FSP/
Articles/
2605003887
  • Open Access
  • Article

Heterogeneous Australian Pigeonpea [Cajanus cajan (L.) Millsp.] Genotypes with Homogeneous in-vitro Proteolysis

  • Danica Malau,   
  • Peter A. Sopade

Received: 21 Feb 2026 | Revised: 09 May 2026 | Accepted: 12 May 2026 | Published: 22 May 2026

Abstract

Pigeonpea is a potential raw material for the growing plant protein industry, and the food properties of six Australian genotypes (ICPLs 14425, 86022, 88039, 90048, 91039, and 98011) were investigated. In-vitro proteolysis was analysed with a pH drop. The genotypes, coloured cream to brown, differed (p ≤ 0.05) in their total (43.3–56.5), whiteness (40.2–53.4), yellowish (35.4–50.7), and browning (32.1–60.2) colour indices. Potassium, phosphorus, and sulphur were the major minerals. Approximating a sphere (mm, major [6.6] and minor [6.0] diameters, and thickness [5.3]), the genotypes differed in starch (20–32 g/100g solids) and protein (22–27 g/100g solids) contents. Although the genotypes revealed identical pasting (p > 0.05) temperatures (85 ± 2 ℃) and slightly-shear thinning behaviours (breakdown ratio = 0.8–0.9), their peak (124–371), trough (108–337), and final (213–520) viscosities (cP) differed. Essentially, the genotypes were heterogeneous in their physicochemical, colour, and pasting properties. However, their protein digestograms, analysed with the Sopade Objective Procedure (objective logarithm of slope), revealed a true monophasic digestion mode; homogeneous in-vitro proteolysis. Seven kinetic models for monophasic digestograms adequately (r2 > 0.78) described the digestograms, and the Peleg model was recommended. There were no genotypic differences (p > 0.05) in the protein hydrolysis index (HIPROTEIN = 17.4–24.7%) relative to reference casein, average in-vitro protein digestibility (IVPDAVG = 69–71%), rate of protein digestion (KPR = 0.09–0.24 min−1), and other protein digestion parameters. This study pioneers time-course protein digestion for pigeonpea, and with rates of food digestion valuable in future food labelling, a solid foundation for pigeonpea utilizations is presented.

References 

  • 1.

    Fasoyiro, S.B.; Ajibade, S.R.; Saka, J.O.; et al. Physical Characteristics and Effects of Processing Methods on Pigeon Pea Varieties. J. Food Agric. Environ. 2002, 3, 59–61.

  • 2.

    Chauhan, Y.; Krosch, S.; Sands, D.; et al. Agronomic Characteristics of Pigeonpea as a Summer Crop for Queensland. In Proceedings of the 20th Australian Agronomy Conference, Toowoomba, QLD, Australia, 18–22 September 2022.

  • 3.

    Locali-Pereira, A.R.; Boire, A.; Berton-Carabin, C.; et al. Pigeon Pea, an Emerging Source of Plant-Based Proteins. ACS Food Sci. Technol. 2023, 3, 1777–1799. https://doi.org/10.1021/acsfoodscitech.3c00268.

  • 4.

    Wu, J.; Zhou, Q.; Zhou, C.; et al. Strategies to Promote the Dietary Use of Pigeon Pea (Cajanus cajan L.) for Human Nutrition and Health. Food Front. 2024, 5, 1014–1030. https://doi.org/10.1002/fft2.381.

  • 5.

    Haji, A.; Teka, T.A.; Bereka, T.Y.; et al. Nutritional Composition, Bioactive Compounds, Food Applications, and Health Benefits of Pigeon Pea (Cajanus cajan L. Millsp.): A Review. Legume Sci. 2024, 6, e233. https://doi.org/10.1002/leg3.233.

  • 6.

    Food and Agriculture Organization of the United Nations. Available online: https://www.fao.org/faostat/en/#data/QCL (accessed on 12 November 2025).

  • 7.

    Benítez, R.B.; Tabares, W.F.E.; Velásquez, L.A.L.; et al. Enzymatic Hydrolysis as a Tool to Improve Total Digestibility and Techno‑Functional Properties of Pigeon Pea (Cajanus cajan) Starch. Heliyon 2021, 7, e07817. https://doi.org/10.1016/j.heliyon.2021.e07817.

  • 8.

    Kumari, B.; Sit, N. Physicochemical, Rheological Properties, and in‑Vitro Starch Digestibility of Flours and Starches from Pigeon Pea, Cowpea, Pinto Bean, and Navy Bean. Starch Stärke 2024, 76, 2300303. https://doi.org/10.1002/star.202300303.

  • 9.

    Sultana, R.; Vales, M.I.; Saxena, K.B.; et al. Waterlogging Tolerance in Pigeonpea (Cajanus cajan (L.) Millsp.): Genotypic Variability and Identification of Tolerant Genotypes. J. Agric. Sci. 2013, 151, 659–671. https://doi.org/10.1017/S0021859612000755.

  • 10.

    Kachare, D.P.; Satbhai, R.D.; Rathod, D.B.; et al. Evaluation of Pigeon Pea (Cajanus cajan L.) Genotypes for Nutritional Quality. Legume Res. 2017, 42, 485–489. https://doi.org/10.18805/LR-3899.

  • 11.

    Ravika, Y.; Yadav, R.; Kumari, N.; et al. Genetic Diversity for Quality Traits and Seed Yield in Pigeonpea [Cajanus cajan (L.) Millsp.]. Int. J. Curr. Microbiol. Appl. Sci. 2019, 8, 2837–2844. https://doi.org/10.20546/ijcmas.2019.806.342.

  • 12.

    Anon. Legumes Program: Quarterly Technical Report—January–March 1993. Available online: https://oar.icrisat.org/8175/1/RP%208228.pdf (accessed on 12 November 2025).

  • 13.

    Tiwari, A.; Singh, P.; Maurya, C.L.; et al. Assessment of Nutritional Attributes in Pigeonpea Genotypes: Protein Quality, Carbohydrate Fractions, and Digestibility Patterns. Int. J. Adv. Biochem. Res. 2025, 9, 4–9. https://doi.org/10.33545/26174693.2025.v9.i9Sa.5461.

  • 14.

    Yohane, E.N.; Shimelis, H.; Laing, M.; et al. Genotype-by-Environment Interaction and Stability Analyses of Grain Yield in Pigeonpea [Cajanus cajan (L.) Millspaugh]. Acta Agric. Scand. B Soil Plant Sci. 2021, 71, 145–155. https://doi.org/10.1080/09064710.2020.1859608.

  • 15.

    Legume Varieties Released by UQ Will Increase Volume for Local Growers. Available online: https://afdj.com.au/legume-varieties-released-by-uq-will-increase-volume-for-local-growers/ (accessed on 12 November 2025).

  • 16.

    Singh, A.K.; Elango, D.; Raigne, J.; et al. Plant-Based Protein Crops and Their Improvement: Current Status and Future Perspectives. Crop Sci. 2025, 65, e21389. https://doi.org/10.1002/csc2.21389.

  • 17.

    Anyiam, P.N.; Phongthai, S.; Pongsetkul, J.; et al. Novel-Assisted Extraction Methods for Protein Recovering from Bambara Groundnut: Composition, Techno-Functional and Digestibility. J. Food Biochem. 2026, 2026, 6622287. https://doi.org/10.1155/jfbc/6622287.

  • 18.

    Ohanenye, I.C.; Sun, X.; Sarteshnizi, R.A.; et al. Germination Alters the Microstructure, in Vitro Protein Digestibility, α‑Glucosidase and Dipeptidyl Peptidase-IV Inhibitory Activities of Bioaccessible Fraction of Pigeon Pea (Cajanus cajan) Seeds. Legume Sci. 2021, 3, e79. https://doi.org/10.1002/leg3.79.

  • 19.

    Rizvi, Q.U.E.H.; Kumar, K.; Ahmed, N.; et al. Influence of Soaking and Germination Treatments on the Nutritional, Anti‑Nutritional, and Bioactive Composition of Pigeon Pea (Cajanus cajan L.). J. Appl. Biol. Biotechnol. 2022, 10, 127–134. https://doi.org/10.7324/JABB.2022.100317.

  • 20.

    Mahendraraj, S.; Collins, M.; Chauhan, Y.; et al. Reliability of Nonlinear Least Square Broken Stick Model in Quantifying the Effects of Temperature and Photoperiod on Flowering of Pigeonpea Genotypes (Cajanus cajan (L.) Millsp.). J. Appl. Nat. Sci. 2024, 16, 502–508. https://doi.org/10.31018/jans.v16i2.4840.

  • 21.

    Winter, B. Pigeonpea: A New Dryland Summer Pulse for Northern Region Farming Systems. Available online: https://grdc.com.au/resources-and-publications/grdc-update-papers/tab-content/grdc-update-papers/2024/07/pigeonpea-a-new-dryland-summer-pulse-for-northern-region-farming-systems (accessed on 12 November 2025).

  • 22.

    Oluwole, O.B.; Nicholas-Okpara, V.A.N.; Elemo, G.; et al. Medicinal Uses, Nutraceutical Potentials, and Traditional Farm Production of Bambara Beans and Pigeon Peas. Glob. J. Epidemiol. Public Health 2022, 20, 41–50. https://doi.org/10.12974/2313-0946.2021.06.01.3.

  • 23.

    Chinma, C.E.; Abu, J.O.; Adedeji, O.E.; et al. Nutritional Composition, Bioactivity, Starch Characteristics, Thermal and Microstructural Properties of Germinated Pigeon Pea Flour. Food Biosci. 2022, 49, 101900. https://doi.org/10.1016/j.fbio.2022.101900.

  • 24.

    Ohanenye, I.C.; Ekezie, F.-G. C.; Sarteshnizi, R.A.; et al. Legume Seed Protein Digestibility as Influenced by Traditional and Emerging Physical Processing Technologies. Foods 2022, 11, 2299. https://doi.org/10.3390/foods11152299.

  • 25.

    Opazo-Navarrete, M.; Burgos‑Díaz, C.; Bravo-Reyes, C.; et al. Comprehensive Review of Plant Protein Digestibility: Challenges, Assessment Methods, and Improvement Strategies. Appl. Sci. 2025, 15, 3538. https://doi.org/10.3390/app15073538.

  • 26.

    Lao, Y.; Ye, Q.; Wang, Y.; et al. Modulating Digestibility and Mitigating Beany Flavor of Pea Protein. Food Rev. Int. 2024, 40, 3129–3158. https://doi.org/10.1080/87559129.2024.2346329.

  • 27.

    Sharma, S.; Singh, A.; Singh, B. Characterization of in Vitro Antioxidant Activity, Bioactive Components, and Nutrient Digestibility in Pigeon Pea (Cajanus cajan) as Influenced by Germination Time and Temperature. J. Food Biochem. 2019, 43, e12706. https://doi.org/10.1111/jfbc.12706.

  • 28.

    Dutta, M.; Dineshkumar, R.; Nagesh, C.R.; et al. Exploring Protein Structural Adaptations and Polyphenol Interactions: Influences on Digestibility in Pigeon Pea Dal and Whole Grains under Heat and Germination Conditions. Food Chem. 2024, 460, 140561. https://doi.org/10.1016/j.foodchem.2024.140561.

  • 29.

    Thomas, D.J.; Lu, Z.; Brummer, Y.; et al. Assessment of Protein Quality and Nutritional Characteristics of Commonly Consumed Pulses in the Caribbean Diet by Different in Vitro Assays. Foods 2025, 14, 283. https://doi.org/10.3390/foods14020283.

  • 30.

    Mackie, A. Insights and Gaps on Protein Digestion. Curr. Opin. Food Sci. 2020, 31, 96–101. https://doi.org/10.1016/j.cofs.2020.03.006.

  • 31.

    Sousa, R.; Portmann, R.; Dubois, S.; et al. Protein Digestion of Different Protein Sources Using the INFOGEST Static Digestion Model. Food Res. Int. 2020, 130, 108996. https://doi.org/10.1016/j.foodres.2020.108996.

  • 32.

    Sopade, P.A. Computational Characteristics of Kinetic Models for in Vitro Protein Digestion: A Review. J. Food Eng. 2024, 360, 111690. https://doi.org/10.1016/j.jfoodeng.2023.111690.

  • 33.

    Nguyen, G.T.; Sopade, P.A. Modeling Starch Digestograms: Computational Characteristics of Kinetic Models for in Vitro Starch Digestion in Food Research. Compr. Rev. Food Sci. Food Saf. 2018, 17, 1422–1445. https://doi.org/10.1111/1541-4337.12384.

  • 34.

    Verkempinck, S.H.E.; Duijsens, D.; Michels, D.; et al. Studying Semi-Dynamic Digestion Kinetics of Food: Establishing a Computer-Controlled Multireactor Approach. Food Res. Int. 2022, 156, 111301. https://doi.org/10.1016/j.foodres.2022.111301.

  • 35.

    Li, Y.; Sopade, P.A. Kinetics of in Vitro Protein Digestion in an Extruded Model Sorghum‑Barley Blend: Processing and Property Relationships. J. Food Eng. 2025, 391, 112437. https://doi.org/10.1016/j.jfoodeng.2024.112437.

  • 36.

    Mahasukhonthachat, K.; Sopade, P.A.; Gidley, M.J. Kinetics of Starch Digestion in Sorghum as Affected by Particle Size. J. Food Eng. 2010, 96, 18–28. https://doi.org/10.1016/j.jfoodeng.2009.06.051.

  • 37.

    Sopade, P.A. Homogeneities in in Vitro Starch Digestion of Compositionally Heterogenous White Wheat Breads. Int. J. Food Sci. Technol. 2022, 57, 4380–4391. https://doi.org/10.1111/ijfs.15766.

  • 38.

    Nguyen, G.T.; Gidley, M.J.; Sopade, P.A. Dependence of in Vitro Starch and Protein Digestions on Particle Size of Field Peas (Pisum sativum L.). LWT Food Sci. Technol. 2015, 63, 541–549. https://doi.org/10.1016/j.lwt.2015.03.037.

  • 39.

    Koa, S.S.; Jin, X.; Zhang, J.; et al. Extrusion of a Model Sorghum‑Barley Blend: Starch Digestibility and Associated Properties. J. Cereal Sci. 2017, 75, 314–323. https://doi.org/10.1016/j.jcs.2017.04.007.

  • 40.

    Waramboi, J.G.; Dennien, S.; Gidley, M.J.; et al. Characterization of Sweetpotato from Papua New Guinea and Australia: Physicochemical, Pasting and Gelatinization Properties. Food Chem. 2011, 126, 1759–1770. https://doi.org/10.1016/j.foodchem.2010.12.077.

  • 41.

    Uriarte‑Aceves, P.M.; Rangel‑Peraza, J.G.; Sopade, P.A. Kinetics of Water Absorption and Relation with Physical, Chemical, and Wet‑Milling Properties of Commercial Yellow Maize (Zea mays L.) Hybrids. J. Food Process. Preserv. 2020, 44, e14509. https://doi.org/10.1111/jfpp.14509.

  • 42.

    Uriarte-Aceves, P.M.; Sopade, P.A.; Rangel-Peraza, J.G. Physical, Chemical and Wet-Milling Properties of Commercial White Maize Hybrids Cultivated in México. J. Food Process. Preserv. 2019, 43, e13998. https://doi.org/10.1111/jfpp.13998.

  • 43.

    Hsu, H.W.; Vavak, D.L.; Satterlee, L.D.; et al. A Multienzyme Technique for Estimating Protein Digestibility. J. Food Sci. 1977, 42, 1269–1273. https://doi.org/10.1111/j.1365-2621.1977.tb14476.x.

  • 44.

    Tinus, T.; Damour, M.; van Riel, V.; et al. Particle Size‑Starch‑Protein Digestibility Relationships in Cowpea (Vigna unguiculata). J. Food Eng. 2012, 113, 254–264. https://doi.org/10.1016/j.jfoodeng.2012.05.041.

  • 45.

    Jin, X.; Li, Y.; Koa, S.S.; et al. In Vitro Protein and Starch Digestibilities of Multigrain Sorghum‑Barley Mixtures. J. Food Eng. 2024, 379, 112135. https://doi.org/10.1016/j.jfoodeng.2024.112135.

  • 46.

    Bera, I.; O’Sullivan, M.; Flynn, D.; et al. Relationship between Protein Digestibility and the Proteolysis of Legume Proteins during Seed Germination. Molecules 2023, 28, 3204. https://doi.org/10.3390/molecules28073204.

  • 47.

    Burstin, J.; Gallardo, K.; Mir, R.R.; et al. Improving Protein Content and Nutrition Quality. In Biology and Breeding of Food Legumes; Pratap, A., Kumar, J., Eds.; CABI: Wallingford, UK, 2011; pp. 314–328.

  • 48.

    Oloyo, R.A. Chemical and Nutritional Quality Changes in Germinating Seeds of Cajanus cajan L. Food Chem. 2004, 85, 497–502. https://doi.org/10.1016/S0308-8146(02)00454-5.

  • 49.

    Sangronis, E.; Machado, C. Influence of Germination on the Nutritional Quality of Phaseolus vulgaris and Cajanus cajan. LWT Food Sci. Technol. 2007, 40, 116–120. https://doi.org/10.1016/j.lwt.2005.08.003.

  • 50.

    Singh, U.; Rao, P.V.; Subrahmanyam, N.; et al. Cooking Characteristics, Chemical Composition and Protein Quality of Newly Developed Genotypes of Pigeonpea (Cajanus cajan L). J. Sci. Food Agric. 1993, 61, 395–400. https://doi.org/10.1002/jsfa.2740610404.

  • 51.

    Mihalyi, E.; Billick, I.H. Transformation of Fibrinogen into Fibrin III. Kinetics of the pH Change Associated with the Clotting of Fibrinogen. Biochim. Biophys. Acta 1963, 71, 97–108. https://doi.org/10.1016/0006-3002(63)90989-2.

  • 52.

    Mihalyi, E.; Godfrey, J.E. Kinetic Studies of the Digestion of Fibrinogen by α‑Chymotrypsin. Biochim. Biophys. Acta 1967, 132, 94–103. https://doi.org/10.1016/0005-2744(67)90195-7.

  • 53.

    Sopade, P.A. Computational Characteristics of Kinetic Models for Lipolysis: Part I—Models with One Rate of Digestion for Monophasic in Vitro Lipid Digestograms. Eur. Food Res. Technol. 2026, 252, 148. https://doi.org/10.1007/s00217-026-05072-1.

  • 54.

    Gallagher, K.M.; Corrigan, O.I. Mechanistic Aspect of the Release of Levamisole Hydrochloride from Biodegradable Polymers. J. Control. Release 2000, 69, 261–272. https://doi.org/10.1016/S0168-3659(00)00305-9.

  • 55.

    González, C.; Simpson, R.; Vega, O.; et al. Effect of Particle Size on in Vitro Intestinal Digestion of Emulsion‑Filled Gels: Mathematical Analysis Based on the Gallagher–Corrigan Model. Food Bioprod. Process. 2020, 120, 33–40. https://doi.org/10.1016/j.fbp.2019.12.009.

  • 56.

    Aleixandre, A.; Benavent-Gil, Y.; Moreira, R.; et al. In Vitro Digestibility of Gels from Different Starches: Relationship between Kinetic Parameters and Microstructure. Food Hydrocoll. 2021, 120, 106909. https://doi.org/10.1016/j.foodhyd.2021.106909.

  • 57.

    Barua, S.; Rakshit, M.; Srivastav, P.P. Optimization and Digestogram Modeling of Hydrothermally Modified Elephant Foot Yam (Amorphophallus paeoniifolius) Starch Using Hot Air Oven, Autoclave, and Microwave Treatments. LWT Food Sci. Technol. 2021, 145, 111283. https://doi.org/10.1016/j.lwt.2021.111283.

  • 58.

    Barua, S.; Tudu, K.; Rakshit, M.; et al. Characterization and Digestogram Modeling of Modified Elephant Foot Yam (Amorphophallus paeoniifolius) Starch Using Ultrasonic Pretreated Autoclaving. J. Food Process Eng. 2021, 144, e13841. https://doi.org/10.1111/jfpe.13841.

  • 59.

    Mahajan, P.; Bera, M.B.; Panesar, P.S. Structural, Functional, Textural Characterization and in Vitro Digestibility of Underutilized Kutki Millet (Panicum sumatrense) Starch. LWT Food Sci. Technol. 2022, 154, 112831. https://doi.org/10.1016/j.lwt.2021.112831.

  • 60.

    Sopade, P.A. Modelling Multiphasic Starch Digestograms with Multiterm Exponential and Non‑Exponential Equations. Carbohydr. Polym. 2022, 275, 118698. https://doi.org/10.1016/j.carbpol.2021.118698.

  • 61.

    Saraswat, S.; Mahajan, P.; Bera, M.B. Comparative Evaluation of Structural, Functional, Textural Characterization, and in Vitro Digestibility of Native and Physically Modified Kodo Millet (Paspalum scrobiculatum) Starch. Food Sci. Biotechnol. 2026. https://doi.org/10.1007/s10068-026-02094-z.

  • 62.

    Castillo‑Gutiérrez, S.; Estudillo-Martínez, M.D.; Lozano-Aguilera, E.D. Influence of the Fitted Straight Line for Confidence Bands Algorithm in Q-Q Plots. Open J. Stat. 2021, 11, 925–930. https://doi.org/10.4236/ojs.2021.116054.

  • 63.

    Bradburn, S. How to Create a QQ Plot in Excel. Available online: https://toptipbio.com/qq-plot-excel/ (accessed on 20 January 2025).

  • 64.

    Sopade, P.A. Criteria for an Appropriate Sorption Model Based on Statistical Analysis. Int. J. Food Prop. 2001, 4, 405–418. https://doi.org/10.1081/JFP-100108642.

Share this article:
Download PDF
Supplementary Materials
DOI
10.53941/fsp.2026.100008
Issue
Volume 2, Issue 2
How to Cite
Malau, D.; Sopade , P. A. Heterogeneous Australian Pigeonpea [Cajanus cajan (L.) Millsp.] Genotypes with Homogeneous in-vitro Proteolysis. Food Science and Processing 2026, 2 (2), 8. https://doi.org/10.53941/fsp.2026.100008.
RIS
BibTex
Copyright & License
article copyright Image
Copyright (c) 2026 by the authors.