Dr. Axe Wire · Food, herbs & supplements · health

Roasting Temperature Changes Nutrient Levels in Camellia Seed Oil

A lab analysis found a roasting window that preserves more nutrients in camellia seed oil than hotter processing.

By Dr. Josh Axe · November 4, 2026 · 1 source · Watch

Photo: Pexels

At a glance

What they found: Roasting camellia seed oil at 120 to 140 degrees Celsius for up to 60 minutes kept more squalene and plant sterols than hotter roasting.
Who was studied: Camellia seed oil samples roasted at 80 to 180 degrees Celsius for 30 to 120 minutes in a lab.
What it doesn't show: Whether it works the same way in people.

A lab analysis published October 24, 2026 in Food Chemistry found that roasting camellia seed oil at 120 to 140 degrees Celsius for 60 minutes or less preserved more of its natural nutrients than hotter roasting did.

120-140°Cideal window

160°C+degrades nutrients

Researchers heated camellia seed oil across a range of conditions, 80 to 180 degrees Celsius for 30 to 120 minutes, then measured changes in its fat molecules and trace nutrients, including squalene, plant sterols, polyphenols and vitamin E compounds called tocopherols. Moderate roasting, 120 to 140 degrees Celsius for 60 minutes or less, largely preserved the structure of the oil's triglycerides (its main fat molecules), released more squalene and plant sterols, and kept extraction yield high.

Intense roasting at 160 degrees Celsius or higher caused the fat molecules to clump together and broke down the trace nutrients, while building up total polar compounds (a degradation marker), free fatty acids, and two aldehydes, nonanal and 2,4-decadienal, linked to oxidized, stale-tasting oil.

The researchers describe a cascade: heat first reorganizes the oil's fat structure, then degrades protective plant compounds, then produces breakdown byproducts past a heat threshold. Roasting is a common step in producing seed and nut oils, and how it's done can change flavor and nutrient content before the oil reaches a bottle. The authors identified 120 to 140 degrees Celsius for up to 60 minutes as the window balancing yield and nutrient retention.

Optimal Roasting Window for Camellia Seed Oil

Food Chemistry, 2026, Chen et al.

This is a chemical analysis under controlled lab conditions, not a study of home cooking or outcomes in people who eat the oil. Camellia seed oil is also a specialty product grown mainly in parts of Asia, not a Western kitchen staple, so these findings describe oil processing, not a tested diet.

Dr. Axe’s Take

Heat is never neutral when it comes to oils. The same roasting step that develops flavor and improves yield in camellia seed oil strips out squalene, plant sterols and other protective compounds once temperatures climb past a threshold. I favor cold-pressed or minimally processed oils when I can find them, and I store any oil away from heat and light to protect what survives processing. For cooking at home, I lean on more stable fats like avocado oil or coconut oil for higher-heat cooking, saving delicate, less-processed oils for finishing dishes rather than roasting or frying.

— Dr. Axe

Take the Cellular Health Quiz →

Story summary

Who: Camellia seed oil samples, not human or animal subjects
Design: Lab analysis of oil roasted at 80-180°C for 30-120 minutes, measuring fat structure and trace nutrients
Dose: Roasting at 80-180°C for 30-120 minutes; optimal window 120-140°C for ≤60 minutes
Primary result: Moderate roasting (120-140°C, ≤60 min) preserved triglyceride structure and raised squalene and phytosterol release while maintaining oil yield
Secondary: Intense roasting (≥160°C) caused triglyceride polymerization, degraded bioactive compounds, and increased total polar compounds, free fatty acids, and the aldehydes nonanal and 2,4-decadienal
Funding / conflicts: Funders listed in the journal record: Hunan Provincial Natural Science Foundation; National Natural Science Foundation of China. Competing interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Date: Oct 24, 2026