Browning

Question 0

Enzymatic browning involves what

Answer 0

Ppo or other enzymes creating melanin

Question 1

Nov enzymatic browning rxns and what they are

Answer 1

Brown color of foods without enzymes
Millard
Carmelization

Question 2

Maillard rxn

Answer 2

Amino acid and reducing sugar - more basic n containing animos react more

Coffe meat syrup desirable

Undesirable is loss of amino acids

Question 3

Steps in Millard

Answer 3

condensation - carbonyl group reacts with reducing end , produces glucosamine
Rearrangement - amadori rearrange - ketoseamines
EnolizAtion - reductions and dehydroreductones produce melanomas and amino acids via the streaker degradation

Question 4

EnolizAtion

Answer 4

Keto and enol in equilibrium tautomerism

Question 5

Hmf is found where

Answer 5

Processed foods such as honey , milk, juice, spirits

Question 6

Streaker degradation products

Answer 6

Amino ketone, aldehyde, co2

Question 7

Optimum conditions for mallard

Answer 7

Alkaline and heat - amino acids in base forms and hexoses in open chain/ reducing form
Rate up with temp
Browning will occur faster in cooked foods
Occurs slowly but significantly at mod temp

Question 8

How does acid help Millard

Answer 8

Moderately acidic ph 4-7, acid catalyze so first step

Too much protonation amine, less of a nucleophile

Question 9

WAter in Millard reaction

Answer 9

Moderate water levels promote mobility between reactants
Water participates in later stages of rxn
Too much water pushes reverse rxn

Question 10

Where find mail lard rxn, optimal wTer activity

Answer 10

Stored dehydrated heated .6-.7

Question 11

Reactivity of sugars and proteins maillard

Answer 11

Pent, hex , di
Gal man, glu
Increase with ph and temp

Question 12

Physical means of controlling Millard rxn

Answer 12

Phys - Decrease water, lower ph biochem - and convert glucose to glu conic acid , chem - add sulphites

Question 13

Steps in maillard rxn

Answer 13

Ini No uv absp, int strong( hmf, dicarbonyl) , fin dRk brown 420

Question 14

Carmelization . What temp and steps , what forms

Answer 14

Isomerism, dehydration, oxidation high t 155, low wAter , enefiols, dicarbs

Question 15

ACrylamide , alas involved

Answer 15

Toxic, cancer propagation, in fried foods starchy, French fries bread that has been heated , temp dependant, , neurotoxin. Asparganine and glutamine, derived from asparganine in the presence of sugar

Question 16

PotAto amino acid content

Answer 16

50% free , asparganine roughly half

Question 17

Steps to minimize acralymide

Answer 17

Avoid foods high in acryllamide hydrolyze asparganine with acid, acetylate asparganine , genetic manipulation

Question 18

Products of maillard

Answer 18

Hmf, furfural, streaker aldehyde, acryllamide , reductions, dehydrored