title: Chromatographic determination of changes in pigments in spinach (Spinacia oleracea L.) during processing.
abstract: The content of individual chlorophyll and carotenoid pigments is determined in three spinach varieties (Lorelei, Springfield, and Ballet) after processing. Raw spinach and spinach that is steam-blanched for 3, 9, or 15 min is stored frozen at -24 degrees C for 6 months. In addition, spinach is air-dried at 75 degrees C, packed in atmospheric air or nitrogen, and stored at ambient temperature for 6 months. Processing has a significant effect on the content of individual chlorophyll and carotenoid pigments; however, there are no differences between varieties in their content of total and individual pigments in raw, frozen spinach. Increasing blanching time resulted in decreased contents of chlorophyll a and b and increased contents of chlorophyll a' and b' and pheophytin a and b because of pheophytinization. Changes in the color because of pheophytinization are only detected after 15 min blanching. The carotenoid pigments are more stable than the chlorophyll pigments during blanching. (all-E)-Violaxanthin is significantly reduced, caused by degradation to other xanthophylls, such as neochrome, during blanching. There are no significant differences in the content of chlorophyll a and b of dried spinach and blanched, frozen spinach. Formation of chlorophyll a' and b', pheophytin a and b, and chlorophyll a-1 and b-1 is observed after drying. The content of pheophytin a and b is significantly lower in dried versus blanched frozen samples. In dried spinach that is stored in atmospheric air, the content of beta-carotene [599 mg/kg dry matter (DM)] is significantly lower compared with nitrogen (766 mg/kg DM), and the content of (all-E)-lutein is lower than in blanched frozen spinach. Neochrome is not detected in raw spinach but in steam-blanched and dried spinach. No differences are observed in the content of (all-E)-neoxanthin, (9'Z)-neoxanthin, (all-E)-violaxanthin, (all-E)-lutein epoxide, or neolutein A and B between spinach that is stored frozen after 3 min blanching and dried spinach.
authors.affiliation: Danish Institute of Agricultural Sciences, Department of Food Science, Kirstinebjergvej 10, DK-5792 Aarslev, Denmark. ulla.kidmose@agrsci.dk
authors.forename: Ulla
authors.initials: U
authors.lastname: Kidmose
authors.forename: Merete
authors.initials: M
authors.lastname: Edelenbos
authors.forename: Lars P
authors.initials: LP
authors.lastname: Christensen
authors.forename: Erling
authors.initials: E
authors.lastname: Hegelund
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004396:Coloring Agents / Q000737:chemistry*; D015203:Reproducibility of Results; D018724:Spinacia oleracea / Q000737:chemistry*
chemical_list: D004396:Coloring Agents