science of food exam 2

healthy eating

• adequacy

• balance

• variety

• moderation

adequacy & balance

• diet provides all the essential nutrients, fiber, and energy

• diet provide all the correct proportions of nutrients

variety

• diet contains a mixture of different food groups and foods within each group

moderation

• diet provides reasonable but not excessive amounts of foods and nutrients

• be aware of portion size and number of servings

malnutrition

• consuming either too much or too little of one or more nutrients or energy will result in this

• undernutrition and overnutrition are both deemed this

2 conditions of malnutrition that affect children

• kwashiorkor

• maramus

kwashiorkor

• severe protein deficiency

• usually occurs after weaning

• edema (swelling) due to low blood proteins

• protein deficiency predominates

maramus

• severe deficiency of calories + protein

• often occurs in infants/young children

• severe wasting and very low body weight

• overall energy deficiency predominates

eating disorders

• anorexia nervosa

• bulimia

• orthorexia

anorexia nervosa

• severe restriction of food intake

• intense fear of gaining weight

• very low body weight may occur

• restricts calories and may avoid certain foodss

• extreme weight loss

• key feature: restriction

bulimia

• binge eating followed by compensatory behaviors

• concern about body weight/shape

• body weight is often normal or near normal

• recurrent episodes of eating unusually large amounts of food

• weight may fluctuate

• key feature: binge + compensation

orthorexia

• obsessive behavior in pursuit of a healthy diet

both excesses and deficiencies in diet can cause illnesses

• high-calories, low-nutrient foods can lead to obesity, heart disease, and type 2 diabetes

• lack of essential nutrients (vitamins, minerals, proteins) can weaken the immune system and increase infection risk

CDC (centers for disease control and prevention)

• collects and analyzes health data, including nutrition and chronic diseases

• monitors health conditions, dietary habits, and nutritional status

• collaborates with other agencies

5 major lifestyle risk factors leading to chronic diseases

• poor nutrition —> lack of essential nutrients can weaken the immune system and increase vulnerability to various diseases

• physical inactivity

• tobacco use

• excessive alcohol consumption

• high stress levels

major risk factor for chronic diseases

• obesity (not considered a disease by itself)

reason for obesity in developing/poor countries

• complex interaction —> population growth impacts

nutrition transition

• overconsumption of high-energy foods

• adoption of the western lifestyle

visceral fat

• belly fat is often subcutaneous, but even fit-looking people can have this harmful stuff

• it is linked to metabolic disease and insulin resistance

• increases risk of death, even for people with a normal BMI

• more dangerous than subcutaneous fat

fat cells (adipocytes)

• actively participate in the immune response

• in obesity, they can become dysfunctional and release pro-inflammatory substances

• effects of weight loss: reverses inflammation

how does the inflammatory response occur in obesity in the first place?

• when something harmful, like germs or injury, enters the body, it sets off a warning system called inflammation

• this system is like and alarm that tells the body to defend itself

cardiovascular diseases/coronary heart disease

• atherosclerosis —> “hardening of the arteries”

• fatty deposits (plaques) of cholesterol build up the inner linings of the heart’s arteries

blood/serum cholestorol

• circulates in the blood

dietary cholesterol

• only in animal products

diabetes

• top reasons for kidney failure

• leads to more cases of adult blindness and amputations of the lower limbs

HDL (high-density lipoproteins)

• the good cholesterol

• connected to a decreased risk of heart diseases

LDL (low-density lipoproteins)

• the bad cholesterol

• connected to an increased risk of heart disease

common misconceptions

• using margarine instead of butter will help lower my cholesterol

• thin people don’t have to worry about high cholesterol

• if a label lists no cholesterol, it’s a “heart-healthy” choice

• eggs - good or bad?

• women don’t need to worry about cholesterol

• only middle-ages people should have their cholesterol checked

food choices linked to pain

• 70% of immune cells reside in the digestive system

• immune system interacts directly with consumed food

• triggers for immune response: bacteria, allergens, hormonal imbalances

• result: inflammation signal

• supplements are not regulated by the FDA for safety and effectiveness

superfood

• refers to foods with perceived health benefits

• ex: blueberries, broccoli, raspberries, green tea

• claims: precents or cures diseases like cancer

• reality: it is a label primarily for a marketing tactic

• scientific basis for claims is lacking

• emphasis on balanced diet for disease risk reduction

microogranisms

• major food-associated groups include bacteria, yeasts, and molds

• pathogenic: viruses and parasites can also cause food borne illness

• beneficial: fermentation, flavor development, preservation, probiotics

temperature & bacterial growth

• refrigeration slows growth of many organisms

• freezing generally stops growth, but does not reliably kill all microorganisms

pH and microbial growth

• acidic foods generally provide less favorable conditions for many bacteria

water activity

• drying, salting, and adding sugar can reduce available water

• ex: dried fruit, jerky, jams

beneficial bacteria: lactic acid bacteria

• converts sugars into lactic acid

• lactic acid is the main end product in dairy fermentation

fermented vegetables

• fermentation produces acids and characteristic flavors

why ferment foods?

• to preserve vegetables and fruits

• to develop characteristic sensory properties (flavor, aroma, texture)

• to destroy naturally occuing toxins and undesirable components in raw materials

• to improve digestibility, especially of some legumes

• to enrich products with desired microbial metabolites

• to create new products for new markets

• to increase dietary value

yeasts in foods

• tolerate acidic environments

baker’s yeast

• ferments sugars and produces carbon dioxide

• carbon dioxide becomes trapped in dough

• gas production helps bread rise

yeast in beer and wine

• yeasts convert sugars into ethanol and carbon dioxide

yeast in other foods

• sourdough is made using a community of yeasts and lactic acid bacteria (LAB)

• yeasts ferment sugars in the flour and produce carbon dioxide

• lactic acid bacteria ferment sugars and produce lactic acid and other organic acids

yeast spoilage

• refrigeration can slow growth but may not eliminate it

yeasts in fruit juices

• are acidic and contain fermentable sugars

• certain yeasts can grow despite low pH

molds in foods

• many produce visible colonies on food

mold in cheese

• controlled cultures are used rather than uncontrolled mold growth

mold on fruits and vegetables

• proper storage and handling slow spoilage

mycotoxins

• some molds can produce toxic secondary metabolites called these

• a food safety-concern rather than an ordinary visible spoilage

• ex: aflatoxin —> peanuts, corn, tree nuts

kimchi

• lactic acid bacteria drive fermentation

sauerkraut

• lactic acid bacteria

pickles

• can be produced by fermentation or by acidification with vinegar

miso

• uses molds, yeasts, and bacteria during fermentation

what is food spoilage?

• does not automatically mean the food is dangerous

• pathogens may be present without obvious spoilage

milk spoilage

• pasteurization reduces many microorganisms but does not prevent all post-processing contamination

fish odor

• generally a sign of loss of freshness and spoliage, but odor alone cannot reliably determine whether this food is safe to eat, because some pathogens may be present without producing and obvious odor

food infection

• living microogranisms are consumed and cause this

food intoxication

• toxin is already present in the food

toxin-mediated infection

• organism is consumed and produces toxin in the intestine

salmonella

• poultry, eggs, meat, produce

campylobacter

• commonly associated with poultry

• raw poultry juices can spread contamination

pathogenic E. coli

• undercooked ground beef, leafy greens, and other contaminated foods

E. coli and ground beef

• grinding distributes surface contamination throughout the meat

• ground beef therefore required thorough cooking

listeria monoctogenes

• can survive and grow at refrigeration temperatures

• important concern in ready-to-eat refrigerated foods

staphylococcus aureus

• can be transferred to foods by food handlers

clostridium botulinum

• produces botulinum neurotoxin under stable conditions

bacillus cereus

• spore-forming bacterium

vibrio

• associated especially with raw or undercooked seafood

norovirus

• virus that causes acute gastroenteritis

viruses

• can survive in foods, but do not grow in foods

the danger zone

• foods should be held below 40F OR above 140F

FATTOM: conditions that promote bacteria growth

• food

• acidity

• time

• temperature

• oxygen

• moisture

FATTOM

• food - nutrients needed for growth

FATTOM

• acidity - most bacteria prefer low-acid foods

FATTOM

• time - allows more microbial growth

FATTOM

• temperature - many pathogens grow rapidly at moderate temperatures

FATTOM

• oxygen - some microbes require oxygen; others do not

FATTOM

• moisture - microorganisms need available water

______ consume a limited number of foods

• specialists

________ consumer a variety of foods

• generalists (omnivores)

food industry application - why sensory evalutations?

• supports decisions about food products and consumers

• new food product development

• “new” and “improved” products

• consumer testing

influences on food choices

• emotions and psychology

• culture and geography

• food costs

• health concerns

• beliefs

• technology

flavor

• a quality of food involving sensory characteristics such as appearance, taste, odor, feel, and sound

• salty, bitter, sweet, sour, and savory (umami) can be recognized without smell

• more complex ones require both taste and smell sensations

• mouthfeel, sound, and consistency collectively contribute to texture

sensory evaluation

• a scientific discipline used to evoke, measure, analyze, and interpret those responses to products that are perceived by the senses of sight, smell, touch, taste, and hearing

• much of what people describe as “taste” is actually influenced by smell

• the tongue detects basic tastes, but much of what you identify as the flavor of a food comes from you sense of smell

• ex: coffee — tongue detects bitterness, nose detects roasted and aromatic compounds, brain combines both signals —> coffee flavor

taste transduction

• how a chemical in food is converted into a signal that the nervous system can understand

tongue structures

• papillae are raised structures that give the tongue its rough surface

taste buds

• located in all papillae except filiform papillae

PROPR and difference in taste sensitivity

• mildly sensitive tasters —> weak to undetectable sensation

• moderately sensitive tasters —> moderate to strong sensation

• high sensitive taste —> very strong sensation

cooling from menthol or mint, and heat from cinnamon or clove, are responses involving …

• the trigeminal nerve rather than taste

allicin

• a compound associated with the aroma of chopped garlic

• mechanically damaging garlic activates enzymes and produces sulfur-containing volatile compounds associated with garlic breath

high fructose corn syrup

• 55% fructose, 45% glucose

• compared with glucose, it is more readily metabolized in the liver and can promote fat synthesis under certain conditions

fructose

• eating this does not automatically cause weight gain - overall calorie intake, food form, portion size, physical activity, and dietary pattern matter

• once digested and absorbed, this from sugar is no different from HFCS

• eliminating HFCS will help fight obesity and health problems, only if it is not replaced with other sugar compounds

sucrose - table sugar

• has about ½ fructose and ½ glucose; pretty similar to HFCS

artificial sweetners

• “non-nutritive sweeteners”

• high-intensity sweeteners

people choose to use high-intensity sweeteners - why?

• they do not contribute calories or only contribute a few calories to the diet

• generally will not raise blood sugar levels

are high-intensity sweeteners safe to eat?

• approved by the FDA that they are safe for the general population under certain conditions of use

are there other sugar substitutes that are not high-intensity sweetners?

• yes, sugar alcohols (sugar substitutes)

  • used to sweeten sugar-free candies, cookies, and chewing gums

trans fats: what were they thinking?

• the idea: partial hydrogenation was used to make oils more solid and shelf-stable

• the benefit: improved texture, stability, and shelf life of foods

• the unintended consequence: partial hydrogenation produced trans fatty acids

who gets food allergies?

• children

  • milk, egg, peanuts, wheat, soy, tree nuts

  • most will outgrow them milk, egg, wheat and soy

food intolerance

• true allergy - avoid food (immune system)

• intolerance - a small amount is okay (digestive system)

proteins & food allergies

• when a protein from a food is absorbed without being completely digested, this is triggered

proteins & food intolerance

• also called food sensitivities

• no involvement of the immune system

• reaction to consuming MSG (monosodium glutamate)