PROCESSING OF CHOCOLATE BARS

Presented by SUMAN KUMAR PAUL

ROLL NO.: 16AG63R09

Department of Agricultural and Food EngineeringIIT KHARAGPUR

INTRODUCTION Chocolate  is a typically sweet, usually brown food. The Mayans and Aztecs were the first to make chocolate in liquid form

known as "Chocolatl". Chocolates are semisolid suspensions of fine solid particles in a

continuous fat phase. Chocolate is derived from cocoa beans, central to the fruit of cacao

tree, Theobroma cacao. Chocolate has an amazing complexities and levels of flavour. Primary chocolate categories are dark, milk and white.

NUTRITIONAL INFORMATION

PROCESS FLOWCHART

Harvesting Fermenting Drying

Testing and

CleaningRoastingCracking &

Winnowing

Grinding Blending or Mixing Refining

ConchingMoldingPackaging

HARVESTING OF CACAO PODS Harvesting the cacao pods when colour of pods changes from green or red

to yellow or orange. Pods are normally harvested every 2–4 weeks. Beans are separated from the pods. Each pod contains 30-45 beans.

FERMENTING The fresh beans are heaped in a pile or

in a wooden box, typically for 5-7 days.

Natural yeasts and bacteria multiply in the pulp, causing the breakdown of the sugars and mucilage.

Fermentation kills the beans, preventing them from germinating later.

Change in color of the seeds from pale yellow or violet to brown.

It develops flavor precursors that are essential to tasty chocolate.

DRYING The fermented beans are of high

moisture content. So they are dried upto a fianl

moisture content of 6-7 %. Then they are bagged and shipped

chocolate manufacturers.

Sample cocoa beans are tested for size and defects, such as insects or mold.

Once the testing is complete and the shipment is accepted by the manufacturer.

Then the beans are thoroughly cleaned to remove any foreign matter.

Testing & Cleaning

ROASTING Roasting dries and browns the cocoa

beans and develop their flovour. Whole Bean Roasting Nib Roasting Batch drum roasters are frequently

used in the cocoa industry for nib roasting.

Generally, the final roasting temperature is between 110oC and 140oC.

CRACKING AND WINNOWING Roasting causes the shells to open and

break away from the nibs. The roasted bins go through a

winnowing machine through which air is blowed across the bins.

This loosens the hull from the nibs without crushing them.

In case of nib roasting cracking and winnowing is done before roasting.

The beans are preheated and then generally broken by a swing-hammer type of breaker.

GRINDING Many machines like stone (granite)

mills, disc mills, hammer mills etc. are used.

Grinding of nib cells releases the cocoa butter into liquor with particle size up to 30 µm,

The heat produced during grinding causes cocoa fat to melt.

This forms cocoa mass or chocolate liquor.

It contains both cocoa solids and cocoa butter.

BLENDING OR MIXING It is an important operation employed to obtain constant

formulation consistency. Dark Chocolate:

Chocolate liquor + Cocoa butter + sugar Milk Chocolate:

Chocolate liquor + Sugar + milk or milk powder + cocoa butter

In batch mixing all ingredients are thoroughly mixed normally for 12–15 minutes at 40–50oC.

The ingredients are finally mixed together to form a paste called “chocolate paste”.

REFINING It is important for the production of

smooth texture of chocolate.

A wide range of chocolate quality is produced by varying particle sizes of sugar and chocolate liquor.

Maximum particle size range in final product is 15–35 µm.

It also distribute the cocoa butter evenly throughout the mass.

Normally a combination of two and five roll refiners is used in refining.

Rollers are water cooled.

CONCHING Conching contributes to

Development of viscosity Final texture Flavour

It removes of certain undesirable flavour active volatiles such as acetic acid.

It also reduce the moisture content. The equipment used is called Conche. Conching times and temperatures vary

typically from 49-82oC for 10-24 hours (Awua,2002).

Sometimes Cocoa butter and lecithin can be added towards the end of conching.

TEMPERING This is a technique of controlled crystallization of cocoa fat. It is necessary to induce the most stable polymorphic form as possible of cocoa fat

in the finished product. Tempering involves the following steps:

I. Melting to completion (at 50 oC)II. Cooling to point of crystallization (at 32 oC),III. Crystallization (at 27 oC) IV. Melting out of unstable crystals (at 29o-31oC).

Proper tempering gives

1. Good surface gloss and colour2. Good snap3. Smooth and fast melting4. Good heat stability.5. Help in proper demoulding

MOULDING Tempered chocolate is deposited into mould and which formed the shape of the bar. The chocolate cools until it becomes solid . Then they are removed from the molds as chocolate bars. Then they are wrapped and lebelled. Finally the finished product packed in cases and stacked on pallets ready to be

shipped to and to be eaten.

Making of Chocolate

CONCLUSION Chocolate is enjoyed by consumers all over the world due to its unique

taste, texture and aroma. It can be made in the form of a liquid, paste, or in a block, or used as a

flavoring ingredient in other foods. Chocolate manufacturing is complex and requires several technological

operations and processes to achieve the desired product quality. During processing, the physical properties, rheological behavior and

sensory perception of chocolate are influenced largely by its processing techniques, particle size distribution and ingredient composition.

REFERENCES Beckett, T.S.(ed.), Industrial Chocolate Manufacture and Use, fourth

edition, ISBN-13: 978-1-4051-3949-6, Blackwell Publishing Ltd., 2009.

Afoakwa, O. E., Chocolate Science and Technology,1st edition, ISBN 978-1-4051-9906-3, Blackwell Publishing Ltd, 2010.

https://en.wikipedia.org/wiki/Chocolate

https://www.youtube.com