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Questions and Answers
The aim of the experiment is to determine moisture content of some food products by different methods such as infrared drying, vacuum drying, oven drying, and ______.
The aim of the experiment is to determine moisture content of some food products by different methods such as infrared drying, vacuum drying, oven drying, and ______.
distillation
Water is the main ingredient of many foods, and moisture content must be known for nutritional and ______ control reasons.
Water is the main ingredient of many foods, and moisture content must be known for nutritional and ______ control reasons.
quality
Dilution of substances such as milk, beer, cream, and butter has long been a common ______, which is illegal and must be tested for.
Dilution of substances such as milk, beer, cream, and butter has long been a common ______, which is illegal and must be tested for.
adulteration
In processed and frozen foods, water can be picked up at different stages and this must be ______.
In processed and frozen foods, water can be picked up at different stages and this must be ______.
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The quality of dried foods often depends on the levels of moisture left in them, for example, milk ______.
The quality of dried foods often depends on the levels of moisture left in them, for example, milk ______.
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Water exists in three forms in foods: bulk or free water, absorbed water, and ______ water.
Water exists in three forms in foods: bulk or free water, absorbed water, and ______ water.
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Bulk or free water is lightly entrapped and therefore easily separated from food by evaporation or ______.
Bulk or free water is lightly entrapped and therefore easily separated from food by evaporation or ______.
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Absorbed water is physically bound as a monolayer on the surface of the food ______.
Absorbed water is physically bound as a monolayer on the surface of the food ______.
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Bound water is chemically bonded as water ______ or as hydrates.
Bound water is chemically bonded as water ______ or as hydrates.
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One of the methods for moisture determination is the ______ method.
One of the methods for moisture determination is the ______ method.
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To determine moisture content, the sample is first dried for 60 minutes and then placed in a ______.
To determine moisture content, the sample is first dried for 60 minutes and then placed in a ______.
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While using the toluene distillation method, you must weigh about 5 g of ______ in the flask.
While using the toluene distillation method, you must weigh about 5 g of ______ in the flask.
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The moisture content in the distillation method can be calculated using the formula: Moisture content (%) = (V/W1) × 100, where V is the volume of ______ in mL.
The moisture content in the distillation method can be calculated using the formula: Moisture content (%) = (V/W1) × 100, where V is the volume of ______ in mL.
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The weight of the dried sample can be found by taking the weight of the empty petri dish and ______ of the dried sample.
The weight of the dried sample can be found by taking the weight of the empty petri dish and ______ of the dried sample.
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Samples like wheat flour and ______ can be processed using the drying oven method.
Samples like wheat flour and ______ can be processed using the drying oven method.
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In the discussion section, you should give brief information about your sample's ______.
In the discussion section, you should give brief information about your sample's ______.
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Study Notes
Food Chemistry Laboratory Experiment 1: Determination of Moisture Content
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Experiment Aim: Determine moisture content of food products using different methods (infrared drying, vacuum drying, oven drying, distillation).
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Importance of Moisture Content:
- Water is a main component of many foods.
- Moisture content is crucial for nutritional and quality control.
- Water content affects the quality of dried foods (like milk powder).
- Water content must be controlled in processed and frozen foods.
- Dilution of substances like milk, beer, cream, and butter is a common adulteration and must be tested for.
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Forms of Water in Foods:
- Bulk/Free Water: Easily separated from food through evaporation or drying.
- Absorbed Water: Physically bound as a monolayer on food constituents' surfaces.
- Bound Water: Chemically bonded as water crystallization or hydrates.
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Methods of Moisture Determination:
- Drying method
- Distillation method
- Chemical method
- Instrumental method
Procedure (Drying Method)
- Step 1: Crush or cut food samples.
- Step 2: Obtain a preheated glass petri dish. Heat to 105°C for several hours and store in a desiccator.
- Step 3: Weigh approximately 2-3 grams of the crushed sample into the pre-weighed dish.
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Step 4: Place the dish in:
- A drying oven at 105°C.
- A vacuum oven at 650 mm-Hg 70°C.
- An infrared dryer for 5 minutes.
- Step 5: Transfer dishes into a desiccator to cool. Weigh the dish and dry sample accurately.
- Step 6: Replace dishes in the drying oven for 30 minutes and repeat steps 5.
- Step 7: Repeat steps 4, 5, and 6 until a constant weight is achieved.
Procedure (Toluene Distillation Method)
- Step 1: Weigh accurately about 5 grams of white cheese in a flask.
- Step 2: Place the flask in the distillation system.
Foods and Methods
- Wheat Flour, Macaroni, Biscuits: Drying oven
- Tomato Paste, Tomato: Vacuum oven, Infrared dryer
- White Cheese: Distillation method
Calculations
- Moisture Content (Dry Basis): ((Wet Weight - Dry Weight) / Dry Weight) * 100
- Moisture Content (Wet Basis): ((Wet Weight - Dry Weight) / Wet Weight) * 100
- Distillation Method Calculation: (Volume of water / Weight of sample before drying) * 100
Discussion
- Provide information about the sample composition.
- Explain the chosen method.
- Compare results with TSE or Codex standards.
- Explain if results are within the legal range. If not, discuss reasons for the difference.
Data Sheet Information
- Collect sample name, weight of empty petri dish, weight of sample, weight of empty petri and dried sample, weight of dried sample.
- Record the name of the person/group submitting the data and the submission date.
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Description
This quiz focuses on the determination of moisture content in food products using various methods such as infrared drying, vacuum drying, and oven drying. Understanding moisture content is vital for quality control and nutritional assessment in food chemistry. Explore the forms of water in food and the significance of accurate moisture measurement.
