2. WHAT IS ACRYLAMIDE ??
Acrylamide (or acrylic amide) is an organic compound with the chemical formula CH2=CHC(O)NH2.
It is an unsaturated , white odorless solid, soluble in water and several organic solvents.
It is produced industrially as a precursor to polyacrylamides, which find many uses as water-soluble thickeners and
flocculation agents.
It is highly toxic, likely to be carcinogenic (2A means, probable carcinogens, for those This designation is applied
when there is limited evidence of carcinogenicity in humans as well as sufficient evidence of carcinogenicity in
experimental animals)
It majorly occurs in carbohydrate-rich cooked foods research was held by Swedish National Food Administration
(SNFA) in 2002
Among other possible reaction pathways, the Maillard reaction represents the main route for acrylamide formation
3. ROASTING HAPPENS BY TWO STEPS
1. Drying: 20-130 ͦ C (shifting from green to light yellow-Brown)
2. Chemical reaction 130-220 ͦ C (flavor and color development)
Endothermic reaction 100-140 ⸰C
Exothermic reaction: > 140 ⸰C
Strongly exothermic : > 210 ⸰C
PHYSICAL CHANGES ARE:
Color changes: (Melanoidin, non-Enzymatic browning reaction)
Puffing of coffee beans: moisture loss there is expansion of volume
Pore size is increased
Crystallite melting
B. ROASTING TEORY: (EXOTHERMIC REACTION)
4. CHEMICAL CHANGES:
CHO get converted in to aroma & Co2
Caramalization: Sugar from bean starts caramelizing, which browns the sugar & release the aromatic
components. releases aromatic and acidic compounds - an important step in the degradation of the bitter
tasting particles. Glycosylamine and melanlidins along with carbon dioxide are the products lending to coffee's
dominant taste.
Lipids: Practically no change. Migration of oils to the surface of the bean (pyrolysis)
Aroma development: on an average 800 compound contributed for the flavor of the compound approximately
25-30 compounds contribute majorly.
6-16 mg of Co2 is liberated by per gram of coffee
Density reduces from 1100-1300 to 500-700 kg/m3
Formation of Acrylamide: Acquired naturally when starchy foods are cooked at high temperatures (above
140°C) - Maillard reaction. Darker the roaster lesser the acrylamide.
B. ROASTING TEORY: (EXOTHERMIC REACTION)
5. HOW ACRALAMIDE FORMS IN COFFEE
2.Roasting (@ high
temperature of >140 °𝑐)
3.Denaturation of Protein to amino acid and
carbohydrate to sugar(reducing sugar)
4.Maillard
reaction
Amine group of
L-Asparagine
Carbonyl group of
Reducing sugar
(glucose)
+
6.C₃H₅NO
1.Green coffee (protein and
carbohydrates in complex form)
Main Parameter For Acrylamide Formation
5
6. HOW IT WILL FORM IN COFFEE
Among other possible reaction pathways
Through Maillard reaction represents the main route for acrylamide formation in coffee, being initiated by the
condensation of asparagine and reducing carbohydrates or reactive carbonyls,
when the beans are subjected to the high roasting temperature Acrylamide formation starts rapidly at the
beginning of the roasting process and it decreases shortly after reaching a maximum level, probably due to physical
and chemical losses Therefore, the degree of roasting will be a key factor in acrylamide content, with light roasted
coffee attaining significantly higher amounts when compared with dark roasted counterparts.
During the early
Maillard reaction
7. PARAMETER RESPONSIBLE FOR ACRYLAMIDE CONTEN IN COFFEE
when comparing the two coffee species of higher economical importance, namely Coffea arabica(Arabica) and
Coffea canephora (Robusta), increased levels of acrylamide are described for the Robusta which reaches maximum
values at light roast, compared to Arabica.
Degree of Roasting (light, medium and dark roast)
Roasting temperature and time combination
8. HOW ACRLAMIDE FORMATION CAN BE REDUCED & ITS LIMITS
1. Roasting time:
Acrylamide content in coffee can be reduced by doing slow roasting, (i.e., low temperature
roasting for a long period of time) LTLT is lower than that of coffee roasted at high temperatures for a short period of
time HTST (fast roasting)
2.Extraction time/Cycle time: By reducing the time of extraction, less contact time less liberation from the coffee
(because acrylamide is water soluble in nature)