January 9th, 2019
|   LOCAL NEWS , MARKET NEWS
New NATA accredited chemistry tests

We are very excited to announce the expansion of our chemistry catalogue with the following NATA accredited tests: Whey Protein Nitrogen Index (WPNI), Insolubility Index and Scorched Particles.

WPNI testing to estimate the amount of undenatured whey protein nitrogen in milk powder

The Whey Protein Nitrogen Index (WPNI) is an analytical method that was originally developed (Harland and Ashworth, 1949) and subsequently modified (Kuramoto et. al., 1959) has been used to provide an indication of the extent of denaturation of whey proteins resulting from heat treatments in the manufacture of milk powders.

The method is applicable to the determination of WPNI of dried milk powder. WPNI (Whey Protein Nitrogen Index) is the determination of un-denatured whey proteins in non-fat dry milk. WPNI is an indicator of heat treatment and not a test to measure the level of whey proteins within a dairy product. Low heat powders have a WPNI of more than 6.0, Medium Heat powders have a WPNI of 1.5 to 6.0 and High Heat powders have a WPNI of less than 1.5

SCOPE

The method is to be used for milk powders, liquid milk and milk concentrates.

PRINCIPLE

The undenaturated Whey Protein Nitrogen Index (WPN) is a measure of the heat treatment applied to the milk during processing to milk powder.

MXNS Method Code: WPNI
Limit of detection: 0.05mg/g
TAT: 7-10 business days 

 

Insolubility Index – Milk Powder

The Insoluble Index is a measure for the ability of a powder to dissolve in water. It is defined as the volume of sediments in ml after centrifuging

SCOPE

This method is normally used for skimmed milk, whole milk and sweet buttermilk powder, but can also be applied to other soluble, dried dairy products.

PRINCIPLE

The powder is dissolved in water at a certain temperature and centrifuged. The supernatant is removed and replaced by water, and is centrifuged again before reading the volume of insoluble residue.

MXNS Method Code: INSOLUB_IN
Limit of detection: 0.10 ml
TAT: 7-10 business days 

 

Scorched particles

The determination of scorched particles is important not only for evaluation of product quality, but also from the point of view of safety, as this is a check of possible occurrence of some undesired combustion processes in the hot zone of the installation or heat generation in powder deposits due to Maillard reaction.

SCOPE

This method is used for milk powder and all other dried dairy products.

PRINCIPLE

The official ADMI method [36] uses 25 g of skim milk powder or 32.5 g whole milk powder mixed for 50 seconds with 250 ml water of 18 - 27°C and addition of antifoaming agent. Using compressed air or vacuum, the solution is filtered through a standard filter pad, 32 mm in diameter. The result is evaluated using the standard ADMI photographic scale. When used as a safety precaution, the frequency and quickness is most important and therefore volume measurement of amount of powder instead of weighing is recommendable.

admi_chart.png

 

MXNS Method Code: SCOR_PART
Limit of detection: it’s a grading of A, B, C, D
TAT: 7-10 business days