Kautkar et al.
by ionic content (Icier and IIlicali, 2005; Gangola
Materials and Methods
et al. , 2013), it is possible to adjust the electrical
The laboratory size ohmic heating device used
conductivity of the product with ion (e.g. salts) levels
to carry out the experiments was designed and
to achieve effective ohmic heating.
fabricated by Patil, (2008) it employed a rectangular
Ginger (Zingiber officinale Rosc.) is tropical spesis
geometry as shown in figure 1. It consisted of two
native to South East Asia and belongs to the family
rectangular electrodes made of stainless steel
zingiberaceae which is one of the largest family
placed on a rectangular plate of Perspex sheet.
of plant kingdom and one of the most important
The dimensions of electrodes were 5 x 12 cm and
herbaceous group and occupy an important place
thickness of 0.1 cm. The AC electric power was
in traditional Indian texts due to antispasmodic,
supplied to these units through an autotransformer.
anti-inflammatory,
antioxidant,
anthelmintic,
A constant voltage stabilizer was used before the
hepatoprotective and antidiarrhoeal activities(Arora
autotransformer to control voltage fluctuations. The
et al. , 2012). Ginger is the most popular hot spice
electrical variables were recorded using an ammeter,
in the world (Mohammed et al. , 2011). India from
voltmeter and wattmeter.
time immemorial is the “home of spices” producing
almost all the spices of the world. There are over 80
Raw materials
spices grown in different parts of the world out of
Fresh, fully matured, yellowish coloured ginger
which 50 spices are grown in India (Purseglove et al. ,
rhizomes without any defect on visual infection was
1981). Fresh spices are perishable in nature and the
procured from local market at Pantnagar.
causes of spoilage are improper handling, growth
of spoilage microorganisms, action of naturally
Sorting, washing and peeling
occurring enzymes and chemical reaction during
storage. The post harvest losses of ginger could be
Ginger rhizomes were washed in cold water to
considerably reduced if processed immediately
remove soil and other foreign materials. For peeling,
after the harvest. Ginger is typically consumed as
ginger were conditioned by dipping in water at room
fresh, in the form of paste, in preparation of powder,
temperature for 15 min and dried in open air for one
bread, confectionary, ginger ale, table souse, ginger
hour, this result in development of cracks on outer
preserved and candy (Siddiqui, Bhuiyan and
skin. The peel was manually removed with the help
Easdani, 2012), in food beverage industries (Ding
of a sharp stainless steel knife.
et al. , 2012) for manufacturing of cordials, cocktails,
Preparation of puree
carbonated drinks, beer, wine etc (Shukla and Singh
2007).Furthermoreconventionalprocessingofginger
After removing the peels manually, ginger puree
which include washing, peeling, drying, grinding
was prepared by grinding the ginger rhizomes in
can cause several quality and hygiene problems
grinder with fruit to water ratio of 1:1 which was
(Legrand, 1986; Rejano, Sanchez and Montano 1997;
recommended by Patil, (2008) and Shetey, (2005).
Schweiggert et al. , 2008). Therefore it is the need to
Grinding was done for 3 min to obtain average
manufacture safe and good quality ginger paste
particle size of 0.353 mm (Mondal, 2006) and puree
by using an advanced thermal processing method
was taken in to 250 ml glass beaker.
like ohmic heating. The objective of this research is
to study the temperature and time dependence of
Preparation of paste
electrical conductivity of ginger paste.
Paste was characterized as the product obtained
after adding salts and organic acid to the puree
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