Midterm 1 Flashcards
Distinguish between the terms: food, nutrient, and nutraceutical
food- pshycological, social, culteral, economic and technological factors effecting food choice
nutrients- balance (ESSENTIAL)
nutraceuticals- not required (health promoting)
What are the differences between and the origins of hunger and appetite
hunger- physiological (low blood glucose)
appetite- psychological (response and desire to food), triggered by hunger
What do we mean by the term satiety in the context of food consumption, and why is it an important concept to study
feeling of being full (fats) which slow down rate of stomach emptying and fibres which increase stomach and SI content viscosity
important due to the rise in obesity
List the regions of the digestive tract and indicate their functions
1) mouth- produce bolus (saliva, amylase, enzymes)
2) stomach- chyme- destroy microorganisms, pepsin- breakdown large food molecules, churning and mixing
(none to little absorption)
3) small intestine- duodenum: releases pancreatic fluid and intestinal juices, jejunum: emulsifies fats by bile, breakdown fats, proteins, carbs; assimilation begins, Ileum- assimilation continues
4) large intestine: site of fermentation (colon- water reabsorption, mineral reabsorption and microbial fermentation, detox and protection) (rectum- water reabsorption and stool evacuated)
Why is digested food first acidified in the stomach and then neutralized in the small intestine?
digested food is acidified in stomach to destroy microorganisms and then neutralized in the small intestine so that enzymes can function
pepsin vs. trypsin
pepsin (peptic enzymes)- in stomach start to breakdown are food molecules
trypsin (proteases)- in duodenum of SI, enzyme induced breakdown occurs by hydrolysis
Why does a high fat meal leave a feeling of satiety longer than a high carbohydrate meal?
fats are digested slowly, carbs are digested quickly
role of liver
- secretes bile to SI to neutralize stomach acid
- accepts nutrients from hectic portal vein
- carb AAs metabolism
role of gall bladder
stores bile from liver
role of pancreas
secretes enzymes and bicarbonate ions to SI for neutralizing stomach acid and enzyme induced breakdown (hydrolysis)
- secretes insulin and other hormones for regulation in body with hormonal control
kidney
absorption and excretion
Lipids and sugars are absorbed differently by the body. Why?
lipids are fat soluble and sugars are water soluble
Describe the fate of lipids, sugars and amino acids after ingestion
lipids go to the lymphatic system which takes fat soluble compounds from GI tract through thoracic duct to bloodstream
sugars and AAs are taken by blood vessels to the liver
Why does a high protein meal put more load on the kidneys than a high fat meal?
because fats just get stored as body fat but proteins replace body protein and then they end up as nitrogen lost in urine and excreted by kidneys
When we discuss “optimal” nutrient intakes, what are we “optimizing” for? How difficult are each of these goals to achieve?
refers to optimizing to
- prevent deficiencies
- maintain healthy weights
- optimize health and delay degenerative disease
difficult to achieve due to difficulty determining biological requirements due to individual variations, lack of food consumption data, human studies restricted and expensive
How many servings of each of the four food groups in Canada’s Food Guide should YOU consume?
Adult (19-50) female veg. and fruits 7-8 grain products 6-7 milk and alternatives 2 meat and alternative 2
What are some of the main “eating right” messages of Health Canada?
- increase fruits & vegetables (especially fruits),
- increase fibre,
- eliminate trans fat,
- reduce saturated fats,
- reduce total fats,
- include a small amount of polyunsaturated fat,
- reduce simple sugars,
- increase calcium,
- reduce energy intake,
- drink water,
- include folic acid, iron (for mature women), vitamin D (over 50s)
- increase physical activity!
Why recommend to Canadians that they should choose a variety of foods from each food group each day?
- balanced diet
- helps maintain a healthy, well balanced, interesting diet that provides adequate nutrition
- can help prevent diseases
What is meant by the “metabolic syndrome”?
refers to combination of factors that greatly increased a persons risk of developing cardiovascular disease
What is the definition of EAR, RDA and AI? How are the numbers determined and by whom?
EAR- estimated average requirements: median required for specific age and gender groups
RDA- recommended dietary allowance: EAR and 2 standard deviations to cover 97-98% of population (specific to age and gender)
AL- adequate intake: when no EAR exists
Howis the % daily value on the Nutrition Facts table calculated?
%daily value= actual content in the food per serving/ reference daily intake
How is the energy content of a food serving, which is declared on a food label, calculated?
found by thermic effect of food avg physiological food values: carbs 16 MJ/kg protein 15 fat 37 ethanol 29 *multiply these values by the % of each and multiply by grams
What does (the abbreviation) BMR mean and what is it?
basal metabolic rate- 60- 70% or more of daily energy
- the use of energy to maintain body function at rest, most accounted for by organs and muscle
- increase with activity
- decrease when energy intake remains below needs for long
- increased during overconsumption (thermos genesis)
What does EER mean and what is it? What is your EER?
estimated energy requirement: 2 standard deviation rule not applied
What does BMI mean and what is it? How is it calculated? In terms of BMI, what is considered normal? Obese? What is your BMI?
Body Mass Index: weight/ height2
normal (18.5-24.9)
obese 1 (30.0-34.9)
Why are health professionals concerned about obesity?
due to the health risks associated:
diabetes, cardiovascular disease, hypertension, cancers, emotional, rest. probe, gall bladder disease
What are the definition and goals of food preservation?
matching the supply of food with demand in both time and space goals: safety (eliminate food hazards) adequate shelf life quality availability and variety convenience favorable economics
What role do microorganisms play in foods (good and bad)? Give two examples of each category.
good- cause spoilage agents , fermentation agents
bad- presence of pathogens
disease
In order to grow, microorganisms need several factors. What are they and why is this of significance to food preservation?
nutrients
moisture
favorable (temp, pH, O2)
absence of antimicrobial constituents
significant to food preservation to avoid these facts with storage
How can our food supply become contaminated with human pathogens? Give several examples.
cough/ sneeze
fingers or clothing
When we talk about foodborne illness, what is the difference between an incident and a case?
incident of food born illness- get sick after eating something
case- many people sick, food found to be bad
Why are large food manufacturers so concerned about microbial foodborne illness?
bc they can be sued, lose business
What is the difference between a food infection and a food intoxication? Which one would be easier to detect the cause of? Why?
infection- samonella (Raw milk, poultry); fever- several days, lower GI tract (flu)
intoxication- staphylococus (ham, poultry from worker with sore throat etc.)- nervous system (no fever), few hours
** due to manufacturer and harder to detect
What good manufacturing practices (GMP) can a food processor take to ensure freedom from pathogenic contamination with a food product?
- raw product and ingredient quality
- separate btw raw and processed
- adequate processing
- packaging
- sanitation/ hygeine
- proper storage and distribution conditions
What are the main components of a HACCP system?
hazard analysis critical control points
- conduct hazard analysis
- identify critical control points on flow diagram
- estimate critical limit for each ccp
- est. ccp monitoring procedures
- est. corrective actions if limits exceeded
- est. record keeping procedures
- est. verification protocals
What are the goals of thermal processing of food in general? What are the specific goals of each of blanching, pasteurization and sterilization?
food safety
preservation
sensory quality
enhanced nutritional quality
blanching- mild heat treatment for fruits and veg.
inactive enzymes prior to freezing
degas products before canning
wilt veg. to facilitate packaging before canning or freezing
pasteurization- moderate heat treatment of liquid products
- eliminate pathogenic bacteria
- reduce the #s of spoilage bacteria
commercial sterilization- destroy all miccroorganisms of commercial sign and produce a shelf stable product
canning: container
UHT/ asseptic processing and packaging: out of container, continuous
What is the primary difference between the processing of aseptic “drinking box” type products and canned products?
canning- in container
aseptic packaging- out of container
Why is Clostridium botulinum such a large concern to food canners?
fatal
- toxing former
- anearobic- grows and produces toxin
- spore former
- grows at pH>4.5
Why would a food canner need to blanch vegetable products before packaging, considering the thermal treatment they are about to receive?
to reduce microbial growth, degas, wilt so they can fit in container and inactivate enzymes that cause deterioration of foods during freezing
Typically, it is much more difficult to can vegetables than fruits. Why?
vegetable are low acid foods and need to be processed in a pressure canner to reach 240C to prevent botulism
botulism doesn’t grow in presence of acid therefore fruits can be processed in boiling water canner
What effects do relative humidity and air velocity have on the moisture content of refrigerated foods when stored in bulk cold storage facilities?
refrigerated foods can lose moisture inside cool environment due to water migration from food to very dry air
cause losses in quality and weight
What types of products would each of the following freezing processes be used for and how does each work: a fluidized-bed freezer, a plate freezer, a scraped-surface freezer.
- fluidized bed freezer- individually quick frozen (IQF) peas, corn * moist products in, dry air in and moisture air out
- plate freezer- flat products (fish or pastries) food firmly pressed btw metal plates that are cooled to submerse temp
- scraped surface freezer- icecream- food frozen onto surface, rotator scraps frozen portion off walls
Why do many frozen foods need to be blanched prior to freezing? Explain in the context of frozen food structure.
blanching stops action of enzymes that cause deterioration of foods while freezing therefore blanch before freezing (enzymes occur to help veg. grow and ripen)
Why should frozen foods be a) frozen rapidly and b) stored at low, constant temperatures?
a) bc factor below danger zone, less spoilage
b) reduce fluctuation for quality and safety of food
Frozen foods are generally considered to be stable, but that is not always the case. What are some of the reasons why frozen foods can deteriorate in quality?
- due to not being processed right away
- water content
- humidity, loss of moisture
- fluctuation in temp
Why is the evaporation of liquid foods done under a vacuum? What is a well-known Canadian exception and why is it not processed under vacuum?
evaporation is done under vacuum to draw water vapour off which cools product
Explain the process of spray drying.
pray liquid foods as fine droplets into warm chamber
the water flashes off and a dry powder remains as small spheres
Freeze-drying produces a high-quality porous product that rehydrates easily. Why is it porous? How does freeze-drying work?
after product is frozen, apply vacuum- water is removed by sublimation (leaves pores) most expensive method
The human body is about 60% water – where is it found?
in extracellular (blood, lymph, digest, inter intestinal fluid) and intracellular- inside cells (muscles, adipose)
What is meant by obligatory water loss?
amount needed to dilute the solutes from diet
What structural role does water play in foods?
key to food structure
-appearance, texture, perishability, taste
What is “water activity” and why is it important? What food components have the most effect at Aw lowering?
Aw- water available for microbial growth
- more predictive of shelf life
- measured as vapour pressure or relative around food product that is enclosed
lower Aw, more stable
If two foods of differing water contents are placed together, as in a multi-component food, what will be the result?
causes sway dry food (icecream cone)
EAR?
-estimated average requirements:
intake levels of nutrients estimated to meet needs of half the healthy individuals in a particular group
-used to asses the adequacy of a populations food supply
-used as basis to calculate RDAs for individuals
RDA?
-recommended dietary allowance:
intake levels of nutrients that meet needs of nearly all healthy individuals of particular group
-used by schools or hospitals to create nutritious meals
AIs
the approximate of needed nutrient intakes when no RDA’s exist
-used as target amount for a certain nutrient to help plan healthy diet
ULs
tolerable upper intake level:
highest level for nutrients that nearly all healthy individuals in particular group can reach without adverse effects
-used to avoid toxicity
(what most bodies can tolerate)
Blood Pressure regulation
low BP
kidney secretes renin and angiotensin secretes angiotensin II
- this causes constriction of the blood vessels which in creases BP
and
-angiotensin II causes the adrenal gland to secrete aldosterone to the kidneys
-which causes increase in Na+ reabsorption which increases the water retention and increases the BP
Blood volume regulation
1) not enough H2O therefore BV is low and solute concentration in blood increases
2) in response, the pituitary gland secretes vasopressin (ADH anidiretic hormone)
3) ADH signals kidneys to increase amount of water reabsorbed into the blood
4) therefore less water lost in urine and blood volume increases
how body fluids circulate around cells
- fluid filters out of blood through capillary whose walls are made of cells with small spaces btw them
-fluid may flow back into capillary or into lymph vessel
-lymph enters bloodstream later through large lymphatic vessel that empties into a large vein
(blood and lymph deliver nutrients and carry waste away)
Blood Pressure in an artery
blood pressure pumping from heart forces the fluid across the wall at the start of the capillary (small molecules, oxygen, glucose, amino acids and salt move out with water)
-fluid forced into tissues
blood proteins and cells remaining are becoming more concentrated. BP decreasing
blood is now so concentrated that it attracts fluid back into the capillary (osmotic pressure). small molecules (waste products) accompany the fluid
high salt or high protein consumption increases urine output
salt attracts water to regulate blood volume and the urines function is to regulate sodium levels therefore too much water increases urine production
protein end up as nitrogen in kidneys which increase excretion
Incident vs case
An incident is an outbreak - a mistake somewhere in the system that allowed a food to become contaminated with a pathogen.
The cases during that incident are the number of people who got sick from that mistake.
Our concern with today’s modern food processing and distribution is that the number of incidents may be very low, but one incident can lead to thousands of cases of illnesses
