| What three things make a healthier chocolate | Increasing solids, incorporating water and clean-label surfactants |
| What is the manufacturing process for chocolate | Cocoa beans (cleaning, fermenting, shelling, roasting and winnowing) -> roasted nibs (grinding and refining) -> Mass/liquor
Then three options depending on processing:
Mass/liquor (pressing) -> cocoa cake (milling, sieving) -> cocoa powder
Mass/liquor (pressing) -> cocoa butter -> sold as cocoa butter or chocolate
Mass/liquor (mixing, grinding and conching (with addition of sugar and milk)) -> chocolate |
| List the ingredients of chocolate | Cocoa mass, cocoa butter, sugar, milk power, alternatives to milk, milk crumb, vanilla, lecithin and PGPR |
| What are the two types of cocoa beans | Fine or flavour and bulk cocoa beans |
| What can cocoa shell be used for | compost |
| What is the moisture content to stop agglomeration in sugar | Less than 0.05% |
| Define lecithin | Mixture of lipids which impacts viscosity |
| What does PGPR do in chocolate | Mainly impacts on yield behaviour |
| What is dark, milk and white chocolate made up of | DARK: cocoa liquor, cocoa butter and sugar
MILK: cocoa liquor, cocoa butter, sugar and milk powder
WHITE: cocoa butter, sugar and milk powder |
| What are the two chocolate types | Crumb and dry mix |
| What does crumb chocolate do in chocolate | Historically to exploit antioxidant properties in cocoa butter to produce milk containing ingredients with a long shelf life. Nowadays creates a strong caramel flavour |
| What are the two different crumb processes | See image |
| What is the method for producing chocolate mass | Raw material -> mixing/kneading -> pre-refining -> final refining -> conching |
| Define 2-stage refining | Sugar crystals shatter if subjected to violent impacts resulting in fine particles. 2 or 2+5 roll |
| Define 2 roll refiner | Mass is passed through 2-roll refiner where sugar is milled where the two rolls have a large speed differential. Removes lumps, grinds the largest particles and provides consistent mass with a suitable texture |
| Why are there magnetic bars placed on the discharge chute | To catch any impurities |
| Why is conching used in the chocolate process | Modifies taste, texture and aroma by removing volatiles including moisture, and by making minor chemical changes in the mix. Powder -> liquid. Provides a homogenous mass of correct viscosity ready to be used. Time for conching depends on throughput and quality |
| What are the four stages of conching | Fill with refined mass -> dry conching -> pasting -> liquefaction (addition of fat and emulsifier) |
| What is the issues when adding fat too early and too little fat in conching | If fat is added too soon, mass will be too liquid to be worked fully.
Too little fat results in poor mixing and possible balling up thus conche will stall |
| What are the key chocolate properties | Cocoa butter crystallisation and polymorphism
Particles size
Flow properties |
| What is the main component of cocoa butter | Triglyceride |
| Why is crystallisation form beta (form V) chosen | Confers chocolate products: proper snap, good demoulding properties and a good quality finish in terms of colour and glass |
| Why does chocolate require tempering | To crystallise the cocoa butter in the most stable forms |
| What are the three tempering methods | Hand tempering, batch tempering and continuous tempering |
| What is the issue with "wrong" temper | This leads to early bloom formation which is an undesirable polymorphic transition |
| What must the size of particles be in chocolate to not feel "gritty" | less than 30 micrometers to be creamy and glossy |
| How can the microstructure of chocolate be described | A suspension with dispersed being sugar, cocoa solids and milk power, and continuous being molten fat |
| What two properties can describe viscosity | Yield value and plastic viscosity |
| Define casson yield value | Force required to start flow of chocolate |
| Define casson plastic viscosity | Describes how viscous chocolate is upon flow |
| Define yield value | Relates to shape retention, pattern holding, tails, moulding and the presence of air bubbles |
| Define plastic viscosity | Relates to pumping, filling and coating properties |
| Draw an image to show importance of having correct yield value | See image |
| How does viscosity vary with particles volume fraction | See image |
| What two techniques can be used to measure chocolate viscosity | Single-value (cost effective, simple and easy to control, single value, limited application to process control)
Multiple-value (more sophisticated, can be automated, more precise and covers broad range of products (thin to thick)) |
| What are the crumb processing stages | 1) Milk pasteurisation and evaporation to desired solids content
2) Addition and dissolution of sugar
3) Heating
4) Addition of cocoa liquor, kneeding/mixing and drying |
| What are the main aims in crystallising sugar | Crumb is less hygroscopic and sticky, so more stable and easier to handle. Traps less fat thus less fat needs to be added to adjust final viscosity (saves cost). Better dissolution properties in mouth (customer satisfaction) |
