Homework Assignment #1
1. (1)Cellulose is a polymer of what type of molecules?
2. (1)Which starch molecule is a branched polymer of glucose? Amylopectin
3. (1)Define the volume of one bushel in cubic feet.
1 bushels = 1.24445602149 cubic feet.
1 cubic meter = 28.3775930707 bushels.
4. (3)What are the conversion factors for crude protein content for cereal grains, if total nitrogen is known?
Factor for Cereal Grains
N x 6.25
This factor is used for all cereals except rice and wheat. 0 Rice protein: N x 5.95
1 Wheat protein: N x 5.7
*A portion of N in some coproducts is found as nonprotein nitrogen (NPN) and, therefore, the value calculated by N x 6.25 is referred to as “crude”, rather than true, protein.
5. (2)Give two limitations of why crude protein is an inaccurate measure (i.e.,“crude”).
Crude fiber levels are guaranteed on feed labels but TDF is a more useful measure of dietary fiber content.
When the crude fiber system was developed, it was thought to represent most of the cell wall portion. However, later it was discovered that it did not account for some of the hemicellulose and lignin components.
6. (5)What do crude fiber, ADF, NDF and TDF actually measure? The method for determining crude fiber consists basically of measuring the residue remaining after acid and basic hydrolysis. It is known that the crude fiber method covers 50%-80%of the cellulose, 10 %- 50% of the lignin, and 20% of the hemicelluloses. http://archive.unu.edu/unupress/food/8F024e/8F024E09.htm
Acid Detergent Fiber (ADF) is a measure of the fibrous part of a plant (cellulose and lignin) that the animal cannot digest. Think of coarse or woody forages (or straw) and so much of the plant is indigestible fiber that http://answers.yahoo.com/question/index?qid=20100920154955AAbfrEP Neutral Detergent Fiber (NDF) measures the fiber content in...