PUREOL^TM

PUREOL^TM is a Fruit Drying Oil, manufactured in accordance to international standards. It is a blend of lower alcohol esters of vegetable oils, sulphonated oils and emulsifiers. It is probably the only Indian Fruit Drying Oil that is certified as NON-TOXIC by Indian Institute Of Toxicology, Pune.


Procedure Involved

A mixture of PUREOL^TM, potassium carbonate, and water applied to fresh grapes to increase their rate of drying. Standard strength oil emulsion is 1.5% PUREOL^TM and 2.4% K2C03 in water. (Other strengths can be used in special circumstances). The second coat of PUREOL^TM should be applied after 5 days.

The emulsion may be applied to the berry surface in various ways, but the aim is always the same of complete wetting of the fruit until the 'bloom' is no longer visible. Ideal drying conditions are provided by a light wind on a hot dry day, so that heat is supplied rapidly to the berries.

Following precautions are taken during the process:

1) Bunches should be wetted completely. Parts of the bunches that are not wetted will dry more slowly, resulting in 'blobs' of higher moisture content and darker colour in the final produce.

2) Ambient temperature should not go below 15°C.

3) If it rains, then second coat should be applied within 3 days.

For a freshly made mixture the pH is about 11. The alkalinity contributes to the increase in drying rate and is necessary to prevent fermentation of the emulsion in a bulk dip under some conditions. Alkalinity may be measured using a suitable pH indicator paper (pH paper available on request).

(Specifications subject to change. Application method and other information are given without obligation.)

What is Fruit Drying Oil?

Fruit Drying Oil or Dipping Oil as it is commonly known in our country is essentially used in quick drying of Grapes to make Raisins.


What is a Raisin?

The word raisin comes form the Latin racemus, which means"a cluster of grapes or berries". The raisin is dark brown and wrinkled with a sweet mellow flavour. It is produced from un-seeded or seeded, white or black grapes. A grape becomes a raisin when its moisture content has been reduced, through sun drying, to around 16 per cent. The grape is harvested when ripened to its fullest and is picked in clusters. At this stage the methods implemented for sun drying vary greatly in accordance with the different countries of origin. Methods used include drying the grapes on clean paper trays between the vines, or placing the grapes on special concrete drying areas. The clusters are spread evenly and turned occasionally so that each grape gets the necessary amount of sunshine required. The fruit lays in the full glaze of the sun, as opposed to partial shade, for 2-3 weeks until the grape's moisture content has been reduced to around 16 per cent into the caramel brown raisin we are familiar with.


Theory of Drying:

The grape berry is naturally very resistant to water loss, as it has a heavy, hydrophobic (water- repellent) 'bloom' consisting of over-lapping wax platelets. The cuticle, in particular the outer waxy layer, is the structure that limits the drying rate of the grape berry. During drying, water moves outward through the cells of the flesh and skin, then passes through the 'bloom' and into the air surrounding the berries. This air becomes very humid and its removal is essential for rapid drying. Ideal drying conditions are provided by a light wind on a hot dry day, when heat is supplied rapidly to the berries and moist air around them is continually removed.


Why Fruit Drying Oil?

Fruit drying oil helps in quick removal of moisture. It is a blend of Lower Alcohol Esters of vegetable oil, Sulphonated Oils and Emulsifiers. This with Potassium Carbonate forms an emulsion in water. This contributes to the increase in drying rate and is necessary to prevent fermentation of the emulsion in a bulk dip under some conditions.