Mango jam
This writeup is basically focused on the science behind mango jam with the ingredients, formulation including calculation of ingredients, procedure, failures in jam making, calculation of preservation index, determination of titrable acidity, and the flow diagram of making mango jam.
Mango jam
Basins for washing fruits
Stainless steel knives / spoons
Chopping board
Stainless steel pan
Heating source
Blenders
Strainers
Balance
Measuring cylinder
Sterilized empty bottles with lids
Refractometer (50°- 80° Brix)
Thermometer
pH meter
Ingredients
Fruit pulp
Sugar
Pectin
Citric acid
Formulation
Calculation of Jam, Jelly and Marmalade Recipe
In the preparation of these products, it is always advisable to work on a predetermined batch size. As in illustration, consider the manufacture of 50kg of mango jam of 40% fruit content and 70% refractometric solids using a pulp having 100% fruit content, 12.3% refractometric solids and 0.8% acidity, pectin of 150 grade. The calculations involved are:
Weight of pulp required = 40 X 50 = 20.00kg
100
Soluble solids derived from the pulp = 12.3 X 20.00 = 2.46 kg
100
Sugar required = 70 X 50 = 35 kg
100
Pectin required = 1 X 35 = 0.23 kg
150
Acidity level required to adjust the pH of the finished product to 3.1 is approximately 0.6%;
Acid required = 0.6 X 50 = 0.3kg
100
= 0.8 X 20.00 = 0.16 kg
100
Acidity contributed by pulp = 0.16kg
Acidity to be added = 0.3 - 0.16 = 0.14
Sugar to be added = 35 - (2.46 +0.23 +0.14) = 32. 17 kg
Mango pulp = 20.00kg
150 grade pectin = 0.23kg
Citric acid = 0.14kg
Sugar
Weight of water = Weight of sugar
3
Procedure
1. Clean and remove the peels of the fruits.
2. Cut into pieces and pulp it using the blender.
3. Pour a weighed quantity of pulp into a stainless steel pan.
4. Weigh the required quantity of sugar and pectin as calculated.
5. Take water equals 1/3 of the weight of the sugar.
6. Separate the weighed amount of sugar into two equal parts.
7. Mix pectin with one part of sugar and add the previously measured volume of water.
8. Add the remaining part of sugar into the stainless steel pan and mix well and boil it.
9. Then add the mixture of pectin, sugar and water to the boiling pulp and heat it until the Brix
comes up to 68.5°. Measure the temperature also.
10. Remove from the heating source and mix with citric acid, which has been dissolved in equal
amount of water (1:1).
11. Check the pH of the jam by mixing one part of jam with one part of water (1: 1, jam: water).
12. Fill while hot (filling temperature is 85 °C) into clean, dry containers.
13. Cap the containers and allow them to air cool (Label the containers, name the product).
Failures in jam making
• Prolonged boiling destroys pectin, which gives the product a syrupy consistency.
• Too high acidity also breaks up the jelly network causing syneresis.
• Too low acidity reduces the setting properties of pectin and frequently inhibits jelly formation.
Check pH and change acidity if necessary. Low sugar content also inhibits jelly formation. Refractometer check of soluble solids is essential (danger line below 66 %).
• Low soluble solid content of the product (danger line 66 %).
• Contamination of the product before sealing of cans or jars leads to mould development and
yeast growth.
• Prolonged boiling causes the caramelization of sugar.
• Insufficient sterilization causes microbial spoilage of the product.
Guidelines
• Fruit content (% by mass, minimum)
Mango 20%
Pineapple 40%
Tomato 35%
Wood apple 20%
Mixed fruit 40%
Any other 40%
Sugar content should not be less than 65% by mass (68.5°).
Acidity- pH 3.2
Calculation of preservation index
This is used to assess whether the product is safe from food spoilage and poisoning microbes. The value can be calculated as given below.
Total acidity X 100 = not less than 3.6%
100 - Total solids
Determination of titrable acidity
Introduction
Fruit juice is the natural liquid expelled out by pressure or other mechanical means from the edible portion of the fruit. The juice is turbid or cloudy containing insoluble cellular components and finely divided tissues. The solid content varies between 5 and 20 % by weight. The composition of the juice is unaltered during preparation and preservation. It is consumed as such without clarification to retain the natural flavor and colour, e.g.Orange juice.
Fruit juices contain a number of simpler organic acids such as malic and citric, which can be readily neutralized by strong bases and may thus be titrated against standard bases such as NaOH. The reaction between citric acid and NaOH is given below.
3NaOH + C3H5O(COOH)3 → C3H5O(COONa)3 + 3H2O
Chemicals and Materials
Lemon
0.1 M NaOH, Phenolphthalein
50 ml Burette
250 ml Conical flask
10 ml Pipette
100 ml Beaker
100 ml Volumetric flask
Filter papers
Procedure
Filter about 25 ml of fruit juice into a clean dry beaker.
Pipette 10.0ml of this filtered juice into a 100 ml volumetric flask and mike to the mark with
distilled water.
Pipette out 10.0 ml of this diluted juice into a conical flask and dilute to about 80 ml with distilled
water.
Add 0.3 ml of phenolphthalein by the pipette and titrate to a faint pink colour end point with 0.1 M NaOH.
% of citric acid = T X 192
3 X 100
T = Mean titre of 0.1 M NaOH
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