The antipolymerization effects of α- and γ-tocopherols were compared in model systems composed of purified high-oleic sunflower triacylglycerols at 180°C. γ-Tocopherol was much more effective as an antipolymerization inhibitor than α-tocopherol, partly due to lower oxidizability/disappearance. Purified triacylglycerols of sunflower, rapeseed, and high-oleic sunflower oils were less stable than their nonpurified forms containing tocopherols. Results confirmed that tocopherols per se can act as antipolymerization agents in high-oleic oils at frying temperatures. No synergism was observed when α- and γ-tocopherols were present together although larger amounts of residuals were left for both tocols. Results suggested that high-oleic/high-γ-tocopherol oils (such as high-oleic canola and high-oleic soybean oils) may provide better frying oils than high-oleic/high-α-tocopherol oils (such as high-oleic sunflower oil).

Effect of α- and γ-Tocopherols on Thermal Polymerization of Purified High-Oleic Sunflower Triacylglycerols

https://aasldpubs.onlinelibrary.wiley.com/doi/pdf/10.1002/hep.21625

Prevention of reperfusion injury and microcirculatory failure in macrosteatotic mouse liver by omega-3 fatty acids†‡

A comparison of the antioxidant properties of steryl ferulates with tocopherol at high temperatures

Most fats and oils consist of triacylglycerides (recently also denoted as triacylglycerols; cf. 3.3.1) which differ in their fatty acid compositions to a certain extent. Other constituents which make up less than 3% of fats and oils are the unsaponifiable fraction (cf. 3.8) and a number of acyl lipids; e.g., traces of free fatty acids, mono- and diacylglycerols.

Edible Fats and Oils

Infrared (IR) heating offers several advantages over conventional heating in terms of heat transfer efficiency, compactness of equipment, and quality of the products. Roasting of sesame seeds degrades the lignan sesamolin to sesamol, which increases the oxidative stability of sesame oil synergistically with tocopherols. IR (near infrared, 1.1 to 1.3 microm, 6 kW power) roasting conditions were optimized for the conversion of sesamolin to sesamol. The resultant oil was evaluated for sesamol and tocopherol content as well as oxidative stability. The defatted flours were evaluated for their nutritional content and functionality. IR roasting of sesame seeds at 200 degrees C for 30 min increased the efficiency of conversion of sesamolin to sesamol (51% to 82%) compared to conventional heating. The gamma-tocopherol content decreased by 17% and 25% in oils treated at 200 and 220 degrees C for 30 min, respectively. There were no significant differences in the tocopherol content and oxidative stability of the oil. Methionine and cysteine content of the flours remained unchanged due to roasting. The functional properties of defatted flours obtained from either IR roasted or conventionally roasted sesame seeds remained the same. Practical Applications: Sesame oil is stable to oxidation compared to other vegetable oils. This stability can be attributed to the presence of tocopherols and the formation of sesamol, the thermal degradation product of sesamolin-a lignan present in sesame. Roasting of sesame seeds before oil extraction increases sesamol content which is a more potent antioxidant than the parent molecule. The conversion efficiency of sesamolin to sesamol is increased by 31% by infrared roasting of seeds compared to electric drum roasting. This can be used industrially to obtain roasted oil with greater oxidative stability.

Effect of infrared heating on the formation of sesamol and quality of defatted flours from Sesamum indicum L.

Frying operations at both industrial and foodservice levels have traditionally used animal fats, animal fat-vegetable oil blends, palm oil or hydrogenated vegetable oils. Saturated and trans fatty acids present in these oils are, however, considered nutritionally unfavorable because of their elevation of plasma cholesterol levels. High oleic acid sunflower oil (HOSO) can be used as a substitute for these fats/oils in order to produce snack foods with more favorable fatty acid composition. However, this oil has the disadvantages of being more expensive and less stable, albeit substantially more stable than conventional sunflower oil. Frying studies were conducted in a gourmet-type restaurant in Belgium to compare the performance of HOSO blended with a specially manufactured sesame oil (SeO) and rice bran oil (RBO) with that of presently used oils/oil blends. The quality of the produced french fries was used as the end point indicator. The order of the performance of the oils was: HOSO-SeO-RBO > palm olein > partially hydrogenated canola > HOSO > groundnut oil. The frying performance of the HOSO-SeO-RBO was quite satisfactory up to 65 effective frying hours (or 954 frying operations) compared to 35 effective frying hours (or 535 frying operations) for HOSO. It was also found that use of french fries prefried in the blended oil together with oil replenishment extends the performance of the new oil frying. Chemical analyses showed that at the discard point, none of the oils had exceeded the regulatory limits for used restaurant frying oils in many EU countries, i.e. 24% total polar materials.

Enhancing the frying performance of high oleic sunflower oil using sesame oil and rice bran oil

Der „Gemeinschaftsausschus fur die Analytik von Fetten, Olen, Fettprodukten, verwandten Stoffen und Rohstoffen (GA Fett)” hat die nachfolgende Methode zur gaschromatographischen Bestimmung von Buttersaure nach Prufung im Ringversuch zur Veroffentlichung verabschiedet. Sie soll in die Abteilung C, Kapitel III, Haupt- und Nebenbestandteile, der DGF-Einheitsmethoden aufgenommen werden. Kommentare zu dieser Methode werden an die Berichterstatter erbeten.

Bestimmung der Buttersäure — Gemeinschaftsarbeiten der DGF, 109. Mitteilung: Deutsche Einheitsmethoden zur Untersuchung von Fetten, Fettprodukten, Tensiden und verwandten Stoffen, 82. Mitt.: Analyse von Fetten XXVI

Zur Erganzung der Methoden zur Untersuchung von fettreichen Lebensmitteln in der Abteilung K der „Deutschen Einheitsmethoden zur Untersuchung von Fetten, Fettprodukten, Tensiden und verwandten Stoffen”1 hat der GA Fett eine Methode zur Bestimmung von Konservierungsstoffen erarbeitet und in Ringversuch gepruft. Vor Ubernahme in die Sammlung wird diese Methode den interessierten Fachgenossen zur Prufung und evtl. Stellungnahme vorgestellt.

Bestimmung der Konservierungsstoffe ‐ Gemeinschaftsarbeiten der DGF, 110. Mitteilung: Deutsche Einheitsmethoden zur Untersuchung von Fetten, Fettprodukten, Tensiden und verwandten Stoffen, 83. Mitt: Analyse von fettreichen Lebensmitteln IV

Eine Entsauerung bzw. eine thermische Belastung von nativen und nicht raffinierten pflanzlichen Olen kann durch die Untersuchung der Polyphenol-Fraktion bzw. isomerer Linolsaure-methylester mittels HPLC nachgewiesen werden. Die Behandlung mit Bleicherde kann in der Regel durch das UV-Spektrum erkannt werden.



Native and Non-Refined Vegetable Oils and Fats



The desacidification and thermical treatment of so-called non-refined and native vegetable oils and fats can be easily detected by the separation of polyphenol fraction and determination of the methylesters of the isomeres of linoleic acid. A treatment with unusual bleaching earth can usually be recognized by measuring the UV-absorption.

Chr. Gertz

Papers

Enhancing the frying performance of high oleic sunflower oil using sesame oil and rice bran oil

Bestimmung der Buttersäure — Gemeinschaftsarbeiten der DGF, 109. Mitteilung: Deutsche Einheitsmethoden zur Untersuchung von Fetten, Fettprodukten, Tensiden und verwandten Stoffen, 82. Mitt.: Analyse von Fetten XXVI

Bestimmung der Konservierungsstoffe ‐ Gemeinschaftsarbeiten der DGF, 110. Mitteilung: Deutsche Einheitsmethoden zur Untersuchung von Fetten, Fettprodukten, Tensiden und verwandten Stoffen, 83. Mitt: Analyse von fettreichen Lebensmitteln IV

Native und nicht raffinierte Speisefette und -öle

Externe Qualitätskontrolle für Labors in der Fettanalytik