High‐performance size‐exclusion chromatographic studies on a high‐oleic acid sunflower oil during potato frying

Abstract

The behavior of a high-oleic acid sunflower oil used for 75 repeated deep-fat flyings of potatoes, with a fast turnover of fresh oil during frying, was evaluated by measuring the total polar content isolated by column chromatography. The total polar content increased in the oil from 3.6 + 0.1 (mean + SD) mg/100 mg unused oil to 7.6 + 0.4 mg/100 mg oil after being used in 20 repeated flyings, followed by a tendency to reach a near-steady state throughout the successive fryings. Further, the polar fraction was examined by high-performance sizeexclusion chromatography. Triacylglyceride dimers increased continuously from 0.18 _+ 0.01 mg/100 mg unused oil to 2.42 _+ 0.12 rag/100 mg oil at the 40th frying with no further significant changes. The amount of triacylglyceride polymers increased from 0.03 ± 0.00 mg/100 mg unused oil to 0.70 + 0.01 mg/100 mg oil at the 60th frying, but did not increase further with continued frying. Oxidized triacylglycerides also significantly increased from 1.13 -+ 0.06 rag/100 mg oil to 3.58 +_ 0.09 rag/100 mg oil at the 50th frying to reach a near-steady state in successive flyings. Diacylglycerides and free fatty acids levels, related to hydrolytic alteration, did not change from the starting oil after continued fryings. Data from this study indicated that repeated fryings of potatoes in high-oleic sunflower oil with a frequent turnover of fresh oil throughout the frying slightly increased the level of polar material in the fryer oil during the first flyings, followed by minor changes and a tendency to reach a near-steady state in successive flyings. JAOCS 72, 1513-1517 (1995).

Column and high‐performance size exclusion chromatography applications to the in vivo digestibility study of a thermoxidized and polymerized olive oil

“…According to previous studies (1,(20)(21)(22)27), HPSEC data show that after repeated frying uses, the amount of thermoxidized compounds clearly increases. In the present study, triacylglycerol polymers that were not detected in the unheated oil rose to be the third major product in the heated oil.…”

Polar content vs. TAG oligomer content in the frying‐life assessment of monounsaturated and polyunsaturated oils used in deep‐frying

“…Cuesta et al (15) found that changes in PC were highly adjusted to a cubic equation. However, Romero et al (17,18) found that a seconddegree equation accurately and significantly reflected (r > 0.99; P < 0.001) the adjustment of the PC levels, which varied according to the number of frying operations.…”

Colorimetric test application to the efficiency and shelf-life assessments of olive oil, sunflower oil and their blend used for frying frozen and fresh foods

“…La concentración de los distintos compuestos polares de la muestra: oligómeros (polímeros + díme-ros de triglicéridos), triglicéridos oxidados, se calculó mediante una combinación de las técnicas de cromatografía en columna y HPSEC (Dobarganes et al, 1988, Romero et al, 1995. Para ello, la fracción polar aislada, tal como se ha comentado en el apartado anterior, se disolvió en tetrahidrofurano (~20 mg/mL).…”