PENDAHULUAN Bahan pengawet senyawa yg mampu menghambat dan menghentikan proses fermentasi, pengasaman atau bentuk kerusakan lainnya dan dapat memberikan perlindungan bahan pangan dari pembusukan.
WHY??? consumer expect food to be: - available year round, - free of food-borne pathogen, - to have reasonably long shelf-life
TUJUAN PENGGUNAAN PENGAWET 1.Menghambat pertumbuhan mikrobia 2.Memperpanjang umur simpan 3.Mempertahankan kualitas gizi dan sensori 4.Memudahkan proses pengolahan
SIFAT ANTIMIKROBIA Menghambat pertumbuhan mikrobia dg cara: 1. Gangguan sistem genetik 2. Menghambat / mengganggu dinding sel ataupun membran sel 3. Pennghambatan enzim 4. Pengikatan nutrient esensial
Factor in selecting antimicrobial agent: The antimicrobial spectrum of the compound to be used must be known. Chemical & physical properties of both the antimicrobial and the food product must be known The condition of storage of the product and interaction with other processes must be evaluated to ensure that the antimicrobial will remain functional over time. A food must be of the highest microbiologically quality initially if an antimicrobial is to be expected to contribute to its shelf-life.
PERSYARATAN BHN PENGAWET YG BAIK 1. Memiliki arti ekonomis dr pengawetan 2. Hanya digunakan jika cara pengawetan tdk mencukupi 3. Memperpanjang umur simpan 4. Tidak menurunkan kualitas 5. Mudah dilarutkan 6. Aman dlm jmlh yg diperlukan 7. Mudah dianalisis 8. Tidak menghambat enzim pencernaan 9. Tidak bersifat toksik 10. Spektra antimikrobia yg luas.
JENIS BAHAN PENGAWET PENGAWET ORGANIK terdiri dari asam-asam organik dan garamnya, seperti asetat, benzoat, propionat, sorbat, epoksida, dll. PENGAWET ANORGANIK - digunakan dlm bentuk garam seperti nitrit, metabisulfit - dalam bentuk gas seperti sulfit (SO 2 ) - dalam bentuk liquid seperti hidrogen peroksida
ORGANIC ACID Commonly used as antimicrobial preservative or acidulan The activity related to pH and generally limited to pH < 5,5 Mechanism: - organic acid influence cell walls synthesis in prokaryotes. - organic acid likely act at the cytoplasmic membrane level. Organic acid penetrates the cell membrane bilayer, and once inside the cell it dissociates because the cell interior has a higher pH than exterior.
a. Acetic acid & acetate salt More effective against yeast & bacteria The activity depend on product, environment, and microorganism. Application: - addition of acetic acid at 0,1% to scald tank water used in poultry processing ddecrease the salmonella & campylobacter (okrend et al., 1986) - used as a spray sanitizer on meet carcases effective for beef, lamb, & catfish fillets. Use of 2 % acetic acid resulted reduction in viable E. coli. - added at 0,1% to bread dough inhibited growth bacillus subtilis in wheat bread (pH 5,14) > 6 days.
Sodium acetate is an inhibitor of rope-forming bacillus in baked goods and of the mold. It is useful in the baking industry because t has little effect on the yeast used in baking.
b. Benzoates & other Primary uses as antimycotic agent (most yeast and mold) Benzoates are most effective at pH 2,5 – 4,0. Mechanism: benzoic acid destroyed the proton motive force of the cytoplasmic membrane by continous transport of proton into the cell causing disruption of the transport system. Benzoates also inhbit enzymes in bacterial cell as those controlling acetic acid metabolism & axydative phosphorylation. Benzoates had no carcinogenic effect were given 1 – 2% and nonmutagenic.
Other organic antimikrobial agents Lactic acid is primary used to many fermented diary, vegetable, and meet product. It is usually used as a food additive for pH control & flavoring. Propionic acid & propionate use to against mold, yeast, & bacteria gram negative. Usually used in baked goods & cheese. Sorbic acid & sorbates have been used in food as effective inhibitor of fungi, including that produce mycotoxin, and certain bacteria.
PARABENS Parabens: alkyl ester of p-hydroxybenzoic acid. Effective at pH 3-8 (effective at acidic an alkaline pH), and generally more active against mold & yeast than bacteria. Mechanism: is most likely related to their effect on cytoplasmic membrane. The parabens were capable of inhibiting both membran transport and electron transport system. To take advantage solubility & increased activity, methyl and propyl parabens are normally used in a combination 2-3 : 1
The used of parabens are application in beverages, soft drink, jelly, juice, salad, etc. The FDA consider parabens total addition limit of 0,1%
NITRITES Nitrite salt (KNO 2 & NaNO 2 ) primarily used to inhibit the growth and toxin roduction of C. botulinum in cured meats. Nitrite is most inhibitory to bacteria at acidic pH and more inhibitory under anaerobic condition Mechanism: the inhbitory effect f nitrite on bacterial sporeformers is apparently due to inhibition of outgrowth and during cell division.
Nitrite does not inhibit spore germination to a significant extend. Nitrite inactivated enzymes associated with respiration. Lethal dose of nitrites in human is 2 – 6 g, prolonged ingestion nitrite cause methemioglobinemia, that is, excessive production of abnormal mioglobin.
NATAMYCIN Natamycin or pimaricin ( C 33 H 47 NO 13 )is a polyene macrolide antibiotic. Natamycin is active against nearly all molds and yeast, but no effect on bacteria or viruses. Several factors affect the stability & resulting antimycotic activity of natamycin: -pH, 100% natamycin activity is retained at pH 5 - 7 -temperature, high temperature will decrease activity -light, -oxidant, -heavy metal.
Mechanism: polyene macrolide antibiotic is binding to ergosterol & other sterol group of the fungal cell membrane. Generally, binding of the natamycin by sterol causes inhibition of ergosterol biosynthesis and distortion of the cell membrane with resultant leakage. Application: cheese, baking industry, fruits, and meets as a mold spoillage inhibitor.
DIMETHYL DICARBONATE (DMDC) The primary target microorganism for DMDC are yeast. It was more effective than sorbate & benzoate. Mold are generally more resistant to DMDC than yeast or bacteria. DMDC used in product: wine, teas, carbonated & noncarbonated juice beverages, and carbonated & noncarbonated nonjuice beverages.
Other antimicrobial agents Lysozyme (1,4-β-N-acetylmuramidase), catalyzes hidrolysis peptidoglican of bacterial cell walls. Nisin, peptide produced by a strain of dairy starter cultur L. lactis Phosphates Sulfites
Pelanggaran Penggunaan Pengawet Menggunakan bahan pengawet yang dilarang penggunaannya untuk pangan. Menggunakan pengawet melebihi dosis yang diizinkan.
PENGAWET DILARANG Formalin (pengawet mayat) Asam Borat (Boric Acid) dan senyawanya Antibiotik (Chloramphenicol) Asam Salisilat dan garamnya (Salicylic Acid and its salt) Dietilpirokarbonat (Diethylpirocarbonate DEPC) Kalium Klorat (Potassium Chlorate) Kalium Bromat (Potassium Bromate) Nitrofurazon (Nitrofurazone)
CASE STUDY Pemutaran video repostase investigasi dg judul/kasus: “penjualan otak-otak berbahaya pengawet”
QUIZ PEWARNA 1. Jelaskan pengertian pewarna tambahan makanan dan sebutkan 3 jenis pewarna sintetik! 2. Sebutkan & jelaskan sifat fisikokimiawi dr pigmen klorofil!