Some feed enterprises do not conduct animal-derived freshness experiments, which poses great potential for product quality, especially animal-derived feeds such as intestinal membrane proteins, plasma proteins, fishmeal, etc. These materials are light if the freshness is exceeded. Will bring great impact on the growth of animals, many feed companies call me to this method, the method is now announced as follows, please see the friends in need, give roses, leave the fragrance.
Determination of volatile base nitrogen (freshness)
Principle: When the protein is decomposed, the amino acid deamination base produces ammonia, the amino acid decarboxylates to form an amine, ammonia and amine (volatile amine) are evaporated in the alkali solution (magnesium oxide), absorbed by boric acid, and counter-titrated with standard hydrochloric acid. , the content is measured.
1 reagents and solutions
1.1 Magnesium oxide solution 10g / L: Weigh 1.0g of magnesium oxide, add 100mL of water, shake and mix into a suspension.
2. Step
Weigh 10g sample into 250ml stoppered flask, add 100.0ml water, shake for 30min, filter, take 10.00ml of solution, add magnesium oxide solution (10g / L) 10ml, quickly cover, add water to prevent leakage, press The crude protein was distilled and titrated with a hydrochloric acid standard solution (0.01 mol/L).
3. Calculation:
Volatile base nitrogen (VBN) (mg/100g) is calculated by the following formula:
VBN(mg/100g)={ [C(V-V0)*14]/m*(10/100)}*100
Example: fish meal sample 8.6706g, VHCl = 0.0200mol / LV = 3.93ml V0 = 0.15ml
VBN={[0.0200*14* (3.93-0.15)]/8.6706*(10/100)}*100= /100g
Application:
Fresh fish meal VBN<100mg/100g (40-80 mg/100g)
Fish meal with poor freshness VBN>150mg/100g (180-350 mg/100g)
Suckling pig fish meal VBN<100mg/100g
Note: The non-protein nitrogen content in the test sample can be referred to this method: alkali NaOH
Frp Roof Panels,Fiberglass Roofing Sheets,Fiberglass Greenhouse Panels,Corrugated Fiberglass Roofing Panels
PINGYUN INTERNATIONAL , https://www.pingyunconstruction.com