Food fermentation One of the oldest methods to

Food fermentation • One of the oldest methods to preserve food • The most common ferment foods – Dairy products – 優酪乳、養樂多 • 優生菌 probiotic bacteria – 乳酸菌 Lactic acid bacteria (LAB) • Lactobacillus, Lactococcus, Streptococcus – 雙叉桿菌 • Bifiodobacterium

objective – Inoculate lactic acid bacteria to ferment milk • Principles – Lactic acid bacteria is the main probiotic bacteria – After fermentation, physical and chemical properties such as texture, flavor, aroma, and p. H are changed. – Bacterial must be alive to offer the beneficial effects.

Materials and Methods • Reconstituted Milk – Milk powder + water • LAB culture Commercial yogurt – A菌: 嗜酸乳桿菌 (Lactobacillus acidophilus） – B菌: 雙叉乳桿菌(L. bifidus; Bifidobacterium lactis) • Each group choose their own culture • Each group has three tubes

– 味全優酪乳 ABLS • A菌-Lactobacillus acidophilus B菌-Bifidobacterium Iongum L菌-Lactobacillus bulgaricus S菌-Streptococcus thermophilus – 養樂多 Yakult代田菌(Lactobacillus casei Shirota) – 比菲多 Bifidobacterium bifidum – Each group must record the bacterial culture and ingredient in the product

Methods • Milk powder add water • Boiling for 1 -2 min • Separate the sanitized milk to the other sterile bottles • Each group has three tubes • Add about 0. 1 m. L of the bacterial culture or the commercial product into one tube • Incubate at 37℃

• After 24 incubation (11/18), take some of the ferment milk into 15 -m. L tubes. One product into one tube. Place the tubes in a refrigerator (4℃). • Keep fermenting. • After 48 incubation, place the ferment product into a refrigerator. On 11/19, take he ferment milk out of the refrigerator.

• On next Monday (11/24), observe the physiochemical characteristics of the products – p. H, texture, aroma, color, taste

• p. H values in last year (24 hour fermentation) – Milk: 6. 641 – Yakult : 4. 572 – Unipresident- AB 3. 945 – 48 hour fermentation – Yakult: 3. 875 – Unipresident- AB: 3. 836 – p. Ka value of lactic acid: 3. 08

Streptococcus and Lactobacillus casei Shirota(養樂多)

Bifidobacterium Lactobacillus