I want to know about different analytical methods (rapid) to determine carotenoids (carotene and Xanthophyll) in maize flour, which gives more accuracy.
Estimation of Carotenoids: In our lab, we use to follow the method of Harborne JB, 1973. Phytochemical methods. The following is the method.
Take 100 mg of sample and add to it 10 ml of 80% acetone and grind it well in a mortar and pestle. Now centrifuge it at 3000 rpm for 10 mins. Take the supernatant and discard the pellet. Make up the supernatant up to a known volume of 10 ml. Now read the OD values at 480 nm in UV-spectrophotometer.
Calculation:
Amount of carotenoids in 100 mg sample = 4 x OD value x Total volume of sample (i.e we have make up the supernatant volume as 10 ml) / Weight of fresh plant tissue (i.e. we have taken 100 mg sample to grind ) = ... mg/g
"Best" has a number of meanings:
- Fastest analysis time
- Most accurate results
- Cheapest per sample
- Reliability of results (not the same as accurate)
- Most appropriate to your needs
You state in your question "rapid" and "accuracy", but you also imply distinguishing between carotene and xanthophyll which implies specificity.
In your question you ask for "More accuracy": than what?
My preference would be for HPLC, which can be optimized to produce results quickly with a short column, or separate the compounds (longer column, but slower). Modern maize doesn't have a huge range of carotenoids, so you might be lucky and get away with a 5-10 minute analysis.
This probably wasn't a very helpful answer, but it might clarify your question a little.
EXTRACTION AND ESTIMATION OF CHLOROPHYLL
Ref: Maclachlam, S. and Zalik, S. (1963). Can. J. Bot. Part II 41, 1053.
EXTRACTION AND ESTIMATION:
Fresh weight of the leaves are taken and then the leaves are macerated together with a little of acid washed sand with 3 ml of 80% acetone and centrifuged at 1000 rpm for 5 min. the debris is than washed 3 times using 1 ml of 80% acetone each time. The supernatants are than pooled and made up to 7 ml with acetone.
Optical densities of these solutions are than recorded at 663nm, 645nm, 480nm and 510nm.
EQUATION:
Chlorophyll a. (mg/g) = 12.3 D663 - 0.86 D645
d x 1000 x w
Chlorophyll b. (mg/g) = 12.3 D645 - 0.86 D663
d x 1000 x w
Total Chlorophyll = Chl. A + Chl. B
Carotenoids (mg/g) = 7.6 D480 – 1.49 D510 x V
D x 1000 x W
If you mean, which approach to utilize, then I will recommend you to utilize Definitive Screening Design, the novel approach. It is useful in screening undesired variables and optimizing with the useful variables.
Here is the link for your information.
(PDF) Multi Response Simulation and Optimization of Gas Tungsten Arc Welding (researchgate.net)
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