United States Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, 1100 Robert E Lee Blvd., New Orleans, LA 70124, USA.
Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
Molecules. 2022 Jan 5;27(1):316. doi: 10.3390/molecules27010316.
Common "glanded" (Gd) cottonseeds contain the toxic compound gossypol that restricts human consumption of the derived products. The "glandless" (Gl) cottonseeds of a new cotton variety, in contrast, show a trace gossypol content, indicating the great potential of cottonseed for agro-food applications. This work comparatively evaluated the chemical composition and thermogravimetric behaviors of the two types of cottonseed kernels. In contrast to the high gossypol content (3.75 g kg) observed in Gd kernels, the gossypol level detected in Gl kernels was only 0.06 g kg, meeting the FDA's criteria as human food. While the gossypol gland dots in Gd kernels were visually observed, scanning electron microcopy was not able to distinguish the microstructural difference between ground Gd and Gl samples. Chemical analysis and Fourier transform infrared (FTIR) spectroscopy showed that Gl kernels and Gd kernels had similar chemical components and mineral contents, but the former was slightly higher in protein, starch, and phosphorus contents. Thermogravimetric (TG) processes of both kernels and their residues after hexane and ethanol extraction were based on three stages of drying, de-volatilization, and char formation. TG-FTIR analysis revealed apparent spectral differences between Gd and Gl samples, as well as between raw and extracted cottonseed kernel samples, indicating that some components in Gd kernels were more susceptible to thermal decomposition than Gl kernels. The TG and TG-FTIR observations suggested that the Gl kernels could be heat treated (e.g., frying and roasting) at an optimal temperature of 140-150 °C for food applications. On the other hand, optimal pyrolysis temperatures would be much higher (350-500 °C) for Gd cottonseed and its defatted residues for non-food bio-oil and biochar production. The findings from this research enhance the potential utilization of Gd and Gl cottonseed kernels for food applications.
常见的“有腺体”（Gd）棉籽含有有毒化合物棉酚，限制了人类对衍生产品的消费。相比之下，一种新型棉花品种的“无腺体”（Gl）棉籽则显示出微量的棉酚含量，表明棉籽在农业食品应用方面具有巨大潜力。这项工作比较评估了两种类型的棉籽仁的化学成分和热重行为。与 Gd 仁中观察到的高棉酚含量（3.75 g kg）相比，Gl 仁中的棉酚含量仅为 0.06 g kg，符合 FDA 作为人类食品的标准。虽然 Gd 仁中的棉酚腺点肉眼可见，但扫描电子显微镜无法区分研磨后的 Gd 和 Gl 样品的微观结构差异。化学分析和傅里叶变换红外（FTIR）光谱表明，Gl 仁和 Gd 仁具有相似的化学成分和矿物质含量，但前者的蛋白质、淀粉和磷含量略高。两种仁及其经己烷和乙醇提取后的残渣的热重（TG）过程均基于三个干燥、挥发和炭化阶段。TG-FTIR 分析显示 Gd 和 Gl 样品之间以及生棉籽仁样品和提取棉籽仁样品之间存在明显的光谱差异，表明 Gd 仁中的某些成分比 Gl 仁更容易受热分解。TG 和 TG-FTIR 观察结果表明，Gl 仁可在 140-150°C 的最佳温度下进行热处理（例如，油炸和烘烤）用于食品应用。另一方面，对于 Gd 棉籽及其脱脂残渣，用于非食品生物油和生物炭生产的最佳热解温度要高得多（350-500°C）。本研究的结果增强了 Gd 和 Gl 棉籽仁在食品应用方面的潜在利用。
