MSc

The objective framed for this study was, to check the quality parameters of ripe
fruits of avocado cultivars (Persea americana) and to develop fruit powder and to test
its suitability for culinary preparations.
Cultivars selected for the study are Kallar round, Purple hybrid, Pollock and
Fuerte which were collected from Regional Agricultural Research Station, Kerala
Agricultural University, Ambalavayal. The study was conducted as three experiments.
On experiment – I, quality parameters of selected avocado cultivars were
ascertained. The results revealed that, the four avocado cultivars had significant
difference at 5% level in physical characteristics. Pollock had shown highest fruit
length (17.00cm), fruit weight (435.20g), seed length (7.20cm), skin waste (35.93g)
and seed weight (50.37g). The highest skin thickness (0.17cm) and cavity length
(7.50cm) was noted in Purple hybrid. The pulp yield (86.20g) was found higher in the
cv. Kallar round.
Nutritional and chemical composition studies were significant at 5% level.
Proximate composition studies had shown that the cultivar Pollock showed highest
Carbohydrate (7.40/100g), protein (1.32/100g), total fat (20.2g/100g), and dietary fibre
(1.43g/100g).
Phytochemical studies of four avocado cultivars shown that total phenolic
content (3.63mg/100g), total antioxidant activity (480mg/100g of ascorbic acid), total
sugar(4.01g/100g), were found higher in Pollock whereas reducing sugar found higher
in Kallar round (3.82g/100g).The higher amount of vitamin C (3.25mg/100g), Peroxide
value (4mEq/Kg) were observed in Fuerte.
Total mineral content was on par in Purple hybrid and Pollock and the iron
content (0.6mg) was higher in purple hybrid. The calcium content among the avocado
cultivars seemed non -significant at 5% level. The sodium content found higher in the
cultivar Pollock (0.80mg/100g) whereas potassium found higher in the cultivar Fuerte
(525mg/100g).
Pollock and Purple Hybrid showed complete spoilage on 5th day, Furte on 6th
day and kallar round completely spoiled on 7th day when stored at room temperature.
Experiment II - The cv. purple hybrid which was popular among the avocado
farmers of Wayanad District were selected for fruit powder development using freeze
drying technique. The steps adopted for the freeze drying process includes ripened
fruits were washed cut and pulped and placed in trays, the detailed process of freeze
drying included primary freezing, drying in vacuum, grinding and weighing and
Packing under vacuum.
Colour of the powder was green to purple, yield ratio was 96.50, water
absorption index 3.2 %, bulk density 0.285 kg/m3 and rehydration ratio was 0.75.
Moisture content of the fruit powder was 4% and fat content was found to be 52g/100g.
All the nutrients were found to be doubled in freeze dried powder when compared to
the fresh fruits. The total phenolic content (7.66mg/100g) was higher in powder than
the fresh fruits, which is responsible for bitterness in the powder.
Shelf life studies conducted in fruit powder showed no incidence of microbial
growth up to a period of three months, packed in aluminium pouches and stored under
refrigerated conditions. Variation in acidity, moisture and peroxide value was
observed.
On Experiment – III, two culinary preparations, instant soup and milk shake
were standardized using fresh avocado pulp and freeze dried avocado powder
independently. Different proportions of fresh pulp T1 (10g), T2 (20g), T3 (30g), T4
(40g) and T5 (50g) was used for the standardization of milkshake and soup. Milkshake
and soup using fruit powder in the proportion T1 (10g), T2 (20g), T3 (30g), T4 (40g)
and T5 (50g) with added adjuncts were standardized and the best proportions were
hedonically rated by using selected panel members. Sensory evaluation highlighted,
adding 50g of avocado fruit pulp to other ingredients, was found to be outstanding for
the preparation of fresh milkshake and soup, whereas 10g of fruit powder found to be
excellent for the development of milkshake and soup.
Culinary preparations viz., avocado milkshake and soup, utilizing fresh and
powder were prepared using the selected combination.
Standardization of milkshake was carried out with avocado pulp 50g
(T1control) with sugar (10g) and milk (100 ml). Various combinations T2 –Banana
(50g), T3- dates (50g), T4-nuts (25g) and T5-badam (25g) were tried out for selecting
the best blend. The sensory evaluation of fresh avocado milkshake shown that T4 was
selected as the best blend and it is on par with T3 at 5 % level.
Standardization of milk shake using avocado powder 10g (T1-control) with
sugar (10g) and milk (100 ml). Various combinations T2 –Banana (50g), T3- dates
(50g), T4-nuts (25g) and T5-badam (25g) were added and studied for their
acceptability. The sensory evaluation of avocado powder milkshake shown that T5 was
selected as the best combination. This is significantly different from T1 and T2 at 5 %
level.
Fresh avocado soup and powder soup were prepared with proportions 50g and
10g respectively. Corn flour (20g), garlic (10g), onion (10g), carrot (10g), tomato
(10g), milk (100ml) was used as base for all the combinations. Various combinations
viz., T1- control, T2- ginger, T3- pepper powder, T4- mint leaves and T5- mushroom
were standardized. The sensory evaluation of fresh avocado soup shown that T5 was
the best combination whereas in avocado powder soup T1 was selected as the best
combination. In fresh avocado soup T5 is significantly different from T1 and T2 and
on-par with T3 and T4 at 5 % level whereas in avocado powder soup T3 was selected
as the best combination in which T4 and T5 was on par with T3 at 5 % level.
On physical characteristics and nutritional characteristics the best cultivar
selected was Pollock. While on reviewing the keeping qualities the cultivar Kallar
round reported the lengthy shelf life period than the other cultivar. On processing point
of view the cultivar were selected based on popularity and scores obtained in sensory
evaluation.
The study “Quality evaluation of Avocado (Persea americana) cultivars and
suitability of fruit powder for culinary preparations” revealed that all the four cultivars
are in excellent quality and sensory parameters. Freeze dried powder has excellent
nutritive value and extended shelf-life period, which can be exploited for making
different products. The powder can be utilized by processing industries, which also
reduce fruit wastage, improves cultivation and add revenue to farming communities.
Future research works could be concentrated on development of therapeutic
nutraceuticals from avocado for different life style disorders.