Pertemuan 13MIKROBIOLOGI BAHAN MAKANAN

PERANAN MIKROORGANISME DALAM BIDANG PANGAN

Penggunaan mikrobiologi, biokimia, dan rekayasa kimia terpadu untuk mencapai penerapan teknologi dari kemampuan mikroba dan sel-sel yang dibiakkan .

Bioteknologi adalah cabang biologi mempelajari penggunaan mikroorganisme dan produk-produknya dengan bantuan teknologi untuk kepentingan manusia

• Mikroorganisme yang terlibat fungi yakni jamur benang dan khamir , bakteri

• Meliputi bidang:

a. peningkatan kualitas bahan pangan, meliputi :

sintesis senyawa organik

sintesis senyawa antioksidan

b. diversifikasi produk makanan

c. pemanfaatan bahan pangan marginal

Oxford Scientific Films/Dr. C.E. JeffreeMicrosoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

MIKROORGANISME SEBAGAI SUMBER MAKANAN

BAKTERI YEAST MIKROALGAE                                                                            

Green Plants and PhotosynthesisAll of our food ultimately results from the process of photosynthesis in green plants and algae. The pigment chlorophyll is responsible for the green color of plants as well as their ability to photosynthesize. In common terrestrial plants photosynthesis is usually carried out in the leaves, although it can also occur in the stem or other parts of the plant.

PENGAWETAN MIKROBIOLOGIS

PENCIPTAAN PRODUK BARU

FERMENTASI

Just as the right hand and left hand are different, optical isomers (known as enantiomers) are different from each other and can have different properties. For example, muscles produce D-lactic acid when they contract, and a high amount of this compound in muscles causes muscular pain and cramps. On the other hand, sour milk contains L-lactic acid, giving the milk its sour taste.

Microsoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

The optical isomers of lactic acid are arranged as follows (dark lines point toward the viewer and dashed lines point away):

The Image Works/GreenlarMicrosoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

Yogurt

Yogurt is packaged at a dairy in New York state. Long consumed in southeastern Europe and Asia Minor, yogurt has become increasingly popular in the United States.

Yogurt, fermented, semifluid milk product, used extensively as a health food. It is

prepared from fresh whole or skim milk, boiled and concentrated by evaporation. Fermentation is caused by the addition of

cultures of bacteria, usually Lactobacillus bulgaricus and Streptococcus thermophilus, and sometimes

Lactobacillus acidophilus. New batches of yogurt can be produced by introducing into concentrated milk a portion of a previously prepared batch. This type of fermented milk has long been an important constituent of the diet in southeastern Europe and in Asia Minor. In recent years yogurt has become

increasingly popular in the U.S.

                                                     

Cheese Factory, WisconsinFermentation, a process in which microorganisms convert complex organic molecules into simpler molecules, is used in the production of cheese. Bacteria convert sugars found in milk into lactic acid, a compound that prevents the growth of other, harmful microorganisms and helps preserve the food. Pictured here is a cheese-making operation in a plant near Kiel in eastern Wisconsin.

Photo Researchers, Inc./Joe MunroeMicrosoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

a chemical reaction carried out by many types of microorganisms to obtain energy. In fermentation,

microorganisms break down complex organic compounds into simpler substances. Although chemical changes and microbial growth usually mean food spoilage, in some cases fermentation is desirable and microorganisms are actually

added to foods. For example, in the production of beer, wine, and other alcoholic beverages, yeasts convert sugar into ethyl

alcohol and carbon dioxide. In the making of yogurt and cheese, bacteria convert lactose, a sugar found in milk, to lactic acid.

Alcohol, acids, and other compounds produced in fermentation act as preservatives, inhibiting further microbial growth. In

addition to its use with alcoholic beverages, cheese, and yogurt, fermentation is used to produce yeast bread, soy sauce,

cucumber pickles, sauerkraut, and other products.

Microsoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

FERMENTATION is …….

Mikroorganisme untuk peningkatan kualitas bahan pangan

Bahan pangan yang mengalami proses bioteknologi menjadi bahan pangan yang berkualitas, tahan lama, lebih segar, lebih beraroma, antara lain :

Penggunaan ragi ( Saccharomyces cerevisiae ) untuk :

- membuat anggur dan bir

- untuk mengembangkan adonan roti

Pembuatan keju

* Keju merupakan bahan makanan dengan bahan dasar susu, yang digumpalkan, dicetak, dan dimatangkan dengan bantuan enzim renin atau bakteri asam laktat, antara lain : Lactobaccillus bulgaricus dan Streptococcus lactis.

*Keju dikelompokkan berdasarkan kadar airnya, semakin tinggi semakin lunak kejunya. Berdasar kadar airnya kita mengenal keju keras, setengah keras, dan keju lunak

Propioni bacterium

Keju keras

Penicillium roqueforti Keju setengah keras

Penicilliu camemberti Keju lunak

Streptococus thermophyllus untuk mengasamkan dan neggumpalkan protein susu sehingga menjadi kental

Lactobaccilus bulgaricus memberi cita rasa dan aroma

*Pembuatan Yoghurt

Untuk pembuatan kecap dibutuhkan bantuan Aspergillus oryzae atau Aspergillus soyae, Jamur ini lebih dulu dibiakkan dalam kulit gandum, selanjtnya bersama bakteri as. Laktat yang tumbuh di kedelai melakukan fermentasi cukup lama menghasilkan kecap

Selain itu mikroorganisme juga dimanfaatkan untuk mengubah bahan makanan menjadi bentuk lain , misalnya :

Rhizopus oligospora untuk membuat tempe dari bahan kedelai

Saccharomyces cerevisiae untuk membuat tape dari ketan atau singkong

Acetobacter xilinum untuk membuat nata de coco dengan substrat air kelapa

Saccharomyces cerevisiae Acetobacter xilinum

Saccharomyces cerevisae Candida utilis

Pembuatan SCP ( single cell protein ), misalnya :

• Fusarium dalam media karbohidrat dari tepung gandum dan kentang

• Spirulina

• Saccharomyces cerevisae dan Candida utilis

NATA Nata de coco, de radia, de pinna, de soya, de skin banana. Bhs. Latin : Natare (= terapung-

apung) Bentuk seperti gel, terapung di

permukaan medium, kenyal, warna putih, hasil aktivitas bakteri Acetobacter xylinum

Populer di Filipina : bahan air kelapa

SYARAT MEDIUM :Agar bakteri Acetobacter xylinum dapat tumbuh dan berkembang membentuk nata, maka harus mengandung :

1.Air 91.23 %

2.Protein 0.29 %

3.Lemak 0.15 %

4.Karbohidrat 7.27 %

5.Abu 1.06 %

6.Vitamin (B kompleks)

KERUSAKAN MIKROBIOLOGIS

Louis PasteurLouis Pasteur made important contributions to the field of organic chemistry during the mid-1800s, developing various vaccines, including one for rabies, and disproving the theory of spontaneous generation. He is considered the founder of the field of microbiology, working with the germ theory of disease to establish and explain the causes for many diseases.

Microsoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

FAKTOR PENYEBAB

INTRINSIK

EKSTRINSIK

Komposisi bahan, pH, Aw, potensial ox-red, ada/tdknya antimikrobial, struktur fisikTemperatur, RH, kondisi

atmosfer

• Jenis mikroorganisme

• Jenis kerusakan

JENIS KERUSAKAN                                 

Home-Canned Foods

Fruits, vegetables, and jams and jellies are preserved shortly after harvest by home canning. Most canned food is pre-cooked, then placed hot in a glass canning jar and partially sealed. The seal is tightened by placing the jar in boiling water. Properly home-canned food remains edible for several months.

FPG International, LLC/Jose Luis BanusMicrosoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

• Dominan Karbohidrat :Sakarolitik, amilolitik, pektinolitik

Sayur : Erwinia carotovora

Wortel mengalami pelunakan

Roti : Serratia marcescens Berwarna merah darah

• Dominan protein : proteolitik

Daging : bakteri anaerobik

Buah : Kapang

Melunakkan & menembus kulit buah

• proteolisis• deaminasi

• bau busuk• lendir

Susu : suksesi 4 tahap 1. Lactobacillus lactis : produksi asam

2. Lactobacillus : produksi lebih banyak asam

3. Molds & yeast : memecah asam

4. Bakteri pendegradasi protein : bau busuk, cair

UPAYA PENCEGAHAN

                                                                           

Codfish Drying on RacksDrying of fruits, fish, or meat is an excellent method of long-term food preservation. Drying reduces an item to roughly 50 percent of its original volume and 20 percent of its original weight through the gradual elimination of water. This dehydration process prevents spoilage by retarding the growth of microorganisms and reducing or halting enzymatic activity and chemical reactions. Dried food items can be kept almost indefinitely, as long as they are not rehydrated.

Oxford Scientific Films/Doug AllanMicrosoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

• Filtrasi

• Temperatur Tinggi / rendah

• Senyawa kimia

• Radiasi

METODE PENGAWETAN MAKANAN