Detoxification and nutritional improvement of defatted cottonseed meal through sequential co-fermentation and the production of a low toxic cottonseed peptides

As one of the most abundant unconventional plant protein resources, cottonseed meal can effectively alleviate the current feed resource shortage. However, research on its high-value development remains relatively limited. This study aims to simultaneously enhance the protein nutritional quality and safety of cottonseed meal through co-fermentation with Bacillus subtilis natto N-2 and Meyerozyma guilliermondii WST-M1. Based on this process, a peptides product was developed to promote the high-value utilization of cottonseed meal. The optimal fermentation conditions of N-2 for cottonseed meal have been determined through optimization experiments. The biological functional complementary between N-2 and WST-M1 was achieved through sequential co-fermentation. The water soluble and trichloroacetic acid soluble protein of sequential co-fermented cottonseed meal reached 34.13 ± 1.02 % and 26.10 ± 0.91 % respectively, with free gossypol decreased to 653.26 ± 16.25 mg/kg. In addition, protein nutritional component in sequential co-fermented cottonseed meal was extracted through enzymatic hydrolysis extraction. Base on the method above, low gossypol cottonseed protein peptides was successfully produced, which the total protein content reaching 59.47 % with high small peptides composition (91.93 % <3000 Da, including 78.24 % <1000 Da), total and free gossypol decreasing to 130.15 mg/kg and 89.73 mg/kg, respectively. • A novel sequential co-fermentation system was successfully developed. • Novel co-fermentation enhance nutritional profiles and safety of cottonseed meal. • Low toxic peptides were generated from co-fermented cottonseed meal. • Peptides show superior nutritional profiles and reduced gossypol content.