नमस्कार विद्यार्थी मित्रांनो To detect the presence of starch added as an adulterant to the milk हे प्रॅक्टिकल Experiments to be performed - PART A मधील आहे. याचाच अर्थ तुम्हाला हे प्रॅक्टिकल Exam मध्ये Examiner ला Performe करून दाखवायचे आहे. म्हणूनच प्रॅक्टिकल Exam च्या दृष्टीने हे Experiment अतिशय महत्त्वाचे आहे. या ब्लॉग मध्ये आपण Practical Book मधील या Experiment Number - 14 ची उत्तरे पाहणारं आहोत. ही उत्तरे काळजीपूर्वक वाचून आपल्या Practical Book मध्ये लिहा किंवा तुमच्या कॉलेजमधील संबंधित विषय शिक्षकांची मदत घ्या.
14. To detect the presence of starch added as an adulterant to the milk.
Aim :- To detect the presence of starch added as an adulterant to the milk.
Requirements :- Test tubes, pipettes, 1% iodine solution, milk samples (minimum 3, preferably raw milk of same animal source cow/ buffalo), etc.
Theory :- Addition of starch increases the SNF (Solid Not Fat) content of milk. Wheat flour, arrowroot starch, rice flour can be added for increasing the SNF (Solid Not Fat) content. Starch is used to prepare synthetic milk, which is, then added to natural milk. This is commonly used to compensate for the added water. Since starch powder is easily and cheaply available, it is the most common adulterant to milk, after water.
Procedure :-
1. Measure out 3ml milk into a test tube/container.
2. Keep the test tube for incubation in a boiling water bath for 5 minutes.
3. After incubation, cool the test tube, add a few (2-3) drops of 1% iodine solution and mix the contents well.
4. The appearance of blue-black color indicates the presence of starch in milk.
5. Note down the observations in the observation table.
Figure :-
Observation table and Calculation :-
| Sample | Observation (Colour change - if any) | Inference |
|---|---|---|
| Sample 1 | No any colour | No adulterated |
| Sample 2 | Blue black colour | Adulterated |
| Sample 3 | - | - |
Conclusion :-
Milk sample 1 shows No any colour; hence, it is adulterated/not adulterated with starch.
Milk sample 2 shows blue black colour; hence, it is adulterated/not-adulterated with starch.
Milk sample 3 shows, - ; hence, it is adulterated/not adulterated with starch.
Questions
1. What do you mean by SNF value?
Ans :- SNF stands for "Solids Not Fat" in milk. It refers to the substances in milk other than water and butterfat. The SNF value represents the residual components left after all the water has been evaporated from the milk.
2. What is the SNF value of natural unadulterated milk?
Ans :- Typically, natural, unadulterated cow milk has an SNF value of about 8.3%, while buffalo milk has an SNF value of approximately 9.0%.
3. Does SNF value of milk change with the charge in animal source (i.e. cow or buffalo)?
Ans :- Yes, the SNF value of milk varies with the animal source. Generally, cow milk has an SNF value of about 8.3%, while buffalo milk has a higher SNF value of around 9.0%.
4. Which type of sugar is present in milk?
Ans :- In both cow's milk and buffalo milk, the primary type of sugar present is lactose, also known as milk sugar.
5. Name the microorganism commonly used in dairy industry.
Ans :- Lactobacillus bacteria are commonly used in the dairy industry because they aid in fermentation by producing lactic acid, which lowers the pH of milk and causes it to curdle.
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