Roasting impact on the chemical composition of glandless cottonseed

Authors: He, Zhongqi; Nam, Sunghyun; Klasson, K Thomas; Cheng, Huai

Submitted to: 2003 Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 5/25/2023
Publication Date: 6/1/2023
Citation: He, Z., S. Nam, K. T. Klasson, and H. N. Cheng. 2023. Roasting impact on the chemical composition of glandless cottonseed. In: Proceedings of Beltwide Cotton Conferences, January 10-12, 2023, New Orleans, Louisiana. p. 70-79.

Interpretive Summary: Roasting is a technological process in most food applications of agricultural products. The chemical changes occurred during roasting could be responsible for changes in product quality attributes like nutrition, color, and flavors. Roasting may also increase the levels of bioactive compounds and antioxidant activities. Thus, this work investigated the impact of roasting on the coloration and chemical composition of the nonpolar oil fraction and polar fraction of glandless cottonseed kernels. Darker coloration with increasing roasting temperature was observed as a general trend for the whole kernels. Roasting did not impact the major chemical composition of the oil fractions. However, roasting changed the composition and abundance of ethanol-extractable bioactive compounds. Among the 15 identified potential bioactive compounds, the most abundant one is an anticancer chemical. Identification of this compound may be helpful in further exploration of functions and mechanisms of ethanol extracts of cottonseed in inhibition of the mitochondrial activity of cancer cell lines derived from breast and pancreas.

Technical Abstract: With an ultralow gossypol content, glandless cottonseed opens the door for food application of cottonseed products. Roasting (i.e., thermal processing without addition of a liquid) is a technological process in most food applications of agricultural products. In this work, glandless cottonseed kernels were roasted at 5 setting temperatures between 110-150 oC for 15 min, respectively. The nonpolar (oil) and polar components in these roasted samples and an unroasted control were extracted by hexane and 80% ethanol, respectively. Darker coloration with increasing roasting temperature was observed as a general trend for the whole kernels and the two extracts. 13C and 1H NMR analysis showed no obvious change in major chemical composition of the oil fractions after roasting. HPLC data revealed that the tocopherol content of these oil fractions decreased slightly in samples roasted at higher temperatures (130-150 oC). Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry identified about 44% to 55% of total formulas in the polar fractions as potential phenolic compounds with double bond equivalent = 4. Upon roasting, carbohydrate-, lignin-, and tannin-like compounds increased, lipid-like compounds decreased, and peptide-like compounds kept basically unchanged in the polar fractions. Further quantitative data comparison indicated that roasting increased the abundance of majority of the potential bioactive compounds in the polar fractions. The information derived from this work would be useful in enhanced utilization of cottonseed as functional foods or food supplement