Mixing and Forming Reviewer

MIXING AND FORMING REVIEWER TIMING AND EQUILIBRIUM IN MIXING MIXING ACCURATE TIMING - Crucial to time the mixing operation BLENDING...

MIXING AND FORMING REVIEWER TIMING AND EQUILIBRIUM IN MIXING MIXING ACCURATE TIMING - Crucial to time the mixing operation BLENDING properly to prevent unmixing - Key process where two or more ACHIEVING UNIFORMITY components are combined to create a - Uniformity of final product depends on uniform mixture balance between mixing and unmixing. - Used to achieve specific functional or - Influence by: type of mixer, operating sensory characteristics such as texture conditions, and component properties. development in doughs or aeration in butters. MEASURING MIXING PROGRESS - Does not preserve food - Essential for processing and meeting Samples will mostly contain one component at product standards. the start of mixing a two-component mixture. PRIMARY GOAL: Develop desirable product As mixing progresses, samples will become characteristics more uniform and approach average composition of the mixture. MULTICOMPONENT SYSTEM: Ingredients with different physical properties and quantities. To track the change in composition, the standard deviation of each sample’s Involves HIGH-VISCOSITY OR NON- composition is calculated. NEWTONIAN FLUID Lower values indicates greater uniformity. Components may be fragile and damaged by overmixing Mixing patters influence the final product characteristics. CRITERIA FOR SUCCESSFUL MIXING 1. Sensory Properties (taste, texture) 2. Functionality (mix consistency, aeration) 3. Homogeneity (even distribution of ingredients) 4. Particulate Integrity (No damage to fragile components 5. Safety and Hygienic Design 6. Compliance with Legal Standards MIXING INDICES 7. Process Efficiency and Flexibility Monitor and compare the extent of mixing THEORY OF SOLID MIXING with different equipment. FACTORS THAT AFFECT MIXING - Particle size, shape, and density - Moisture content - Surface and flow characteristics - Tendency to aggregate - Mixer effieciency More uniform mixing is achieved when materials have similar shape, size, and density. Difference in material properties can cause unmixing. Uniformity may only temporary Overmixing can cause separation. APPLICATION OF MIXING INDICES Dilatant - exhibit increasing viscosity as the shear M1: Used for approximately equal masses of rate increases. components at low mixing rates. - When subjected to sudden, high shear M2: Used for small quantities mixed into larger stresses, these fluids become thicker and bulk and at higher rates. more resistant to flow. M3: Used for liquids or solids in a similar - Examples: corn flour and chocolate manner to M1 Viscoelastic MIXING TIME - exhibit both elastic and viscous properties. - When subjected to a stress, they exhibit both a viscous response (deformation) and an elastic response (recovery). - Examples: honey, bread dough THEORY OF LIQUID MIXING RATE OF MIXING Key velocities in liquid mixing: Longitudinal velocity - parallel to the mixer shaft Rotational velocity - tangential to the mixer shaft Radial velocity - perpendicular to the mixer shaft LIQUID FLOW AND POWER REQUIREMENTS Effective mixing technique: Use baffles or angled blades to maximize radial and longitudinal velocities. Avoid vortex formation, which leads to ineffective mixing. MIXING HIGH-VISCOCITY LIQUIDS Mixing in Viscous Materials: Methods: - Kneading: Pressing material against vessel VISCOSITY FOR BAFFLED MIXERS walls. - Folding: Incorporating unmixed material into the mixture. - Shearing: Stretching the material. DENSITY OF MIXTURES Challenges: - Non-Newtonian liquids (pseudoplastic, dilatant, viscoelastic) require special EQUIPEMENTS attention to mixer design. Pseudoplastic MIXERS - exhibit decreasing viscosity as the shear Types rate increases. 1. dry powders or particulate solids - When stirred or shaken vigorously, these 2. low- or medium-viscosity liquids fluids become thinner and flow more easily 3. high-viscosity liquids and pastes - Examples: sauces, ketchup 4. dispersion of powders in liquids.  BREAD MOULDER MIXERS FOR DRY POWDER AND PARTICULATE SOLID Has three stages - SHEETING. Dough is passed through three TUMBLING MIXING. A rotating drum or barrel that sets of rollers that successively decrease mixes materials through tumbling action. the gap (nip) size, turning the dough into RIBBON MIXER. A horizontal mixer with two helical thin sheets without causing any tears. ribbons rotating in opposite directions - CURLING. The sheeted dough is loosely curled into a cylindrical shape. VERTICAL SCREW MIXER. A vertical mixer with a - ROLLING-SEALING. A revolving drum seals rotating screw that pushes materials upward and the dough by pressing it against a pressure downward. plate, gradually increasing pressure to MIXERS FOR LOW OR MEDIUM-VISCOSITY LIQUIDS remove trapped air. The moisture content increases at the trailing end of the dough, FLAT BLADE AGITATOR. This type features broad, flat and various moulder designs (e.g., cross- blades that rotate within the vessel. grain, reverse sheeting) are used to ensure VANED DISC IMPELLER. A disc-shaped impeller with the moist part is at the center of the radial vanes that rotate within the vessel. cylinder. - PROPELLER AGITATOR. A three-bladed propeller that rotates within the vessel. MIXERS FOR HIGH-VISCOSITY LIQUIDS AND PASTE Z-BLADE MIXER. A horizontal mixer with a rotating Z- shaped blade that pushes and folds materials. DOUGH ENCASING EQUIPMENT PLANETARY MIXER. A mixer with a central rotating Co-extrusion process. Inner and outer bowl and planetary arms that rotate in the opposite materials are co-extruded, then shaped by direction, creating a kneading action. 'encrusting discs'. SCREW CONVEYOR MIXER. A mixer that combines conveying and mixing functions, using a rotating screw to move and blend materials. EFFECTS ON FOOD The action of a mixer has no direct effect on either the nutritional quality or the shelf life of Thickness Control. The flow rates of each a food but may have an indirect effect by material control the thickness of the outer allowing components of the mixture to react layer and inner sphere, providing flexibility in together. product design. FORMING Process of shaping raw materials into specific forms or sizes to create desired end product. Done for several key reasons, each related to improving the quality, consistency, and appeal of food products.  APPLICATIONS Food can be deposited as single type, layered, or center-filled (e.g., liquid centers, chocolate Developed in Japan for rice dough and bean paste around hard-boiled sweets) paste cakes Food is cooled in a cooling tunnel, then ejected Sweetbreads with jam once sufficiently hardened, restarting the cycle Doughnuts, meat pies Hamburgers with cheese THREE MAIN TYPES OF EQUIPMENT Fish with vegetable fillings 𝟭. 𝗠𝗲𝘁𝗮𝗹 𝗺𝗼𝘂𝗹𝗱𝘀 𝘄𝗶𝘁𝗵 𝗲𝗷𝗲𝗰𝘁𝗼𝗿 𝗽𝗶𝗻𝘀 for hard PIE FORMERS confectionery (e.g., butterscotch). A piece of dough is placed 𝗶𝗻𝘁𝗼 𝗮𝗹𝘂𝗺𝗶𝗻𝗶𝘂𝗺 𝟮. 𝗙𝗹𝗲𝘅𝗶𝗯𝗹𝗲 𝗽𝗼𝗹𝘆𝘃𝗶𝗻𝘆𝗹 𝗰𝗵𝗹𝗼𝗿𝗶𝗱𝗲 (𝗣𝗩𝗖) 𝗺𝗼𝘂𝗹𝗱𝘀 , 𝗳𝗼𝗶𝗹 𝗰𝗼𝗻𝘁𝗮𝗶𝗻𝗲𝗿𝘀 or 𝗿𝗲-𝘂𝘀𝗮𝗯𝗹𝗲 𝗽𝗶𝗲 𝗺𝗼𝘂𝗹𝗱𝘀. ejection by mechanical deformation, used for soft The dough is pressed into shape using a 𝗱𝗶𝗲, confectionery (e.g., toffee, fudge, jellies, caramel, forming the pie casing. fondant, chocolate). The 𝗳𝗶𝗹𝗹𝗶𝗻𝗴 is added into the dough casing. A 𝟯. 𝗣𝗼𝗹𝘆𝘁𝗲𝘁𝗿𝗮𝗳𝗹𝘂𝗼𝗿𝗼𝗲𝘁𝗵𝘆𝗹𝗲𝗻𝗲-𝗰𝗼𝗮𝘁𝗲𝗱 𝗮𝗹𝘂𝗺𝗶𝗻𝘂𝗺 continuous sheet of dough is laid over the top 𝗺𝗼𝘂𝗹𝗱𝘀 with compressed-air ejection, used for jellies, to cover the filling. 𝗥𝗲𝗰𝗶𝗽𝗿𝗼𝗰𝗮𝘁𝗶𝗻𝗴 𝗯𝗹𝗮𝗱𝗲𝘀 gums, fondant, crèmes. cut the dough sheet to form the pie lid. EXTRUSION AND SHAPING BISCUIT FORMERS Other equipment extrudes sugar confectionery Biscuit Formation Methods: into a ‘rope,’ which is shaped by rollers and 𝟭. 𝗥𝗼𝘁𝗮𝗿𝘆 𝗠𝗼𝘂𝗹𝗱𝗲𝗿 dies. - Dough is pressed into shaped cavities in a MICROPROCESSOR-CONTROLLED DEPOSITORS metal moulding roller. 𝟮. 𝗠𝗼𝘂𝗹𝗱𝗶𝗻𝗴 𝗥𝗼𝗹𝗹𝗲𝗿𝘀 Used for cake mixes and high-viscosity liquids. - Shapes are cut from a sheet of dough using Can store sizes, shapes, and weights for up to a cutting roller. A printing roller simultaneously 99 different products, which can be called up imprints a design on the upper surface of the using a two-digit product code. biscuit. 𝟯. 𝗪𝗶𝗿𝗲-𝗖𝘂𝘁 𝗠𝗮𝗰𝗵𝗶𝗻𝗲 - Soft dough is extruded through a series of dies. A wire cuts the dough into shapes. 𝟰. 𝗥𝗼𝘂𝘁 𝗣𝗿𝗲𝘀𝘀 : - A continuous ribbon of dough is extruded. Dough is cut to the required length by a reciprocating blade (no cutting wires used). Additional Equipment (Levine and Drew, 1994): 𝗟𝗮𝗺𝗶𝗻𝗮𝘁𝗶𝗻𝗴 𝗱𝗼𝘂𝗴𝗵 𝘄𝗶𝘁𝗵 𝗳𝗮𝘁 (for croissants and pastries). 𝗙𝗼𝗹𝗱𝗶𝗻𝗴 𝗱𝗼𝘂𝗴𝗵𝘀 (for pasties and rolls). 𝗙𝗶𝗹𝗹𝗶𝗻𝗴 𝗱𝗼𝘂𝗴𝗵𝘀 (for sausage rolls, fruit bars like fig rolls, and cakes). CONFECTIONERY MOLDERS Individual moulds of required size/shape attached to a continuous conveyor. Moulds pass below a depositor equipped with a piston filler to deposit accurate volumes of hot sugar mass.