Water sorption behaviors of cottonseed meal, washed cottonseed meal, and cottonseed protein isolate

Authors: He, Zhongqi; Zhang, David; Cheng, Huai

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/15/2021
Publication Date: 5/15/2021
Citation: He, Z., Zhang, D., Cheng, H.N. 2021. Water sorption behaviors of cottonseed meal, washed cottonseed meal, and cottonseed protein isolate. In: Boyd, S., Huffman, M., Krogman, L., Sarkissian, A., editors. Proceedings of the Virtual National Cotton Council Beltwide Cotton Conferences, January 5-7, 2021. p. 56-60.

Interpretive Summary: In view of their hygroscopic characteristics, agricultural products and byproducts are often studied for their equilibrium moisture contents. Excessive critical moisture content would promote hydrolytic/enzymatic cleavage of macromolecules in these natural products. Defatted cottonseed meal (CSM) and its water washed product (washed cottonseed meal -WCSM) appear promising as renewable and green industrial raw materials, especially as wood adhesives. While the pilot-scale production of relevant products has been reported, information on their moisture adsorption behaviors is needed to design or select appropriate equipment for their handling, aeration, storage and processing. Thus, this work measured the equilibrium moisture sorption isotherms of CSM, WCSM and cottonseed protein isolate (CSPI, as a control) at 15, 25, 35 and 45 0C, and tested selected mathematical equations to fit the experimental sorption behaviors. This work provides some insight on designing or selecting appropriate procedures for the handling, aeration, storing and processing of these cottonseed meal products.

Technical Abstract: Due to their hygroscopic characteristics, equilibrium moisture contents of agricultural products and byproducts are very important for their quality. Defatted cottonseed meal (CSM), washed cottonseed meal (WCSM), and cottonseed protein isolate (CSPI) can be used as an energy and protein source of animal feedstuff or industrial raw materials. Information on their moisture adsorption behaviors is needed for their storage conditions and quality control. Thus, this work measured the equilibrium moisture sorption isotherms of CSM, WCSM and CSPI, at 15, 25, 35 and 45 0C. When the moisture contents of the samples were compared at a constant temperature, the general trend of decreasing moisture content was in the order of CSPI < WCSM < CSM at the water activity < 0.6, but the trend reversed to the order of CSM < WCSM < CSPI at the water activity > 0.6. Relevant 13 sorption isotherm equations were tested for goodness-of-fit of these moisture adsorption data. Modelling results indicated that the G.A.B. model was a consistently good fit for the data among all sample types and all temperatures. This work provides some insight on designing or selecting appropriate procedures for the handling, aeration, storing and processing of these cottonseed meal products.