Effects of processing and storage on chlorophyll derivatives in commercially extracted canola oil

Abstract

This study characterizes the chlorophyll pigments present in canola oil immediately after commercial extraction and following oil storage to determine the best storage conditions for analytical samples and to examine the changes that chlorophyll derivatives undergo during oil processing and storage. Samples of pressed, solvent~extracted, crude and degummed canola oils, obtained from a commercial crushing plant, were stored for one month under four different conditions--in the freezer, in a refrigerator and at room temperature both in the light and in the dark. Chlorophyll derivatives (chlorophylls, pheophytins, pyropheophytins) were measured by high-performance liquid chromatography immediately after sampling and then on a weekly basis. The main pigments present in commercially extracted canola oil were pheophytin a, pyropheophytin a, chlorophyll a and chlorophyll b. The "a" derivatives comprised 81 to 100% of total chlorophyll pigments in the fresh oil samples. During degumming, the remaining chlorc~ phylls were converted to pheophytins and pyropheophytins. During oil storage, exposure to light at room temperature affected the compositio~ of chlorophyll derivatives as chlorophyll b was converted to pheophytin b and chlorophyll a was converted first to pheophytin a, then to pyropheophytin a.

Routine and sensitive SPE-HPLC method for quantitative determination of pheophytin a and pyropheophytin a in olive oils

“…Chlorophylls (chls) are the natural pigments responsible for the green colour of vegetable oils (Gandul-Rojas & Mínguez-Mosquera, 1996; Mínguez-Mosquera, Gandul-Rojas, Garrido-Fernández, & Gallardo-Guerrero, 1990; Mínguez-Mosquera, Gandul-Rojas, Montaño-Asquerino, & Garrido-Fernández, 1991;Usuki, Suzuki, Endo, & Kaneda, 1984;Ward, Scarth, Daun, & Thorsteinson, 1994). In general terms, chlorophylls are prone to experience chemical and physical modifications as a result of processing and storage of green vegetables (Heaton & Marangoni, 1996;Mínguez-Mosquera, Garrido-Fernández, & Gandul-Rojas, 1989;Schwartz & Lorenzo, 1990) mainly due to their structural properties and their ability to harvest energy (Bacon & Holden, 1967).…”

Application of an electronic nose for determination of pre‐pressing treatment of rapeseed based on the analysis of volatile compounds contained in pressed oil

“…Virgin rapeseed oil is produced by pressing seeds without additional processing measures except for filtration or sedimentation (Brühl & Matthäus, ; Rusinek et al ., ). Storage conditions (Mildner‐Szkudlarz et al ., ) as well as seed processing and pre‐treatment (Ward et al ., ) exert a considerable effect on the quality of oil. Hence, it is advisable that the conditions of post‐harvest treatment of rapeseed should be controlled.…”

A comparison of high‐performance liquid chromatography and spectrophotometry to measure chlorophyll in canola seed and oil

“…Previous studies have never indicated a decrease in total chlorophyll during oil storage. In another paper (7), we showed that during oil storage chl b was converted to phy b, and chl a was converted to phy a and pyropheophytin a. This conversion occurred most quickly in oils stored at room temperature in the light, followed by storage at room temperature in the dark and in refrigerated storage, respec- tively.…”