Dados do Trabalho

Título

PRACAXI OIL AS A SOURCE OF LONG-CHAIN SATURATED FATTY ACIDS: EFFECT OF COMPOSITION ON THERMAL BEHAVIOR, SOLID FAT CONTENT PROFILE AND OXIDATIVE STABILITY

Introdução

Pracaxi oil (PO) is extracted from Amazonian oilseeds. It’s mostly composed of oleic acid, but also shows an expressive content of behenic and lignoceric acids, long-chain saturated fatty acids rarely found in vegetable oils. The singular composition is expected to influence its properties and stability that could be exploited for future applications. This study aimed to characterize the PO in terms of solid fat content (SFC) profile, thermal behavior and oxidative stability.

Material e Métodos

The SFC was analyzed using a Nuclear Magnetic Resonance (NMR) spectrometer, with measurements taken at 10, 15, 20 and 25 °C. The crystallization/melting profiles of PO were determined by Differential Scanning Calorimetry (DSC), while the thermal oxidative stability was evaluated at 140 °C using a RapidOxy equipment, and expressed as induction time (IT), in minutes.

Resultados e Discussão

The SFC of PO at 10, 15, 20 and 25 °C were 26.3, 13.63, 4.12 and 0.71, respectively. A continuous decrease in SFC was noticeable as the temperature increased, indicating that PO melting begins at temperatures below 10 °C. The results also suggest that PO has fat crystals at refrigeration temperatures (<10 °C), but is completely liquid above 25 °C. The DSC analysis corroborated the results obtained from SFC. The thermograms displayed two broad exothermic peaks in the crystallization curve (Tonset: 25.3 and -44.8 °C), and, accordingly, two endothermic peaks in the melting curve (Tofset: -6.48 and 29.7 °C). The broad peaks are indicative of the heterogeneity of triacylglycerols, which are directly influenced by the heterogeneous fatty acid composition. The peaks located at higher temperatures in the crystallization/melting processes are related to the high-melting triacylglycerol fraction, including behenic and lignoceric acids. The peaks found at lower temperatures may correspond to the crystallization/melting of unsaturated fractions, mainly composed of oleic and linoleic acids. In terms of oxidative stability, PO exhibited IT of 110.8 ± 2.5 min, proving to be more stable than olive oil (59.5 min) and sunflower oil (30.7 min).

Conclusão

In conclusion, PO has great oxidative stability and can be applied in high-temperature processes. Additionally, the wide melting/crystallization temperature range makes it suitable for application in products that require prolonged melting sensory characteristics.