microbial biotech in the food industry 1.docx

**Microbial Biotechnology in the Food Industry** **Fermented Foods** **Fermented Food --** food processed through activities of microorganisms. **Advantages of fermenting food** 1. **Enhanced Nutritional Value:** Fermentation can increase the availability of nutrients as well as improve the...

**Microbial Biotechnology in the Food Industry** **Fermented Foods** **Fermented Food --** food processed through activities of microorganisms. **Advantages of fermenting food** 1. **Enhanced Nutritional Value:** Fermentation can increase the availability of nutrients as well as improve the digestibility of food. Fermentation process can produce additional vitamins, such as B vitamins, and vitamin K. 2. **Improved Digestion:** Fermented foods contain probiotics, which are beneficial bacteria that support gut health. These probiotics can help balance the gut microbiome, improve digestion, and enhance overall gut health. 3. **Extended Shelf Life:** Fermentation acts as a natural preservative method, extending shelf life of perishable foods without the need for refrigeration and artificial preservatives. 4. **Enhanced Flavor and Texture:** The fermentation process develops unique flavors and textures that are often complex and desirable. 5. **Safety:** Fermentation can reduce the presence of harmful microorganisms in food. 6. **Economic Benefits:** Fermentation requires minimal equipment and ingredients, allowing it to be an economical method of food preservation and preparation. **Types of Fermented Foods** **Bread** - Ingredients: Flour, Water, Salt, Yeast, and additives. Flour Sugar (carbon source) Salt (stabilize yeast fermentation) **Baker's Yeast (*Saccharomyces cerevisiae)*** - Easy dispersal in water - Rapid growth (20-25 C) - Can produce large amount of CO2 - Good keeping quality - Can adopt to rapidly changing substrate - Has high enzyme activity - Can grow in anaerobic conditions - Osmophilic - High competitiveness How much yeast? Flour Type -- more protein levels Duration of baking -- longer dough formation Inhibitory components -- high amount Yeast Food: calcium salt, ammonium salt, oxidizing agent **Leavening --** 2-6 hours **Factors that Affect Leavening** - Osmotic pressure - Sugar nature - Effect of nitrogen and other nutrients - Effect of fungal inhibitors - Yeast concentration **Enzymes** - Amylase: *Bacillus subtilis* - Proteolytic enzyme: *Aspergillus oryzae* **Mold inhibitors** - Antimycotics - To avoid bread spoilage **Cheese** **Lactic Acid Bacteria** - *Lactococcus lactis:* Temp \< 40 C - *Streptococcus thermophilus, Lactobacillus bulgaricus, L. helveticus:* Temp \> 40 C - Uses - Coagulation of casein at pH 4.6 - Aids the action of rennin - Shrinkage of cur - Contributes to flavor **Disadvantages of using LAB** 1. Attack by bacteriophages 2. Undesirable strain 3. Inhibition by antibiotics 4. Inhibition by sterilant and detergent residues **Rennet --** material used for milk coagulation - Originally from slaughtered calves - Microbial rennets - *Mucor miehi* - *M. pussilus* - *Endothia parasitica* - *B. subtilis* A black and white logo Description automatically generated **Yogurt** - From Turks, means to blend - Microorganisms involved - Lactococcus spp. - Lactobacillus spp. - Lactic Acid - Lowers the pH for milk coagulation - Inhibits the growth of spoilage bacteria **Fermented Vegetables** **Sauerkraut** - Fermentation of cabbages - Initiated by *Leuconostoc mesenteroides* then by LAB, gram negative coliforms, and pseudomonads. - Flavor came from different metabolites - Temp: 15C - Salt: about 2.5% salt **Pickles** - Production - Dry salting - Brine salting - Microorganisms involved is similar in Kraut but Leuconostoc sp. Is not the dominant species. - Major organisms - *Lactobacillus plantarum* - *L. brevis* - Pediococcus spp. **Soy Sauce: Shoyu** - Microorganisms involved (moromi) - *Pediococcus halophilus\\* - Lactic acid production - *Saccharomyces rouxii* - Alcohol - *Torulopsis spp.* - Phenolic compounds (flavor) **Fermented Beverages** **Beer** - From bibere -- to drink **Types** - **Top fermented**: - Ale - fermented with top-fermenting yeast strains at warmer temperatures (15-25 C). - *Saccharomyces cerevisiae* - **Bottom fermented** - Lager beer - Fermented bottom-fermenting yeast strains ; cooler temperatures (7-13 C) - Takes longer that top fermentation - *Saccharomyces uvarum* *\ * **Ingredients** - **Barley Malt** - Thick husk for protection - Has high beta amylase - **Hops** - Dried cone-shaped flower of hop plant - Bitter taste and beer aroma - Antimicrobial - Inhibits growth of beer sarcina and other spoiling bacteria - Colloidal property and retention - **Adjuncts** - Increase alcoholic content - Starch products - **Water** - Nitrates: slow down fermentation - Iron: destroy colloidal stability of beer - Calcium: for better flavor - pH: enzyme action  **Brewer's Yeast** - produce alcohol under aerobic conditions - Produce balanced proportion of metabolites - Flavor - Problems: - Mutation - Contamination 1. Malting 2. Mashing and wort preparation 3. Fermentation 4. Post Treatment A diagram of a process Description automatically generated  **Top Fermentation** - Temp: 15-16 C to 20C - 6 days - Treatment - Inoculation of yeasts - Priming with sugar or caramel - Duration: 1 week **Bottom Fermentation** - Temp: 6-10 C to 10-12 C - 2-4 days - Formation of Krausen - Treatment: Lagering - Secondary fermentation - Duration: months **Continuous Brewing** - Open system - Wort is fed continuously at the same time beer flows out at the same rate - Yeasts are reused - Partially closed system - Yeast is held to a concentration before inoculated **Biological turbidities** - Spoilage due to poor hygiene and pasteurization - Kloeckera, Hansenula, Brettanomyces, and Saccharomyces - Beer sarcina **Physiochemical Turbidities** - Heavy metals - Beer tannins - Polysaccharide **Gushing** - Over foaming - Usage of old barley - Presence of Fusarium sp. During production **Off-Flavor** - Formation of mertacaptans when exposed to sun **Grape Wine** **Broad classification of grape wines** A. **Natural wines:** 9-14% alcohol, nature and keeping quality mostly dependent on complete yeast fermentation and protection from air a. **Still Wines:** Known as table wines, intended as part of meals. No carbon dioxide added i. **Dry table wines:** No noticeable sweetness. White, rose, red. ii. **Sweet table wines:** White and red. b. **Sparkling wines:** appreciable CO2 under pressure iii. **White** (champagne) iv. **Rose** (pink champagne) v. **Red** (sparkling burgundy, cold duck) B. **Fortified (Dessert and appetizer wines):** Contain 15 to 21% alcohol, nature and keeping quality depends heavily on addition of alcohol distilled from grape vine c. **Sweet Wines** vi. White (Muscatel, White port, angelica) vii. Pink (California Tokay, Tawny port) viii. Red (Port, Black Muscat) d. **Sherries:** white sweet or dry wines with oxidized flavors ix. Aged Types x. Flor types xi. Baked Types e. **Flavored Specialty Wines:** usually white port base xii. **Vermouth** (pale dry, Italian sweet types) xiii. **Proprietary brands** **Grape Wine Production** **Crushing of Grapes/Must Production** - Juicing of grapes to produce must. Sometimes skins were included **Fermentation** - Microorganisms: natural microflora, *S. cerevisiae* var. *ellipsoideus, S. fermentati, S. oviformis, S. bayanus* - Should grow at high acidity, resistant to alcohol content and sulfite, - Temp: 24 C - Sugar can be added as yeast nutrition - Oxygen (early stages) **Ageing and storage** **Wine Spoilage** - Factors - Wine composition - Storage condition - Initial Contamination during bottling process - Microorganisms - LAB - *Bretanomyces* - *Saccharomyces spp.* **Sparkling Wine (Champagne)** **Bottle Champagne** Traditional Method 1. **Cuvee:** After wines complete first fermentation, the winemaker creates a blend, or cuvee, with a selection of base wines. 2. **Tirage:** Wines are bottled blended with a small mixture of yeast and sugar/must to initiate second fermentation. This is called the **Liqueur de Tirage.** 3. **Aging:** wines are ages for a period of time on the lees (dead yeast particles). Aging lasts from about 9 months to about 5 years (depending on quality level). 4. **Riddling/Disgorging:** bottles are rotated so that lees descend to the neck of the bottle, Then the bottle necks are placed in a frozen bath and opened such that frozen block of lees pops out 5. **Dosage:** Some wine and sugar/must (called residual sugar -- RS) is added back to the bottle. This mixture is also called **Liqueur d'Expedition** **Bulk Production/Charmat Process** Tank Method (aka Charmat) 1. **Base Wine + Sugar + Yeast:** A mixture of yeast and sugar is added to the base wine and the wine is transferred into an autoclave. 2. **2^nd^ Fermentation:** Wines complete their second fermentation in a pressure-resistant tank in about 10 days. 3. **Filtering:** Wines are sent through a pressure-resistant filter to remove sediment. 4. **Dosage:** After wines are filtered and prior to bottling, wines received a mixture of sugar/must. **Distilled Spirits** Measurement of Alcoholic Strength - Proof - Percentage by weight - Percentage by volume **Preparing:** The raw material is ground into a coarse meal. The process breaks down the protective hull covering the raw material and frees the starch. **Mashing:** The starch is converted to sugar, which is mixed with pure water, and cooked, This produces a mash. **Fermenting:** The sugar is converted to alcohol and carbon dioxide by the addition of yeast. With the addition of yeast to the sugar, the yeast multiplies producing CO2 which bubbles away and a mixture of alcohol, particles, and congeners, or the elements which create flavor to each drink, **Distilling:** The alcohol, grain particles, water, and congeners are heated. The alcohol vaporizes first, leaving the water, grain particles, and some of the congeners in the boiling vessel. The vaporized alcohol Is then cooled or condensed, to form clear drops of distilled spirits. **Ageing:** Certain distilled spirits are matured in wooden casks where they gradually develop a distinctive taste, aroma, and color. **Blending:** Some spirits go through a blending process whereby two or more spirits of the same category are combined. This process is not the same as mixing, since the blended spirit remains of the same category as its components. ~­~ **Different Types of Distilled Spirits** - Whiskey - Cereal - Yeast with *lactobacillus spp.* - Brandy - Fruit juice - Eau de vie - Rum - Sugar cane or sugar molasses - *Schizosaccharomyces pombe* - *S. cerevisiae* - Gin - Clear - Maize - Amylases **Vinegar** **Grain :** Multiplying acidic content of vinegar by 10 - Types of vinegars: Cider, Wine, Malt, Sugar/Glucose, Spirit. - **Specialty Vinegars**: Herbal, Fruit, Balsamic, Coconut, Cane Mycoderma/acetobacter: mother of vinegar Strains used: - Tolerance to high concentrations of acetic acid - Require minimum amount of nutrient - Do not over oxidize the acetic acid - High yield **Orlean Method** A diagram of a barrel Description automatically generated **Trickling Generators**  ***A bottle of wine contains more philosophy than all the books in the world -- Louis Pasteur***