Nutrition and Institutional Food Preparation

11 Questions

What are some examples of foodborne viruses mentioned in the content?

Norwalk virus

Name one type of microorganism found in muscle tissue (red meat, poultry, and seafood) as mentioned in the content.

Salmonella

Lactobacillus Bulgaricus or Lactic Acid Bacteria (LAB) are used in particular in fermented __________ production from all over the world including yogurt, cheese, butter, and buttermilk.

milk

Match the following food production methods with their descriptions:

Heat treatment = Effective methods for killing or inactivating microorganisms Refrigeration and freezing = Lowers temperature to reduce microbial growth and extend shelf life Drying = Removes moisture to inhibit microbial growth in dried fruits, meats, and herbs Fermentation = Encourages growth of beneficial microorganisms in fermented foods

What role do enzymes play in food preparation?

Enzymes contribute to processes such as ripening, flavor development, texture modification, and preservation in food preparation.

What is true about enzymatic reactions in food?

Enzymatic reactions can bring about both desirable and undesirable outcomes.

Enzymatic oxidation-reduction reactions occur when oxygen is added to food molecules.

True

Enzymatic browning is caused by the enzyme ____.

polyphenol oxidase (PPO)

Match the enzyme with its function:

Lipase = Hydrolyze fats into fatty acids and glycerol Amylase = Convert starches into sugars Protease = Break down proteins into peptides and amino acids Pectinase = Treatment of fruit pulp to facilitate juice extraction

What factors can influence enzymatic activity?

Temperature, pH, substrate concentration, inhibitors, and activators can influence enzymatic activity.

Which microorganism type is parasitic in nature?

Protozoa

Study Notes

Enzymatic Aspects of Food Preparation

Enzymes are biological catalysts that speed up chemical reactions in food.
They are present in living systems, including plant and animal tissues, and microorganisms.
Enzymes are substrate-specific, meaning they only break down specific molecules.
Factors influencing enzymatic activity include: • Temperature: enzymes can be denatured at extreme temperatures. • pH: enzymes have optimal pH ranges for activity. • Substrate concentration: enzyme activity may increase with substrate concentration until saturation. • Inhibitors and activators: certain substances can modulate enzyme activity.

Types of Enzymatic Reactions

Enzymatic Hydrolysis: breaks down large molecules into smaller fragments (e.g., lipases, proteases, carbohydrases).
Enzymatic Oxidation-Reduction Reaction: causes changes in food molecule chemical structures (e.g., browning of fruits and vegetables).

Practical Applications of Enzymes in Food Preparation

Control of enzymatic browning in fruits and vegetables through pH adjustment or enzyme inhibitors.
Enzymatic browning can be minimized by peeling or cutting at 5 to 7°C and dipping immediately in water or water plus vitamin C.
Utilization of enzymes in meat tenderization to improve texture and palatability.
Optimization of enzymatic reactions in brewing and baking processes for desired flavor and texture profiles.

Enzymes Used in Food Industries

Dairy production: rennet, lactase, protease, catalase.
Brewing: beta-glucanase, alpha-amylase, protease, and amyloglucosidase.
Baking: maltogenic amylase, glucose oxidase, and pentosenase.
Wine and fruit juice: pectinase, beta-glucanase.
Other enzymes used in food preparation: papain, chymosin, lactase, glucose oxidase, cellulase.

Microbiological Aspects of Food Preparation

Microorganisms can influence food safety, spoilage, fermentation, and preservation.
Microorganisms are living entities that cannot be seen with the naked eye.
Microbes are ubiquitous, found in air, water, soil, human body, plants, and animals.
Microbes are responsible for spoilage of food, but they are also used for the production of valuable materials.

Types of Microorganisms

Bacteria: unicellular, spherical, rod-shaped, or spiral in shape.
Fungi: include molds and yeasts.
Protozoa: single-celled eukaryotes, parasitic in nature.
Viruses: obligate parasites, simple in structure, composed of a protein capsule and nucleic acid.

Microorganisms in Food

Spoilage microorganisms: cause undesirable changes in food, rendering it unfit for consumption.
Pathogenic microorganisms: pose health risks when consumed, leading to foodborne illnesses.
Fermentation microorganisms: facilitate fermentation processes, contributing to the production of fermented foods and beverages.

Factors Affecting Microbial Growth

Temperature: microorganisms have specific temperature ranges for growth.
Moisture: water availability is crucial for microbial growth.
pH: microorganisms exhibit varying pH preferences.
Oxygen availability: aerobic microorganisms require oxygen, while anaerobic species can thrive in oxygen-deprived environments.
Availability of nutrients: microorganisms require nutrients for growth.

The Hurdle Concept

A strategy used in food production and preservation, combining non-lethal levels of factors affecting microbial growth to inhibit or reduce microorganisms in foods.

Food Preservation Techniques

Heat treatment: cooking, pasteurization, and sterilization.
Refrigeration and freezing: lowering temperature reduces microbial growth.
Drying: removing moisture inhibits microbial growth.
Fermentation: encouraging beneficial microorganisms inhibits spoilage and enhances flavor and texture.