Abstract

Seed roasting is a critical step for fragrant oil as it achieves the development of aroma and flavor, but also it is the way of polycyclic aromatic hydrocarbons and other harmful substances generated. In this study, for the purpose of mimic moderate roasting as well as powerful roasting condition, five oilseeds (peanut, sesame, sunflower, rapeseed and flaxseed) were submitted to roast at six selected temperatures (160 °C, 180 °C, 200 °C, 220 °C, 240 °C and 260 °C) for increasing time. The PAH levels in the five oils which obtained from corresponding roasted seed were quantified via GC-MS. The results showed that the concentrations and types of PAH substances in oils rapidly became more plentiful over seed roasting temperature and time, resulting an increase in total PAH concentrations, particular at temperature above 200 °C. The PAHs produced during the roasting of oilseeds may be mainly attributed to the lipid content and the degree of unsaturation (or P/S index) of the oilseeds. The higher lipid content in the oilseed, the easier it is to produce PAHs during seed roasting pretreatment. Oilseed with high polyunsaturated fatty acids tend to produce HPAH, on the contrary, low polyunsaturated fatty acids tend to produce LPAH.

摘要

种子焙烧是香油发展的关键步骤，它实现了香气和风味的发展，也是多环芳烃等有害物质产生的途径。在这项研究中，为了模拟适度烘烤和强力烘烤条件，将五种油籽（花生、芝麻、向日葵、油菜籽和亚麻籽）在六个选定温度（160°C、180°C、200° C、220 °C、240 °C 和 260 °C）用于增加时间。通过 GC-MS 对从相应的烤种子中获得的五种油中的 PAH 水平进行量化。结果表明，随着种子烘烤温度和时间的延长，油中 PAH 物质的浓度和种类迅速增加，导致总 PAH 浓度增加，特别是在温度高于 200 ℃时。油籽烘烤过程中产生的 PAHs 可能主要归因于油籽的脂质含量和不饱和度（或 P/S 指数）。油料中的脂质含量越高，越容易在种子烘烤预处理过程中产生 PAHs。具有高多不饱和脂肪酸的油籽倾向于产生HPAH，相反，低多不饱和脂肪酸倾向于产生LPAH。