded more gradually and developed a secondary peak in degradation near 400°C, confirming superior thermostability as explained by Taarji et al., (2024). Glutelin and prolamin developed intermediate profiles with greater initial moisture losses but moderate structural resistance. Residual mass at 600°C was highest for globulin, perhaps due to mineral and non-volatile residues as stated by Ortega et al., (2024). Globally, thermal behavior suggests that globulin is most suitable for high-temperature applications, while albumin does better under mild conditions.

    Fig 4: Thermogravimetric analysis of CSM protein fractions.

    CONCLUSION

    The extraction, fractionation and characterization of cottonseed meal protein isolates (CSMPI) demonstrated that CSM is an excellent source of high-quality plant proteins with functional and nutritional potential. Conventional extraction yielded substantial protein recovery, suggesting that advanced methods could further enhance the yield. Thermal analysis revealed moderate denaturation temperatures, desirable for nutritional applications. FTIR spectra confirmed typical amide I, II and III protein bands, with β-sheet as the predominant secondary structure. Functional assessments showed favorable foaming and emulsifying capacities comparable to other plant proteins. SEM micrographs exhibited distinct microstructural variations among fractions, explaining their functional differences. Notably, the high albumin content underscores CSM’s potential to reduce reliance on animal-derived albumin. Overall, cottonseed meal protein fractions exhibit desirable functional and structural properties suitable for food, nutraceutical and pharmaceutical applications, though further optimization of extraction and evaluation under varied processing conditions remain necessary.

    CONFLICT OF INTEREST

    The authors have no conflicts of interest to declare.

    REFERENCES


    1. AOAC. (2009). Official Methods of Analysis of AOAC International (18th ed., Rev. 2). AOAC International, Gaithersburg, MD, USA.

    2. Akpossan, R.A., Digbeu, Y.D., Koffi, M.D., Kouadio, J.P.E.N.G., Dué, E.A. and Kouamé, P.L. (2015). Protein fractions and functional properties of dried imbrasia oyemensis larvae full-fat and defatted flours. International Journal of Biochemistry Research and Review. 5(2): 116.

    3. Borchani, M., Yaich, H., Abbès, F., Blecker, C., Besbes, S., Attia, H. and Masmoudi, M. (2021). Physicochemical, functional and antioxidant properties of the major protein fractions extracted from prickly pear (Opuntia ficus indica L.) seed cake. Waste and Biomass Valorization. 12(4): 1749-1760.

    4. Chen, M., Xu, F., Nsor-Atindana, J., Chen, X., Liu, F., Wu, J. and Zhong, F. (2022). High protein and high oil emulsions: Phase diagram, stability and interfacial adsorption. Lwt.  153: 112464.

    5. Cheng, H. N., He, Z., Ford, C., Wyckoff, W. and Wu, Q. (2020). A review of cottonseed protein chemistry and non-food applications. Sustainable Chemistry. 1(3): 256-274.

    6. Dabbour, M., Hamoda, A., Mintah, B.K., Wahia, H., Betchem, G., Xu, H. and Ma, H. (2023). Ultrasonic-aided extraction and degossypolization of cottonseed meal protein: Optimization  and characterization of functional traits and molecular structure. Industrial Crops and Products. 204: 117261.

    7. Deb, S., Kumar, Y. and Saxena, D.C. (2022). Functional, thermal and structural properties of fractionated protein from waste banana peel. Food Chemistry: X. 13: 100205.

    8. Gandhi, K., Litoriya, N., Shah, A. and Talati, J.G. (2017). Extraction, fractionation and characterization of cotton (Gossypium herbaceum L.) seed proteins. Indian Journal of Agricultural Biochemistry. 30(1): 21-26.

    9. Hinze, L.L., Horn, P.J., Kothari, N., Dever, J.K., Frelichowski, J., Chapman, K.D. and Percy, R.G. (2015). Nondestructive measurements of cottonseed nutritional trait diversity in the US national cotton germplasm collection. Crop Science.  55(2): 770-782.

    10. Kamani, M.H., Liu, J., Fitzsimons, S.M., Fenelon, M.A. and Murphy, E.G. (2024). Determining the influence of fava bean pre- processing on extractability and functional quality of protein isolates. Food Chemistry: X. 21: 101200.

    11. Kashyap, P., Riar, C.S. and Jindal, N. (2023). Detoxification of Meghalayan cherry (Prunus nepalensis) kernel and its effect on structural and thermal properties of proteins.  Food Research International. 164: 112437.

    12. Kong, J. and Yu, S. (2007). Fourier transform infrared spectroscopic analysis of protein secondary structures. Acta Biochimica  et Biophysica Sinica. 39(8): 549-559.

    13. Kumar, M., Potkule, J., Patil, S., Saxena, S., Patil, P.G., Mageshwaran, V. and Kennedy, J.F. (2021). Extraction of ultra-low gossypol protein from cottonseed: Characterization based on antioxidant activity, structural morphology and functional group analysis. Lwt. 140: 110692.

    14. Mir, N. A., Riar, C.S. and Singh, S. (2018). Nutritional constituents of pseudo cereals and their potential use in food systems: A review. Trends in Food Science and Technology. 75: 170-180.

    15. Ortega, M.L.S., Orellana-Palacios, J.C., Garcia, S.R., Rabanal-Ruiz, Y., Moreno, A. and Hadidi, M. (2024). Olive leaf protein: Extraction optimization, in vitro digestibility, structural and techno-functional properties. International Journal of Biological Macromolecules. 256: 128273.

    16. Osborne, T.B. and Voorhees, C.L. (1894). Proteids of the wheat kernel. Journal of the American Chemical Society. 16(8): 524-535.

    17. Patel, P., Pang, Y.L.J., Choi, W.J. and Wong, A. (2025). Protein extraction and isolation from legumes and algae: An industry primer. Food and Bioprocess Technology. pp 1-29.

    18. Rigney, D. (2025). Investigating Genetic Influences on Nutritive Value of Whole Cottonseed (Master’s thesis).

    19. Rudra, S.G., Sethi, S., Jha, S.K. and Kumar, R. (2016). Physico- chemical and functional properties of cowpea protein isolate as affected by the dehydration technique. Legume  Research-An International Journal. 39(3): 370-378. doi: 10.18805/lr.v0iOF.9441.

    20. Srinath, S., Kaur, J. and Hundal, J.S. (2025). Chemical composition, in vitro gas production and ruminal fermentation of cottonseed meal and certain conventional protein sources in buffalo inoculum. Asian Journal of Dairy and Food Research. 44(5): 850-855. doi: 10.18805/ajdfr.DR-1918.

    21. Singh, A., and Kaur, A. (2019). Comparative studies on seed protein characteristics in eight lines of two Gossypium species.  Journal of Cotton Research. 2(1): 6.

    22. Sun, X.D. and Arntfield, S.D. (2010). Gelation properties of salt- extracted pea protein induced by heat treatment. Food Research International. 43(2): 509-515.

    23. Sunilkumar, G., Campbell, L.M., Puckhaber, L., Stipanovic, R.D. and Rathore, K.S. (2006). Engineering cottonseed for use in human nutrition by tissue-specific reduction of toxic gossypol. Proceedings of the National Academy of Sciences. 103(48): 18054-18059.

    24. Taarji, N., Lyamlouli, K., Barakat, A., Tominaga, K., Isoda, H. and Nakajima, M. (2024). Biochemical and techno-functional investigation of argan press-cake proteins foreseeing food application. LWT-Food Science and Technology.  192: 115734.

    25. Tounkara, F., Amza, T., Lagnika, C., Le, G.W. and Shi, Y.H. (2013). Extraction, characterization, nutritional and functional properties of Roselle (Hibiscus sabdariffa Linn) seed proteins. Songklanakarin. Journal of Science and Technology. 35(2): 159-166.

    26. Ulloa, J.A., Barbosa, M.C.V., Vazquez, J.A.R., Ulloa, P.R., Ramirez, J.C.R., Carrillo, Y.S. and Torres, L.G.  (2017). Production, physico-chemical and functional characterization of a protein isolate from jackfruit (Artocarpus heterophyllus) seeds. CyTA-Journal of Food. 15(4): 497-507.

    27. Verma, P., Kumar, V., Das, K. and Parashar, M. (2022). Biochemical compositions of milling by product of mungbean and its fractions. Asian Journal of Dairy and Food Research.  41(4): 417-423. doi: 10.18805/ajdfr.DR-1840.

    28. Wu, J., Zhou, X., Zhou, L., Liu, W., Zhong, J., Zhang, Y. and Liu, C. (2022). Physicochemical, structural and functional properties of protein fractions and protein isolate from jackfruit seeds. Journal of Food Science. 87(4): 1540- 1551.

    29. Ware, K., Kashyap, P., Gorde, P. M., Yadav, R. and Sharma, V. (2025). Comparative analysis of RSM and ANN-GA based modeling for protein extraction from cotton seed meal: Effect of extraction parameters on amino acid profile and nutritional characteristics. Food and Bioproducts Processing. 150: 63-77.

    30. Xie, X., Liang, X., Wang, H., Zhu, Q., Wang, J., Chang, Y. and Wang, J. (2023). Effects of paraprobiotics on bile acid metabolism and liver health in largemouth bass (Micropterus salmoides) fed a cottonseed protein concentrate-based diet. Animal Nutrition. 13: 302-312.

    31. Zeng, H.Y., Cai, L.H., Cai, X.L., Wang, Y.J. and Li, Y.Q. (2011). Structure characterization of protein fractions from lotus (Nelumbo nucifera) seed. Journal of Molecular Structure.  1001(1-3): 139-144.
    In this Article
      Contact us
      Follow us
      Published In
      Asian Journal of Dairy and Food Research

      Editorial Board

      View all (0)