Sauerkraut Fermentation

Microbial fermentation of Sauerkraut

1. Sauerkraut Prepared by- Abhikarsh (4608) 19081564005 B.Sc.(H) Microbiology 3 rd Sem. Submitted to- Dr. Anjana Kapoor Deptt . Of Microbiology Swami Shraddhanand College, Univ. of Delhi

2. Sauerkraut is the clean, sound product of characteristic flavor , obtained by full fermentation , chiefly lactic, of properly prepared and shredded cabbage in the presence of not less than 2% and not more than 3% salt . The word has German origin, meaning “sour cabbage”. Sauerkraut It has a sour taste with a clean acid flavor . Mild flavoured , sweet, solid, white-headed cabbage is the best choice for making superior kraut.

3. History of Sauerkraut Although "sauerkraut" is a German word, the dish did not originate in Germany, as fermenting cabbage as  Suan cai   was already practised back in the days of the building of the  Great Wall of China . The practice was likely transmitted from China to Europe by the  Tartars . Suan cai  It then took root mostly in  Central  and  Eastern European  cuisines, but also in other countries including the Netherlands, where it is known as  zuurkool , and France , where the name became  choucroute .  The English name is borrowed from German where it means "sour cabbage "

4. Preparation of Sauerkraut

5. Cabbages are willed for 1-2 days. Spoiled spots and defective outer leaves are trimmed. Heads are washed with pure water. The core is drilled out and shredded, then added to the rest of the cabbage. The head is cut into desirable size(2-5mm thick), usually slim ones. Deleaf , core, trim, shred.

6. Addition of salt 2.25% to 2.5% of salt by weight must be added to the shredded cabbage to obtain kraut of the best quality. The salt should be distributed evenly. The salt added serves the following functions- It extracts moisture from the shredded cabbage by osmosis to form the brine in which the fermentation will take place. (ii) It helps to inhibit the natural micro-flora of the cabbage such as Pseudomonads which would otherwise cause spoilage and helps to select for the lactic acid bacteria. (iii) It helps to maintain the crisp texture of the cabbage by withdrawing water and inhibiting endogenous pectolytic enzymes which cause the product to soften. (iv) Salt contributes to flavor of the product.

7. Fermentation Anaerobic conditions develop quickly in the salted, shredded cabbage and the surrounding juice in the fermentation vats, chiefly as a result of removal of O 2 by respiration of plant cells and also due to bacteria . The juice contains natural flora from soil and some contaminants from soil and water. At first different kinds of bacteria grow but then acid-forming soon predominate . Early microbes to predominate include Enterobacter cloacae, Erwinia herbicola , w hich produce volatile acids and gas and contribute to some flavor. Soon, Leuconostoc mesenteroides bacteria begin to outgrow all other organisms and continue producing lactic acid . These Streptococci are not inhibited but rather stimulated by 2.5% salt. They attack sugars to form lactic acid, acetic acid, ethanol, mannitol, dextran, esters and carbon dioxide, which contribute to good flavor of sauerkraut. Similarly, lactic acid rods and cocci metabolize the lipids of cabbage to produce volatile fatty acids giving good flavor.

8. Next, non-gas forming lactobacilli , especially, Lactobacillus planarum continue the production of acid(chiefly lactic acid) and raise it to 1.5-2%. They also utilize the mannitol produced by Leuconostoc and thus remove the bitter taste . L. planarum completes the desired fermentation till the final acidity reaches 1.7% which is most desirable. At this point, fermentation can be stopped by canning or refrigerating the sauerkraut. The fermentation can last from 4-8 weeks with the ratio of volatile to non-volatile acid of around 1-4.

9. Pic courtesy- Meatandsausage.com

10. Characteristics of good sauerkraut Light coloured Crisp. Acidity of about 1.7%. Clean, acid flavor. Small amounts of diacetyl gives pleasant aroma and taste. pH of 3.4 to 3.6. Lactic acid= 1.25%. Acetic acid = 0.3%.

11. Sauerkraut defects and spoilage Soft kraut Pink kraut Slimy/ ropy kraut Black kraut Faulty fermentation and exposure to air, or excessive pressing. Exposure to air, yeasts and molds, uneven salting and high temperature . Red, asporogenous yeasts in the presence of air and high salt, iron salts, pigments in cabbage Encapsulated varieties of Lactobacillus plantarum .

12. Health benefits of sauerkraut- It is rich in fiber, Sodium, B vitamins, Vit K1, Iron, and other minerals. Beneficial probiotics . Combats inflammation. Reduces the risk of depression and Alzheimer’s disease. Supports natural antibodies of the body. Aids in weight loss. According to a study from King’s College, London, sauerkraut’s large amounts tyramine , a neurotransmitter, makes it one of the most powerful aphrodisiacs . Maintains healthy gut flora. Good for gum diseases and heart diseases .

13. Kimchi Kimchi ( Korean origin ) is similar to sauerkraut in some respect since both are fermented cabbage The level of salt used is low , <3%. It has a shorter fermentation time. The best kind of kimchi get ready within 3 days at 20*C when the acidity is 0.6 % and the pH is around 4.2. Leuconostoc mesenteroides is the principal organism. Kimchi is rather salty whereas sauerkraut is more tart. Pic courtesy- Pinterest.com

14. References- Adams, M.R. and Moss, M.O.(2000). Food Microbiology, 2 nd edition. New Age International Publishers, India. Banwart , P.M., Sofors , J.N. and Branen , A.L. (2005). Antimicrobials in foods. 3 rd edition. CRC Press, UK. Frazier, W.C., Westhoff , D.C. and Vanitha, N.M.(2013). Food Microbiology. 5 th edition, Tata McGraw-Hill Publishing Company Ltd, India. Ray, B. and Bhunia , A.Fundamental Food Microbiology,4 th edition. CRC press, U.S.A.

15. Thank You! For your patience .