ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
A method was developed for estimation of chlorophylls a and h, pheophytins a and h, lutein, and carotene in processed spinach. The method, developed primarily for calorimetric studies, involves extraction of the spinach with acetone and chromatographic separation on a sugar-starch (70:30) column. Equations were developed for spectrophotometric estimation of the amount of each pigment in the eluate from the column. The method gave recovery values of 95–98% for a wide range of pigment mixtures, and a coefficient of variation of approximately 1.5% for reproducibility on the same extract.Fresh spinach was blanched, pureed, packed in glass thermal-death-time tubes and processed in an oil bath at 240, 250, 260, 270, and 280°F for a process value equal to Fo 4.9. Color measurements indicated a difference of 4.1 units between the controls and the samples processed at 280°F, and 11.6 units between the controls and the samples processed at 240°F. The pigment changes indicated a progressively smaller change in chlorophylls a and h to pheophytins a and h as the processing temperature was raised. Chlorophyll a was degraded more rapidly than chlorophyll b, and the ratio of the two changed from 1.55 for the samples processed at 280°F, to 0.92 for the samples at 240°F. Some degradation of lutein was observed, particularly at the lower processing temperatures, whereas carotene was unchanged. The pigment-free tissues also showed more change in color at the lower temperatures, but the contribution of the pigment-free tissues and the degradation of lutein to the over-all color change was very small. The major reasons for the change in color of the spinach puree upon processing were, first, the degradation of chlorophyll a to pheophytin a, and second, the degradation of chlorophyll b to pheophytin b.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.1962.tb00086.x
Permalink
