DIFFERENT METHODS OF FOOD PROCESSING FOLLOWING THE INDUSTRY FOOD PROCESSING

 

DIFFERENT METHODS OF FOOD PROCESSING FOLLOWING THE INDUSTRY

Food Processing is the process of transforming food items into a form that can be used. It can cover the processing of raw materials into food via different physical and chemical processes. Various activities covered in this process are mincing, cooking, canning, liquefaction, pickling, macerating and emulsification.

 

Objectives of Food Processing

Food technology is a very vast domain concerning the production and processing of food. Food processing has certain objectives, such as:

·       It boosts the shelf life of food products.

·        Prevent food contamination.

·       Food storage and Transportation.

·        Turns raw food materials into attractive, marketable products.

·       Provide employment to a large population.

Food Processing Methods

There are certain criteria that must be compiled for the appropriate processing of food, right from the possibility of a pest or bacteria invading and multiplying on foods to the biological activity of foods. The following methods are applied for the proper processing of food: 

1. Sugar Concentration

 Preparing Raw Materials

Sorting and Grading Fruits The product should not have physical defects as these could be entrance doors for pathogens that cause rotting. While the characteristics of good fruits vary for every type of produce, there are a number of attributes that indicate quality.

a.    Integrity of shape - The produce should not have physical defects as these could be entrance doors for pathogens that cause rotting.

b.    Uniformity - Each product in the batch should be uniform in size, form, and color.

c.    Freshness - The product should be harvested right on time to achieve maximum turgidity, color, flavor, and crispness. This can be ensured by asking for information from the supplier.

d.    Ripeness or maturity - Usually indicated by color and firmness, ripeness or maturity refers to the maximum edible quality of the fruit. Color and firmness are indicators of maturity.

e.     Juiciness - Juice content in fruits is directly related to the ripeness of the fruit.

f.     Flavor - Can be checked by measuring the total soluble solids with a refractometer.

 

Preparing Fruit and Other Ingredients for Processing

a)    Washing and Cleaning Fruits - helps to remove soil and chemical residues from produce.

b)    Knife Peeling - fruits and vegetables are pressed against stationery or rotating blades to remove the skin. Knife peeling is used for fruits that have skin that can be easily removed with little damage.

c)    Slicing - Slicing refers to cutting food into broad or flat thin pieces.

d)    Mincing - is mainly done for size reduction and homogenization.

e)    Testing Pectin Content - Pectin is a jelly stabilizer naturally found in fruits.

To test for pectin content:

1.    Boil the fruit in water until a thick consistency is reached.

2.    Take one teaspoon of the fruit juice and transfer it into a container. Leave to cool down.

3.    Add three tablespoons of denatured alcohol and gently shake the container. Leave to stand for a minute.

4.    Observe the jellied lumps. A large, firm lump means that the fruit has high pectin content; while small, soft lump means the fruit has low pectin content.

 Sugar as a Preservative - Sugar, like salt, preserves food by drawing out water and replacing it with sugar molecules, dehydrating and killing microorganisms.

Adjusting Sugar and Acid in Jams and Jellies Sugar activates pectin, breaking the pectin-water equilibrium and binding water, allowing pectin to form a gel. Acid strengthens the pectin gel network. Pectin is naturally present in fruit, and the balance of sugar and acid should match the fruit's pectin content. Excess acid makes the gel unstable, while too little acid results in soft lumps. Too much sugar weakens the gel, making it watery.

Based on the pectin test; sugar is added in the following proportions:

a.    If juice is rich in pectin, add 1 cup of refined sugar per cup of juice.

b.    If juice has moderate pectin content, add ¾ cup sugar per cup of juice.

c.    If juice if poor in pectin, add ½ cup sugar per cup of juice

·       Large firm lumps = more sugar = less acid

·        Soft, small lumps = more acid = less sugar

Sugar Concentrated Products

·       Jellies: Transparent, bright gels made from fruit juice, with the fruit's characteristic flavor and a mild acidic taste. They mold to the container's shape and slip out when poured, having a smooth, thick, and quivery texture. Juice is extracted by boiling fruit in water, which softens the tissue and converts pectose to pectin, and then draining through a cheesecloth.

·       Jams: Made by cooking fruit with sugar syrup until thick. Jams contain the fruit's pulp and fiber and do not retain the fruit's shape. Good jams are soft, thick, and smooth. Blending the fruit before boiling enhances consistency. Jams can combine various fruits for diverse flavors and acidity; fully mature fruits provide the best texture and flavor.

·       Marmalades: Similar to jellies but include suspended slices of fruit or peel, usually from citrus fruits. They have a blend of bitter, acidic, and sweet tastes, with a smooth, thick, and quivery texture.

·        Preserves: Essentially jellies with whole fruits or large pieces. They retain the fruit's flavor and have a thick, non-watery syrup.

2.Fermentation - Fermentation is an enzyme-driven metabolic process where organisms convert starch or sugar into alcohol or acid anaerobically, releasing energy. The study of fermentation is called zymology.

Types of Fermentation

1.    Homofermentation: Produces one type of product.

2.    Heterofermentation: Produces multiple products.

End Product-Based Categories:

1.    Lactic Acid Fermentation:

·       Produces lactic acid from pyruvate via lactate dehydrogenase, generating NAD+ from NADH.

·       Used by Lactobacillus bacteria to make curd and by muscles during intense exercise, causing fatigue.

2.     Alcohol Fermentation: ○ Produces alcohol and CO2, used in wine, beer, and biofuel production.

·       Pyruvic acid converts to acetaldehyde and CO2, then to ethanol.

·       Catalyzed by pyruvic acid decarboxylase and alcohol dehydrogenase.

3.    Acetic Acid Fermentation:

·       Produces vinegar in two steps: sugar to ethyl alcohol anaerobically by yeast, then ethyl alcohol to acetic acid aerobically by acetobacter bacteria.

4.    Butyric Acid Fermentation:

·       Characteristic of Clostridium bacteria, used in jute retting, rancid butter, tobacco processing, and leather tanning.

·       Produces butyric acid from acetyl-CoA, yielding 3 ATP molecules.

·        Occurs in the human colon as a byproduct of dietary fiber fermentation, providing energy to the colorectal epithelium.

Fermentation is adaptable to various environments and is one of the oldest metabolic processes, present in both prokaryotes and eukaryotes. It is widely used across different industries. Using suitable microorganisms and specified conditions different kinds of fermentation products are formed namely:

3.   Pickling - Pickling is one of the ancient methods of food preservation. It began 4000 years ago. The term pickle is derived from the Dutch word “peckle” meaning brine. It is called “achaar” in north India. The process of preservation of food in common salt or vinegar is called pickling. Pickles are good appetizers, and they aid in digestion by stimulating the flow of gastric juice.

Raw materials: Raw materials used in pickling should process definite characteristics.

·       Salt – for pickling, any variety of common salt is suitable, provided it is pure

·       Vinegar o Vinegar of good quality containing at least 4% acetic is suitable for pickling.

·       Spices - are added depending upon the kind of fruit or vegetable took and the kind of flavor desired. The spices commonly used in a pickle are leaves, cardamom, chilies, cinnamon, turmeric, clove, coriander, ginger, mace, mustard, black pepper, cumin, garlic, fennel, aniseed, etc.

·       Water - Only potable water should be used for the preparation of brine. o If hard water is to be used, a small quantity of vinegar should also be the brine to neutralize its alkalinity.

·       Coloring and Hardening Agents -mColors are not generally added to pickles, although they are used to some extent in sauces.

·       Common Fruits and Vegetables used in Pickling- Raw Mango, Lemon, Amla, Green Chilies, Garlic, Onion Cauliflower, Tomato, Plums, Grapes, Apples, Papaya, Beetroot, Boiled beans, Cucumber, Cabbage, Radish, Ginger    

    4. Salting Process:

Dry Salting

·       Select, wash, drain, and weigh the vegetable.

·       Use 3 kg of salt for every 100 kg of vegetables.

·       Place vegetables 2.5 cm deep in a keg, sprinkle with salt.

·       Repeat layering vegetables and salt until the keg is three-quarters full.

·        Cover with two layers of cheesecloth, tuck sides, and place a wooden board on top.

·       Weigh down with a 4.5 kg clean, non-reactive stone to form brine (usually within 24 hours).

·       Place the keg in a warm, dry area for fermentation.

·       Osmosis causes vegetable juice to form brine, covering the mass.

·       Bubbles of CO2 indicate the start of fermentation.

·        Fermentation completes in 8-10 days under favorable conditions.

·        Preserve by excluding air to prevent "pickle scum" (wild yeast) which can spoil the pickles.

Fermentation in Brine

·       Brining: Steeping vegetables in a salt solution for a set time.

·       Use Case: Ideal for cucumbers and vegetables lacking sufficient juice for dry salting.

·       Preparation: Dissolve common salt in water, filter to remove impurities.

·       Brine Volume: Typically, half the volume of the vegetables.

·       Duration: Critical for proper texture and taste; usually takes 4-5 weeks.

·       Curing Indicators: Vegetables become semi-translucent, color changes to dark olive green or yellowish green.

·       Effects: Vegetables lose raw flavor, become firm and crisp.

·        Storage: Properly cured vegetables can be stored indefinitely.

Pickling with Salt

·       Salt Method: Pack vegetables with a large amount of salt to inhibit fermentation.

·        Salt Ratio: Use 25 kg of salt per 100 kg of vegetables.

·       Post-Curing: Drain and soak cured vegetables in cold or warm water to remove excess salt.

·       Storage: Store vegetables in 10% strength vinegar for several weeks to prevent shriveling.

Packing Methods

·       Pack pickled onions and mixed pickles loosely in bottles or jars to maintain shape.

·       Add fresh vinegar to fill gaps between pieces.

·        Store pickles for a few days to ensure vinegar absorption before marketing, depending on vegetable type, piece size, and curing conditions.

The Science Behind Salting Food Preservation

·       Mechanism: Salt inhibits bacterial growth by creating a hostile environment, drawing out moisture, and dehydrating bacterial cells.

·        Flavor Enhancement: Salt amplifies food flavor, enhancing enjoyment.

·        Salt Types: Kosher, sea, and Himalayan pink salt are popular for their high mineral content and preservation properties.

·        Balance: Proper salt-to-food ratio is crucial to avoid under or over-salting.

Benefits of Salting Food Preservation

·       Extended Shelf Life: Salting delays spoilage, extending the usability of seasonal and perishable items.

·       Flavor Enhancement: Salt intensifies natural flavors, especially in cured meats, making them more complex and enjoyable.

·       Culinary Transformation: Salting not only preserves but also elevates food quality.

 Types of Salt Used for Food Preservation

·       Kosher Salt: Favored by chefs for its purity and versatility in preserving and seasoning.

·        Sea Salt: Less processed, retaining natural minerals and flavors, suitable for various preservation techniques.

·       Himalayan Pink Salt: Known for its unique flavor and high mineral content, adding richness to preserved foods.

·       Curing Salt: Contains salt and sodium nitrite, specifically for preserving meats and maintaining color and flavor.

Choosing the right salt depends on personal preference, availability, and desired flavor profile. Experimenting with different salts can enhance culinary experiences.

The Process of Salting and Its Effects on Food Salting involves preparing the food, applying salt, and allowing it to cure. This process not only preserves but also enhances the texture and flavor of the food.

·       Preparation: For meats, trim excess fat and remove bones. Wash and cut vegetables, and scale and gut fish. Proper prep ensures even salt penetration.

·       Application: Use 1-2% salt of the food's weight, adjusting for taste and preservation needs. Ensure even distribution over the food's surface.

·        Curing: Let the food rest, allowing the salt to draw out moisture and inhibit bacterial growth. This process also tenderizes meat, enhancing flavor and texture.

Tips for Effective Salting

·       Right Amount: Balance salt quantity; too little won't preserve, too much makes food inedible. Experiment to find the ideal ratio.

·       Even Distribution: Ensure salt covers all food surfaces for uniform preservation and seasoning.

·       Size and Thickness: Adjust curing time based on food's size; thicker cuts need more time, smaller pieces less.

·       Monitor: Check curing progress to avoid under or over-salting. Taste periodically to achieve desired saltiness.

·       Curing Time: Different foods require different times; delicate fish need less time than dense meats. Follow specific recipes or guidelines.

Common Mistakes to Avoid When Salting Food - Salting food seems simple, but common mistakes can affect the outcome. Here are some pitfalls to avoid:

·       Underestimating Curing Time: Rushing the process can result in poorly salted and less flavorful food. Allow enough time for the salt to fully cure the food.

·       Over-Salting: Excessive salt can make food too salty and unpleasant. Taste periodically to ensure the right balance.

·        Not Rinsing or Soaking: Some techniques require rinsing or soaking after curing to remove excess salt. Follow specific instructions for the method used.

·       Using Iodized Table Salt: Iodized salt contains additives that can affect taste and texture. Use natural salts without additives for better results.

·       Improper Storage: Proper storage is crucial to maintaining the quality and safety of preserved food. Follow recommended guidelines for storage.

 Salting is an ancient preservation method that enriches culinary traditions. Understanding its principles and techniques can help you master this valuable skill, extending the shelf life of food and enhancing flavors. By avoiding common mistakes, you can make the most of this timeless preservation method.

5. Curing - Curing is a method in preserving selected raw materials into processed products like salted eggs, sausage, skinless longanisa, bacon, tocino, and many others.

 

Function of the Curing Agents

·       Enhance the taste and color of meat.

·        Increased the water binding capacity of the meat.

Curing ingredients

·       Salt: Extracts moisture, prevents bacterial spoilage. Pink salt, or Prague powder, a mix of sodium chloride and nitrate/nitrite, controls botulinum toxin.

·       Sugar: Reduces salt's harshness, prevents hardening.

·        Nitrate/Nitrite: Preserves color, flavor, prevents spoilage and bacterial growth.

·       Phosphate: Boosts yield, moisture.

·        Ascorbic acid/Sodium erythorbate: Retains meat color.  

·       MSG: Enhances taste, aroma.

·        Texture vegetable proteins: Added to meat.

·        Spices: Adds flavor.

Curing Methods:

·       Dry curing: Uses salt as preservative.

·       Pickle curing: Uses sugar, vinegar immersion.

·        Injection curing: Injects brine solution into meat muscle.

Tips in Curing:

·       Use appropriate container to prevent oxidation, contamination.

·        Consider curing time.

·        Maintain temperature at 36-40°F.

·        Regularly inspect for spoilage.

·       Ensure even distribution of curing mixture.

·        Freeze cured product for storage.

 6. Smoking

         The smoking process involves exposing cured meats, poultry, game, and seafood to smoke generated from burning hardwood chips, herbs, fruit skins, or spices in a controlled environment. This imparts flavor, aroma, texture, appearance, and extends shelf life. Smoking can occur between 65°F to 250°F, with cold smoke infusing flavor and hot smoke cooking the food.

Reasons for Applying Smoke to Meat:

·       Preservation: Antimicrobial compounds in smoke affect surface bacteria, but penetration is limited.

·        Acids: Smoke coats meat, aiding surface coagulation and preventing mold and bacteria growth.

·        Flavor & Aroma: Phenols, carbonyl compounds, and organic acids contribute to smoky taste, but excess can lead to bitterness.

·       Color Enhancement: Carbonyl compounds combine with meat proteins, creating reddish-brown hues characteristic of smoked products.

·       Product Innovation: Smoky flavor extends shelf life and improves appearance.

·       Oxidation Protection: Smoke guards against lipid oxidation and stale flavor

·        Protective Coating: Acids in smoke help form a protective protein skin on meats and emulsion-type sausage.

 7. Drying - Drying and dehydrating fruits and vegetables is an ancient preservation method, reducing water content to 75-90%, which lowers water activity, making them resistant to spoilage. Heat, typically from solar energy or hot air, removes moisture, but can result in texture loss, nutrient depletion, discoloration, and flavor loss.

Why Dry Foods?

·       Water activity reduction controls chemical and microbiological changes.

·        Decreased weight, size, and volume ease transportation.

·       Simple, cheap packaging requirements.

·        Facilitates further processing, like grain drying for flour production.

 Drying Mechanism:

·       Hot air evaporates water from food surfaces.

·       Water vapor diffuses through air boundary and is carried away.

·        A gradient from moist food interior to dry air drives water removal.

Effects of Drying:

·       Shrinkage: Moisture loss reduces food size and density, causing internal stress and shriveling. Rapid drying improves texture.

·        Case Hardening: Formation of hard outer layer due to rapid initial drying, common in solute[1]rich foods. Lower temperatures prevent it.

·        Browning: Color change due to enzymatic oxidation (residual enzymes), Maillard reaction (protein-amino and sugar interaction), or caramelization (sugar conversion).

Types of Drying Methods:

·       Hot Air Drying: Includes spray drying, tray drying, fluidized bed drying, etc. Spray drying involves atomizing pre-concentrated food into fine droplets and spraying them into heated air flow. Tray dryers use insulated cabinets with mesh trays and blow hot air through ducts for uniform drying.

·        Microwave Drying: Utilizes microwaves for drying.

·       Freeze Drying (Lyophilization): Used for heat-sensitive foods, freezing material and then reducing pressure to allow frozen water to sublimate into vapor.

·       Osmotic Drying: Involves immersing high-moisture products in concentrated solutions (sugar or salt) to initiate counter-current mass transfer

8. Dehydration

 Food Dehydration: A Timeless Preservation Method

·       Purpose: Dehydration extends food shelf-life by removing water content, making it one of the oldest and most widespread preservation techniques.

·        Spoilage Prevention: Moisture is a breeding ground for microorganisms like bacteria, yeast, and molds, leading to food spoilage. Dehydration prevents their growth by reducing moisture and slowing enzymatic reactions.

·       Dehydration Basics: Successful dehydration requires heat (around 140°F), dry air to absorb moisture, and air movement to carry away moisture.

Benefits of Food Processing

·       Bacteria Reduction: Processing methods like drying and pickling dehydrate food, altering pH levels and inhibiting harmful microorganism growth.

·        Extended Shelf-Life: Food processing enhances shelf-life, reducing waste and promoting food sustainability.

·       Health Benefits: Processing reduces health risks by eliminating harmful bacteria and addressing major health concerns.