C9 Fermented Vegetables

Question 1

Why is young cucumbers used for pickling instead of mature cucumber?

Answer 1

Mature cucumbers contain polygalacturonase enzymes that causes liquefaction of the seed area during fermentation and storage.

Question 2

Describe the common problem in cucumber fermentation.

Answer 2

• Bloating caused by the accumulation of CO2 produced by respiration of the cucumber tissue and fermentation by P. cerevisiae and Lb. plantarum
• Solved by N2 bubbling to remove CO2 and create anaerobic conditions.
• Softening in defective pickles due to pectinolytic enzymes.
• Controlled fermentation and chlorinated, acidified brine with added sodium acetate.

Question 3

Why is kimchi fermented in an earthen jar underground?

Answer 3

• Jar contains micropores which allow for the exchange of gases during fermentation.
• The temperature underground is more stable and controlled than ambient temperatures.
• Stone weights create pressure and excludes oxygen from the fermentation process.

Question 4

State two microorganisms involved in the fermentation of vegetables.

Answer 4

• Leuconostoc spp.
• Weissella spp.
• Pediococcus spp.
• Lactobacillus spp.

Question 5

What are the factors affecting the kimchi fermentation process?

Answer 5

• Salt concentration
• Fermentation temperature
• Starter culture