Chocolate Behavior — What Influences Your Selection?
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Chocolate Behavior — What Influences Your Selection? Marlene B. Stauffer The Blommer Chocolate Company hocolate behavior—what do we mean ing, enrobing, hand-dipping, one-shot Cwhen we say this? How does chocolate depositing, panning or for the manufac- act in the many processes used in the con- ture of chocolate chips? fectionery industry? I will be touching on The chocolate type in any application some of the issues that relate to changes in needs a balance between the chocolate and As quality control chocolate behavior and that influence your the center. Milk chocolate can stand on its own and goes well with peanut butter, manager at Blommer, chocolate selection. Stauffer is responsible What issues need to be considered for caramel, nuts and inclusions. White cocoa for quality assurance, chocolate selection based on application butter based chocolate coating with just a product development, hint of chocolate aroma is often used for technical services and and what influences chocolate behavior in contrast in boxed goods or for its rich dairy, employee training. She these applications? What should we be vanilla flavor. Dark chocolate is more robust has been with the com- looking for? Many of these issues have pany since 1982. and aromatic and pairs better with tart fruits, been talked about before, but I want to strong coffee, liqueurs and mint centers. Stauffer is currently a try to give the practical aspects of why member of AACT and Compound coatings are used for their cost, chocolate acts the way it does. IFT, and is a board functionality and support in confections. member of PMCA. Viscosity, or how the product flows, is CHOCOLATE SELECTION key to many confectioners when selecting First, let’s talk about chocolate selection. a chocolate. The correct flow properties The main issues to consider when selecting influence how the product will work in the a chocolate are application, chocolate type, given application. viscosity, fineness, color and flavor. Each of Fineness selection is typically based on these items has an influence on how the fin- what the chocolate will be used for and ished piece will appear to the consumer. what market is being targeted. For example, The first consideration is the chocolate if a smooth, creamy center is being coated, application. Is it for hollow or solid mold- one could easily be distracted if a coarse Marlene Stauffer The Manufacturing Confectioner • September 1998 75 Chocolate Behavior Since our first coating is used. On the other hand, a coarse temperature, using a specific bulb diameter taste of any food coating would not be noticed on choco- and depth. It gives a number indicating late containing noisy inclusions such as how thick or thin a product is, but does is with our eyes, crisp rice, oats or nuts. not tell a lot about the flow characteristics the color of a The next item to be considered in choco- of the product. This is not as commonly chocolate gives late selection is color. Since our first taste used today, but the original numbers gen- us some of any food is with our eyes, the color of a erated from this method are still referred to indication of chocolate gives us some indication of what when selecting a specific coating. For exam- to expect. Color is determined by the type ple, a 65 viscosity refers to hollow molding, what to expect. and amount of chocolate liquor, sugar and a 145 viscosity might be used for enrobing dairy ingredients in a chocolate coating, and a 200 viscosity for solid molding. hence formulation. The Brookfield viscometer or rheometer Flavor is often considered to be the can give MacMichael numbers, but it can determining factor of whether or not a also give a more complete measurement of product will make it in the market. The the chocolate performance or flow prop- correct balance of acceptable attributes erties. Brookfield and Haake take a sample helps to determine the success of any prod- at a specific temperature and then readings uct. There are some 9,000 taste buds on are taken at increasing rates of shear rang- the human tongue, each containing 15–18 ing from 1 to 50 rpm, followed by similar sensory cells. Flavor perception and pref- readings at decreasing speeds. Using Cas- erence might be completely different from son’s calculations, viscosity is determined. Rheology is defined as the study of the one consumer to another, so pleasing flavor deformation and flow of matter with stress. is definitely an important issue for the cor- Viscosity is the name given to the internal rect chocolate selection. friction of fluids. Essentially, there are two CHOCOLATE BEHAVIOR types of liquids — Newtonian and non- Newtonian. Newtonian fluids are inde- What determines behavior of chocolate or pendent of shearing. Examples would be how the chocolate will perform? Following water, alcohol, liquid fat or glycerol. are some factors determining the behavior Chocolate is non-Newtonian and its vis- of chocolate: cosity is affected by the presence of solids • Product flow in suspension. Chocolate is often referred • Fat content to as a suspension of particles in a fat phase. • Particle size and distribution Therefore chocolate viscosity will decrease • Equipment with increasing rates of shear. This is why • Moisture the Brookfield and Haake rheometers will Let’s concentrate on flow properties of give more accurate measurements of flow chocolate and particle size due to their properties due to procedural shearing at a great influence on chocolate behavior and given rpm indicating a product’s resistance also chocolate selection. to flow.The MacMichael will not be able to shear the entire sample between the gap Viscosity and the wall of the sample cup; it is only Viscosity is a measurement used to describe measuring the torque at a given rpm.Think the flow properties of a product. Some ways of the friction created when sliding a deck of measuring viscosity are the MacMichael, of cards back and forth or the friction cre- Brookfield and Haake methods.All of these ated between sugar and cocoa particles in methods are used in industry today, with a fat phase.These products need a force to Brookfield being the most common. start them to flow. This is known as yield The MacMichael is a single-point sys- value. More specifically, the yield point tem. The product is measured at a specific should be redefined as the shear stress at 76 September 1998 • The Manufacturing Confectioner Chocolate Behavior which not only deformation occurs but sta- (>0.5 percent). Polyglycerol polyricinoleate It is best to add tionary flow begins. (pgpr) and ammonium phosphatides lecithin as late in (yn)— manufactured from rapeseed oil — Yield value is reported in dynes/square the process as centimeter. Plastic viscosity is then the are also known to greatly reduce viscosity. force needed to maintain this flow once it Their usage depends on the legislation of possible so it is moving, which is known as poise. Brook- the particular country. does not bind up field can measure these values, known as Percent moisture, fat content and par- moisture. Casson values.Yield value has a number of ticle size also influence yield value. Figure practical aspects. For example, a high yield 1 shows a comparison of percent fat in value is needed for drops so the curl will chocolate, plastic viscosity, yield value stand up on the drop and not produce a and MacMichael number.As you can see flat-looking drop like a disc. Also, a high in Figure 2, the yield value and plastic vis- enough yield value is needed in enrobing to cosity for solid items are the highest. The prevent decorations from collapsing and yield value and plastic viscosity decrease to avoid feet formation on the bottom of with increased fat, which would correlate pieces, in other words, so chocolate will to different applications in confectionery flow over the piece and not off the center. manufacturing such as enrobing, hollow A lower yield value is desired for molding, items and panning.Actual values for yield especially with inclusions, so proper shake- value and plastic viscosity need to be determined based on what will work best out can occur and removal of air pockets is in your specific application and equip- successful. A low yield value is also desir- able for enrobing bakery items. Percent Fat versus Viscosity Measurement 26% 27% 30% 34% Yield Value Influences 180 Proper emulsification in the chocolate 160 140 mass is necessary to aid in yield value 120 reduction. Lecithin was introduced to the 100 80 industry over fifty years ago. It is primar- 60 ily extracted from soybean oil. Lecithin 40 has both lipophilic (fat loving) and 20 0 hydrophilic (water loving) properties.This Plastic Yield MacMichael surface-active agent greatly affects choco- Viscosity Value late fluidity. The degree of flow is depen- Figure 1 dent on the ease with which the solid par- ticles are able to move over one another Viscosity at Various Fat Percentages 140 Four samples within the liquid phase, which is cocoa YV butter. Lecithin is an economic value to Decreasing yield value with 120 PV chocolate due to the ability to manufacture added fat 26 percent solid items chocolate with less cocoa butter.The time 100 27 percent enrobing and amount of lecithin is critical for its 30 percent hollow full effect on changing viscosity. It is best 80 34 percent panning to add lecithin as late in the process as 60 possible so it does not bind up moisture and maximum cocoa butter has been made 40 available through the conching process. 20 An addition of 0.1–0.3 percent has the same viscosity-reducing ability as ten times 0 the amount of cocoa butter.