Pumpkin has high nutritional value. Each 100g of fresh pumpkin fruit contains 91.9-97.8g of water, 1.3-5.7g of carbohydrates, 0.57-2.4mg of carotene, and other vitamins (VC, VB, VE, etc.), amino acids (citrulline, aspartic acid, etc.) and minerals (Fe, P, Zn, Se, etc.). Pumpkin also has certain medicinal value. It is a maintenance food for children, the elderly, indigestion, hypertension, nephritis and other patients. People with diabetes who cannot eat too much sugar can only eat pumpkin.
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Identification of alkaloids
1. Preparation of test solution:
Take about 2g of the pulverized plant sample, add 20~30ml of distilled water, and add a few drops of hydrochloric acid to make it acidic. It was heated on a 60 ° C water bath for 15 minutes, filtered, and the filtrate was subjected to the following test.
2. Identification of alkaloids:
Alkaloids (with a few exceptions) produce a precipitation reaction with a variety of alkaloid precipitation reagents in an acidic solution (aqueous or dilute alcohol). The operation is as follows:
(1) Take four parts of the aqueous acid immersion solution (about 1 ml per part), and add iodine-potassium iodide, potassium iodide reagent, cesium iodide reagent, and silicotungstic acid reagent respectively. If all four have or mostly have a precipitation reaction, it indicates that the sample may contain alkaloids, and then the next test is carried out to further identify.
(2) Take the remaining acid water immersion solution, add Na2CO3 solution to be alkaline, set the separatory funnel, add about 10ml of diethyl ether to shake, leave the ether layer after standing, then use ether 3ml, extract as before, and combine Ether solution. The ether solution was placed in a separatory funnel, shaken with 10 ml of acid water solution, and allowed to stand for separation. The acid water solution was separated, and then 5 ml of the acid water solution was extracted as before, and the acid water solution was combined, so that the acid extract was four times. The following precipitation reactions were carried out separately.
a. Potassium iodide reagent (Mayer reagent): acid water extraction droplets plus potassium iodide reagent to produce a white precipitate.
b. Potassium iodide reagent (Dragendorff reagent): acid water is added dropwise to add cesium iodide reagent to produce an orange-red or red-brown precipitate.
c. Iodine-potassium iodide reagent (Wagner reagent): acid water is added dropwise to add iodine-potassium iodide reagent to produce a brown precipitate.
d. The silicotungstic acid reagent: the acid water extraction droplet plus the silicotungstic acid reagent produces a pale yellow or off-white precipitate.
The aqueous acid extract and the above four reagents all (or most) produce a precipitation reaction, which indicates that the sample contains an alkaloid.
(3) Remarks: The results of the above (1) and (2) precipitation reactions: the number of precipitates is represented by "+++", "++", "+", and the absence of precipitation is indicated by "-". If all the tests in (1) are negative, another alkaloid precipitation reagent (refer to relevant data) may be used for the test. If it is still negative, the presence of alkaloids in the sample may be negated. 2) Test.