Fruit and Vegetable Processing

Marmalade

        Marmalade is generally a citrus fruit where the shredded peels of a fruit is included as suspended materials.

Recipe:  

• 1 Kg pectin fruit extract
• 1 Kg sugar
• 10 gms readymade pectin
• 5 gms citric acid
• 62 gms shreds

Extraction of Pectin or Fruit Extract:  

        The outer yellow flavedo portion of tight skin citrus fruits containing colouring matter and volatile oil are peeled off thinly from the fruit, where as loose skin citrus fruits like orange, the whole skin is removed by hand. Portion of the peels may be kept for preparing shreds for suspension in the marmalade. The fruits are then cut into thin slices (i.e.,. 0.3cm to 0.45cm thick) and boiled gently by simmering with water 2 to 3 times of its weight for 45 to 60 minutes.

Straining and Pectin Test (Same as in Jelly Making)  

Preparing of Shreds

        The yellow portion of the peels of tight skin citrus fruits and in case of loose skin fruits the white portion of the loose skin fruit the white portion of the skin are first removed and cut into shreds of 0.8cms to 1.2cms thick and 1.9cms to 2.5cms long. The shreds are then boil first for 10 to 15 minutes and strain the content. Continue boiling for three times using fresh water each time to avoid bitterness. Keep the shreds after boiling covered with water till they are ready for use.

Cooking

        The pectin extract is heated with equal amount of sugar over brisk fire till the sugar is dissolved and filter through a muslin cloth to remove impurities. Boil it again when it starts boiling ready made fruit pectin mixed with a small quantity of sugar (approx 10 gms) is added. Continue the boiling till the end point reaches 680 Brix. Strain the prepared shreds and tie in a muslin cloth and dip in the marmalade while boiling. When it reaches the end point. The shred or peels are removed from the muslin cloth and added to marmalade. Boiling process should not take more than 20 minutes. Short boiling produces a bright and sparkling marmalade.

        Pour the marmalade in a shallow pan, and stir slowly to keep the shreds uniformly distributed in the marmalade. When the temperature comes down 82° C to 88° C a thin film begins to form on the surface of the marmalade and it becomes thick to prevent floating of the shreds to the surface. When the marmalade is cooled, the scum on top is removed and if the prepared marmalade is to be kept for more than six months time, 9 gms pre dissolved potassium meta-bisulphide in a spoon of water is added per 100 kgs marmalade, stir well and pack in jars only.

Flavoring

        It is desirable to add a small amount of flavor to the product, because most of the natural flavor volatize during the boiling and cooking process. Generally a small quantity of orange oil may be added to the marmalade at the time of filling into or cans.