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Effects of roasting on hazelnut lipids
Joana S Amaral1, Susana Casal, Rosa M Seabra
1REQUIMTE, Serviços de Farmacognosia and Bromatologia, Faculdade de Farmácia, Universidade do Porto, R. Aníbal Cunha 164, 4030-099 Porto, Portugal.
Journal of Agricultural and Food Chemistry
|February 16, 2006
Summary
Roasting hazelnuts causes minor changes in fatty acids and triacylglycerols. Beneficial compounds like phytosterols and vitamin E slightly decrease, while trans fatty acids negligibly increase.
Area of Science:
- Food Science
- Nutritional Biochemistry
- Agricultural Chemistry
Background:
- Hazelnuts (Corylus avellana L.) are a popular food source rich in lipids.
- Understanding the impact of processing, like roasting, on hazelnut's nutritional profile is crucial for food quality and health.
- The lipidic fraction contains valuable compounds such as fatty acids, triacylglycerols, phytosterols, and tocopherols/tocotrienols.
Purpose of the Study:
- To investigate the effects of different roasting temperatures and times on the nutritional characteristics of the hazelnut lipidic fraction.
- To quantify changes in moisture, crude fat, fatty acids, triacylglycerols, phytosterols, and vitamin E homologues after thermal treatment.
Main Methods:
- Hazelnuts were subjected to thermal treatments at temperatures ranging from 125-200°C for 5, 15, and 30 minutes.
- Analysis included moisture and crude fat content determination.
- Advanced analytical techniques such as Gas Chromatography-Flame Ionization Detection (GC-FID), High-Performance Liquid Chromatography with Evaporative Light Scattering Detection (HPLC-ELSD), and High-Performance Liquid Chromatography with Diode Array Detection/fluorescence spectroscopy (HPLC-DAD) were employed.
Main Results:
- Roasting resulted in minor alterations to the fatty acid and triacylglycerol profiles.
- Increased roasting temperatures and durations led to a modest rise in oleic and saturated fatty acids, and a decrease in linoleic acid.
- A slight reduction in beneficial phytosterols (up to 14.4%) and vitamin E homologues (up to 10.0%) was observed, alongside a negligible increase in trans fatty acids.
Conclusions:
- Roasting hazelnuts induces subtle modifications in their lipid composition.
- While generally minor, the observed decreases in beneficial phytosterols and vitamin E warrant consideration.
- The study provides valuable data on the nutritional impact of roasting on hazelnut lipids, informing food processing and consumer choices.
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