🚲 Curd, Cells, and Cycles: Unfolding the Science of Fermentation and Respiration

Sailekshmi · July 11, 2025, 5:32pm

CUBE ChatShaala Summary | 11 July 2025

Main Topics Discussed:

Sanika’s Curd Making Experiment
Fermentation vs. Cellular Respiration
Role of Glycolysis, Pyruvate, and ATP in Metabolism
Comparison of Traditional and Alternative Curd Setups
TCA/Krebs Cycle and Energy Yield
Observation Strategies for Curd Formation

Sanika’s Curd Setup (01.07.2025 | 4:45 PM)

Milk Used: 100 ml of NADEC brand milk ( boiled )

Temperature maintained : 30°C

Curd Inoculum : 1 tsp of curd

Observation : After >15 hours, at 10:00 AM next day

Result : Curd formation observed successfully.

This experiment paralleled Batal’s method, where curd was made in 250 ml milk with Amul curd, incubated for 6 hours at 28°C.

Biochemical Angle: Glycolysis & Cellular Respiration

Discussion moved toward glycolysis—a fundamental metabolic process occurring in the cytoplasm, where glucose breaks into pyruvate and releases *2 ATP and 2 NADH .

Pyruvate (CH₃–CO–COOH) can either undergo fermentation ( in absence of oxygen ) or enter the Krebs Cycle in the mitochondria ( in presence of oxygen ).

ATP Yield :

Glycolysis : 2 ATP

TCA Cycle (Hans Krebs) : 36 ATP per glucose molecule

Electron Transport Chain : Final step for energy release

Key queries were raised :

Is curd formation a fermentation process or a cellular respiration-linked metabolic event?

How do lactic acid bacteria use pyruvate to convert milk into curd?

Experimental Variations with Milk Coagulation

A different set of experiments involved acid and salt treatments:

2 tsp lemon juice + boiled milk
2 tsp salt + boiled milk
2 tsp orange juice + boiled milk

These were compared against the traditional curd inoculation method:

1 tsp curd + lukewarm milk (100 ml)
Stirred well and left overnight
Result : " Reasonably good curd " observed the next day.

Discussion Highlights :

The role of temperature, starter culture quantity, and incubation time in curd formation.

Scientific parallels drawn between food biology and cellular metabolic pathways.

Introduction to anaerobic glycolysis in lactic acid bacteria.

Importance of controlled variables in household-level fermentation studies.

Follow-Up Questions

1. “Curd Culture or Curd Chemistry?”

How does the source and brand of milk (e.g., NADEC vs. Amul) influence the rate of curd formation?

2. “Bacteria’s Metabolic Secret?”

Is lactic acid fermentation just another form of cellular respiration, or is it entirely different in how it generates energy?

3. “Can You Make Curd Without Curd?”

Among lemon, salt, or orange, which additive gave better coagulation, and why?

4. “ATP and Taste?”

Could there be a link between ATP yield in microbial metabolism and flavor or texture of curd?

5. “From Milk to Microbes: What’s Happening?”

Can we visualize or track the metabolic steps (like glycolysis) happening in a spoon of curd?

Group photographs from ChatShaala

Let’s continue experimenting, questioning, and understanding how everyday kitchen science connects with life’s deepest metabolic secrets.

Reference

@Arunan @Ayana_Sudheer @KiranKalakotiR @sakshiconsultant2002 @Akantidas @Chitralekha
@magpie and others.