Analysis of the headspace of foodstuffs near room temperature

Formation of volatiles in onion varieties, aging of coffee, and the quality of birch syrup were studied by using near room temperature headspace GC‐MS analysis. Accurate volumes (1–500 mL) of the gaseous samples were introduced into the capillary column either by a syringe or by sucking with a pump. The standard deviation of the contents was typically 1‐7% depending on the foodstuff and the compound. The ratio of 2,3‐butanedione to 2‐methylfuran decreased during the storage of coffee and was a typical measure of aging. Analysis of even the very polar 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone in the headspace of birch syrup was possible. The distribution patterns of the sulfur‐containing volatiles generated by crushed onions were close to each other in different varieties. The rate of the total formation of the compounds varied from cultivar to cultivar.