Term
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Definition
| the active sites of these enzymes will only cleave bonds following or preceeding certain amino acids (trypsin/chymotrypsin) |
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Term
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Definition
| hydrolyzes bonds after charged arginine and lysine, can only attacked exposed peptide bonds as in denatured proteins |
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Term
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Definition
| only cleaves peptide bonds that follow large, hydrophobic residues like phenylalanine, tyrosine, or tryptophan |
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Term
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Definition
| cleave single amino acids from the ends of polypeptide chains |
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Term
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Definition
| remove amino acids from the C terminal end of polypeptide chains, version A has an essential zinc atom in its active site, which can be inhibited in EDTA, which is a chelating ingredient |
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Term
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Definition
| the principal protein-digesting enzyme found in the very acidic medium of the stomach |
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Term
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Definition
| the acid protease that is the major enzymatic component of rennet. It is one of the most important endopeptidase proteases for food processing. It is not a serine protease and has a similar catalytic mechanism to pepsin |
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Term
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Definition
| class of proteases also called serine endopeptidases, containing essential serine residue in active sites. Also have histidine and aspartic acid in active site |
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Term
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Definition
| a sulfhydryl protease extracted from papaya latex that has a reactive thioalcohol S-H group of a cysteine residue as its catalytic residue, which cleaves bonds following Phe, Asn, Glu, and Tyr. Active site is between the two subdomains |
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Term
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Definition
| a sulfhydryl protease from pineapple; a homolog of papain; used as a commercial meat tenderizer but don’t spread evenly throughout piece of meat. Hydrolyzes collagen so gelatin won’t “gel” |
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Term
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Definition
| a pectic enzyme that converts methoxyl group to acids in pectin and is used to produce low methoxyl pectins. It is not a glycosidase |
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Term
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Definition
| also called polygalacturonase; hydrolyzes glycosidic linkages in pectins, which can cause softening |
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Term
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Definition
| esterases that catalyze the hydrolysis of ester linkages in lipids, which produces an alcohol and a free fatty acid. Produced by humans, bacteria, mold, plants, animals and can be found in milk |
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Term
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Definition
| copper-containing oxidoreductase enzymes that can oxidize phenolic compounds to o-quinones which are responsible for the browning of fruits and vegetables (especially apples, potatoes, and bananas). Dihydroxylphenols are colorless but light-colored quinones are highly reactive and can react with proteins to form dark-pigmented complexes |
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Term
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Definition
| carboxylic acid with long hydrophobic chains attached, R-COOH, where the R group is usually 10 or more carbons long. |
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Term
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Definition
| can have 1, 2, or 3 fatty acids esterified to glycerol, with triaglycerols being the most abundant. Phospholipids are ester of glycerol, where one of the hydroxyl groups is esterified to a phosphate group |
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Term
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Definition
| 14:0; systematic name is tetradecanoic acid |
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Term
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Definition
| 16:0; systematic name is hexadecanoic acid |
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Term
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Definition
| 18:0; systematic name is octadecanoic acid |
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Term
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Definition
| produces an angle of about 120 degrees and introduces a slight kink into the direction of the chain (NOTE: not as much as cis!!!!!!); interferes with the packing of a crystalline lattice. See page 405 for example pictures. |
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Term
| Polyunsaturated fatty acid |
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Definition
| (PUFA): fatty acid chains that contain more than one double bond; in most foods the first double bond happens between the C9 and C10 atoms, at an area called delta9 |
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Term
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Definition
| no double bonds in the fatty acid chain |
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Term
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Definition
| 18:1 (9), systematic name is 9-octadecenoic acid |
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Term
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Definition
| 18:2 (9,12), systematic name is 9,12-octadecadienoic acid; omega-6 |
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Term
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Definition
| 18:3(9,12,15), systematic name is 9,12,15 octadecatrienoic acid; omega-3 |
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Term
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Definition
| fatty acid triesters of glycerol |
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Term
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Definition
| result from esterfying a long-chain alcohol with a fatty acid; have a regular and hydrophobic nature; can aggregate into glossy, water-impervious layers; more resistant to hydrolysis and require higher temperatures or more extreme pHs than lipids; used as candy glaze or fruit polish |
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Term
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Definition
| if the chains on the triaglycerol are different, need to use stereospecific numbering to indicate the exact structure |
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Term
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Definition
| can occur with the action of milk lipases on milk triglycerides, where fatty acid chains are removed from the outer ends of triglycerides, producing 1,2 and 2,3 diglycerides, further action of milk lipases produces monoglycerides, where the only remaining fatty acid chain is at position 2. |
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Term
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Definition
| derivatives of the molecule cyclopentanoperhydrophhenanthrene; they are unsaponifiable |
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Term
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Definition
| stands for Short and Long Acyltriglyceride; is a synthetic tricylglycerol in which one or two of the fatty acid chains in significantly shortened, so it possesses some physical properties while giving fewer calories when metabolized (less carbon atoms available for oxidation) |
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Term
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Definition
| second method of designation, which counts from the other end of the chain. Long chain omega 3 PUFAs can significantly reduce coronary heart disease risk. Most important are eicosapentaenoic acid (EPA) 20:5 and docosahexaenoic acid 22:6 (DHA), which is important for brain development as it comprises brain’s phospholipids |
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Term
| Sucrose polyester Olestra |
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Definition
| have similar physical properties of fat but can’t be hydrolyzed enzymatically, so they don’t provide calories. Is a sucrose molecule in which every free hydroxyl group is esterfied with a fatty acid chain |
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Term
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Definition
| most abundant steroid in animals; hydrophobic, waxy sterol that is insoluble in water, its C3 hydroxyl group is polar and hydrophilic, not aromatic but puckered and not planar. Precursor in the synthesis of estrogen, testosterone, and vitamin D; levels are a function of dietary intake and internal regulation. Circulate in the body as lipoproteins, that consist of surfactant phospholipids, triglycerides, proteins & cholesterol. (419) |
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Term
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Definition
| glycerophospholipid with “X” being a proton |
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Term
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Definition
| glycerophospholipid with “X” being choline |
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Term
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Definition
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Term
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Definition
| the use of repeated heating and cooling to partially separate mixtures of fats by exploiting the differences in melting temperatures of the different triglycerides. Lower melting triglycerides are melted, and can be decanted or filtrated |
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Term
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Definition
| the process of changing the positions of fatty acid chains in a triglyceride using sodium methoxide as a catalyst to produce triglycerides with different physial properties, such as melting temperature and crystallization. Occurs after an exchange of acyl radicals between triacylglycerol molecules. |
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Term
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Definition
| forms hydroperoxides; further degradation occurs in these four stages: initiation, propagation, decomposition, and termination |
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Term
| Lipid autoxidation Initiation |
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Definition
| how a lipid free radical is generated, by one of several processes activation by absorpton of visible or UV radiation, heat, or hydroxyl radicals, or metal catalysts |
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Term
| Lipid autoxidation propagation |
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Definition
| its reaction with oxygen in a chain reaction; alkyl free radicals react with ground state/triplet oxygen to produce alkylperoxyl radicals, which can abstract a hydrogen atom from another fatty acid alkyl chain to generate a hydroperoxide and another alkyl radical |
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Term
| Lipid autoxidation Decomposition |
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Definition
| the unstable hydroperoxide molecules break down via 2 steps: (1) the O-O bond is broken, to give an alkoxy lipid radical and a hydroxyl radical (2) alkoxy radical leaves one of the C-C bonds on either side of the alkoxy group |
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Term
| Lipid Autoxidation Termination |
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Definition
| radical-induced chain reaction can be terminated example of linoleic acid into hexanal |
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Term
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Definition
| a pathway in which a hydroxyl radical is produced, which allows ferrous iron (Fe2+) to indirectly initiate autoxidation (attack on fatty acid to produce alkyl free radical) |
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Term
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Definition
| a nonenzymatic reaction with triplet oxygen to form hydroperoxides and their degradation compounds. Induced by free-radical chain reaction, involving four stages: initiation, propagation, decomposition, & termination |
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Term
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Definition
| an excited, reactive atom that will attack a double bond @ either location (13,9,12,10) |
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Term
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Definition
| only attacks at 13, 9. Ground state oxygen in the air that is relatively unreactive, most reactive towards free radicals (not really organic molecules) |
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Term
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Definition
| species with unpaired electrons |
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Term
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Definition
| induces phosphosensitizer-induced singlet oxygen oxidation. Excites triplet oxidation to singlet state, which results in oxidation of unsaturated fatty acids’ double bonds. Can be quenched by carotenoids, BHA, lycopene, lutein, astaxanthin |
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Term
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Definition
| enzyme that removes hydrogen atoms from methylene carbon between nonconjugated double bonds (like linoleic acid’s C11). Needs to be heat-denatured. |
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Term
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Definition
| can control the oxidation of lipids (and its intermediates) by scavenging free radicals, most are phenolic compounds. What they produce are phenolic radicals, but their oxidation potential is lower |
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Term
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Definition
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Term
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Definition
| synthetic, phenolic compounds that have higher scavenging abilities than vitamin E that have GRAS status |
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Term
| Hexanal headspace-GC analysis |
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Definition
| a method to determine the progress of the autoxidation of linoleic acid |
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