Experiment Manual
Experiment Manual
Experiment Manual
Perf-50
Theory-20
Viva-20
Record 10
Exercise No.: __________ Date: _____________
Relevance : Maturity indices are important for deciding when a given commodity
should be harvested to provide some marketing flexibility and to ensure
the attainment of acceptable eating quality to the consumer. Fruits picked
at the wrong stages of maturity may develop physiological disorders in
storage and may exhibit poor eating quality. Therefore, for selecting the
harvest maturity of fruits or vegetables it should be kept in mind that
harvested commodity should have its peak acceptable quality with
adequate shelf life.
It is the TSS/acid ratio which contributes towards giving many fruits
their characteristic flavour and so is an indicator of commercial and
organoleptic ripeness. At the beginning of the ripening process the
sugar/acid ratio is low, because of low sugar content and high fruit acid
content, this makes the fruit taste sour. During the ripening process the fruit
acids are degraded, the sugar content increases and the TSS/acid ratio
achieves a higher value. Overripe fruits have very low levels of fruit acid
and therefore lack characteristic flavour. Characteristic TSS/acid ratio at
maturity for different fruits are as follows-
Citrus :- 12:1
Guava (Allahabad Safeda) :- 35.81:1
Pomegranate :- 19.5:1
Grape (Thompson Seedless) :- 32.83:1
Grape (Pusa Seedless) :- 29.24:1
Principle : Total acid is estimated by titrating the sample aliquot against 0.1N NaOH.
It is calculated as equivalent amount of NaOH required to neutralize all
free carboxylic groups present in the sample aliquot.
Soluble solids content can be determined in a small sample of fruit juice
using hand refractometer. The hand refractometer employs the principle of
total internal reflection to measure refractive index, which indicates how
much a light beam will be refracted when it passes through the fruit juice
which is then correlated with TSS as degree brix or % TSS. The TSS
reading should be corrected for temperature using correction factor from
the table.
The TSS reading is then divided by the acidity percentage to obtain TSS/
Acid ratio.
Reagents : 1. 0.1N NaOH: Dissolve 2 g of NaOH pellets in distilled water and make
and up the volume to 500 ml.
Materials 2. Phenolphthalein indicator solution: Dissolve 1 g in 100 ml of ethanol.
3. Hand Refractometer
4. Temperature correction chart
Procedure : Measurement of Acidity
(a) Weigh approx. 20 g of the sample to a 100 ml beaker.
(b) Transfer it to 50 ml volumetric flask and make p the volume to 50 ml
by distilled water.
(c) Take 10 ml sample aliquot to 100 ml conical flask.
(d) Add few drops of phenolphthalein to the conical flask
(e) Take the 0.1N NaOH solution in a 25 ml burette.
(f) Titrate the sample solution against 0.1N NaOH. Appearance of light
pink colour indicates the end point.
(g) Note the volume of NaOH consumed.
(h) Repeat the titration twice more.
Measurement of TSS
(a) Rotate the eye piece knob and adjust eyepiece to focus clear image of
scale.
(b) Make the prism surface clean and dry. Place one drop of distilled water
on specimen chamber and close the cover tightly. Look into the
eyepiece with projection inlet facing the light and the boundary line
appears on the scale. Now, adjust the scale correction device by a screw
driver to align boundary line with zero line on the scale.
(c) Again make the prism surface dry by wiping the water using tissue
paper. Now, place one or two drop of the test solution in the specimen
chamber and close the cover tightly. Look into the eyepiece with
projection inlet facing the light and the boundary line appears. Read the
measurement of the point where the boundary line coincides with the
scale for desired percentage of sugar content.
(d) As the scale is graduated upon standard temperature of 20 oC, correct
reading value according to the correction table; in case of measuring
substances does not correspond with standard temperature.
Observation : (i) Weight of sample taken (g) =
(ii) Final volume made up to (ml) =
(iii) Volume of sample aliquot taken for titration (ml) =
(iv) Volume of NaOH consumed (ml) = (a) (b) (c)
(v) Average of three observations (ml) =
(vi) % TSS observed =
(vii) Temperature of the test solution =
(viii) Correction to be made (from temperature correction table) =
(ix) % TSS at 20oC =
Calculation : Titre X Normality X Volume X Equivalent X 100
of NaOH made up wt. of acid
Total Acidity (%) =
Volume of sample X Wt. of sample taken X 1000
taken for estimation
𝐴𝑐𝑖𝑑𝑖𝑡𝑦
TSS/Acid ratio= =
𝑇𝑆𝑆 𝑎𝑡 20𝑜 𝐶
Conclusion :
Remarks :
Signature :
Reading
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
10 0.50 0.54 0.58 0.61 0.64 0.66 0.68 0.70 0.72 0.73 0.74 0.75 0.76 0.78 0.79
11 0.46 0.46 0.53 0.55 0.58 0.60 0.62 0.64 0.65 0.66 0.67 0.68 0.64 0.70 0.71
12 0.42 0.45 0.48 0.50 0.52 0.54 0.56 0.57 0.58 0.59 0.60 0.61 0.61 0.63 0.63
Deduct from reading
13 0.37 0.40 0.42 0.44 0.46 0.48 0.49 0.50 0.51 0.52 0.53 0.54 0.54 0.55 0.55
14 0.33 0.35 0.37 0.39 0.40 0.41 0.42 0.43 0.44 0.45 0.45 0.46 0.46 0.47 0.48
15 0.27 0.29 0.31 0.33 0.34 0.34 0.35 0.36 0.37 0.37 0.38 0.39 0.39 0.40 0.40
16 0.22 0.24 0.25 0.26 0.27 0.28 0.28 0.29 0.30 0.30 0.30 0.31 0.31 0.32 0.32
17 0.17 0.18 0.19 0.20 0.21 0.22 0.21 0.22 0.22 0.23 0.23 0.23 0.23 0.24 0.24
18 0.12 0.13 0.13 0.14 0.14 0.14 0.11 0.15 0.15 0.15 0.15 0.16 0.16 0.16 0.16
Temperature oC
19 0.06 0.06 0.06 0.07 0.07 0.07 0.07 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08
20 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
21 0.06 0.07 0.07 0.07 0.07 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08
22 0.13 0.13 0.14 0.14 0.15 0.15 0.15 0.15 0.15 0.16 0.16 0.16 0.16 0.16 0.16
23 0.19 0.20 0.21 0.22 0.22 0.23 0.23 0.23 0.23 0.24 0.24 0.24 0.24 0.24 0.24
Add to reading
24 0.26 0.27 0.28 0.29 0.33 0.30 0.31 0.31 0.31 0.31 0.31 0.32 0.32 0.32 0.32
25 0.33 0.35 0.36 0.37 0.38 0.38 0.39 0.39 0.40 0.40 0.40 0.40 0.40 0.40 0.40
26 0.40 0.42 0.43 0.44 0.45 0.46 0.47 0.47 0.48 0.48 0.48 0.48 0.48 0.48 0.48
27 0.48 0.50 0.52 0.53 0.54 0.55 0.55 0.55 0.56 0.56 0.56 0.56 0.56 0.56 0.56
28 0.56 0.57 0.60 0.61 0.62 0.63 0.63 0.63 0.64 0.64 0.64 0.64 0.64 0.64 0.64
29 0.64 0.66 0.68 0.69 0.72 0.72 0.72 0.72 0.74 0.73 0.73 0.73 0.73 0.73 0.73
30 0.72 0.74 0.77 0.78 0.79 0.80 0.80 0.81 0.81 0.81 0.81 0.81 0.81 0.81 0.81
Experiment No.: __________ Date: _____________
Relevance : In canning fruits, sugar in the form of syrup is used to bring out the full
flavour of the fruits. Care must be taken not to make the contents
excessively sweet. Strength of the syrup would depend on the kind and
variety of fruit. Generally the more acidic fruits require denser syrup.
In commercial practice, syrups of desired Brix are prepared according to a
formula by which a known weight of sugar is added to a given volume of
water. Sometimes, it will be found necessary in practice to dilute a syrup or
increase its strength. This is facilitated by what is known as the "Pearson
Square Method".
Procedure : Draw a square ABCD with the centre marked E. at A, note the Brix reading
of the heavy syrup and the amount of sugar present per liter of the syrup.
At D, write the Brix degree of the light syrup and the amount of sugar
present per liter of the syrup. This is marked zero when water is only to be
added for dilution, and 100 when sugar is to be added. At E, write the Brix
degree and the sugar present per liter of the desired syrup. Now work
diagonally across the square. Subtract the smaller number from the larger
and write the difference at the opposite corners C and B. These numbers
represent the ratio in which the two syrups are required to be mixed.
A B
D C
Problem : Example: Prepare a syrup of 45o Brix from syrups of 62oBrix and 10o
Brix.
62oBrix A B 438 (542-104)
liter (805 g sugar per liter) or 35 kg
E
45o (542g
Per liter)
Remarks :
Signature :
Relationship between degree Brix reading and composition of syrup
Degree Brix at Weight of sugar to be added to Volume of syrup from one liter Weight of sugar contained in
20oC each liter of water (g) of water (liter) one liter of syrup (g)
10 111 1.067 104
11 123 1.076 114
12 136 1.085 125
13 149 1.093 136
14 163 1.101 147
15 176 1.111 158
16 190 1.119 170
17 204 1.127 181
18 219 1.137 193
19 234 1.146 204
20 250 1.157 216
21 266 1.167 228
22 282 1.176 240
23 300 1.187 252
24 317 1.198 264
25 334 1.208 276
26 352 1.220 289
27 370 1.231 301
28 389 1.243 313
29 409 1.256 326
30 430 1.269 338
31 450 1.281 351
32 472 1.294 364
33 794 1.309 377
34 517 1.323 390
35 540 1.338 403
36 564 1.353 417
37 589 1.369 430
38 614 1.384 444
39 641 1.401 458
40 669 1.419 471
41 697 1.437 485
42 726 1.454 499
43 756 1.474 513
44 788 1.494 517
45 820 1.514 541
46 855 1.536 557
47 890 1.558 571
48 926 1.580 586
49 964 1.604 601
50 1003 1.628 616
51 1044 1.654 631
52 1086 1.681 645
53 1131 1.710 661
54 1177 1.739 677
55 1236 1.770 693
56 1277 1.803 708
57 1329 1.837 723
58 1385 1.871 740
59 1443 1.907 757
60 1505 1.948 773
61 1569 1.988 789
62 1637 2.032 805
63 1708 2.077 831
64 1784 2.124 839
65 1862 2.174 857
66 1947 2.229 875
67 2039 2.287 892
68 2132 2.344 910
69 2223 2.411 927
70 2340 2.480 944
Experiment No.: __________ Date: _____________
Relevance : Blanching is a mild heat treatment given to vegetables slices before drying
or canning. It is also known as scalding, parboiling or precooking. The
activity of polyphenol oxidase, catalase and peroxidase often carry out
undesirable changes (browning, off-flavour etc.) in fruits and vegetables.
Blanching is mainly done to inactivate enzyme by denaturing the protein
part of the enzyme. The degree of enzyme inactivation indicates the
effectiveness of the blanching treatment. Of the various enzymes present
in fruits and vegetables, peroxidase is considered to be most heat stable.
Therefore, in blanching study, peroxidase is taken as index enzyme.
Blanching is mainly done in case of vegetable. There are different methods
of blanching viz., Hot water blanching, Steam blanching, Microwave
blanching etc. Hot water blanching is most commonly carried out.
Principle : Peroxidase present in the vegetable tissue produces brown colour when
treated with Guaiacol solution in presence of hydrogen peroxide.
Therefore, if a blanched vegetable tissue does not give brown colour with
Guaiaol, then it may be concluded that peroxidase in the tissue is
completely inactivated i.e., the vegetable is sufficiently blanched.
Reagents : 5. 0.08% H2O2: Dilute 2.7 ml of 30% H2O2 to 100 ml with water and
store in a dark bottle in a refrigerator.
6. 0.5% Guaiacol solution: Dilute 0.5 ml Guaiacol to 100 ml with 50%
ethyl alcohol.
Procedure : (i) Cut the vegetable into thin slices. Put the cut slices into a beaker
containing water.
(j) Take water into a pan and place over an electric heater and let it boil.
(k) Check the temperature of the water intermittently using a thermometer.
(l) Take the slices in a stainless steel strainer and immersed in the hot
water when the temperature of the water reaches 90oC.
(m) Try to maintain the temperature within 90 ± 2oC by putting the
switch on and off.
(n) Take out 3-4 slices after each one minute interval in Petri dishes.
(o) Then to these blanched slices, add 1 ml 0.5% Guaiacol solution and
then 1 ml 0.08% H2O2. Then look for brown colour development.
(p) If the colour develops within 3.5 min, the test is considered to be
positive i.e., the product is not sufficiently blanched. Then repeat the
test using slices that are blanched for longer time.
(q) If no colour develops in 3.5 min, considered the test to be negative and
that the product is adequately blanched.
(r) Consider this to be the blanching time and temperature for the product.
Any further boiling will over cook the product.
Observation :
Sl No. Time (min) Temperature (oC) Test Response
1 0
2 1.0
3 2.0
4 3.0
5 4.0
6 5.0
7 6.0
Conclusion :
Remarks :
Signature :
Exercise No.: __________ Date: _____________
Objective : To understand the process for estimation of pectin content in fruits and
vegetables.
Relevance : Pectic substances abundantly exist in the middle lamella of the plant cells.
There are three types of pectic substances – pectic acids, pectinic acids and
protopectin. Pectic acid is an unbranched molecule made up of about 100
units of D-galacturonic acid residues. The monomers are linked through ∞-
1, 4- glycosidic linkage. Pectinic acid is an extensively esterified pectic acid.
Several carboxyl groups exist as methyl esters. Pectic acid is water soluble
whereas pectinic acid forms a colloidal solution. Protopectin is a larger
molecule than pectic and pectinic acid. During ripening of fruits, conversion
of protopectin into pectic acid and pectinic acid takes place. The pectinic
acids in fruits vary in their methoxyl content and in jellying power.
Principle : Pectin is extracted from plant material and saponified with alkali. It is
precipitated as calcium pectate by the addition of calcium chloride to an acid
solution. The calcium pectate precipitated is washed thoroughly to eliminate
chloride ions, dried and then weighed.
Procedure : (a) Weigh 50 g of blended sample into a 1 L beaker and add 300 ml 0.01 N
HCl. Boil for 30 min and filter. Wash the residue with hot water and
collect the filtrate.
(b) To the residue add 100 ml 0.05 N HCl; boil for 20 min, filter, wash and
collect the filtrate.
(c) To the residue now add 100 ml 0.3 N HCl; boil for 10 min, filter, wash
and collect the filtrate.
(d) Pool the filtrates. Cool and make up the volume to 500 ml.
(e) Pipette out 200 ml aliquot into 1 L beaker.
(f) Add 250 ml distilled water and neutralize the acid with 1 N NaOH using
phenolphthalein indicator. Add an excess of 10 ml 1 N NaOH with
constant stirring and allow it to stand overnight.
(g) Add 50 ml 1 N acetic acid and after 5 min, add 25 ml 1N calcium
chloride solution with stirring. Allow it to stand for 1 hour.
(h) Boil for 1-2 min.
(i) Filter through a pre-weighed Whatman No. 1 filter paper (Wet a
Whatman No. 1 filter paper in hot distilled water, keep it in a covered
Petri dish, dry in oven at 102oC for 2 h. Cool in a desiccator and weigh).
(j) Wash the precipitate with almost boiling water until the filtrate is free
from chloride.
(k) Take the filtrate in a test tube and test with silver nitrate for chloride.
(l) Once the filtrate is free of chloride, transfer the filter paper containing
the calcium pectate to the original Petri dish, dry overnight at 100o C,
cool in a desiccator and weigh.
% Calcium pectate
% Protopectin =
1.10
% Protopectin =
Conclusion :
Remarks :
Signature :
*The empirical formula for calcium pectate is C17H22O16Ca. The calcium pectate yield of
highly purified pectinic acid is usually about 110% of the pectinic acid.
Experiment No.: __________ Date: _____________
Relevance : The raw materials for preparation of jam, jelly and marmalade are fruit pulp, acid,
pectin, sugar and water. Fruit pulp contributes a part of acid, pectin, water and
TSS required for jam preparation. But the quality of fruits with respect to TSS,
acidity and pectin content may vary from fruit to fruit even from variety to variety
for a particular fruit. In order to meet the specification laid down by the regulatory
agencies, it is important to formulate a recipe for preparing jam, jelly and
marmalade from different fruit.
Problem : Calculate the amount of pulp, pectin, citric acid, and stock syrup required for the
preparation of 50 kg mango jam of 40% fruit content and 70% TSS. The pulp
contains 98% fruit, 12.3% TSS and 0.8% acidity. 150 grade Pectin and 64 o Brix
stock syrup should be used for this purpose. It is assumed that only 25% of the
sugar is inverted during boiling.
Solution : 40
Weight of the pulp required = x 50 = 20.41 kg
98
12.3
Soluble solids derived from the pulp = x 20.41 = 2.51 kg
100
70
Sugar required = x 50 = 35 kg
100
1
Pectin required = x 35 = 0.23 kg
150
Acidity level required to adjust the pH of the finished product to 3.1 is
approximately 0.6%.
0.6
Acid required = x 50 = 0.3 kg
100
0.8
Acidity contributed by the pulp = x 20.41 = 0.163 kg
100
Acid to be added = 0.3 – 0.163 = 0.137 kg
Sugar to be added = 35 – (2.51 + 0.23 + 0.137) = 32.123 kg
It is assumed that only 25% of the sugar is inverted.
Sucrose ⎯⎯⎯⎯→
INVERSION
Glucose + Fructose
342 g ⎯⎯⎯⎯→
INVERSION
180g + 180g
Inversion of 342 g sucrose yields 360 g of invert sugar (Glu+Fru).
Therefore, 100 kg of Sugar (sucrose) with 25% inversion will originally yield
360
75 kg + 25 x kg = ( 75 + 26.32 ) kg =101.32 kg sugar
342
As 101.32 kg sugar is obtained from 25% inversion of 100 kg sugar (sucrose),
100
32.123 kg sugar will be obtained from x32.123 = 31.70 kg sugar
101.32
We have a stock syrup of 64o Brix,
100
Therefore, weight of stock syrup to obtain 31.70 kg sugar = x 31.70 = 49.53 kg
64
Hence, the basic recipe is:
Mango pulp = 20.41 kg
Stock syrup = 49.53 kg
150 grade = 0.23 kg
pectin
Citric acid = 0.137 kg
Quantity of = 70.31-
water to be 50.0 =
boiled off 20.31 kg
Assignment : Calculate the amount of pulp, pectin, citric acid, and stock syrup required for the
preparation of 40 kg pineapple jelly of 38% fruit content and 65% TSS. The pulp
contains 95% fruit, 11% TSS and 0.75% acidity. 100 grade Pectin and 60o Brix
stock syrup should be used for this purpose. It is assumed that only 40% of the
sugar is inverted during boiling.
Remarks :
Signature :
Experiment No.: __________ Date: _____________
Relevance : Mango, orange and pineapple are used for making squash commercially. It can
also be prepared from lemon, lime, bael, guava, litchi, pear apricot, pummelo,
musk melon, papaya etc., using potassium metabisulphite (KMS) as
preservative, or from jamun, passion fruit, peach, phalsa, plum, mulberry,
raspberry, strawberry, grapefruit, etc., with sodium benzoate as preservative.
According to the specification of FPO, the squash should have minimum of
40% total soluble solid (TSS), 1.5% acidity and a minimum of 25% fruit juice.
Permissible limits of sulphur dioxide and benzoic acid as preservative are 350
ppm and 600 ppm respectively. Therefore, before formulating a recipe for
squash from different fruits, one has to consider the TSS and acidity content of
the fruit juice.
Problem : Calculate the amount of different ingredients required to prepare 1000 kg jamun
squash following the specification of FPO. The jamun juice contains 120 Brix
TSS and 0.5 % acidity. KMS available is of 80% purity.
45
TSS required for 1000 kg squash = x 1000 = 45 kg
100
Sugar to be added = 450 - (30 + 13.75 + 0.76) = 405.49 kg
Water to be added = 1000 - (405.49 + 250 + 13.75 + 0.76) = 330 kg
Acid to be added = 0.3 – 0.163 = 0.137 kg
Hence, the basic recipe is:
Assignment : Calculate the amount of different ingredients required to prepare 500 kg orange
squash. The final product should have minimum of 45% total soluble solid
(TSS), 1.25% acidity and a minimum of 25% fruit juice. The orange juice
contains 110 Brix TSS and 0.75 % acidity. KMS available is of 85% purity.
Remarks :
Signature :
Experiment No.: __________ Date: _____________
Relevance : This is a type of fruit beverage containing at least 25 per cent fruit juice or pulp and
40 to 50 per cent total soluble solids, commercially. It also contains about 1.0 per
cent acid and 350 ppm sulphur dioxide or 600 ppm sodium benzoate. It is diluted
before serving.
Mango, orange and pineapple are used for making squash commercially. It can also
be prepared from lemon, lime, bael, guava, litchi, pear, apricot, musk melon,
papaya, etc. using potassium metabisulphite (KMS) as preservative or from jamun,
passion-fruit, peach, phalsa, plum, mulberry, raspberry, strawberry, grapefruit, etc.
with sodium benzoate as preservative.
Procedure : (m) Select fully ripe fruit to get maximum amount of juice and complete flavour
profile of the fruit.
(n) Remove the damaged and immature fruits and wash thoroughly.
(o) Prepare the fruit for juice extraction as per requirement of individual fruit. It
may be peeling, cutting into pieces or grating.
(p) Take the prepared fruit into nylon net and squeeze to extract the juice. Juice
can be also be extracted by using juicer or pulper.
(q) The juice is then strained to remove any impurities.
(r) Measure the amount of extracted juice. Keep the juice under cover to avoid
contamination and oxidation in contact with air.
(s) Weigh the required amount of sugar, citric acid, water and preservative.
(t) Mix water, sugar and acid and heat just to dissolve.
(u) Cool and strain the syrup to remove suspended impurities.
(v) Mix the cold syrup and fruit juice.
(w) Take a small amount of the squash in a beaker and dissolve the preservative
in it. Now this concentrated preservative solution is mixed with the bulk of
the squash and stirred well for uniform mixing.
(x) The prepared squash is then filled in a previously sterilized bottle leaving 1
inch at the top of the bottle.
(y) For sterilization of bottles, fill the bottle with water and place them in a
vessel containing water. Care should be taken to avoid introduction of any
air bubble into the bottle. The vessel along with the bottles is then heated to
boil.
(z) The bottle is then corked and capped. To make the capping air-tight the neck
of the bottle with cap is dipped in molten paraffin wax.
(aa) Store in a cool, dry place.
1. Fruit Rs.
2. Sugar Rs.
3. Citric acid Rs.
4. Preservative Rs. Profit
5. Bottles Rs.
6. Energy Rs.
7. Labour Rs.
8. Miscellaneous Rs.
TOTAL = Rs.
Conclusion :
Remarks :
Signature :
Experiment No.: __________ Date: _____________
A)
Preparation of i) Sorting and grading
fruit and :
vegetable for ii) Washing
canning iii) Peeling, coring and pitting
Observations
Precautions
• The cans used should be checked for corrosion.
• Fruits and vegetables should be absolutely fresh. It should be free from
all-unsightly blemishes, insects damage and malformation
• Ripe, firm and evenly matured fruits should be selected. Over ripe fruit
is generally infected with microorganisms and would yield a pack of
poor quality. Under-ripe fruit will generally shrivel and toughen on
canning.
• Worker should wear apron and cover the head with a cap.
EXPERIMENT No. ……….. Date……………..
It is made from strained tomato juice or pulp and spices, salt, sugar
and vinegar, with or without onion and garlic, and contains not
less than 12% tomato solids and 25% total solids.
Recipe: Tomato pulp 1 kg, sugar 75g, salt 10g, onion (chopped)
50g, ginger (chopped) 10g, garlic (chopped) 5g, red chilli powder
5g, cinnamon, cardamom (large), aniseed, cumin, black pepper
(powdered) 10g each, clove (headless) 5 numbers, vinegar 25 ml
c) Tomato Puree or glacial acetic acid 5 ml and sodium benzoate 0.25g per kg final
and Paste product.
118127
118128
129
130
133
134
135
137
139
140
141
144
145
147
149
150
151