2.15.1. Molisch test, bendict test, barfoed test, seliwanoff test, bial test, and iodine test

It is aromatic (alpha-naphthol-α) when added to the sugary substance in an acidic medium of H₂SO₄ acid. The center forms a violet ring, a general carbohydrate detection. (1/2 ml) of date, syrup solution was added in a test tube (3 drops) of Molish's reagent shaken well, then (1/2 ml) of H₂SO₄ was carefully added to the tube walls [28].

Benedict's reagent is a blue solution of copper sulfate, sodium carbonate, and sodium esters. When added to the sugar solution, the copper ions are reduced to copper, and the color changes from yellow to reddish-brown in the presence of reducing sugars. In the absence of reducing sugars, the reagent retains its blue color. A 1/2 ml of diluted date syrup solution was added to a test tube, and then 1 ml of Benedict's reagent was added and placed in the water bath for 3–5 min [29].

This detection is done in an acidic medium and only in the presence of monosaccharides (because they are the most vital reducing properties of the dimers). A 1/2 ml of diluted date syrup solution was added in a test tube, 1 ml of Parfoid reagent, and then placed in the water bath for 3–5 min [30].

The seliwanoff test is used to distinguish between aldehyde and ketone monosaccharides. A 1/2 ml of diluted date syrup solution was added to a test tube, and 1 ml of Sulfa-Nof reagent was added and placed in the water bath for 3–5 min [30].

It is a unique detection for pentoses, and the basis of its action is the reaction of Furfural compounds with orcinol in the presence of ferric ions in this reagent. A 1/2 ml of diluted date syrup solution, five drops of concentrated HCL acid, and 1 ml of Biel reagent were added to a test tube and placed in the water bath for 1–5 min [28].

The iodine test distinguishes between polysaccharides (starch-glycogen-dextrin-inulin). A 1/2 ml of diluted date syrup solution was added to a test tube, and two drops of iodine reagent were added [28].