Study on various green aqueous extraction techniques for extracting cottonseed milk to improve nutritional quality

Abstract Background Plant-based milk is in demand worldwide due to issues such as lactose intolerance, milk allergies, and the environmental impact of dairy farming. Gossypol, which is toxic at certain levels, underutilizes cottonseed for human consumption, despite its high protein and oil contents for emulsion formation. The nutrient contents and interaction of gossypol with protein compounds of the different extracted cottonseed milk samples from modified aqueous extraction (MAE), ultrasonic-assisted aqueous extraction (UAAE), enzymatic-assisted aqueous extraction (EAAE), and conventional aqueous extraction (CAE) methods were analyzed. Results The extraction techniques substantially affected the protein levels and amino acid composition of the milk samples, whereas the fatty acid profile content remained unaltered. Additionally, physicochemical properties such as extraction yield, viscosity, color values, and total acidity are significantly influenced by the extraction methods. The crude protein, crude fat, and gossypol content in the extracted cottonseed milk samples ranged from 2.44 to 3.52 g per 100 mL, 1.594 to 2.953 g per 100 mL, and 42.0 to 67.3 mg·kg −1 (wet basis), respectively. Fourier transform infrared spectroscopy (FTIR) spectra revealed α-helix bands at 1 656.74 cm⁻ 1 in CAE, MAE, and UAAE, and at 1 659.63 cm⁻ 1 in EAAE, indicating alterations in gossypol levels and amine/amide group intensities. EAAE cottonseed milk presented the highest protein and crude fat contents, as well as superior total phenology, flavonoid, and antioxidant activities, making it the most nutritious among all approaches. Conclusions The cottonseed milk samples from the adopted treatments provided the right amount of nutrients and permissible levels of gossypol for human consumption. This study highlights the potential use of cottonseed as a cottonseed-based milk by using the EAAE extraction method, which effectively mitigates gossypol toxicity while preserving essential nutrients and bioactive compounds. The results provide a foundation for future research into the nutritional and functional properties of cottonseed milk as a potential plant-based milk source and alternative dairy system. Graphical Abstract