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Effect of Processing Temperature on Pigments and Color of Spinach a
Author(s) -
TAN C. T.,
FRANCIS F. J.
Publication year - 1962
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1962.tb00086.x
Subject(s) - spinach , pheophytin , lutein , pigment , chemistry , chromatography , acetone , extraction (chemistry) , chlorophyll a , carotene , sugar , chlorophyll , analytical chemistry (journal) , carotenoid , food science , photosynthesis , biochemistry , organic chemistry , photosystem ii
SUMMARY 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.