COCOA PROCESSING TECHNOLOGY Flashcards
Cocoa Beans consists of
two cotyledons (nib) and a
small embryo plant, all enclosed in a skin (the shell).
The cotyledons consists
50% of fat (cocoa butter),
which is half weight of the dry seed.
Two important types of cells within the cotyledons:
- Storage cells containing fat and proteins
- Pigment cells containing polyphenolic
compounds and methylxanthines (theobromine
and caffeine).
Three major types of cocoa bean use in chocolate production
Criollo, Forastero, Trinitario
Cocoa Bean Processing-Tree to Factory-Harvesting
Harvesting is done by separating the ripe pods
from the tree by using a sharp knife without causing injury to the “cushion” from which they are developed.
Each pod contains about
25-40 cocoa beans which are arranged in
rows and covered with pulp or mucilage.
The pods are opened to remove the beans
within a week to 10
days after harvesting.
The yield (cocoa beans) obtained from cocoa trees depends on:
- Variety of cocoa
- The age of the trees
- Local environment
- Loses cause by pests and disease
Fermentation should start within
24 hours after breaking the pods otherwise fungi may enter the bean and affect flavor and quality.
The bean may be turned once on the 3rd day to
prevent mold growth on the surface and for uniform fermentation.
Fermentation of beans is generally completed
within 5-7 days depending on the weather conditions
Aims of the fermentation:
Ø Separate the flesh from the beans effectively
Ø Kill the germination capacity of the seeds
Ø Form chocolate flavoring and color
Three methods are normally adopted for
fermentation:
Basket fermentation
Box fermentation
Tray fermentation
Basket fermentation
– bamboo or baskets can
be used, which could accommodate from 5 to
30kg of cocoa beans.
Box fermentation
box made of thick hard
wood with perforated bottom which could
accommodate 50kg of cocoa beans.
Tray fermentation
wooden tray with
perforated bottom which could accommodate
up to 50kg of cocoa beans.
Fermentation:
Microbiological activity and chemical changes
The pulp (10-15% sugar) is inoculated naturally with a variety of
microorganism from the environment.
Stage 1 (24-36h) of fermentation process:
Yeast grow on the pulp surrounding the beans convert the sugars in the
pulp to ethanol.
Stage 2 (48-96h) of fermentation process:
- The lactic acid bacteria convert sugars into lactic acid.
- Acetic acid bacteria start to oxidize the ethanol to acetic acid, CO2 and H2O, producing more heat and raising the temperature.
- The pulp starts to break down and drain away during the second day.
- The temperature is raised to 40oC – 45oC during the first 48 hours of fermentation.
Stage 3 (96-120h)of fermentation process:
- The process of turning or mixing the beans increases aeration and consequently bacterial activity.
High temperatures during fermentation
kill the cocoa bean and
break down cell walls.
Chemical changes in the bean such as
enzyme activity, oxidation and the breakdown of proteins into amino acids – various
compounds react together - develop chocolate
flavor and color.
Glycosidase enzymes hydrolysed
anthocyanins to
cyanidins and sugars which cause bleaching/ lightening of the purple color of cotyledons in forestero cocoa)
- Completion of fermentation is initially determined by:
a) The color of external mucilage will turn into milky brown chocolate.
b) When squeezed, should give out a brown and a purple liquid.
c) The shell is crisp, either loose or close fitting.
d) Has acidic aroma due to the production of alcohol by yeast and bacteria during fermentation.
