*3.1.3. Detection of hexose sugars*

*3.1.2. Detection of reducing sugars*

**Table 3.** Qualitative screening of carbohydrates.

ars in aqueous extracts (**Figures 4** and **5**) (**Table 3**) [25].

**Figure 4.** Carbohydrates in sea buckthorn aqueous extract.

**Figure 5.** Reducing sugars from gooseberry aqueous extract.

The general definition of reducing sugars is any type of sugar that can act as a reducing agent due to the free aldehyde or ketone groups. All monosaccharides are reducing sugars, along with some di-, oil- and polysaccharides. Several tests are available for detecting reducing sug-

**Phytochemical test Sea buckthorn Gooseberry** Carbohydrates (general)—Molisch Purple red solution Purple coloration Carbohydrates (reducing sugars)—Benedict Brick-red precipitate Brick-red precipitate Carbohydrates (reducing sugars)–Fehling A Khaki solution Green-yellow solution Carbohydrates (reducing sugars)—Fehling B Brown-yellow solution Brown solution Carbohydrates (monosaccharides)—Barfoed Blue-green solution Brick-red precipitate Carbohydrates (reducing sugars)—Trommer Red precipitate Red-brown precipitate

166 Phytochemicals - Source of Antioxidants and Role in Disease Prevention

Carbohydrates (reducing sugars)—Tollens Black precipitate Silver mirror

Carbohydrates (reducing sugars)—Moore Red-brown solution Red-brown solution

Hexoses are monosaccharides that contain six carbon atoms and are divided into aldohexoses and ketohexoses depending on the functional group [26]. Three qualitative methods reveal the presence of hexose sugars and the results are presented in **Table 4**.


**c.** *Ammonium molybdate test*: this test reveals the presence of ketohexozes as follows: to 2 ml aqueous extract, 2 ml ammonium molybdate solution are added, the solution is then heated to form a bluish-green solution.

As it is clear from the **Table 4**, hexose sugars are present in both sea buckthorn aqueous extract as well as in gooseberry aqueous extract.
