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Te Kura Māori O Porirua Food Testing
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Learning Objectives: To understand the main components of the human diet. To test for the presence of starch, glucose protein and fat in a food sample. Starter: List the 7 parts of the human diet.
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Seven Parts of the Human Diet
Carbohydrates Water Protein Vitamins Minerals Fibre Fats
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Practical Activity Safety First: Wear safety goggles Stand up
Tuck your chair & bags under your desk Tie back long hair
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We can test foods to find out what chemicals they contain.
8A What’s in food? We can test foods to find out what chemicals they contain. Orangey-brown iodine turns blue-black when it reacts with starch. drop iodine solution onto the food black = starch
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8A What’s in food? Blue Benedict’s solution turns orangey-red when it is boiled with glucose. blue turns orange/red = glucose chopped up food hot water heat
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In the Biuret test the solution turns purple.
8A What’s in food? In the Biuret test the solution turns purple. potassium hydroxide copper sulphate shake purple = protein chopped up food
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Fats go cloudy white when they are mixed with ethanol and water.
8A What’s in food? Fats go cloudy white when they are mixed with ethanol and water. add water filter grind food with ethanol cloudy = fat Now see if you can use these tests to identify the food chemicals on the next slides.
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Food sample Test Result
8A What’s in food? For each food, decide on the chemicals found in them. Food sample Test Result Iodine solution orangey-brown Benedict’s test blue Biuret test purple Ethanol test cloudy white Protein Fats Starch Glucose
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Food sample Test Result
8A What’s in food? For each food, decide on the chemicals found in them. Food sample Test Result Iodine solution blue-black Benedict’s test blue Biuret test Ethanol test clear Protein Fats Starch Glucose
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Food sample Test Result
8A What’s in food? For each food, decide on the chemicals found in them. Food sample Test Result Iodine solution orangey-brown Benedict’s test orangey-red Biuret test blue Ethanol test clear Protein Fats Starch Glucose
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Food sample Test Result
8A What’s in food? For each food, decide on the chemicals found in them. Food sample Test Result Iodine solution orangey-brown Benedict’s test orangey-red Biuret test blue Ethanol test clear Protein Fats Starch Glucose
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Experiment! You’ve been given a sample of foods. Test these foods using the four food tests to see what energy chemicals they contain! Complete this table with your results. Food Starch Glucose Protein Fat Cream Cake ?
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a) contains the same amounts of the main food groups
8A A food test for YOU! 1. A balanced diet… a) contains the same amounts of the main food groups b) contains healthy amounts of the main food groups c) doesn’t fall off the table. 2. A balanced diet for most people has more… a) fat than water b) carbohydrate than protein c) crisps than fruit.
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3. To test for protein in food you… a) add iodine solution
8A A food test for YOU! 3. To test for protein in food you… a) add iodine solution b) do the Biuret test c) poke it with a big stick. 4. Sugar and starch are both… a) proteins b) fats c) carbohydrates.
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5. Iodine solutions turns blue-black with… a) starch b) protein
8A A food test for YOU! 5. Iodine solutions turns blue-black with… a) starch b) protein c) age. 6. A food went orangey-red when it was boiled with Benedicts solution. It could be… a) a carrot b) a boiled sweet c) a sausage.
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Food Tests Learning Objectives:
To understand the main components of the human diet. To test for the presence of starch, glucose protein and fat in a food sample.
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