Presentation on theme: "Microorganisms used in food production"— Presentation transcript:
1 Microorganisms used in food production BiotechnologyMicroorganisms used in food production
2 Yeast (fungus)Used to make bread, beer and wine in the process of fermentation.
3 Learning Intentions Success Criteria All can Most Can Understand biotechnology’s use of bacteriaSuccess CriteriaAll canI can state 3 uses of yeast and describe yeastI can state the word equation for glucose fermentationMost CanI can describe and compare aerobic and anaerobic respirationI can describe the manufacture of beerI can explain batch processingWhile discussing the need to malt barley I can give ideal growing conditions for yeast.
4 Biotechnological Process This is a process in which living cells are used to convert a raw material into a useful substance.
6 Yeast at Work Yeast is a tiny living thing, called a microbe. As you can see it is made of single cells.It is a type of plant called a fungus, (no chlorophyll).It is used in baking and brewing.Budding.
7 Yeast Yeast is seen as a grey dust (bloom) on fruits. A long time ago people crushed fruit and due to the yeast on the surface of this fruit it fermented making alcohol.
8 Yeast at Work Remember the equation for aerobic respiration? Glucose + Oxygen water + carbon dioxide energyAll cells carry out this process, including yeast.However, biotechnology is about creating useful products and carbon dioxide and water are not very profitable.If you take away oxygen though (anaerobic respiration)Glucose (sugar) alcohol + carbon dioxide energySo this is how alcohol is produced.This is called Fermentation
9 When making alcohol the process is called alcoholic fermentation. Yeast obtains energy by doing this.
10 Barley GrainsThe energy seeds need to grow is stored inside them as starch.When they start to grow they convert this starch to simple sugars using what enzyme?AmylaseBeer making uses Barley for energy for the yeast.However starch is too large for yeast to digest so the grains have to be first left to germinate to make sugar.This is called malting.
11 Grains allowed to germinate to make sugar (seeds stopped for using sugar themselves) Spend grains = cattle foodDead sprouted grains (malt) mashed and dissolved into water = wortHops added for flavour and wort boiled to kill bacteria and wild yeastSpent hops = fertiliserCooled and yeast added. Fermentation stops when alcohol kills yeastBeer stored to allow it to mature and filtered to remove sediment.
12 Learning Intentions Success Criteria All can Some Can Understand biotechnology’s use of bacteriaSuccess CriteriaAll canI can state 3 uses of yeast and describe yeastI can state the word equation for glucose fermentationSome CanI can describe and compare aerobic and anaerobic respirationI can describe the manufacture of beerI can explain batch processingWhile discussing the need to malt barley I can give ideal growing conditions for yeast.
13 Bacteria in food production Converting Milk to Yogurt or Cheese uses lactobacillus
14 Describe the uses of bacteria in biotechnology Success Criteria Learning IntentionsDescribe the uses of bacteria in biotechnologySuccess CriteriaAll canI can describe the process of cheese makingI can describe the process of yoghurt makingI can state that the souring of milk is a fermentation processI can explain the souring of milk in terms of fermentation of lactose
15 Milk Fresh milk straight from the cow usually has a lot of bacteria. These bacteria feed on the milk (source of food) and grow and multiply.It is for this reason milk is treated.
16 The bacteria respire anaerobically (with out oxygen) and feed on the sugar in milk (lactose) turning it to lactic acid.This makes milk sour.The souring of the milk is a further example of fermentation.Lactose Lactic acidThis is called Lactic acid fermentation
17 Cheese and YoghurtTo make cheese and yoghurt milk has to curdle and lactic acid makes this happen.
18 To make YoghurtPasteurise milk (heated 73oC for 15s)Let cool to 40 degrees celciusAdd yoghurt making bacteria (converts sugar to lactic acid = curdling)Notice the lowering pH as bacteria convert lactose to lactic acidYoghurt is formed as lower pH denatures proteins in milk (curdling) over several hours.Stored in fridge to slow down bacteria growth
19 Describe the uses of bacteria in biotechnology Success Criteria Learning IntentionsDescribe the uses of bacteria in biotechnologySuccess CriteriaAll canI can describe the process of yoghurt and cheese makingI can state that the souring of milk is a fermentation processI can explain the souring of milk in terms of fermentation of lactose
21 Learning ObjectivesTo understand how microbes are cultured on a large scale.To know how fungi can be used as a meat substitute.
22 On a small scaleYou can grow microbes on a small scale in a petri dish.They can get plenty of food, oxygen and warmth to grow.
23 On a small scaleWaste that bacteria produce is not a problem on a small scale.
24 Simple Fermentation in the School Laboratory In the school laboratory you may have used apparatus similar to that shown below to investigate the effect of temperature or glucose concentration on the rate of respiration in yeast.The yeast culture is growing in conditions where the temperature is controlled and glucose is provided - this is a basic fermenter.24
25 On a large scaleOn an industrial scale, waste can become a problem.
27 How do we go fromthis…………….….to………….…..this…..?
28 A graph to show what is happening in the fermenter
29 Problems with fermenters As numbers of microorganisms increase;1. The food is used up.2. The temperature increases as they respire.3. Oxygen levels decrease as they respire.4. As the carbon dioxide levels increase, the pH changes.5. As waste increases the microorganisms begin to die.
32 So what do we have to do to overcome these problems? Oxygen is supplied for respiration.There is a stirrer to keep the microorganisms spread out (not settling to the bottom) and the temperature the same.There is a water cooled jacket around the outside, to try and maintain the temperature, as the microbes release heat.There are sensors to monitor the pH and temperature.
33 Mycoprotein Production A new substance was discovered not long ago, a food based on fungi, and it is called mycoprotein.
34 It is produced using the fungus Fusarium, which grows and reproduces very rapidly based on a cheap energy supply (an inexpensive sugar syrup made from waste carbohydrates) in a large fermenter.
35 Mycoprotein Production It does require areobic conditions to grow. Its mass doubles every 5 hours or so, and this biomass is harvested, purified and dried to leave mycoprotein.
36 Mycoprotein Production On its own, it is pale yellow in colour and tastes faintly of mushrooms.But a range of colours and flavours can be added to it to enhance it.
37 Mycoprotein Production Mycoprotein serves as a high-protein, low-fat meat substitute. This means it is good for dieters and vegetarians.