Midterm 1 - UNIT 02A Flashcards
FOOD COMPOSITION
- Animal nutrition =
= deals with the nutr needs of food
= science of prep & formulation of animal feed to produce: FOOD - meat, milk, eggs
NON FOOD - wool
Factors in determining food composition and animal nutrition (1-3)
1 - Cost - feeds, housing, health
2- Environment - manure, wasted nutr, air, ground, water contamination
3- Animal feed… ~ 65% of farm expenses for pig/chicken nutr
Balanced Nutrition for animals
1
2
1- enhances immune health, welfare and productivity/longevity of animal
2- specific to raising animal in confinement
PROXIMATE ANALYSIS
Purpose:
= quantitative analysis of macromolecules in food - combo of chemical analytical procedures
Purpose: estimate nutr content (molecular components) of food – different compounds in a mixture
Analysis considerations:
(1-4)
developed by:
1 - obtain sm sample (2-10g) 2 - prep = grinding and drying feed 3 - storage = temp sensitive 4 - transportation \: 1865 Hennhberg & Strohmann
BASIS
1)
2)
Why extract _____?
1) Eliminate water from feed - feed placed in oven overnight
2) Determine 5 proximate principles in the remaining dry matter
? Water - all feeds will have different water content, remove water = accurate comparison
Dry Matter
- 2 types of content
- Dry matter determination:
- sources of error
1 - inorganic - minerals
2 - organic - vitamins and Macros
: Dry weight / Fresh Weight x 100% = DM%
- loss of FA, essential oils, lactic acid, fermentation products
5 PROXIMATE PRINCIPLES (1) - developed: - basic Idea: ex: - what is measured
CRUDE PROTEIN
: danish - kjeldhal, technology to isolate Nitrogen from organic samples
: convert test material (N) -> protein
THEN multiply by correction factor (6.25 b/c ~ 16g of N is derived from 100g of protein (100/16) )
ex - 7.35 of N x 6.25 = 45.9g crude protein
: nitrogen is measured NOT protein
(1) How is nitrogen content determined?
Step 1:
Step 2:
1: Dry (soybean) sample
2: Boil sample in sulfuric acid
- process converts N to ammonium sulfate
- ammonium sulfate is THEN cooled and neutralized with Sodium Hydroxide
- WHY NaOH - helps to rest the denaturing process
- ionized ammonium is released – sample gets dried and further titrated with sulfuric acid
Errors:
PROS
CONS
: assumes all N comes from protein (it doesn’t - can be DNA/RNA(nucleic acids)/UREA
P: accurate and repeatable
C: time consuming and hazardous materials
(2) involves: what is collectively referred to as \_\_\_\_? GOAL: HOW: Limitation:
ETHER EXTRACT
: the use of organic compounds soluble in organic solvents
? CRUDE FAT = fats, FA esters, fat soluble vitamins
G: isolate the high caloric fraction (lipids and lipid soluble compounds)
H: sample boiled in ether (organic solvent) for 4 hours
L: no indication of fat quality in food (sat or unsat)
(3) refers to: therefore is a measure of: HOW: Problem:
ASH
: residue after ALL organic nutrients have been burned off/oxidized
: inorganic compounds (minerals)
H: 500-600 degrees - 2-4hours
P: High ash values may indicate contamination of feed or dilution (limestone/salt)
- ash values are cumulative of all mineral elements & can underestimate mineral value of feed - high temp can burn off Cl, Zn, Se, I
(4) measures: - fermented by resistant to: made up of (components of): * plant cell in notes *
CRUDE FIBER
: indigestible fraction of feed
- by hindgut microbes
: digestive microbes
: (of crude fibre = ) cellulose, hemicellulose, lignin, pectin
- Cell wall allows
:
Turgor pressure =
: osmotic swelling
= osmotic imbalance between cell interior and surrounds environment
how is crude fibre determined: 1 2 why 2 different pH levels? Problem:
1- sample is dried, baked in weak sulfuric acid then filtered
2- residue boiled in weak alkali solution, filtered, dried and ashed(inorg components removed)
? b/c it stimulates digestive system of an animal (w/o digestive enzymes)
P: some fibre lost - underestimated
