HW #3 due Jan. 30 th in class

1. Lecture 4 – Physical AttributesAnnouncements HW #3 due Jan. 30th in class BAE2023 Physical Properties of Biological Materials Lecture 4

2. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Quick Review Describe size, shape, style Sphericity Determining volume, equipment Surface area Electronic method for estimation BAE2023 Physical Properties of Biological Materials Lecture 4

3. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Density: Definition: weight per unit volume Liquid density determined by pycnometer, hydrometer Common liquid food product in Table B.1 in Appendix B May change significantly with temperature Specific Gravity: Definition: ratio of density of liquid to density of water Change due to temperature is small BAE2023 Physical Properties of Biological Materials Lecture 4

4. Hydrometer • Brix: sucrose • Lactometers: milk density • Oleometers: veg.oil BAE2023 Physical Properties of Biological Materials Lecture 4

5. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Foams: products with large amounts of air incorporated during processing Whipped cream, sherbet, ice cream Describe using “overrun”: % increase in volume attributed to air Icemilk: 30-40% Sherbet: 50-80% Cream: 100-120% BAE2023 Physical Properties of Biological Materials Lecture 4

6. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Particulate Materials Solid Density: weight per unit volume excluding interior pores Particle Density: weight per unit volume of individual kernel Bulk Density: weight per total volume occupied by large quantity of kernels Density of water is different than other components…we can distinguish solid density and water density BAE2023 Physical Properties of Biological Materials Lecture 4

7. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 For water and solids: BOOK CORRECTION ex. 2.4 BAE2023 Physical Properties of Biological Materials Lecture 4

8. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 “particle density is highly dependent on moisture content” EX: suppose the soybean moisture content were 0.16 and the kernel density were 1.232 g/cm3 BAE2023 Physical Properties of Biological Materials Lecture 4

9. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Density of fruits and vegetables: Determined by water displacement method. Example 2.5 Table BAE2023 Physical Properties of Biological Materials Lecture 4

10. BAE2023 Physical Properties of Biological Materials Lecture 4

11. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Bulk density Determined by pouring a sample into a container with known dimensions. Variables: method of filling and striking surface Conversion: 1 bushel = 1.244 ft^3 or 0.035239 m^3 BAE2023 Physical Properties of Biological Materials Lecture 4

12. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Test Weight Factors affecting test weight…moisture content, broken kernels, fines, variety/hybrid, growing conditions Bulk density Table 2.3 (you will need this table later on!!!) Porosity: space between particles, not within particles Calculated from bulk density and particle density Example 2.6 BAE2023 Physical Properties of Biological Materials Lecture 4

13. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Regression and Statistical Distribution Equation 2.6 What is this business about logs? Mean and standard deviation (measure of variability) r^2 Normal distribution Influences how we design equipment to handle particles BAE2023 Physical Properties of Biological Materials Lecture 4

14. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Sieve analysis Sized by the 64th BAE2023 Physical Properties of Biological Materials Lecture 4

15. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Radius of Curvature Sharpness of curvature will determine how readily an object will roll Determined by radius of curvature Figure 2.6 BAE2023 Physical Properties of Biological Materials Lecture 4

16. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Applications Separate foreign material Proper singulation during planting Separate germs, pericarps, hulls from endosperm or cotyledon Size grades and shape Density separation (milk separator) Watermelon sorting by shape and weight Sorting by shape…orientation is a problem Optical sorting BAE2023 Physical Properties of Biological Materials Lecture 4

17. Lecture 4 – Physical AttributesChapter 2, pgs. 21-48 Homework #4 Due 2/6 Problem 1: #2.2 in book Problem 2: #2.8 in book Problem 3: #2.10 in book BAE2023 Physical Properties of Biological Materials Lecture 4