Production of tropical fruit powders is rapidly increasing in popularity
among consumers as well as manufacturers due to their natural
color, flavor, nutrition and taste. Fruit powders are taken either directly
as drinks or used as secondary ingredients in baby foods, candies, fruit
yogurt drinks and soups. There are various drying techniques used to
prepare fruit powders and spray drying is the most convenient and
most widely practiced in industry [1] . In many cases pulpy fruits need
to be clari fied. Technically it is quite impossible to convert pulpy fruits
into powder by spray drying. This operation removes part of the pulp
and coarse particles (which are rich sources of fiber and phenolic compounds)
to enable proper functioning of the atomizer, [2] . Secondly, it
is necessary to add quite high amounts of carriers to change the amorphous
state by increasing glass transition temperature (Tg). Amorphous
materials are frequently associated with the problem of stickiness or
agglomeration due to the nature of the changing phase at the glass transition
temperature (Tg) [3] . However, addition of additives eventually
contributes to the increase in solid content as bulky materials, which
adversely aects the sensory as well as nutritional properties. Due to
the high sugar content of tropical fruits, high temperature drying by mechanical
drier makes it sticky, and is thus dif ficult to convert into powder.
Therefore, for producing whole fruit powder, drying fruits at low
temperature and reduced pressure with low amounts of carrier (maltodextrin
in our case) is apparently the best alternate [1] . For producing whole fruit powder, freeze drying though costly, is the best option in
relation to sensory and nutrition properties. Hence, in this study freeze
drying was used to produce whole fruit powder.
In a typical pharmaceutical industry, compaction of powder is one of
the important key operations in developing solid oral dosage forms. In
the food industry applications of compaction are rather at the developing
stages. However, candies and several types oood supplements
produced by compaction are becoming popular in the retail market.
Compaction oruit powder into tablets is an excellent alternate for
overcoming problems associated with post-processing handling, packaging
and storage oruit powder. Fruit powder in tablet form will be
less hygroscopic due to reduction of surface area, which in turn facilitates
in reducing packaging cost. Most importantly, transformation of
fruit powder into compacted tablets will result in much reduced volumes
andwill be bene ficial for increased shelife, storage and transportation.
The tablet form will also be convenient to use and aordable to
consumers at all levels. Literature on the direct compression of whole
fruit powder into tablets is scarce. Food tablets containing various
food powders obtained from dates, spirulina and orange were investigated
by Adiba et al. [4] . This report is mostly concerned with material
properties and tablet dissolution behavior in dierent media. Satya
Prakas et al. [5] investigated flowability, compressibility and in-vitro release
of a laxative formulation of Terminalia chebula fruit powder tablets
in relation to its use in herbal medicine. Compression behavior of a formulation
containing about one third of the fruit powder along with
other ingredientswas reported. Themajor problemassociated with tablet
foods is the poor dissolution. Biopharmaceutical properties like dissolution
and disintegration time are very important in the case of medicinal tablets or capsules. However, information on dissolution
properties of formulated food tablets is lacking.
Pitaya and guava are two tropical fruits and are popular for their
unique characteristics. Both the fruits are known to be high in nutritional
properties. They are relatively high in antioxidant activity. Pitaya is a
beautiful fruit containing water soluble betacyanins responsible for the
intense red color and antioxidant activity [6]. Powder of this fruit has already
been explored as a potential source of natural red colorant [7,8].
On the other hand, guava is well-known for its high vitamin C and
fiber content [9]. However, the light greenish color of ripe fruits is lost
during spray drying, which is quite usual [10]. Hence, a new tablet formulation
blending the powders of both fruits to compensate for the
color as well as the nutrition imbalance may results in a new product
which is highly acceptable to consumers.
The present study was therefore designed to prepare (a) a composite
formulation using whole fruits freeze-dried powder of pitaya and
guava compressed into tablet form, (b) evaluate in-vitro release of its
active ingredients, and (c) assess its suitability as a natural fruit drink
tablet.