TOXICANTS in Food Chemistry II

Flashcards covering the classification, formation, and control of toxicants and contaminants in food chemistry, including naturally-occurring toxins, process-induced toxicants, adulterants, and the protective role of phenolic compounds.

What is the definition of toxicants in food science?

Substances that can cause harmful effects to a living organism, distinguished by whether they are naturally "built-in" or "triggered" by processing.

How are naturally-occurring toxicants defined?

Chemicals produced by plants, animals, or microorganisms as a natural defense mechanism (e.g., to ward off insects or fungi) that are inherent to the food material.

Which naturally-occurring toxicant is found in cassava and bamboo shoots and releases hydrogen cyanide?

Cyanogenic Glycosides.

What is Solanine and where is it found?

A glycoalkaloid found in green or sprouted potatoes.

Which naturally-occurring toxicant found in raw kidney beans requires thorough boiling to deactivate?

Lectins.

What are process-induced toxicants?

Toxicants not present in raw ingredients that form through chemical reactions during processing steps like heating, drying, or fermenting.

At what temperature threshold does acrylamide typically form via the Maillard reaction in starchy foods?

Above $120\,^{\circ}\text{C}$.

How are Polycyclic Aromatic Hydrocarbons (PAHs) formed during grilling or smoking?

Fat drips onto the heat source and the resulting smoke deposits toxins back onto the meat.

What occurs when oilseeds are heated excessively regarding their sterol content?

Healthy plant sterols can oxidize into harmful derivatives known as oxidized sterols.

How are food contaminants defined?

Unintended and undesirable substances not intentionally added that may enter food at any stage of the food chain.

What are the three common classifications of food contaminants?

1. Chemical contaminants, 2. Biological contaminants, 3. Physical contaminants.

What are some specific examples of chemical contaminants?

Heavy metals such as lead ($Pb$), mercury ($Hg$), and cadmium ($Cd$), and pesticide residues.

What are examples of biological contaminants and their metabolites?

Pathogenic bacteria such as Salmonella and Escherichia coli, and fungi that produce mycotoxins like aflatoxins.

What is the difference between acute and chronic toxicity?

Acute toxicity refers to immediate effects like food poisoning, while chronic toxicity refers to long-term effects like organ damage or cancer.

What are toxic residues?

Trace amounts of harmful substances that remain in food after production, processing, or environmental exposure.

What are adulterants in the context of food science?

Substances intentionally added to food to reduce quality and safety, usually for economic gain.

In the "thumb test" for honey, what indicates the product is fake?

The honey spreads or runs rather than staying in place.

How does the water test distinguish pure black pepper from papaya seeds?

Pure black pepper settles at the bottom of the glass, while papaya seeds float on the surface.

List the five specified factors that affect the activity of toxicants.

1. Dose (amount consumed), 2. Duration of exposure, 3. Individual Susceptibility, 4. Chemical Nature of the Toxicant, 5. Environmental and Processing Conditions.

Rank the hierarchy of control measures from most to least effective.

1. Elimination/Substitution, 2. Engineering Controls, 3. Administrative & Work Practice Controls, 4. Personal Protective Equipment (PPE).

How do catechins (flavonoids) from green tea control toxicants during high-heat cooking?

They act as "chemical interceptors" by donating hydrogen to stabilize reactive intermediates, blocking the formation of heterocyclic amines (HCAs).

Which phenolic acid found in coffee and whole grains acts as a "decoy" to inhibit acrylamide?

Ferulic Acid.

What is the role of lignans like sesamin during industrial frying?

They act as natural "bodyguards" that protect healthy phytosterols from oxygen attack and heat, preventing the formation of toxic products like MDA.