__MAIN_TEXT__
feature-image

Page 99

+ AMINO COMPOUND - H20

ALDOSE

N-SUBSTITUTED GLYCOSYLAMINE

A C

SCHIFF BASE OF HMF OR FURFURAL

B

AMADORI REARRANGEMENT

1-AMINO-1-DEOXY-2-KETOSE -3 H20

C

-2 H20

H

D

FISSION PRODUCTS

REDUCTONES SUGARS

-AMINO COMPOUND

HMF OR FURFURAL

F

G

E

F

ALDOLS AND N-FREE POLYMERS

G

-2H

DEHYDROREDUCTIONS

+ H 20

+ AMINO COMPOUND

+2H

(acetol, butanedione, 2-oxypropanal, etc.)

+ AMINO COMPOUND

F

STRECKER DEGRADATION

E

+AMINO ACID -CO2

ALDEHYDES

F G

+ AMINO COMPOUND

G

G

+ AMINO COMPOUND

MELANOIDINS BROWN NITROGENOUS POLYMERS AND COPOLYMERS

+ AMINO COMPOUND

FIGURE 1 — A simplified schematic of the processes involved in the Maillard reaction. Three stages are considered:

Stage I: A — Sugar-amine condensation, B — Amadori rearrangement. Stage II: C — Sugar dehydration, D — Sugar fragmentation, E — Amino acid degradation (Strecker degradation). Stage III: F — Aldol condensation, G — Aldehyde-amine condensation and formation of heterocyclic nitrogen compounds. Recent information adds H to the list which represents freeradical breakdown of Maillard intermediates. These reaction steps are discussed further in the text. Adapted from Hodge (1953) as referenced in Nursten (2005).

CONDITIONS FOR THE MAILLARD REACTION As the Maillard process is a series of chemical transformations, factors that influence a chemical reaction also affect the Maillard reaction. The rates of chemical reactions depend primarily on temperature, pressure, time and concentration of reactants. Maillard reaction products increase with increasing temperature, with longer heating time and at pH values above 7.0. The relative moisture content is also important, and metal ions such as copper and iron have been noted as stimulating the reaction. As temperature is a key condition for the Maillard reaction further details are presented in Table 1. WWW.ARTISANSPIRITMAG.COM  

Some similar products to Maillard compounds are produced during the caramelization process, but we note here that caramelization reactions, unlike Maillard reactions, require the input only of sugars not amino acids. The topic of caramelization could form the basis of a paper of its own and we only point out here that, at higher temperatures (see Table 1), caramelization can interfere or

TA B L E 1

TEMPERATURE and the RATE and EXTENT of MAILLARD REACTIONS TEMPERATURE

CONDITIONS AND RATE OF REACTION

< 55°C (130°F)

Days, months, years (e.g., products stored on the shelf).

55-100°C (130-212°F)

Water, high protein concentration. High sugar concentration and alkaline conditions — pH above 7.0 — reaction over hours or days.

100-150°C (212-300°F)

Hours when close to the boiling point (BPt.) of water.

150-165°C (300-330°F)

Fast — browning in mins. The “sweet spot” for Maillard.

165-200°C (330-400°F)

Increase in caramelization (sugar only reactions) — Maillard inhibited. Sugars interacting with amino acids limited!

200+°C (400+°F)

Caramelization and burning.

99

Profile for Artisan Spirit Magazine

Artisan Spirit: Spring 2017  

The magazine for craft distillers and their fans.

Artisan Spirit: Spring 2017  

The magazine for craft distillers and their fans.