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The investigation entitled “Protocol development for gel stabilization and
nutraceuticals in Aloe vera (L.) Burm. f.” was carried out in the Department of
Plantation Crops and Spices, College of Agriculture, Vellayani during March
2016 to December 2019. The project envisaged formulation of a low cost
stabilization technique for aloe gel using herbal extracts and aromatic oils and
development of protocols for the preparation of dried latex and marketable
nutraceuticals using aloe gel. The study was carried out as four experiments. The
first experiment was to study the keeping quality and natural spoilage flora of
fresh gel while the second experiment was for the standardization of curacao aloe
(dried latex). The third experiment was on gel stabilization using herbal extracts
and essential oils. Preparation of nutraceuticals from the stabilized liquidized aloe
gel juice was the final experiment.
The keeping quality and natural spoilage flora of fresh gel were assessed by
subjecting the liquidized aloe gel juice to storage in glass bottles under ambient
condition for seven days. The liqudized aloe gel juice was off white in colour for
first three days of extraction with mild vegetative odour and got sedimented with
foul smell from fourth day onwards. The liquidized aloe juice could not be stored
for more than a day due to increased microbial population from the second day of
storage. Preliminary trails conducted by pasteurizing the liquidized aloe gel juice
at 65 0C and 15 psi pressure for 13 minutes followed by flash cooling registered
no microbial population even after seven days of storage.
The latex collected from aloe leaves was subjected to different methods of
drying such as boiling followed by cooling, sun drying, shade drying and oven
drying. Appearance, colour and aloin content (271.62 mg/ml) of dried latex was
significantly higher for shade drying.
Liquidized aloe gel juice was pasteurized and added with varying
concentrations of three forms (aqueous, tincture, decoction) of herbal extracts and
essential oils after adjusting the pH to 3.5 by adding 0.5 per cent of citric acid for
gel stabilization. The treated samples were kept for a month and based on
microbial population and minimum inhibitory concentration best treatment of
each form was selected from preliminary trials for aloe gel stabilization.
Gymnema sylvestre aqueous extract (1 ml), tincture (1 ml), decoction (2 ml),
Centella asiatica aqueous extract (1 ml), tincture (2 ml), decoction (1 ml),
Achyranthes aspera aqueous extract (2 ml), tincture (2 ml), decoction (1.50 ml),
Tridax procumbens aqueous extract (2 ml), tincture (2 ml) , decoction (1 ml),
Terminalia chebula aqueous extract (1 ml), tincture (1 ml), decoction (1 ml),
Punica granatum aqueous extract (1 ml), tincture (2 ml), decoction (1 ml), green
tea aqueous extract (2 ml), tincture (1 ml) and decotion (2 ml) and 1 ml each of
sacred basil oil, lemon grass oil, cinnamon bark oil, clove oil and cardamom oil
were selected and added to pH adjusted , pasteurized and liquidized aloe gel juice
(25 ml) for gel stabilization. The gel stabilization was thus done using the selected
twenty six treatments in a Completely Randomised Design replicated five times
and compared with 0.08 per cent sodium benzoate as control and stored for six
months. Appearance, colour and odour of all forms of the herbal extracts reduced
on storage while those treatments with aromatic oils showed lesser percentage
reduction in these parameters. Total solids, amylase and lipase activity decreased
on storage. The amino acid content was the highest for liquidized aloe gel juice
added with aqueous, tincture and decoction of Achyranthes aspera (0.08
ppm).Vitamin A and C were highest for treatment with green tea leaf aqueous
extract which decreased subsequently on storage. An increase in microbial load
was observed for all the treatments with herbal extracts from first month of
storage. But addition of 1 ml clove oil resulted in stabilization of liquidized aloe
gel juice which could be stored upto five months without microbial contamination
or affecting the nutritive and sensory parameters.
Nutraceuticals were prepared using stabilized liquidized aloe gel juice
containing clove oil blended with lemon juice, orange juice and honey in
proportions of 50 : 50, 75 : 25 and 90 : 10 followed by pasteurization, flash
cooling and stored for 6 months. Appearance, colour and vitamin C were
significantly higher for Lemon juice (50 ml) + Liquidized aloe gel juice (50 ml) +
2 ml clove oil while odour, taste, overall acceptability, pH, TSS, carbohydrates
and calories were significantly superior for Honey (50 ml) + Liquidized aloe gel
juice (50 ml) + 2 ml clove oil. Growth of microbes could be detected from third
month of storage for all the treatments. Aloe health drink with honey in the ratio
50 : 50 added with clove oil were selected as the accepted drink which could be
preserved for two months without microbial contamination.
The preparation of aloe herbal powder by solar drying, air drying, oven
drying or freeze drying resulted in a sticky product which could not be
reconstituted with distilled water for quality comparison with fresh gel, thus
warranting further investigation.
The present study revealed that liquidized aloe gel juice pasteurized and
mixed with clove oil (4 per cent) is a low cost stabilization method which can be
taken as a base material for the preparation of health drink. The nutraceutical with
liquidized and stabilized aloe gel juice mixed with equal proportion of honey and
preserved with clove oil is a palatable drink having higher calories which could be
stored for two months. The dried aloe latex a byproduct produced by shade drying
is superior with high aloin content and can also be used for the development of
marketable product. |
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