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    Pharmacognosy Activity Carbohydrates Different Types of Starch Powder

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    Arlene Forteza
    Starch is a complex polysaccharide found naturally in plants. The main types of starch are amylose and amylopectin. Amylose is linear while amylopectin is branched. Common starch sources include corn, wheat, rice, and potatoes. Starches are white powders that are insoluble in cold water but form gels or solutions when heated in water. They turn blue or violet when mixed with iodine. The procedure describes observing physical properties of different starches like corn, wheat, rice and potato and recording results. Microscopic examination is also done to identify starch granule structures.

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    Pharmacognosy Activity Carbohydrates Different Types of Starch Powder

    Uploaded by

    Arlene Forteza
    370 views4 pages
    Starch is a complex polysaccharide found naturally in plants. The main types of starch are amylose and amylopectin. Amylose is linear while amylopectin is branched. Common starch sources include corn, wheat, rice, and potatoes. Starches are white powders that are insoluble in cold water but form gels or solutions when heated in water. They turn blue or violet when mixed with iodine. The procedure describes observing physical properties of different starches like corn, wheat, rice and potato and recording results. Microscopic examination is also done to identify starch granule structures.

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    PHARMACOGNOSY ACTIVITY

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    Starch is a complex polysaccharide found naturally in plants. The main types of starch are amylose and amylopectin. Amylose is linear while amylopectin is branched. Common starch sources include corn, wheat, rice, and potatoes. Starches are white powders that are insoluble in cold water but form gels or solutions when heated in water. They turn blue or violet when mixed with iodine. The procedure describes observing physical properties of different starches like corn, wheat, rice and potato and recording results. Microscopic examination is also done to identify starch granule structures.

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    © All Rights Reserved
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    Download as docx, pdf, or txt
    370 views4 pages

    Pharmacognosy Activity Carbohydrates Different Types of Starch Powder

    Uploaded by

    Arlene Forteza
    Starch is a complex polysaccharide found naturally in plants. The main types of starch are amylose and amylopectin. Amylose is linear while amylopectin is branched. Common starch sources include corn, wheat, rice, and potatoes. Starches are white powders that are insoluble in cold water but form gels or solutions when heated in water. They turn blue or violet when mixed with iodine. The procedure describes observing physical properties of different starches like corn, wheat, rice and potato and recording results. Microscopic examination is also done to identify starch granule structures.

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    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
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    PHARMACOGNOSY ACTIVITY

    CARBOHYDRATES

    Different Types of Starch Powder


    Background Starch (Amylum) is a complex polysaccharide with very high molecular weight and consists of large number
    of monosaccharide units linked together through glycosidic linkage. Starch is a natural plant product which is a mixture
    of amylose (25%) and amylopectin (75%).
    Amylose: - Linear molecule consists of 250 – 300 glucose units of α – D – glucose units linked together through α – 1, 4
    glycosidic linkage. - More water soluble than amylopectin. - Amylose + Iodine (I2)= Blue color
    Amylopectin: - Branched molecule consists of more than 1000 units of α – D – glucose units linked together through α –
    1, 4 and α – 1, 6 glycosidic linkage. - Less water soluble than amylose. - Amylopectin + Iodine (I2) =Violet color S

    Sources of starch
    Starches are obtained from maize (Zea mays L.) (Graminae), wheat (Triticum aestivum L. (Graminae), rice (Oryza sativa
    L.) (Graminae), and potato (Solanum tuberosum L.) (Solanaceae).
    Properties of Starch
    - White mass powder, odourless with starchy taste.
    - Insoluble in water (form colloidal solution).
    - Starch + Iodine (I2) Deep blue color.
    - Starch + H2O gel (with heat).
    - Corn and wheat starches have neutral pH, rice starch has slightly alkaline pH, and potato starch has slightly acidic pH.

    Measurement of starch are necessary for the quantitative identification of closely allied substances. In most cases, the
    original drugs are adulterants or substitutes. By comparing the sizes of starch grains in different species, the adulterants
    and/or substitutes in crude drugs can be distinguished using optical microscopy

    Procedure:
    - Observe the physical characters (colour, odour, texture and taste) of maize, wheat, rice and potato starches. -
    Observe the solubility of starch in water before and after heating. - Determine the pH of starch: mix 0.2 g of starch
    with 5 ml water, dip in a piece of pH paper and read the pH.

    Fill the results for these physical and identification tests in the following table:
    CORN STARCH WHEAT STARCH RICE STARCH POTATO STARCH
    COLOUR WHITE WHITE TO OFF- WHITE WHITE
    WHITE
    TEXTURE GRITTY FINE GRANULARITY FINE TEXTURE
    WITH GRANULES
    ODOR CEREAL ODOR CEREAL ODOR EARTHLY ODOR
    TASTE Tastes like flour or NEUTRAL TASTE NEUTRAL TASTE NEUTRAL TASTE
    none at all
    SOLUBILITY IN COLD INSOLUBLE
    WATER
    SOLUBILITY IN HOT
    WATER

    Microscopical examination:
    • Prepare amount of starch in water (half spatula of starch on a clean slide and add 2- 3 drops of water).
    • Smear the paste on the slide using cover slip to make a thin smear.
    • Observe the starch granules and identify the structure of different starch grains by microscope using 10X and 40X.

    Draw the microscopically features of the following:

    1. Corn starch

    2. Wheat starch

    3. Rice starch

    4. Potato starch

    5. Maize starch
    1. Corn starch

    2. Wheat starch
    3. Rice starch

    4. Potato starch

    5. Maize starch

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