Blanching: Food Preservation

Blanching

• Blanching involves scalding food in boiling water briefly, then shocking it in ice water to halt cooking
• Used to remove skins, inactivate enzymes, and reduce microorganisms
• Important for maintaining color, texture, and nutritional value

History of Blanching

• It became popular in the 19th and 20th centuries with industrial frozen food production
• Clarence Birdseye popularized it as a pretreatment for freezing in the mid-20th century

Mechanisms of Blanching

• Enzyme inactivation prevents oxidative browning and degradation
• Air removal stabilizes products during freezing or dehydration
• Reduces microorganisms for improved safety and shelf life
• Softens tissues for canning and skin removal
• Preserves natural colors by inactivating enzymes and removing air

Blanching Methods

• Immerse food in boiling water, return to a boil, then shock in ice water
• Drain after shocking to prevent a sloppy texture

Effects on food from blanching

• Preserves color and texture
• Reduces microorganisms and enzymatic activity
• Enhances flavor and reduces bitterness
• Helps in peeling and prepping
• Reduces nutrient loss

Pasteurization

• Pasteurization is a process that kills microbes in food and drink
• It was invented by Louis Pasteur during the nineteenth century to prevent beverages to become sour
• It reduces the number of microorganisms to prolong the quality of beverages

How Pasteurization Works

• Pathogenic microbes are eliminated and microbial numbers lowered
• Unlike sterilization, pasteurization does not kill all microorganisms
• It targets enough pathogens to prevent disease assuming proper storage
• It's used in the dairy and other food industries for preservation

History of Pasteurization

• The name comes from French chemist Louis Pasteur
• In 1864 heat wine to 50 to 60 degrees Celsius to kill microbes and reduce acidity
• A similar technique had been used since at least 1117 AD in China to preserve wine
• In 1795, French chef Nicolas Appert sealed foods in glass jars
• In 1810, Peter Durand applied a similar method to preserve foods in tin cans

Why is it called "pasteurization?"

• Pasteur's experiments demonstrated that particles in the air did caused food spoilage
• Research pointed to microorganisms as the culprit for spoilage and disease

Pasteurization Techniques

• High-Temperature Short Time
• Low-Temperature Long Time

Method

• Heat kills pathogens and inactivates some proteins
• The precise process varies by product
• Liquids are pasteurized while flowing through a pipe
• Temperature and duration is carefully controlled

Effects of Pasteurization on Foods

• Reduces food poisoning risk and extends shelf life
• Impacts texture, flavor, and nutritional value

Examples of impact

• Increases vitamin A, decreases vitamin B2 in milk
• Homogenization, not pasteurization, causes color changes in milk
• Fruit juice loses some aroma and reduces vitamin C and carotene
• Vegetables may soften and change nutrient levels

Importance

• Ensures food safety and extends the shelf life of perishable products
• Protects public health and maintains the nutritional integrity of commonly consumed items

Frying

• It involves transferring heat from hot oil to food
• It does change the sensory and nutritional characteristics

Origins

• Ancient Egypt; used for frying fish
• Ancient Egyptians- olive oil and animal fats
• The Greeks and Romans used olive oil
• Middle Ages Europe : lard or butter was more common
• Renaissance- batter-dipping foods
• Southern US both African and Native American cooking

Key foods

• Fried chicken, tempura, fritters

Industrial Revolution

• Advances in technology made deep fryers more accessible
• It created a uniform, crispy texture to food items

Modern production

• The mass production of cooking oils, allowed frying to be more popular
• French Fries and Fish and Chips, in the late 19th century, they were more popularized

Rise of fast food

• Globalized frying
• Fast food companies relied heavily on frying as a cooking method

Examples

• McDonalds and French Fires- standardized the frying process
• KFC and Fried chicken- Known for popularizing the use of 11 herbs and spices

Household use

• The expansion of people cooking foods at home in the 1960s and 1970s increased.

Contemporary Era

• Healthier frying alternatives came to light
• Air Fryers mimicked the crispy texture of fried food
• Healthier Oils such as olive oil, avocado, and coconut oil became more popular

Modern frying

• One of the most popular cooking methods worldwide
• All over the world, each culture has their own methods

Types of frying

• Deep frying- food if fully submerged in hot oil
• Pan frying- Cook food in a pan with a small amount of oil
• Stir frying- Food is cooked quickly over high temperatures
• Air frying- A healthy way of frying with hot air instead of fat

The process of how it works

• Oxidation process; when frying food, the hot oil and the food itself interact in the air to oxidizing the food.- Leads to unstable compound.
• Breaking down products affect the taste and quality of a food product

Taste, texture, and structure implications

• Steam makes the food crispy
• Flavors from aldehydes being released contributing to aroma
• The best results are achieved with high quality oil.

Nutrition information

• Sensitive ingredients cant be fried

High level list of whats not good

• Increases fat, production of toxic substances, trans fat increases

High-Temperature Short Time (HTST) Definition

• Thermal processing method: rapidly heats and cools food to eliminate harmful microorganisms
• Key features for microbial reduction without impact to nutritional value

History High-Temperature Short Time (HTST)

• Louis Pasteur discovered heating wine prevents spoilage
• Lower temperature, longer durations used for milk often impacted the flavor and nutritional content
• Development of High-Temperature Short Time (HTST) technology revolutionized the dairy industry

Effects of High-Temperature Short Time (HTST)

• Enhanced food safety by eliminating harmful bacteria
• Increases shelf life of food products
• Safely gives efficient distribution and storage
• Modern High-Temperature Short Time (HTST) techniques designed to minimize impact on taste, texture, and nutritional value
• Enables food producers to process large volumes of products quickly and safely

Definition of Low-Temperature Long Time (LTLT)

• Food preservation heats food at lower temperature for long and while maintaining quality
• The technique is employed in various applications, including pasteurization and sous vide cooking

High level Key Aspects of Low-Temperature Long Time (LTLT)

• Temperature is well regulated
• Time is well managed to help properly break down foods

Low-Temperature Long Time (LTLT) examples

• 63°C for 30 minutes to kill pathogens; Salmonella, Mycobacterium tuberculosis
• More vitamins and proteins, High-temperature methods
• Primarily for milk, dairy, juice, liquid egg products
• Called- batch or val pasteurization

Low-Temperature Long Time (LTLT): Sous Vide

• A method of cooking in a water bath for longer periods of time; common for beef, and vegetables
• Pralus in 1974- cooked foie gras at low temperature under pressure

Canned Foods

• The method involves sterilizing food by sealing it to airtight containers -jars, or cans

History in short

• Late 18th early 19th century; Military problem

Napoleon's Challenge

• Process began due to wanting to feed the troops -1795- through preservation
• Nicolas Francios Appert was inspired and experimented

How It progressed

• Invented method of food preservations by sealing airtight with glass and boiling in water.
• Durand creates preservation in 1810- and involved sealing and refrigerating.

Food Canning Mechanism

• Sterilizing of jars, filling with food, then heating to destroy microorganisms- followed by sterilizing lids to seal shut

Water Bath Canning

• It's to preserve bacteria in items like jam, pickles, or fruit
• The Acidity - high acidity prevents bacterial growth
• The temperature consists of 212 degrees or boiling.

Pressure Canning

• Requires pressure
• Steam is used due to low acid requirements to help prevent bacteria.

Raw V Hot Canning

• Raw is about food
• Hot is about food and is a bit more processed. Heat is added to transfer throughout.

Canning: Benefits

• High vitamin, food safety, and improves the texture
• Overall canned foods lower rates of food borne illnesses and can be considered eco-friendly.

Canning: Downsides

• Canned foods can sometimes consist of high sodium. Sugar; altering the texture and taste

Journey Through Time: Food and Product Production

• Food can be defined as food processing.

Early beginnings notes on food production

• The nature of food begins to spoil the moment it is harvested
• It's not about just animals; but about the foods that we choose to eat.
• Ancient cultures all around the world preserve their food.

How It progressed through product control

• Trade and travel of foods and trade.

Industrial revolution of production

• Mechanization of tools, - canning and using glass in sealed jars