2/15/2016BAE2023 Physical Properties of Biological Materials Lecture 4 1 Lecture 4 – Physical Attributes

2/15/20162 Lecture 4: Physical Attributes Chpt 2, Pages For grain, seeds, fruits, vegetables –Size described by 3 dimensions Major diameter: longest dimension of the max projected area (fat part) Intermediate diameter: min. diameter on the max projected area, assumed to be equal to the longest diameter of the min projected area (thickness) Minor diameter: shortest dimension of the minimum projected area (skinny part) –May be referred to differently in industry Usually called length, width, and depth BAE2023 Physical Properties of Biological Materials Lecture 4

2/15/20163 Shape: used to describe unprocessed foods –Example: carrots = cones Style: used to describe processed foods –Example: carrot coins, french cut beans, apple wedges, banana chips Shape: use geometric solids…sphere, truncated cone (see appendix C) Lecture 4: Physical Attributes Chpt 2, Pages BAE2023 Physical Properties of Biological Materials Lecture 4

2/15/20164 Sphericity: –Ratio of volume of triaxial ellipsoid to a circumscribed sphere (show correction in book for 2a, 2b, 2c, page 13 and pg 14 example) –Blueberry example Lecture 4: Physical Attributes Chpt 2, Pages BAE2023 Physical Properties of Biological Materials Lecture 4

2/15/20165 Sphericity, S c : –Aspect ratio, R a = (b/a)*100 –R a >50%...tends to slide –S c >50%...tends to roll –Both > 50%, will tend to roll with some sliding Lecture 4: Physical Attributes Chpt 2, Pages BAE2023 Physical Properties of Biological Materials Lecture 4

2/15/20166 Volume –Volume determined by liquid or gas displacement –Pycnometers or graduated burettes –Weight of fluid displaced by solids divided by the density of the fluid = volume of the solid particles Buoyant force of water on object, page 16, 2.3 –Platform balance Optical method Lecture 4: Physical Attributes Chpt 2, Pages BAE2023 Physical Properties of Biological Materials Lecture 4

2/15/20167 Volume –Volume determined by gas displacement –Page 17 Fig.2.2 –Gas penetrates grains and seeds Coat with wax Lecture 4: Physical Attributes Chpt 2, Pages BAE2023 Physical Properties of Biological Materials Lecture 4

2/15/20168 Volume –Estimation through calculation –Use Appendix C for equations of similar geometries –Error determination, %: [(Your calculation – test value)/(test value )]*100 Example: calculated volume using equation…48.7 mm 3 Gas pyncnometer measure 50.1 mm 3 Lecture 4: Physical Attributes Chpt 2, Pages BAE2023 Physical Properties of Biological Materials Lecture 4

2/15/20169 Surface Area –Peel –Coating and peeling –Bread loaf estimation example Estimate Surface Area –Similarity to geometric solids –Appendix C (not A!!!) Example 2.3 page 19 Lecture 4: Physical Attributes Chpt 2, Pages BAE2023 Physical Properties of Biological Materials Lecture 4

2/15/ HW#4 Assignment Due 1/25 Problem 1: –A) Calculate the sphericity of a blueberry, a Red Haven peach, and a Norchip potato. –B) Which one is more spherical? Problem 2: –Calculate the volume of a Bart 46 Wheat kernel Reference data –What is the percentage error when compared to the volume determined by testing? Problem 3: –Using a piece of fruit or vegetable of your choice, and example 2.3 in Chpt 2, determine the volume and surface area. BAE2023 Physical Properties of Biological Materials Lecture 4

2/15/ HW#4 Part Assignment Due 1/25 Problem 4: #2.6 in book Problem 5: #2.12 in book BAE2023 Physical Properties of Biological Materials Lecture 4