# Effects of Frying Temperature and Composite Spices on the Release Characteristics of Rapeseed Seasoning Oil

## TL;DR

This study finds that frying at 160°C with specific spice blends maximizes the flavor diversity of rapeseed seasoning oil.

## Contribution

The paper identifies optimal frying conditions and spice ratios to enhance flavor release in seasoning oil.

## Key findings

- Frying at 160°C for 15 minutes produced the most diverse volatile organic compounds (VOCs).
- High heat (170°C) reduced flavor complexity by decreasing the number of key VOCs.
- 2-methoxy-3-(1-methylethyl)-pyrazine was identified as a core aroma compound contributing to sweet and roasted notes.

## Abstract

In Chinese cuisine, seasoning oil enhances the aroma and appearance of dishes. This study examined how processing affects flavor release in multi-ingredient oils. Volatile organic compounds (VOCs), relative odor activity value (ROAV), and variable importance projection (VIP) were used to assess flavor changes. Optimal frying was 160 °C for 15 min with 11% green Sichuan peppercorn, 3% ghost pepper, 6% green onion, 0.1% bay leaf, 0.2% deseeded tsaoko, 0.5% star anise, 0.3% fennel seeds, 1.5% dried Erjingtiao chili, 5% ginger, and 2.5% red Sichuan peppercorn. Gas chromatography–ion mobility spectrometry (GC-IMS) and gas chromatography–mass spectrometry (GC-MS) analyzed heating at 150 °C, 160 °C, and 170 °C. Temperature strongly influenced VOC formation; 160 °C produced the most diverse VOCs, including aldehydes, ketones, terpenes, esters, and alcohols. Multivariate analysis identified 73 key compounds (VIP > 1) between 150 and 160 °C, but only 39 between 160 and 170 °C, indicating that high heat reduces complexity. Compounds such as 2-methylpyrazine and (E)-2-heptenal contributed caramel, nutty, buttery notes, with 2-methoxy-3-(1-methylethyl)-pyrazine as the core aroma. Frying at 160 °C balanced sweet, floral, and roasted aromas, offering guidance for precise seasoning oil flavor control.