Effects of processing methods on the chemical composition and content of Phleum pratense

Timothy grass (Phleum pratense) is an excellent forage plant with good palatability that is rich in natural oil. Drying is the primary way to store forage, which can effectively alleviate the problem of insufficient forage supply in winter and spring. However, drying can affect chemical composition and quality. This study focused on the effects of oven drying, air drying, and compression on the chemical composition and content of P. pratense. Oven drying resulted in the highest total fat content (9.82 mg·g⁻¹). Air drying resulted in the highest total flavonoid (24.16 mg·g⁻¹) and polyphenol (0.45 mg·g⁻¹) contents. Gas chromatography–mass spectrometry identified 46 volatile oil compounds in samples from the three processing methods, including esters, alkanes, alkenes, alcohols, ketones, aldehydes, acids, and benzene derivatives. Sulfurous acid, cyclohexylmethyl heptyl ester, and bis (2-ethylhexyl) phthalate were all identified in the volatile oil of every processing method, indicating that these two compounds were the main chemical components of the volatile oil in P. pratense. These data should provide a theoretical reference for selecting drying methods for P. pratense.