Food Chemistry Flashcards
What compund in chocolate stimulates the central nervous system and also makes dogs sick?
theobromine
What chemical hormone do fruits release upon ripening?
ethylene
Chlorophyll molecule reacting with hydrogen exhibits what shade of green?
olive green
What two common compounds are used together as an antioxidative system?
Ascorbic Acid and Citric Acid
What is the name of the final degradation compound of chlorophyll?
Pheophorbide
What is an isomer that is cheaper than Vitamin C?
Erythorbic Acid
What is the enzyme responsible for browning in apples and lettuce?
Polyphenol Oxidase
What are the acids present in fish oil?
Arachidonic Acid, DHA, and EPA
What is surimi?
A concentrate of microfibrillar proteins of fish muscle.
What is Carboxyl-methyl cellulose often used for?
Thickener in foods (and stabilizer)
Does Kosmotrope ion discourage water structure?
No (they cause water molecules to favorably interact)
What is the main class of color compounds found in raspberries?
Anthocyanins
What is the major color compound in tomatoes?
Lycopene
What is the structural difference between chlorophyll and chlorophyllide?
Chlocophyllide does not have a phytol tail
What happens to chlorophyll on heating?
Pheophytin forms
Alar is the trade name for what chemical compound?
Daminozide
How many polypeptide chains make up an antibody?
Four
What is the winterization process for an oil?
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
What is the structural difference between chlorophyll and pheophytin?
Pheophytin does not have magnesium in porphyrin ring.
Peptide bond formation results in the formation of what secondary compound?
water
What metabolic end product does the Voges-Proskauer test detect?
Acetoin in a baceterial broth culture
Will lipid oxidation be higher at a water activity of .05 or .5?
0.05
How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
What are the three stages of oxidative rancidity?
Initiation, Propagation, and Termination
What ketohexose is most significant to food chemists?
Fructose
How many carbon atoms are there in the fatty acid myristic acid?
14
What is the Peroxide Value a measure of?
Fat Oxidation
Waxes are composed of what two basic chemical entities?
Fatty Acid (Ester linked) to Fatty Alcohol
Name three effects of protein denaturation.
Decreased solubility, altered water-binding capacity, loss of biological activity, increased susceptibility to attack by proteases, increased intrinsic viscosity, inability to crystallize.
Name 3 physical agents capable of denaturing proteins.
Temperature Changes, Mechanical Actions, Change in pH, Irradiation, Sound Waves, and Exposure to Mineral Salt and Metals
Name two main gluten proteins.
Gliadins and Glutenins
How do sodium chloride and sucrose affect foam stability?
Sodium chloride reduces foam stability and sucrose improves foam stability.
Name three factors useful in controlling enzyme activity.
Temperature, Water Content and Activity, Extremes of pH, Chemicals, Alterations of Substrates, Alterations of Products, Preprocessing Controls
Name 3 chemical agents capable of denaturing proteins.
Acids, Alkalis, Metals, Organic Solvents, and Aqueous Solutions of Organic Solvents
Name 5 proteins with good foaming properties.
Egg white proteins, the globin part of hemoglobin, bovine serum albumin, gelatin, whey proteins, casein micelles, B-casein, wheat proteins, soy proteins, and some protein hydrolyzates.
Name 3 reasons it is advantageous to obtain enzymes from microorganisms.
Microorganisms are very versatile, MO’s can be altered by mutations or genetic engineering to produce a greater quantity of enzyme or different enzymes, recovery of enzymes is often easy, readily available, high rate of growth and enzyme production.
What effect would the addition of sodium bicarbonate have to chocolate?
Smoother, less acid and less bitter chocolate flavor, darker color, and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Name 5 chelating agents used in the food industry.
EDTA, citric acid, malic acid, tartaric acid, oxalic acid, succinic acid, adenosine triphosphate, pyrophosphate, porphyrins, and proteins.
Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
Lipase, lipoxygenase, catalase, chlorophylase, peroxidase, pectinase, protease, ascorbic acid oxidase, alkaline phosphotase.
A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bright green
Name one way foam stability can be assessed.
The degree of liquid drainage or foam collapse (foam reduction) after a given time, the time for total or half-drainage (or half-reduction in volume), or the time before drainage starts.
Name 4 advantages of using enzymes in food processing.
They are natural, nontoxic substances, generally catalyze without unwanted side-effects, active under very mild conditions of temperature and pH, active at low concentrations, rate of reaction can be controlled, can be inactivated after reaction.
S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds in what foodstuff?
Onions ( or leeks)
What kinds of food emulsions are?
(1) Butter
(2) Mayonnaise
(3) Milk
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
What is the fundamental driving of electrophoresis?
The speed of a molecule is proportional to the surrounding voltage gradient.
How can a molecular weight of protein, DNA, and RNA be determined?
For proteins: SDA-PAGE.
For DNA & RNA: Agarose gel.
How does HPLC differ from FPLC?
HPLC has higher pressure than FPLC
What are two common reducing agents that break disulfide bonds in proteins?
2-mercaptoethanol (2-ME), dithiothreitol (DDT)
In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
They act as catalysts, speeding the polymerization of acrylamide.
What does the acronym NPN stand for?
Non-protein nitrogen
Name three nonpolar polar, and charged amino acids.
Nonpolar: (Valine, Alanine, Leucine, Isoleucine, Proline, Tryptophan) Polar: (Glycine, Serine, Cystein, Threonine, Tyrosine) Charged: (Lysine, Arginine, Histidine, Aspartic Acid, Glutamic Acid)
What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
plasmids
In genetics what is conjugation?
DNA transferred by cell to cell contact (bacterial sex).
Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl, distilled water, or 1M solution of sucrose?
NaCl (it dissociated to a 2M solution)
What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Phenylketonuria
What does MSG stand for?
Monosodium Glutamate
What happens to a bottle of wine if before you bottle it you forget to put the stuff in it that prevents it from fermenting?
It explodes
If you take 20 ml of .1 M NaOH to titrate 40 mL of an HCL solution to the penolphthalein end point what is the molarity of the HCL solution?
.05 M HCL
What does the “c” stand for in the equation E=mc2?
Speed of Light
20 grams of amylose is added to 80 grams of water in a beaker; the boiling point is measured with an ordinary mercury-in-glass thermometer. What is the observed boiling point of the material in the beaker?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
If oxygen attacks an unsaturated fatty acids at the double bond what is the resultant product?
Two aldehydes
In the enzyme Taq Polymerase what does Taq stand for?
Thermus Aqauticus
What are the primary secondary, tertiary, and quaternary structures?
Primary-amino acid sequence. Secondary-alpha-helix, beta sheet. Tertiary-one complete protein chain with cross bonds linking it together. Quaternary-four separate protein chains assembled as one.
Define molarity, molality, and normality.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
How is pH defined?
Negative log of the hydrogen concentration (mol/l).
What charge will a protein have when the pH of its solution is below, at, and above its pKa?
pH below positive charge; pH at no charge; pH above negative charge
What does the saponification value measure and how is it measured?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
What does Acid Degree Value measure and how is it measured?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Water
A) Is the major component of most foods.
B) Controls shelf-life or storage capability
C) Regulates chemical and microbiological reactions
D) All of the above
D) All of the above
Which of the following foods contain the lowest content of water? A) Fresh Carrots B) Fresh Tomatoes C) Whole Milk D) Fresh Celery
C) Whole Milk
Which of these food additives could be used to prevent cocoa particles from settling in chocolate milk? A) BHA (butylated hydroxyanisole B) Carrageenan C) Thiamine Hydrochloride D) Citric Acid
B) Carrageenan
Which of the following examples of browning is enzymatic in nature? 1. Browning of sugars as a result of heating 2. Browning of freshly cut surfaces of fruits and vegetables 3. Browning of bread during toasting 4. Browning of potato chips
Browning of freshly cut surfaces of fruits and vegetables.
What would be a safe processing time for heat processing green beans in a boiling water bath? A. 30 minutes B. 300 minutes C. Depends on the size of the food container D. None of the above
D: None of the above
Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
A: Orange Juice
To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Bitter
At what pH is benzoic acid most effective?
pH 3-5
What is acid proteolysis?
Degradation of protein and production of acid from sugar at the same time.
What is catalase?
An enzyme that converts hydrogen peroxide to water plus oxygen.
What reaction does the enzyme “reverse transcriptase” catalyze?
RNA transcribed to DNA
What pigment was first designated as anthocyanins?
Blue pigment in flowers
What is the chemical nature of anthocyanins?
Glycosides of anthocyanidins
Name a naturally occurring protein sweetener.
Thaumautin
What is the chemical nomenclature for caffeine?
1, 3, 7-trimethylxanthine
Name three non-nutritive sweeteners approved for use in USA?
Acsulfame-K, Saccharin, Succralose, Aspartame
Which two amino acids is the aspartame derived from?
Aspartic Acid and Phenylalanine
Are sorbitol and mannitol sweet?
yes
What are the fructose contents in commercial HFCS products.
45%, 52%, 90%
What are the limiting amino acids in corn, potato, and green peas?
Corn- Lysine, Potato-Methionine, Green Peas-Methionine
Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Tryptophan
Give one word for a carbon atom involved in hemiacetal or acetal formation.
Anomeric
What degradative enzyme causes browning in apples, pears, bananas, and peaches?
Polyphenoloxidase
Name the two components that comprise the relaxing factor in muscle fibers.
Troponins and Tropomyosin
An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Oil in Water
What is the protein efficiency ratio (PER) of casein?
2.5
What two enzymes degrade pectic substances?
Pectin methylesterase & polygalacturonase
Match the number of carbon atoms with the common name of these saturated fatty acids. Carbon #: 4:0 10:0, 12:0,14:0, 16:0, 18:0Common Name: Myristic, Butyric, Capric, Lauric, Stearic, Palmitic
4:0 (Butyric), 10:0 (Capric), 12:0 (Lauric), 14:0 (Myristic),16:0 (Palmitic), 18:0 (Stearic)
What is a polymorphism?
Solid phases of the same chemical composition that differ by crystalline structure, but yield identical liquid phases upon melting.
Name 3 factors influencing the consistency of commercial fats.
Proportion of solids in the fat, number, size, and kinds of crystals, viscosity of the liquid, temperature treatment, and mechanical working.
What does HLB stand for and what does a high and low HLB value indicate?
HLB (hydrophilic-lipophilic balance); a low value (3-6) promotes water in oil emulsions and a high value (8-18) promotes oil in water emulsions.
Name 3 factors influencing the rate of lipid oxidation in foods.
Fatty acid composition, free fatty acids versus the corresponding glycerols, oxygen concentration, temperature, surface area, moisture, pro-oxidants, antioxidants
Name two reasons why fats are hydrogenated.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Name three compounds capable of poisoning the catalyst during commercial hydrogenation.
Phospholipids, water, sulfur compounds, soaps, partial glycerol esters, carbon dioxide, and mineral acids.
Name the three positively charged amino acids.
Lysine, Arginine, and Histidine
If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Blue/purple
What enzyme is most responsible for browning bananas?
Polyphenol Oxidase
During freezing what are the two stages in the crystallization process?
Nucleation or crystal formation and crystal growth.
In what food is butyric acid typically found?
milk
What is the name given to a mixture of equal parts of Darel Lisomers?
racemix mixtures
What enzyme causes hyrolytic rancidity in milk?
lipase
Name two enzymes that are involved in softening fruits.
Pectin Esterase, Polygalacturonase, Pectin Layase
Name the strongest biochemical bond and the weakest biochemical bond.
Covalent (strongest) and Hydrophobic (Weakest)
What is the enzyme that softens tomatoes?
Pectin Esterase
Name a commonly used household chemical leavening agent and the gas it generates.
Sodium bicarbonate generates CO2
Name two non-enzymatic browning reactions.
Carmelization and Maillard
What are the three main steps in the autooxidation of lipids?
Initiation, Propagation, Termination
What are the only phenols approved for use in the microbiological preservation of foods?
Parabens
What is the common name for 9 12, cis-cis-octa dienoic acid?
Linoleic Acid
What are 3 mesomorphic structures associated with lipids in the liquid state?
Lamellar; Hexagonal I, II; Cubic
What are proteins which are soluble in 50-80% ethanol known as?
Prolamines
What are colloids that are stabilized by a layer of solvation called?
Emulsoids
What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
What is the geometric configuration of double bonds in most natural fatty acids?
cis
The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
Pectin methyl esterase or galacturonase
What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
Osmosis
What is the name of the structural carbohydrate found in lobsters crab, shellfish, and insects?
Chitin
What chemical compound is responsible for the “hot” principle of jalepeno peppers?
Capsaicin
When heated ammonium bicarbonate decomposes to form what end products?
Ammonia, Water, Carbon Dioxide
What two types of compounds are joined with an ester bond to make a wax?
Fatty Acid and Alcohol
What compounds oxidize to form brown color in fruits and vegetables?
Polyphenols
What toxic pigment is found in cottonseed endosperm?
Gossypol (it is removed during the oil refining process)
What are the four basic flavors perceived by the tongue?
Sweet, Salty, Sour, and Bitter
What is BHA’s full name and purpose?
Butylated hydroxylated anisole, antioxidant
What is the full name of EDTA?
Ethylenediaminetetraacetic acid
What is the full name of EGCG?
Epigallo catechin galate.
HFCS sweetness increases as you increase DE?
No, DE refers to reducing power compared to dextrose, since fructose is not reducing and sweeter than glucose (which is reducing), less DE means sweeter.
What it the morphology of how polymers can be classified?
Linear and branched
Absence of what amino acid causes black spots in shrimp or lobster?
Tyrosine
What is the difference of homopolymers and copolymers?
A homopolymer is synthesized using a single type of monomer; a copolymer is synthesized using more than one species of monomer.
The more branches a polysaccharide has, the more non-reducing ends it has.
FALSE
What is the reaction of acid-catalyzed combination of two monosaccharide molecules?
Reversion
When hydrated, a linear polymer has higher viscosity than a branched polymer (linear polymer and branched polymer have the same MW)
true
what are the types of intermolecular forces can be formed in colloids?
ion-dipole; ion-ion, dipole-dipole, covalent bond
Mg is more effective than Li in causing salting out phenomenon in hydrocolloids.
true
What two components are required for a buffer?
Mixtures of weak acid and conjugate salt
What is the Isoelectric Point?
The pH where the sum of charges (+ and -)is equal to 0 for an amino acid/protein
Why do you not want the pH of frankfurters to be at an isoelectric point of myosin?
the product will not be able to bind water and you cannot form a gel, etc.
What are three forms of water in foods?
Free Water,Adsorbed Water (loosely bound), and water of hydration (tightly bound)
When does buffering occur in foods?
When a weak acid and a salt (its conjugate base) are present in the same food
When does the maximum buffering capacity occur in a food product?
At the pKa, the point where equal amounts of the undissociated acid and weak base (salt) exist in the food matrix
What are myosin and actin?
the major contractile proteins in muscle (accounts for ~65% of contractile proteins)
Name 3 items that effect water activity in a food product.
solute concentration,moisture concentration, &temperature
What is an emulsion?
A system containing 2 immiscible liquids
Are frankfurters an emulsion?
Not a true emulsion because they have more than 2 components in them. However, they do have lipid separated from water by myofibrillar proteins
What term does the acronym PSE abbreviate?
Pale, Soft, and Exudative
What is the predominant meat source that PSE occurs in?
Pork (and one could argue for turkey)
What meat protein is primarily responsible for color in meat products?
myoglobin
Why are caseinates good functional ingredients in a number of processed food products that have both water and fat?
caseinates have amphiphilic structure; this means that these protein derivatives both have regions that are hydrophobic and hydrophilic
what are the minimum reactant requirements for maillard browning?
amino-bearing compound (usually a protein) a reducing sugar water
someone has suggested that you use sucrose in your confectionary product where Maillard browning is desireable, will this cause a problem?
yes, because sucrose is a non-reducing sugar
why is sucrose added to dough when making bread?
it increases viscosity & increases foam stability
does volume increase or decrease when a solid goes to a liquid?
increases
does volume increase or decrease when a liquid goes to a gas?
increases
why is titratable acidity an important measurement in food products?
it predicts the acid’s impact on flavor in a food product
is a pectin a CHO, a Protein, or a fat?
Carbohydrate
what is pectin utilized for in food chemistry/food processing?
stability of jams, jellies, fruit juices, tomato sauces, etc.
What is the polysaccharide that is the main storage form of carbohydrate, largely stored in the liver, with lesser amounts in muscle tissue?
Glycogen
What are the nitrogen-bearing compounds that form the structural units of protein?
amino acids
what is the botanical term for certain plants belonging to the mustard family, such as broccoli and cauliflower, so-called because of the cross-like leaf markings?
Cruciferous/Brassica
what are the various complex proteins produced by living cells that act independently of these cells. They are capable of producing certain chemical changes in other substances w/o themselves being changed in the process?
enzymes
The process by which a chemical compound is split into other simpler compounds by the elements of water, as in manufacture of infant formulas, to produce easier-to-digest derivatives of the main protein (casein) on the cow’s milk base…
Hydrolysis
Compounds that consist of one molecule of fatty acid esterified to glycerol are called?
monoglycerides
what types of acids are found in apples, grapes, oranges, and lemons?
apples have malic acid, grapes have tartaric acid, oranges & lemons have citric acid
What are the main natural antioxidants found in foods?
lecithin, vitamins C and E, certain sulfur-containing amino acids
what pigment imparts green color to lettuce and peas?
chlorophyll
Plants that contain no vitamin A but contain its precursor called what?
Beta Carotene
what pigment gives the orange color to carrots and corn?
carotene
What B vitamin’s main responsibility is in the utilization of CHO to supply energy, where it functions as the coenzyme thiamine pyrophosphate, or cocarboxylase, in glucose oxidation?
Thiamin
what pigment contributes to the red color of tomatoes and watermelons?
lycopene
what pigment contributes to the purple color grapes and blueberries?
anthocyanins
True/False: Riboflavin is quite resistant to heat but very sensitive to light and this is why brown milk bottles have seen limited use in the past
TRUE
what pigment gives the red color to meats?
oxymyoglobin
True/False: a complete protein is one that contains all of the essential amino acids in amounts and proportions to maintain life and support growth when used as the sole source of protein
TRUE
(___)proteins are generally not as high in biological values as animal proteins because of amino acid limitations
Plant proteins
what type of proteins can be supplemented w/ the missing essential amino acids either in the form of synthetic compounds or as protein concentrates from natural sources?
Incomplete proteins
What are the organic chemicals, other than essential amino acids and fatty acids, that must be supplied to an animal in small amounts to maintain health?
Vitamins
what is the only major vitamin the human body that is known to be capable of manufacturing but may not be synthesized in adequate amounts?
Vitamin D
True/False: Vitamins function in enzyme systems, which facilitate the metabolism of proteins, Carbohydrates, & fats
true
Vitamins B and C’s absorption by the body depends on the normal absorption of fat from the diet.
false
What vitamin naturally occurs only in animal materials such as meat, milk, eggs?
Vitamin A
True/False: Thiamin is not stable to heat in acid foods, but less so in neutral and alkaline foods.
False, thiamin is heat stable
What causes the yellow-green pigment of skim milk and whey?
Riboflavin
True/False: riboflavin functions in the oxidative processes of living cells and is essential for cellular growth and tissue maintenance.
TRUE
What are good sources of riboflavin?
liver,Eggs,& Milk
A deficiency of what vitamin adversely affects tissue respiration and oxidation of glucose and results in the disease known as pellegra in humans?
Niacin
True/False: the adult Recommended Daily Allowance is 13-20mg/day for niacin, depending on age and gender.
TRUE
True/False: Niacin is very stable to heat, light, and oxidation, but like other water-soluble vitamins, it can be leached from foods during processing and cooking.
TRUE
What is the name of vitamin B6?
pyridoxine
What B vitamin is called the anti-pernicious anemia factor and is important in nucleic acid formation and in fat and Carbohydrate metabolism?
B12
What is the name of vitamin B12?
cobalamin
True/False: cyanocobalamin is the largest vitamin molecule and contains cobalt in its structure, giving rise to an essential requirement for the mineral cobalt in nutrient.
true
True/False: vitamin B12 is not synthesized by bacteria and molds and is a commercial by-product of antibiotic production
false
what vitamin is responsible for the prevention of certain kinds of anemias, is involved in the synthesis of nucleic acids, and is synthesized by microorganisms?
Folacin (or folate/folic acid)
What is a TTC test? What is it used for?
2,3,5 triphenyl tetrazolium chloride test. this test is used for detection of antibiotics in milk
for milk, what does titratable acidity refer to? what terms is it expressed in?
titratable acidity is natural acidity (from udder. Due to casein, phosphates, albumin, CO2, citrates) plus the real acidity (microbial acidity; ie. conversion of lactose to lactic acid). It is expressed in terms of % lactic acid.
What is catabolism and anabolism?
catabolism is breakdown of complex organic molecules releasing energy. Anabolism is synthesis of cell constituents from simpler molecules, usually requiring energy.
What kind of emulsion system does butter have?
butter has a water in oil emulsion, where water is in dispersed phase and oil is in continuous phase
name the major components of dietary fiber
cellulose,pectin,lignin,hemicellulose,hydrocolloids
what state does the milk protein casein occur in milk, and what is its Zeta potential?
casein occurs in colloidal dispersion phase in milk. Its zeta potential is about 18mV
what is the pH range of the indicator phenolphthalein?
8-9.6
What is the difference between free water, adsorbed water, and water of hydration in foods?
Free water retains its physical properties and is available for reaction. Adsorbed water is held tightly to proteins. Water of hydration is the chemically bound water.
what is PSE in reference to meat?
Pale, Soft, and Exudative. It is due to excess production of lactic acid. Most of it is contributed to stress and rigor
what are isotonic solutions?
solutions which has same osmotic pressure at same temp
what should be the size of milk fat globules after homogenization?
< or equal to 2 microns
which amino acids are indispensable?
Phenylalanine,Valine,Threonine,Tryptophan,Methionine,Histadine,isoleucine,Lysine,Leucine
What are colligative properties?
physical properties of a solution that depend entirely on number of solute molecules present in the solution and not upon the chemical nature of the solute. Ex. vapor pressure, osmotic pressure, boiling point, freezing point
Name the lean and primal cuts of pork
Lean cuts: ham, loin, boston butt, and picnic Primal cuts: the above along w/belly
What are the essential amino acids?
Phenylalanine, Valine, Threonine, Tryptophan, Methionine, Histadine, Isoleucine, Leucine, Lysine
what are vitamis D2 and D3 better known as?
vitamin D2: ergocalciferol. vitamin D3: cholecalciferol
what is the chemical name of enzyme lactase?
Beta-D-galactosidase
what is pyrolysis?
dehydration and fragmentation of sugar molecule. AKA carmelization. it is responsible for browning and burnt flavor
what is lactulose, and how does it influence bifidus production?
lactulose is an anomer of lactose formed during high heat treatment. It stimulates growth of bifido bacteria that provides immunity to infants. It helps cure GI disorders.
What are exopeptidases and endopeptidases?
exopeptidases are enzymes that cleave amino acids or dipeptides in a stepwise manner from terminal end of protein. Endopeptidases are proteinases that hydrolyze linkages within the peptide chain, and don’t touch the terminal peptide bonds.
what are carotenes and xanthophylls?
classes of carotenoids. Carotenes are purely poly-ene hydrocarbons while xanthophylls contain oxygen in form of hydroxyl, epoxy, or oxo group
what is protopectin?
a component of cementing material between plant cell wall. In fruits, it is converted to pectin as fruit matures.
what pigments cause yellow, red, and green colors in plants and vegetables?
yellow is due to carotene, green is from chlorophyll, and red is due to lycopene
what are catechins?
flavonoid phytochemical compounds that appear predominantly in green tea. Smaller amounts of catechins are also found in black tea, grapes, wine, and chocolate.
the structure of the enzyme polyphenol oxidase (PPO) contains which metal?
Copper
What is the eutectic point?
Temp where solid and liquid phase of a material exist in equilibrium
from a food safety standpoint, what temp range is considered “the danger zone”?
40-140 degree F (4.4-60 degree C)
what are cryoprotectants?
substances that protect against the dehydration which destroys structure and texture caused by freezing.
what is starch retrogradation?
realignment (crystallization) of the amylose and amylopectin to form a pocket.
which enzymes are used for corn syrup production?
alpha amylase and glucoamylase
define kinetic viscosity
ratio of absolute viscosity and density
Individuals who are extremely sensitive to the compound PROP are called what?
super-tasters
at which pH does the indicator phenolphthalein turn from colorless to red?
8.2-8.3
which of the following elements is found in a molecule of the pigment xanthophyll but not in a molecule of betacarotene: nitrogen, oxygen, hydrogen, carbon
oxygen (this is the difference between betacarotene and retinol/al)
the protein efficiency ratio (PER) is based on the comparison of the weight gain of rats fed a test protein to those fed what controlled protein?
casein
which are the 2 essential fatty acids for human beings?
Linoleic (omega 6) and linolenic (omega 3)
what is amelioration as it refers to wine making?
alteration of the sugar concentration, total acidity, and/or pH of musts
what is levulose, a common monosaccharide found abundantly in honey, saps, and fruits more commonly known as?
Fructose
a pH value is a measure of acidity. what is a pKa value the measure of?
acid strength, which are measured by titration
in enzymatic reactions, what is “activation energy”?
the energy required by the reactant to reach transition state from the ground state
what is “margarine disease” (AKA Planta Disease)?
allergic reaction to the emulsifier “ME18”, which is added to margarine to keep fat from spattering during frying.
what is BT corn?
genetically modified corn that contains a gene taken from Bacillus thuringiensis (a bacterium); the gene allows the plant to manufacture a protein crystal that is toxic to certain insects
what is BHT?
Butylated hydroxytoluene; phenolic antioxidant used to preserve fats and oils
what is BGH?
Bovine Growth Hormone: regulates growth and milk production
what does the acronym PCB stand for?
Polychlorinated biphenyls
the diet and health recommendations advise limiting salt to less than 6 grams per day: it emphasizes moderation, not adequacy. What are the symptoms of sodium toxicity and chlorine toxicity?
Na: edema, acute hypertension. Cl: vomiting
Amino acids can be classified according to the chemical structures of their sidechains. What are these 7 classes?
Aliphatic, alcohols, Aromatic, Bases, Sulfur-containing, Acids, Amides
Federal SOIs for jellies, preserves, and jams require: A. not <43% soluble solids in finished product, B.not <45% sugar to 55% fruit in the formula, C.not > 65% soluble solids in the finished product, D. not<45% fruit to 55% sugar in formula
D. not < 45% fruit to 55% sugar in the formula
the degree of unsaturation of a fat is measured by the ______value
iodine value
If you have 2 different foods, food A w/pH=4 and food B w/pH=6. which one is more acidic and by how many times?
A, 100 times more acidic than B
Enzyme used for debranching of starch molecule is: A.alpha amylase, B. Beta amylase,C. Glucoamylase, or D. Pullalanase
D. pullalanase
Which is a non-reducing sugar: A.glucose, B.sucrose, C.maltose, or D. fructose?
B. sucrose
What is the pressure (in kPa) of apple juice that is held at a 10m high tank assuming the density of 1kg/m3
density x gravity x height= 1 x 9.81 x 10= 98kPa
Which dairy breed of cow averages the highest fat content of raw milk?: A.Holstein, B.Guernsey, C. Ayrshire, or D. Jersey
D. Jersey
foods relatively high in fat are frozen prior to irradiation to: A.inactivate some foodborne illnesses,B. preserve the frozen food, C. minimize nutrient loss and flavor changes, or D. help drive oxygen out?
C. minimize nutrient loss and flavor changes
adverse reaction to a food or food component that occurs through unknown mechanisms even including psychosomatic illnesses is called: A.food anaphylaxis, B.food idiosyncrasy, or C.metabolic reaction?
B.food idiosyncrasy
name the most common food idiosyncrasy
Chinese restaurant syndrome
True/False: chlorophylls which are responsible for the green color of plants are permitted as food colors in the US
FALSE
Duplicates of naturally occuring aromatic compounds which have been synthesized and added to food but which are known to be naturally occuring are called: A.Nature-identical, B.natural-artificial, C.synthetic-nature, or D.plastic surgery flavors
A.nature-identical flavors
what percentage does lactose take up in whole milk?
4.80%
which amino acids contain sulfur?
Methionine, cysteine, homocysteine, and taurine are the 4 common sulfur-containing amino acids
a technology that will enable the use of aspartame in baked goods is:
encapsulation
which one is NOT a nutritive sweetener: A.sucrose, B.aspartame, C.honey, D.cyclamate, or E.corn syrup?
D. cyclamate
which non-nutritive sweetener is the derivative of sucrose produced by fungal enzyme: A.L-sugars, B.Aspartame, C.Neosugar, or D.Saccharin?
C. Neosugar
Black spot formation on shrimp can be prevented by using: A.beta carotene, B.ascorbic acid, C.tocopherol, or D.ascorbyl palmitate?
B. ascorbic acid
the addition of nutrients to achieve concentrations specified in SOIs is referred to as: A.enrichment, B.restoration, C.fortification, or D.identification?
A. enrichment
what are beta-glucans?
glucose polymers containing both beta 1-3 and 1-4 links
dietary fiber has several physiological effects except: A.increase fecal bulk, B.increase nutrient availability, C.reduce cholesterol, or D.improve large bowel function?
B. increasing nutrient availability
which of the following products is NOT a pseudoplastic fluid: A.mayonnaise, B.fruit purees, C.condensed milk, or D.60% suspension of starch in water
D. 60% suspension of starch in water (its a colloid)
why are sulfides prohibited from use in foods that are recognized sources of thiamin?
because sulfides destroy thiamin, which could lead to deficiencies
ESL in dairy cow product means: A.estimated shelf life, B.extremely short-lived, or C.extended shelf life
C.extended shelf life
what is 1U (unit) in determining enzyme activity?
Micromoles/minute
if the HUE value is 10, you are measuring the color of: A.tomato, B.lemon, C.green apple, or D.onion?
A. tomato
for the sugar-free jellies, pectin used needs to have a degree of esterification of: A.99, B.67, C.55, or D.35?
D. 35
put these amino acids in order from smallest to largest molecular size: arginine, alanine, and cysteine
alanine smallest, cysteine, arginine largest
which of the following is NOT a globular protein: A.myoglobin, B.collagen, C.amylase, or D.pepsin?
B. collagen
what is the difference between an aldose and ketose?
aldose has a carbonyl group at the end of the atom, while the carbonyl group is at any other position in a ketose
why is HFCS used for sweetening of cold but not hot drinks?
fructose is found either as pyranose or furanose; increasing the temp shifts the equilibrium toward the furanose form (which is less sweet)
butter w/what other ingredient, used as an emulsifier, is used in preparation of Bearnaise Sause?
Egg yolk, which have lecithin (natural emulsifier)
the problem of cloud loss in orange juice is due to: A.high temp, B.low acidity, C.activity of pectin methyl esterase, or D.activity of polyphenol oxidase?
C. activity of pectin methyl esterase
if fluid milk is priced at $10 per 100lb, how much does the water cost in the milk?
milk is 87% water, so $8.70
buffalo milk is what % of fat: A.20%, B.5%, C.8%, or D.who drinks buffalo milk?
C. 8% fat
what enzyme is used as the measure of adequate pasteurization of milk product: A.peroxidase, B.protease, C.alkaline phosphatase, or D.catalase?
C. alkaline phosphatase
which of these contain the LEAST amount of fruit juice: A.fruit punch, B.fruit nectar, C.juice beverage, or D.juice blend?
A. Fruit punch (only 1% fruit juice)
how much fruit juice is found in fruit punch?
1% fruit juice
how much fruit juice is found in fruit nectar?
25-50% fruit juice
how much fruit juice is found in a juice beverage?
10-20% fruit juice
how much fruit juice is in a juice blend?
100% fruit juice
clarified orange juice is referred to as: A.clear orange juice, B.see-through orange juice, C.orange serum, or D.no-pulp orange juice?
C. orange serum
what is the milkfat % of pasteurized whole milk sold in the grocery store?
3.25% milkfat
what does pH stand for?
hydrogen potential
what is the largest dairy farmer cooperative and what does it stand for?
DFA= Dairy Farmer’s of America
using 4 significant figures, tell us how many pounds a gallon of water weighs
8.345 lbs
what is “honey laundering”?
honey harvested in one country that is exported to a second country, where it is relabeled as a product of the second country
a US gallon is equivalent to how many UK gallons (one sig fig)?
0.8
which of the following foods contain the lowest content of water: A.fresh carrots, B.fresh tomatoes, C.whole milk, or D.fresh celery?
C. whole milk (87.2% water). Carrots contain 88.2% water, fresh tomatoes contain 93.5% water, and fresh celery contains 94.1% water
what is “candling”
holding eggs or fish up to light to check their quality
how many eggs does a typical laying hen produce in a year?
250-290 eggs per year
what characteristic typifies a pome fruit, and name 2 examples?
has a compartmented core;apples, pears
in what test is Kovac’s reagent used?
indole test of IMViC (series of tests to identify organisms in coliform group)
what is semolina?
the purified middling obtained from durum wheat
what is farina?
a fraction of middlings from hard wheat
what water activity value is where max rate of quality loss occur?
0.8
what water activity value is where mold growth can occur?
0.6
what water activity value is where monolayer moisture value is present?
0.25
what water activity value is where there is a loss of crispness and onset of caking occurs?
0.4
what term describes the process of surgically de-sexing male livestock?
castration
what is the name for the compound that has a cyclic structure of glucose units?
cyclodextrin
which laws, appearing in the general form of driving force over resistance force, describes the following processes: mass transfer, heat transfer, and electrical conductance
mass transfer=Fick’s Law; heat transfer= Fourier’s Law; electric conductance= Ohm’s Law
what is the most commonly added synthetic antioxidant in breakfast cereals?
BHT (Butylated hydroxytoluene; phenolic antioxidant used to preserve fats and oils)
what is the most commonly used food ingredient produced enzymatically?
High Fructose Corn Syrup
name the 4 antimicrobial defenses of eggs
shell,membranes,lysozyme (lysis of cell walls),avidin (binds biotin; needed for m/o growth),conalbumin (chelates iron)
what are the 4 major components of whey proteins?
alpha-lactalbumen, beta-lactoglobulin, bovine serum albumen, immunoglobulins
in the human mouth, Streptococcus mutans converts sugar into what substance that causes tooth decay?
Lactic acid
name the 5 structures that D-Glucose may be present as in water
alpha and beta glucofuranose, alpha and beta glucopyranose, and open-chain aldehyde
name 3 chemical properties of food phosphates that governs their usefulness as food additives
Buffering and pH control, Inactivation of metal ions by sequestrations or precipitation, polyvalency (inhibition of certain surface interactions, or promotion of certain molecular cross-linking)
state the non-caloric sweetener(s) found in the following beverages: Fresca, Bottled Pepsi, diet coke from a soda fountain
Fresca= aspartame;Bottled Diet Pepsi= aspartame;Diet Coke from a soda fountain= aspartame and saccharin
what fermented beverage is made from mare (horse)’ s milk?
koumis
what will occur in a sample of milk at 20 degrees C when the pH is lowered to 4.6?
the casein will precipitate OR it will curdle
what is the predominant character compound in banana oil?
isopentyl acetate
what structural property gives emulsifiers their emulsification ability?
hydrophilic (polar) head and a hydrophobic (hydrocarbon)tail
which step in the Maillard reaction involves a reaction between a dicarbonyl and amino acid?
Strecker Degradation
which of the following pH values in a food would yield the highest rate of non-enzymatic browning: A.5.5, B.8.5, C.9.5, or D.3.5
B. 8.5
What are myoglobins? What are its 3 forms?
Myoglobins are pigments responsible for color of meats. The 3 forms are: metmyoglobin, oxymyoglobin, and dexoxymyoglobin
Anthocyanins are pigments responsible for what colors, and in what type of foods?
Red, blue, and purple colors of some flowers, fruits, vegetables, juices, wines, etc.
