Experiments were conducted to assess the effect of blanching and drying air temperature on the quality attributes of dried amla flakes. The raw amla fruits were subjected to three different treatments i.e., untreated UT, steam blanching SB and hot water blanching prior to convective tray drying at temperature of 50°C, 60°C and 70°C and refractive window drying at temperature of 60°C, 70°C and 80°C. In addition to the evaluation of drying rate of different combinations of amla pulp in both methods of drying, the dried amla flakes (nearly 7% db) were analyzed for different quality attributes such as moisture content, water activity, ash content, bulk density, ascorbic acid, antioxidants, total phenolic content, color and overall acceptability. The data indicated that different quality parameters of dried amla flakes were significantly affected by blanching and drying type. In addition to increasing the moisture content, water activity and ash percentage of amla pulp, blanching treatment increased the drying rates for amla samples. The untreated samples generally had lower drying rates than those of the treated samples. The flakes blanched had a bright visual appearance as compared to UT amla flakes. Refractive window drying resulted in minimal loss of overall quality of amla flakes when compared with convective tray drying. Steam blanched amla flakes refractive window dried witnessed highest retention of ascorbic acid content, antioxidant activity and total phenolic content with lower levels of moisture content, water activity and ash content. Maximum yield recovery (14.13%) was found in steam blanched amla flakes refractive dried at 60C.

1. PRESENTED BY:
ARSHPREET KAUR
L-2K17-AE-10-BIV
B.TECH.
(AGRI. ENGG. AND TECH.)
MAJOR ADVISIOR:
Dr. PREETINDER KAUR
(SENIOR RESEARCH
ENGINEER)
DEPTT. PROCESSING & FOOD
ENGG.

2. CONTENT
• Introduction
• Review of literature
• Material and Methods
• Results and Discussion
• Summary and Conclusion
• References

3. SCIENTIFIC NAME-
EMBLICA
OFFICINALIS
AVERAGE
WEIGHT-
30-60g
Possesses
medicinal and
therapeutic
values
Consumed in
the form of
candy, trifala,
jam, pickle
Rich in
antioxidant
and
polyphenols
VIT-C
CONTENT-
600-700 mg
INTRODUCTION

4. • INDIA
PRODUCTION: 111.1
million tons
AREA: 49.62 million
hectares
(Indian Horticultural database
2016)
• Recommended
Varities in PAU
Balwant
Neelum
Kanchan
PROBLEMS
• Post harvest losses
during peak
harvesting periods
• Highly perishable
nature makes amla
prone to damage
• Improper handling
at various stages

5. • Improve the quality of
the dried fruits.
• Prevents enzymatic
spoilage.
• Common way to preserve
agricultural produce.
• Increase shelf-life
• Promote food security.
• Also reduce post harvest
waste
• Reduce transportation cost
SOLUTIONS

6. Steam Blanching
Hot Water Blanching
BLANCHING METHOD
USED FOR AMLA
PUREE

7. • It involves scalding
vegetables in boiling
water or steam for a
short time
• It stops enzyme actions
which can cause loss of
flavor, color and texture.
• Products are immersed in hot
water (70 to 100°C) for several
minutes.
• Then blanched samples are
drained and cooled before being
sent to the next processing
operation.
• Increases leaching losses

8. Convective Tray drying
Refractive Window drying
DRYING METHOD USED
FOR AMLA PUREE

9. CONVECTIVE
TRAY DRYING
SYSTEM
• Traditional drying
method
• Used for drying
of the solids like
pasty materials
and lumpy
solids of wet
powder
• Requires longer
time and high
energy

10.  The general design of tray dryer
includes a cabinet containing removable
trays on which wet solid material is
placed in plates and hot air is blown
from across and bottom of the tray in
cross-circulation manner to evaporate
moisture from solids.
 To operate the drier on electric energy,
electric heater consisting of heating
rods attached to the drying chamber.
 After reaching desired drying state, the
product is removed.
 The general batch drying cycle in
convective Tray dryer is of 4-48 hrs.
 This dryer is useful when the production
rate is small and in batch and have
lower moisture to be removed.

11. REFRACTION
BASED
DRYING
SYSTEM
• Novel drying
method
• Used for drying
heat sensitive
products
• Used for drying
juices and
purees
• Maintains
flavour, colour
and nutrients

12.  The loss of thermal energy from water
to the environment occurs through
conduction, convection and radiation.
 If the metalized polyester film is
placed on the surface of the water, the
loss of energy can only occur by
conduction.
 When a wet raw material is spread on
the surface of the metalized polyester
film, the water in the material creates
a "window" that allows infrared energy
to pass through the material.
 The heat behaves as if there were no
membranes present and is transferred
directly to the material to be dried.
 This window closes slowly when
moisture loss and heat transfer of the
product decrease and the infrared
energy window is closed.
HOT WATER BATH
CONVECTIO
N
CONDUCTION
RADIATION
WET MATERIAL
METALIZED
POLYESTER FILM

13. 1. To compare the effect of three different types of treatments i.e.
no blanching, steam blanching and hot water blanching on amla
flakes.
OBJECTIVE
2. To conduct comparison analysis of convective and refractive
window based drying of amla puree

14. REVIEW OF
LITERATURE

15. Reference Title Observations
Geetha et al
(2006)
Effect of blanching on
physicochemical
characteristics of amla.
Evaluated the effect of blanching
done prior to processing of amla
fruit and concluded that
blanching has marked effect on
retention of nutrients and various
fruit quality parameters .
Alam et al (2019) Influence of shape, pre-
treatment and drying air
temperature on quality of
dried amla
In order to inactivate the
peroxidase enzyme in amla,
various pre-treatments were
given before mechanical
treatment with highest Vit-C
retention of 83% in steam
blanching
Alam et al (2002) Studies on drying of amla
(Phyllanthus Emblica)
Chakaiya and Banarsi varities of
amla were dried in mechanical
tray dryer at 60℃ after pre-
treatment and compared with
sun dried samples.

16. Reference Title Observations
Clarke (2004) Refractance window-
“down under”
Reviewed new novel dehydration
technology i.e. refractance window
which offers both relatively low
cost operation with excellent
retention of colour, flavour and
nutrients.
Zalpouri et al (2020) Influence of developed
refractance based
drying method on
physical parameter of
potato flakes.
Developed and evaluated
refractive window dryer for
dehydration of potato. It was
observed that the physical
properties of potato flakes were
significantly affected by TSS,
blanching time, and drying
temperature

17. MATERIAL
AND
METHODS

18. DESIGN OF EXPERIMENT
Item Description
Crop Variety Neelum
Pretreatment Washing, Peeling
Blanching methods 1. Hot water blanching for 10
minutes(90-100°C)
2. Steam Blanching (90-100° C)
Drying methods 1. Refractive Based Drying
2. Convective Tray Drying
Quality Physical Parameters
Chemical Parameters
Moisture Content, Water Activity, Ash
Content, Color, Bulk density
Total Phenol Content, Antioxidant
Capacity, Ascorbic Acid Content

19. S.No. Equipment Description
Make/ Model/
Manufacturers
Test performed/
Quality
measured
1
Universal
weighing balance
5kg capacity with
least count of 0.05g.
Excell ZERO NET DC
balance
Weighing (g)
2 Hot air oven Range 0-2500C
Model SNW-143,
Kilburn oven
Macneil & Magor
Ltd, India
Moisture content
3 Colorimeter Color Reader CR-10
Make: Miniscan XE
plus hunter lab
colorimeter
Colour (L, a, b)
LIST OF EQUIPMENTS

20. 4
Electronic UV
– vis
spectrophoto
meter
Digital spectronic
Model: Rayleigh,
UV-2601
Protein (mg/g),
Reducing sugar (mg/g),
Total sugar (mg/g),
Starch content (mg/g)
5
Refractromete
r
Having range 0-
32°Brix
Make: Erma TSS (°B)
6
Refraction
based drying
system
Novel contact
dryer
Fabricated in Pilot
plant, Department
Processing and
Food Engineering,
PAU
Drying
7
Convective
tray dryer
Maximum
attainable
temperature of
200ºC
Model- 012E, Type
Elect,
Manufactured by
Macneil and Magor
Ltd
Mechanical drying

21. PROCESS FLOW CHART FOR PROCESSING OF AMLA FLAKES

22. PREPARATION OF AMLA PUREE
 Pre-cooled fruits were sorted to obtain uniform sized fruits free from
any injury, diseases or bruising and washed thoroughly with running tap
water to remove any foreign material adhering to them. Three different
treatments were used on raw amla. One of the sets of amla of about 5Kg
was left unblanched (UB) and the other two sets of raw amla of 5Kg each
were blanched. For the inactivation of enzymatic browning, the samples
were blanched by two different methods i.e.,
 (i) Steam Blanching (SB): Raw amla’s were steamed over boiling water
in a water bath at 100-110℃ for 20 minutes and cooled immediately in ice
cold water before pulping
 (ii) Hot water blanching (HWB): Raw amla’s were submerged in boiling
water for 10 minutes at 98-100℃ and cooled immediately in ice cold water
before pulping

23. DESIGN OF EXPERIMENT FOR
DRYING OF AMLA PUREE
Treatment Temperature (℃)
Unblanched
(100g)
50 60 70
Hot Water
Blanched(100g)
50 60 70
Steam
Blanched(100g)
50 60 70
Treatment Temperature (℃)
Unblanched
(500g)
60 70 80
Hot Water
Blanched(500g)
60 70 80
Steam
Blanched(500g)
60 70 80

24. Convective tray dried amla flakes
UB SB HWB

25. REFRACTION BASED DRYING SYSTEM
AT 0 min After 15 min
After 30 min
FINAL PRODUCT
UB SB HWB

26. Experiment
Name of the experiment
To study the effect of blanching and air drying temperature on
quality of amla
Location
Department of Processing and Food Engineering, College of
Agricultural Engineering and Technology, PAU, Ludhiana
Methodology
The blanched and dried product will be evaluated on the basis of
 Products parameters:
A) Physico-chemical parameters
B) Bio-active compound characteristics

27. MOISTURE
CONTENT
(MC)
The moisture content of
fresh and dried amla was
determined by standard
oven method (Anon
1975).
Moisture content (%wb) =
𝑾𝟏−𝑾𝟐
𝑾𝟏
x 100
Moisture content (%db) =
𝑾𝟏− 𝑾𝟐
𝑾𝟐
x 100
Where,
W1 = initial weight of the sample (g)
W2 = final weight of the sample (g)

28.  Bulk density of the dried amla powder was determined using a container or
cylinder of known volume and electronic balance.
Bulk density =
𝑴
𝑽
Where,
M = mass of the sample in grams
V = volume of the same sample in cc
BULK DENSITY
ASH CONTENT
 Bulk density of the dried amla powder was determined using a muffle furnace
and the sample was ignited at 550℃ for 4-6 hrs.
Ash Content =
𝑾𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒓𝒆𝒔𝒊𝒅𝒖𝒆
𝑾𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒔𝒂𝒎𝒑𝒍𝒆
X 100
Where,
M = mass of the sample in grams
V = volume of the same sample in cc

29. WATER
ACTIVITY
• Mc Donald et al
(1956) method was
followed to
determine the total
phenolic content in
amla sample
TOTAL
PHENOLIC
CONTENT
(TPC)
• The water activity
determined by using
water activity meter
(Hygrolabrotronic,
Mumbai, India)

30. DETERMINATION
OF
ASCORBIC ACID
• Ranganna et al
method (1986) was
followed to
determine the
ascorbic acid content
in amla samples.
• Antioxidant Capacity
was measured by the
method of De et al
(2002)
DETERMINATION
OF
ANTIOXIDANT
CAPACITY

31. Color:- Colour was determined using Hunter
Lab Miniscan XE Plus Colorimeter.
Colour change, (∆E) = √ (ΔL2 + Δa2 + Δb2)
Chroma, (𝐶) = 𝑎2 + 𝑏2
Hue angle, (α) = tan-1(
𝑏
𝑎
)
Where,
ΔL, Δa and Δb are deviations from L, a, and b values
of fresh sample.

32. RESULT
AND
DISCUSSION

33. ASH
CONTENT
8-9%
WATER
ACTIVITY
(0.55-0.56)
MOISTURE
CONTENT
(83-85%)
ASCORBIC
ACID
CONTENT
(2154-
2200mg/100g)
ANTIOXIDANT
CAPACITY
(657-664 %)
TOTAL
PHENOLIC
CONTENT
(270-300 mg
GAE/100g)
PHYSICO-CHEMICAL COMPOSITION OF
RAW AMLA
BULK
DENSITY
(0.84-0.85
g/ml)

34. PHYSICO-CHEMICAL
COMPOSITION OF AMLA PUREE
S. No. Parameter Pulp
Unblanched Steam Blanched Hot-Water
Blanched
1 Moisture Content(%wb) 83.87±1.553 85.83±2.984 87.02±0.685
2 Ash Content (%) 8.04±0.05 8.86±0.032 9.62±0.036
3 Water Activity 0.55±0.002 0.55±0.001 0.24±0.006
4 Bulk Density(g/ml) 0.84±0.0007 0.84±0.008 0.84±0.001
5 L value 66.9±1.2 71.11±2.77 73.1±1.07
6 Color Change(∆E) 2.49±0.560 6.07±1.886 7.66±0.953
7 Chromaticity 16.51±0.445 21.92±0.582 21.71±0.817
8 Hue angle (a) 27.9±0.918 -88.05±0.523 -85.35±0.588
7 Ascorbic Acid(mg/100gm) 2154.3±42.846 1960.2±35.79 1798.3±39.058
8 Antioxidant Activity (%) 657.96±5.945 712.14±5.944 734.50±9.984
9 Total Phenolic Content, (mg
GAE/100gm)
270.26±27.536 289.55±31.344 276.49±34.207

35. OPTIMIZATION OF
DRYING PROCESS

36. 0
100
200
300
400
500
600
0.00 15.00 30.00 45.00 60.00 75.00 90.00 105.00 120.00
Moisture
Content
9%db)
Time (mins)
70°C
UB SB HWB
Variation in moisture content at 70℃
0
100
200
300
400
500
600
0 60 120 180 240 300 360 420
Moisture
Content
(%db))
Time (mins)
70°C
UB SB HWB
CONVECTIVE
TRAY DRIER
REFRACTIVE
WINDOW
DRIER

37. Variation in drying rate at 70℃
CONVECTIVE
TRAY DRIER
REFRACTIVE
WINDOW
DRIER
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
0 60 120 180 240 300 360 420
Drying
Rate
(gm/min)
Time (mins)
70°C
UB SB HWB
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 15 30 45 60 75 90 105 120
Drying
Rate
(gm/min)
Time (mins)
70℃
UB SB HWB

38. Recovery % of dried product
Parameter Recovery %
Convective Tray
Drying Treatment
Unblanched 50°C 12.8
60°C 12.15
70°C 11.64
Steam-Blanched 50°C 12.21
60°C 12.08
70°C 11.55
Hot Water Blanched 50°C 11.37
60°C 11.24
70°C 10.71
Refractance
Window Drying
Treatment
Unblanched 60°C 13.4
70°C 12.6
80°C 11.2
Steam-Blanched 60°C 14.13
70°C 13.6
80°C 12.16
Hot Water Blanched 60°C 13.12
70°C 12.4

39. Effect of blanching and drying temperature
on Color (Hue Angle) of amla
Convective Tray Drier Refractive Window Drier
-200
-150
-100
-50
0
50
100
150
50 60 70
Hue
Angle
(°)
Temperature (°C)
UB SB HWB
-150
-100
-50
0
50
100
60 70 80
Hue
Angle
(°)
Temperature (°C)
UB SB HWB

40. Effect of blanching and drying temperature
on Total Phenolic Content of amla
Convective Tray Drier Refractive Window Drier
0
10
20
30
40
50
60
70
80
50 60 70
Total
Phenolic
Content
(mg
GAE/100gm)
Temperature (°C)
UB SB HWB
0
10
20
30
40
50
60
70
80
60 70 80
Total
Phenol
Content
(mg
GAE/100gm)
Temperature (°C)
UB SB HWB

41. Effect of blanching and drying temperature
on antioxidant activity of amla
0
10
20
30
40
50
60
70
80
90
50 60 70
Antioxidant
Capacity(%)
Temperature (°C)
UB SB HWB
0
10
20
30
40
50
60
70
80
90
60 70 80
Antioxidant
Capacity
(%)
Temperature (°C)
UB SB HWB
Convective Tray Drier Refractive Window Drier

42. Effect of blanching and drying temperature
on Ascorbic Acid Content of amla
Convective Tray Drier Refractive Window Drier
0
50
100
150
200
250
300
350
400
50 60 70
Ascorbic
Acid
(mg/100gm)
Temperature (°C)
UB SB HWB
0
50
100
150
200
250
300
350
400
60 70 80
Ascorbic
Acid
(mg/100gm)
Temperature (°C)
UB SB HWB

43. SUMMARY
AND
CONCLUSION

44.  Blanching had significant effect on physico-chemical composition of raw amla.
Blanching increased the moisture content, water activity and the ash
percentage. Bulk Density was to found to be nearly same in all the three
treatments. Blanched samples had higher L value when compared with
unblanched sample.
 Blanching had a positive impact on protecting the antioxidant activity of raw
amla. However, ascorbic acid content and total phenolic content reduced
after hot water and steam blanching.
 The blanching pre-treatment increased the drying rates for amla samples. The
untreated samples generally had lower drying rates than those of the pre-
treated samples.
 Moisture content of Refractive window dried samples was lower than
convective tray dried samples.
 The flakes blanched had a bright visual appearance. However, the unblanched
flakes appeared to have more darkness after drying. Therefore, they lost their
natural brightness and showed redness when dried. This change was
manifested by an increase in a-value and a decrease of the b-value.
 Refractive window drying system allowed higher retention of bioactive
compounds when compared to convective tray drying
 In conclusion, steam blanched sample refractive window dried at 70℃ showed
best retention in terms of physical parameters and bio active compounds.

45. REFERENCES

46. Alam M S, Sharma S R, and Nidhi (2002) Studies on drying of amla (Phyllanthus
Emblica). In paper presented in XXXVI annual convention of ISAE, IIT Kharagpur,
January 28-30.
Alam M S, Singh A and Chawan P (2019) Influence of shape, pre-treatment and
drying air temperature on quality of dried amla. Int Com. Agri Bio Engg 22(1).
Clarke P T (2004) Refractance window- “down under”. Proc of the 14th Int
Drying Symp pp 813-20. São Paulo, Brazil São Paulo, Brazil.
Geetha N S, Kumar S, Rana G S (2006) Effect of blanching on physicochemical
characteristics of amla. Haryana J.Horti.Sci 35(1&2): 67-68.
Zalpouri R, Kaur P, Kaur A (2020) Influence of developed refractance based drying
method on physical parameter of amla flakes. Int J Chem Stud 8(3): 2833-2838.