Fruit-based Terms

Heat damage has detrimental impacts on food and its nutrients when they are cooked or processed at temperatures above 46°C (115°F), which is enough heat to damage human skin as well as the heat-sensitive nutrients in food.

Cooking can result in the following health damaging issues:

• Carcinogenic or potentially carcinogenic compounds: High-temperature cooking can produce heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), particularly when meat is grilled, charred, or exposed to smoke.
• Acrylamide can form when carbohydrate-rich foods such as potatoes, bread, and cereals are heated at high temperatures, especially during frying, roasting, and baking.
• Advanced glycation end products (AGEs): High temperature Dry-heat cooking methods such as frying, grilling, and roasting tend to produce more AGEs than moist-heat cooking methods.
• Loss of nutrients: Heat can destroy or reduce some heat-sensitive nutrients including:
  • vitamin C
  • folate
  • some B vitamins
  • omega-3 fatty acids
  • carbohydrate
  • protein
  • fat
  The extent of the nutrient loss depends heavily on the food and cooking method.
• Oxidation of fats: High temperatures—particularly prolonged heating or repeatedly heating oil—can cause fats to oxidize and form various degradation products.
• Loss of beneficial compounds: Some antioxidants and phytochemicals can decrease with cooking.
• Formation of smoke/irritants: Burning food, fat, or cooking oil can produce irritating compounds and particulate matter that are undesirable to inhale.
• Formation of undesirable compounds from processed foods: Certain cooking conditions can promote formation of compounds such as nitrosamines, particularly in foods containing nitrites/nitrates.
• Production of health damaging substances including tumorigens, mutagens and antinutrients.

Factors that affect the degree of heat damage caused by cooking include:

• Temperature
  Higher temperatures generally increase thermal degradation and oxidation.
• Time
  Longer exposure generally increases degradation.
• Water exposure
  Increases leaching of water-soluble compounds.
• Oxygen exposure
  Promotes oxidation.
• Surface area
  Cutting food into smaller pieces increases the area exposed to heat, water and oxygen.
• Water-to-food ratio
  More cooking water can increase the opportunity for nutrient leaching.
• Oil/fat temperature
  Higher temperatures accelerate oxidation and thermal degradation of fats.
• Type of food
  Different nutrients have very different sensitivities to heat, water and oxygen.
• Type of nutrient
  When heated, vitamin C behaves very differently from minerals, protein, starch, etc.
• Degree of browning
  Increasingly intense browning indicates increasingly severe thermal reactions.
• Charring
  Represents particularly intense heating and should be distinguished from less strong browning.
• Repeated heating/reheating
  Can compound some degradation and oxidation processes.
• Whether cooking liquid is consumed
  Determines whether leached nutrients are also lost from the meal.
• Whether the food is subsequently cooled
  Particularly important for starch and resistant starch formation.