Topic : Milk Curdling by Lemon Juice vs Red Chili β What is Real Curd?
The ChatShaala began by observing and comparing two methods of milk curdling:
1. Addition of Lemon Juice
2. Addition of a Ripped Red Chili into Milk
Key Discussions and Observations
What happens when lemon juice is added to milk?
β 4 drops of lemon juice were added to a bowl of milk.
β This caused acidification, primarily due to citric acid in lemon juice.
β Citric acid acts on:
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Proteins β Especially casein, a milk protein
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Lipids/Fats β No precipitation observed
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Carbohydrates β Dissolved in water
Casein and Protein Precipitation
Casein proteins in milk carry negative charges and remain dissolved in water under normal conditions.
On acidification ( pH drop ), the negative charge is neutralized, causing proteins to clump and precipitate, forming curd.
Molecular Understanding
οΈ Milk protein chains ( polypeptides ) are formed by amino acids of (Aa) with functional groups like βNHβ and βCOOH.
οΈ Upon acidification, ionic interactions break, causing structural collapse and aggregation of proteins.
What about Red Chili-induced curdling?
A ripped red chili was placed in milk and left for several hours.
Preliminary observation: some thickening/coagulation was noticed.
Suggests possible microbial action or leaching of acidic compounds or enzymes from the chili.
But is it the same as traditional curd? β This remains an open question.
Control Observations with Oil, Water & Lemon Juice
Coconut oil and lemon juice separated into distinct layers, showing that fats donβt precipitate upon acidification.
Water layer remained separate; sugars dissolved, as expected.
This supports the idea that only proteins like casein are responsible for curd formation.
Open-ended Queries for Further Discussion:
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Is the milk curdled by red chili truly curd or just a precipitate?
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Can microbes ( like Lactobacillus ) grow on red chili skin and initiate fermentation?
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Is there a pH difference measurable between lemon-curdled and chili-curdled milk?
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What is the role of time and temperature in chili-induced milk thickening?
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Can ripped red chili be used to culture milk like traditional curd starters?
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What does the white precipitate from lemon-juice milk consist ofβpure casein or a mixture?
Reference
Please reflect on these questions and post your thoughts or experimental plans in the group. Letβs continue the exploration!
@Arunan @KiranKalakotiR @sakshiconsultant2002 @2020ugchsncnseethala @Akantidas @akanksha @Chitralekha @SN1261 and others