TLE 8 AFA W7D2: Food Processing (Cont.)

1. Identify and explain the principles of curing, smoking, drying, and dehydration as methods of food preservation by the end of the lesson.
2. Differentiate the functions of ingredients, tools, and conditions used in these methods through guided activities and discussions with at least 80% accuracy.

• Curing – preserving raw materials using different ingredients, seasoning, and extenders.
• Salt – extracts moisture, prevents bacterial spoilage; pink salt (Prague powder) contains sodium chloride and nitrate/nitrite to control botulinum toxin.
• Sugar – reduces salt’s harshness and prevents hardening in cured meats.
• Nitrate/Nitrite – preserves color and flavor, prevents spoilage and bacterial growth.
• Phosphate – improves yield and moisture retention in meat.
• Ascorbic Acid / Sodium Erythorbate – retains meat color during curing.
• Monosodium Glutamate (MSG) – enhances taste and aroma in processed meats.
• Texture Vegetable Proteins (TVP) – added to meat products for texture.
• Spices – add flavor and aroma during curing.
• Dry Curing – curing method using salt as the main preservative.
• Pickle Curing – curing method using sugar and vinegar immersion.
• Injection Curing – curing method where brine solution is injected into meat muscle.
• Smoking – exposing cured foods to smoke from burning hardwood, herbs, or fruit skins in a controlled environment to enhance flavor and shelf life.
• Cold Smoking – infuses flavor without cooking the food.
• Hot Smoking – cooks the food while adding smoky flavor.
• Acids in Smoke – help coagulate proteins, prevent mold, and protect against bacteria.
• Phenols – compounds in smoke contributing to flavor, aroma, and antimicrobial properties.
• Carbonyl Compounds – combine with proteins to create the characteristic reddish-brown color of smoked meats.
• Drying – ancient preservation method that removes water from food using heat, sunlight, or hot air.
• Water Activity – the availability of water in food for microbial growth; reduced by drying.
• Shrinkage – size reduction caused by moisture loss during drying.
• Case Hardening – formation of a hard outer layer due to rapid drying, preventing proper dehydration inside.
• Browning – discoloration caused by enzymatic oxidation, Maillard reaction, or caramelization during drying.
• Hot Air Drying – drying method using heated air circulated around food (tray drying, spray drying, etc.).
• Microwave Drying – drying using microwaves to heat water inside food.
• Freeze Drying (Lyophilization) – drying heat-sensitive foods by freezing and sublimating water under low pressure.
• Osmotic Drying – immersing foods in concentrated solutions of sugar or salt to remove moisture.
• Dehydration – controlled removal of moisture to prevent microbial growth and enzymatic activity.

Matching Type Review
Directions: Match the preservation method in Column A with its correct description in Column B.

Column A

a. Salting
b. Fermentation
c. Pickling
d. Sugar Concentration
e. Curing

Column B

1. Preserving food by immersion in brine or vinegar.
2. Adding specific ingredients like nitrates, sugar, and spices to preserve meat.
3. Replacing water molecules with sugar to prevent microbial growth.
4. Preservation method involving microorganisms that produce acids or alcohol.
5. Extracting moisture using salt to inhibit bacterial growth.

Show Answer

a-5, b-4, c-1, d-3, e-2

Introduction
On Day 1, we studied the basics of food processing, including sugar concentration, fermentation, pickling, and salting. These methods are essential for prolonging shelf life and making food safe and appealing. In this lesson, we continue with other vital methods: curing, smoking, drying, and dehydration. Each of these methods has its own processes, ingredients, tools, and scientific principles. They are widely used both in households and in industries, and understanding them helps us appreciate how food is preserved and enjoyed across cultures.

Curing

Curing is one of the oldest and most effective ways of preserving food, especially meat and fish. It involves adding ingredients such as salt, sugar, nitrates, nitrites, phosphates, spices, and other substances to raw materials. The combination of these curing agents helps extend shelf life, prevents spoilage, improves flavor, and gives food an appealing color and aroma.

Ingredients in Curing:
- Salt – The main preservative in curing. Salt draws out water from meat or fish through osmosis, creating conditions where bacteria cannot thrive. Ordinary table salt may cause uneven curing, so special curing salts like Prague powder (pink curing salt containing sodium chloride and nitrates/nitrites) are used. This type of salt not only preserves but also controls the growth of Clostridium botulinum, a dangerous bacterium.
- Sugar – Reduces the harshness of salt and prevents meat from hardening during curing. It also adds flavor and balances the taste.
- Nitrate and Nitrite – These are chemical agents that help preserve the natural pink or red color of meat, prevent rancidity, and stop the growth of harmful bacteria. Nitrites are especially important in preventing botulism.
- Phosphates – Improve the yield of cured meat by helping it retain water, making it juicier.
- Ascorbic Acid and Sodium Erythorbate – Work as antioxidants, helping meat maintain its color and freshness during curing.
- Monosodium Glutamate (MSG) – Used in some processed meats to enhance taste and aroma.
- Texture Vegetable Proteins (TVP) – Plant-based proteins added to meat products to improve texture.
- Spices – Provide flavor and aroma. Examples are black pepper, garlic, and paprika.

Methods of Curing:
1. Dry Curing – Meat is covered directly with curing ingredients like salt, sugar, and spices. The meat is left for days or weeks until the curing agents penetrate.
2. Pickle Curing – Food is immersed in a mixture of sugar, salt, vinegar, and sometimes spices. This method is often used for meats, vegetables, and even fish.
3. Injection Curing – A solution of curing ingredients (called brine) is injected into the meat to ensure even distribution. This speeds up the process and is often used in commercial food production.

Curing is not just about preservation — it also improves the sensory qualities of food. Bacon, ham, tocino, and longganisa are examples of cured foods.

Smoking

Smoking is often done after curing. It enhances flavor, color, and preservation by exposing food to smoke from burning hardwood, herbs, or fruit skins. The process must be carefully controlled because the type of wood and smoking conditions affect the flavor and safety of the food.

Why smoke food?
- Extends shelf life by adding compounds that inhibit bacterial growth.
- Adds appealing color and smoky aroma.
- Develops unique flavors depending on the wood used.

Types of Smoking:
1. Cold Smoking – Uses smoke at a low temperature (usually below 30°C). The food is exposed for hours or days, giving it flavor without cooking it. Cold smoking is often used for cheese, fish, and sausages.
2. Hot Smoking – Uses higher temperatures (above 60°C), which cook the food while giving it a smoky flavor. This is used for meats, poultry, and some fish.

Compounds in Smoke:
- Acids – Coagulate proteins, help prevent molds, and protect food from bacteria.
- Phenols – Provide flavor and aroma while also working as antioxidants and antimicrobials.
- Carbonyl Compounds – React with proteins to give meats a reddish-brown color.

Smoking is both an art and a science. Traditional smoked foods include smoked fish (tinapa in the Philippines), smoked ham, bacon, and sausages.

Drying

Drying is one of the most ancient methods of preserving food. It works by removing water, which microorganisms need to survive and grow. Without enough water, bacteria, yeasts, and molds cannot multiply.

How drying works:
Food is exposed to heat, sunlight, or hot air to remove moisture. The aim is to reduce the water activity to a level where spoilage organisms cannot thrive.

Effects of Drying:
- Shrinkage – As food loses moisture, it reduces in size and may become wrinkled.
- Case Hardening – When food dries too quickly, the surface becomes hard, trapping moisture inside. This prevents proper drying and may lead to spoilage.
- Browning – Discoloration may happen due to enzymatic oxidation, Maillard reaction (between sugar and protein), or caramelization. This affects both color and flavor.

Types of Drying:
1. Hot Air Drying – Heated air is circulated around food. Examples include tray drying (common for fruits and vegetables) and spray drying (used for milk and coffee).
2. Microwave Drying – Uses microwaves to heat water molecules inside food, speeding up the drying process.
3. Freeze Drying (Lyophilization) – Food is frozen, and water is removed by sublimation under low pressure. This method is excellent for heat-sensitive foods like coffee, fruits, and instant meals.
4. Osmotic Drying – Food is soaked in a concentrated sugar or salt solution. Water leaves the food due to osmosis, and the process is often combined with other drying methods.

Examples of dried foods include dried mangoes, dried fish, raisins, and powdered milk. Drying reduces weight, making foods easier to store and transport.

Dehydration

Dehydration is closely related to drying, but it refers to the controlled process of removing moisture using modern equipment. While traditional drying may rely on the sun or air, dehydration uses machines to regulate temperature, humidity, and airflow.

Advantages of Dehydration:
- Prevents microbial growth by reducing water activity.
- Preserves food flavor and nutrients when carefully managed.
- Provides long storage life and lightweight products.
- Can be combined with packaging methods like vacuum sealing for maximum preservation.

Processes of Dehydration:
- Pre-treatment (washing, peeling, slicing, blanching).
- Loading into dehydrators.
- Exposure to controlled hot air or specialized drying techniques.
- Packaging in moisture-proof containers.

Examples: Instant noodles, powdered soup mixes, dehydrated vegetables, dried herbs, instant coffee, and survival rations.

Dehydration is widely used in the food industry today because it allows mass production of shelf-stable products while maintaining convenience for consumers.

Integration of Concepts

Curing, smoking, drying, and dehydration are not isolated techniques. They are often combined to ensure better results. For example, fish may first be salted (curing), then dried under the sun, and finally smoked for added flavor and preservation. Similarly, ham is cured, smoked, and sometimes dehydrated before reaching markets.

These methods also contribute to sustainability. By extending food shelf life, they help reduce waste, make transport easier, and allow communities to make use of seasonal harvests year-round.

Summary of Day 2 Content

• Curing uses ingredients like salt, sugar, nitrates/nitrites, and spices to preserve meat and fish while improving flavor and color.
• Smoking exposes foods to wood smoke, enhancing taste and shelf life through chemical compounds such as acids, phenols, and carbonyls.
• Drying removes water naturally or with heat, but must avoid issues like case hardening and browning.
• Dehydration is a modern, controlled method of drying using machines for better quality and stability.
• These preservation methods are vital in both household practices and food industries, supporting sustainability by reducing waste and making food widely available.

Worked Example 1 – Curing

A butcher prepares tocino using a curing mix of salt, sugar, and nitrates. After a week, the meat has retained a pinkish color and has a sweet-salty flavor.
Q: Which ingredient is responsible for maintaining the meat’s pink color?

Show Answer

Nitrates/Nitrites.

Now You Try 1
A family makes bacon by mixing curing salt, sugar, and spices. Which ingredient balances the harshness of salt and improves taste?

Show Answer

Sugar.

Worked Example 2 – Smoking

A fish vendor cold-smokes bangus (milkfish) for 12 hours using mango wood. The fish absorbs a smoky flavor but remains uncooked.
Q: What type of smoking method was applied?

Show Answer

Cold smoking.

Now You Try 2
A meat processor exposes ham to smoke at high temperatures, which cooks the meat while giving it a smoky flavor. What type of smoking is this?

Show Answer

Hot smoking.

Worked Example 3 – Drying/Dehydration

A factory uses freeze-drying to preserve strawberries for breakfast cereals. The strawberries are frozen, and then water is removed by sublimation under low pressure.
Q: Why is freeze-drying preferred for heat-sensitive foods?

Show Answer

Because it removes moisture without using high heat, preserving flavor and nutrients.

Now You Try 3
A household dries mango slices under the sun. The outer part hardens quickly while the inside stays moist, leading to spoilage. What problem occurred?

Show Answer

Case hardening.

Directions: Answer the following exercises.

1. Define curing and list two common ingredients used in this method.
   Show Answer

   Curing is the preservation of meat or fish using ingredients such as salt, sugar, nitrates, nitrites, or spices. Common ingredients include salt and sugar.
2. Differentiate between cold smoking and hot smoking.
   Show Answer

   Cold smoking adds flavor without cooking food (below 30°C), while hot smoking both cooks and flavors food (above 60°C).
3. Give one example of a food product preserved by drying and another by dehydration.
   Show Answer

   Drying – dried fish; Dehydration – instant noodles or powdered soup mix.
4. Explain what case hardening is and why it is a problem during drying.
   Show Answer

   Case hardening is when the outer layer of food hardens too quickly, trapping moisture inside and preventing proper drying, which may cause spoilage.
5. Match the following:
   a. Bacon
   b. Smoked cheese
   c. Dried mangoes
   d. Instant coffee
   e. Longganisa
   
   - Drying
   - Cold smoking
   - Curing
   - Dehydration
   - Curing + Smoking
   Show Answer

   a - Curing, b - Cold smoking, c - Drying, d - Dehydration, e - Curing + Smoking.

Directions: Answer the following questions.

Multiple Choice (1–4)

1. Which ingredient in curing is mainly responsible for preventing botulism?
   a. Sugar
   b. Nitrates/Nitrites
   c. MSG
   d. Phosphates
   Show Answer

   b. Nitrates/Nitrites
2. Which type of smoking both flavors and cooks the food?
   a. Cold smoking
   b. Hot smoking
   c. Dry smoking
   d. Oven drying
   Show Answer

   b. Hot smoking
3. Which drying method is best for heat-sensitive foods such as coffee and strawberries?
   a. Microwave drying
   b. Freeze drying
   c. Hot air drying
   d. Osmotic drying
   Show Answer

   b. Freeze drying
4. Which curing method involves injecting brine solution directly into the meat?
   a. Pickle curing
   b. Dry curing
   c. Injection curing
   d. Sugar curing
   Show Answer

   c. Injection curing

True or False (5–6)

5. Phenols in smoke help create a reddish-brown color in smoked meats.
   Show Answer

   False – Carbonyl compounds create the reddish-brown color.
6. Dehydration is simply traditional sun drying with no temperature control.
   Show Answer

   False – Dehydration is a controlled process using machines.

Short Answer (7–8)

7. What are two main advantages of curing meat?
   Show Answer

   It extends shelf life and enhances flavor/color.
8. Explain why case hardening is considered a problem in food drying.
   Show Answer

   It causes the outer layer to harden too quickly, trapping moisture inside and risking spoilage.

Matching Type (9–10)

Match the product to the preservation method:

a. Ham
b. Dried anchovies
c. Smoked fish (tinapa)
d. Instant soup mix

- Smoking
- Curing
- Drying
- Dehydration

Show Answer

a - Curing, b - Drying, c - Smoking, d - Dehydration.

1. Recipe Research
   Look up a traditional Filipino cured or smoked food (e.g., tocino, longganisa, tinapa). Write down the ingredients and the method used.
   Show Answer

   Examples: Tocino – sugar, curing salt, spices (curing method); Tinapa – salt + smoking.
2. Mini Experiment
   At home, place thin slices of fruit (like banana or apple) under the sun for several hours. Observe and record changes in texture, color, and smell.
   Show Answer

   Answers vary, but expected: fruit shrinks, becomes chewy, may darken in color due to browning.
3. SDG Connection
   Explain how curing, smoking, and drying help in achieving SDG 12: Responsible Consumption and Production.
   Show Answer

   They extend food shelf life, reduce spoilage, minimize waste, and make food available during off-seasons.
4. Poster-Making
   Create a poster showing the step-by-step process of smoking or drying food. Include at least 3 safety reminders.
   Show Answer

   Poster should include steps like preparing food, choosing wood/heat source, controlling time/temp, with safety reminders (clean tools, avoid contamination, proper storage).
5. Critical Thinking
   If your community faces frequent power outages, which method (curing, smoking, drying, dehydration) would be the most practical for preserving food? Why?
   Show Answer

   Drying or smoking – because they don’t require electricity and can be done with natural heat or firewood.

Write your answers in your notebook.

Write 3–5 Sentences

Reflect on what you learned about curing, smoking, drying, and dehydration. How do these methods help preserve food, and which one do you think is most useful for your family?

Checklist Reflection

• ☑ I can explain what curing is and name its common ingredients.
• ☑ I can differentiate between cold smoking and hot smoking.
• ☑ I can describe at least two drying methods.
• ☑ I can explain why dehydration is important in modern food processing.
• ☑ I can connect food preservation methods to sustainability.