Determination of Total Beta-Carotene in Sweet Potatoes and Sweet Potato Products. An Improved Method

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.

show abstract

“…d Curl, 1953. e Aronoff, 1950. 'O'Connor et al, 1946 PROCESSING TEMPERATURE AND SPINACH COLOR photometer.…”

Section: Methodsmentioning

confidence: 99%

“…The calculation for carotene was based on the observation that beta-carotene has a specific absorption coefficient of 245 L per g cm at 447 rnp in petroleum ether (O'Connor et al, 1946) :…”

Section: Methodsmentioning

confidence: 99%

Effect of Processing Temperature on Pigments and Color of Spinach^a

Tan

Francis

1962

Journal of Food Science

View full text Add to dashboard Cite

show abstract

“…Elution is effected by means of 4% acetone-Skellysolve B, and (3-carotene and neo-/3-carotene-D are estimated with a Beckman spectrophotometer. In a method adapted to the determination of (3-carotene in sweet potatoes and products, isomerization is claimed to be avoided by extraction with ethyl alcohol (275). This paper contains'an extensive discussion of the effect of the solvent on the spectrophotometric characteristics of the carotenes.…”

Section: Vitaminsmentioning

confidence: 99%

Food

Oser¹

1949

Anal. Chem.

View full text Add to dashboard Cite

THE ultimate objectives of the food analyst and the variety of techniques employed to achieve them make this branch of chemistry particularly fascinating. The analytical methods of the food chemist may be applied in the development and enforcement of standards of identity, purity, or value; in problems of decomposition or spoilage under either normal or abnormal storage conditions; in studies designed to improve or control the quality of natural or processed foods; or in the determination of the nutritive value of foods for scientific, dietary, or labeling purposes. Interest in many of these objectives stems directly or indirectly from our federal and state food laws which are probably '

show abstract

“…THE determination of carotene in plant tissues, the two general methods of removal of noncarotenoids are phasic and chromatographic separations (4,30,34)• In view of the recognized variations in the extent of digestion and absorption of carotene and its interdependence on the presence of varying amounts of antioxidants (1,7,14,15,16,39,40), complete chromatographic analysis, involving the separation of various carotene isomers, is neither practical nor necessary for routine analytical purposes, particularly in the nutritional evaluation of foods, feeds, and fodders (89). The phase separation method, on the other hand, is not always quantitative (11,83,24,25); certain biologically inert degradation products are also taken up in the epiphasic layer (36,50).…”

Section: Inmentioning

confidence: 99%

Determination of Carotene in Plant Materials

Sreenivasan¹,

Vaidya²

1948

Anal. Chem.

View full text Add to dashboard Cite

A rapid method for the routine determination of carotene in plant materials has been worked out by which the green tissues are triturated with a mixture of lime and anhydrous sodium sulfate. This results in their disintegration as well as adsorption of chlorophyll and other noncarotenoid pigments; the carotene itself is rendered readily extractable by petroleum ether or benzene and can be determined either as gross carotene or as its isomerides after chromatographic resolution. The method is particularly suitable for the analysis of green, leafy materials, feeds, and fodders and gives excellent agreement with standard procedures, but it can be applied with equal success to fresh fruits and vegetables.

show abstract

Determination of Total Beta-Carotene in Sweet Potatoes and Sweet Potato Products. An Improved Method

Cited by 8 publications

References 21 publications

Effect of Processing Temperature on Pigments and Color of Spinach^a

Effect of Processing Temperature on Pigments and Color of Spinach^a

Food

Determination of Carotene in Plant Materials

Contact Info

Product

Resources

About

Determination of Total Beta-Carotene in Sweet Potatoes and Sweet Potato Products. An Improved Method

Cited by 8 publications

References 21 publications

Effect of Processing Temperature on Pigments and Color of Spinacha

Effect of Processing Temperature on Pigments and Color of Spinacha

Food

Determination of Carotene in Plant Materials

Contact Info

Product

Resources

About

Effect of Processing Temperature on Pigments and Color of Spinach^a

Effect of Processing Temperature on Pigments and Color of Spinach^a