Moisture and ash are crucial analytical values in food samples and are often needed as calculation reference for other analytical parameters too. Furthermore ashing is part of the sample preparation for the analysis of individual elements in the mineral content. Moisture is a critical parameter for shelf life time of food and ash gives information on the salt content.
Automation of the moisture and ash analysis brings efficiency, quality and security into the laboratory.
The nutrient content of meat and meat products is determined with the following analysis and often calculated as packages by contract laboratories:
Moisture, ash, total fat, total protein, carbohydrate (calculated) and kcal/kJ (calculated). Here the ash is a quality characteristic itself and is needed to calculate the carbohydrate.
Carbohydrate = 100 % – moisture – ash – fat – protein.
Similar for other food:
Nutrient with moisture, ash, dietary fibre, total protein, total fat, fatty acid composition, total sugar (saccharose, glucose fructose, lactose, galactose, maltose) carbohydrate (calculated), energy value (kcal/kJ).
Fat and Proteins content are calculated on dry mass. Ash gives the totals mineral content of milk: Calcium and phosphorous are the major minerals found in milk. These minerals are required in large quantities by the rapidly growing neonate for bone growth and development of soft tissues.
Calcium and phosphorous mostly are associated with the casein micelle structure. Milk also contains most other minerals found in the body.
The determination of the ash content in flour serves to estimate the degree of the endosperm separation from the bran during milling, i.e. the grade of flour. The more refined the flour the less ash is produced. In pasta production the ash determination of flour is crucial. The grade of milling determines the properties of the flower and therefore the possible use: e.g. pasta or bread.
The final analysis of pasta contains an ash determination too. This ash contains the minerals from the flower plus the salt given to the dough.
Most food samples have to be dried at 105°C and ashed at 550°C (SLMB) until a stable weight is reached. Flour and some flour products are dried at 105°C or 130°C and ashed at 600°C or 900°C (see special application sheet).
Standard Method with oven
|Annealing empty crucibles for stable weight||possibility to pre-define a "heating out"|
|Measuring tare of crucible one by one||Automatic Procedure|
|Weighing + documentation of each crucible||Dry Matter||Automatic + entering the sample|
|Samples in drying over + START||START PROGRAM|
|Removing samples from over + cool down||Results (moisture)|
|Back weighing samples, calculation (moisture)|
|Pre-ashing with rapid incinerator or hot plate||Results (ash)|
|Samples in muffle furnace|
Removing samples + cooling down in exicator
|Calculation and documentation (ash)|
|Back weighing for stable results (repeat?)|
UFAG Laboratories AG (Official webpage of http://www.ufag-laboratorien.ch/)
Sursee, Switzerland, contract laboratory, 2 prepASH
As the leading independent service laboratory in Switzerland, UFAG LABORATORIEN AG offer integral analytical solutions for the food industry. (1 company, 2 business units, 90 employees)
UFAG LABORATORIEN AG define their level of performance and quality as TOTAL QUALITY MANAGEMENT (TQM), including compliance with:
EN ISO/IEC 17025
Good Manufacturing Practice (GMP)
UFAG LABORATORIEN AG created a basis for national and international recognition of their study reports.
Contract laboratories have to deal with a huge variety of samples.
The profit of automation is maximal since the time consuming weighing back until stable weight has been reached is omitted. (Industries with only a few samples will have extensive knowledge of these samples and can therefore dry and ash for a fixed time. Therefore, manual work is not as extensive as it would be for “unknown” samples which may require weighing to be carried out several times until the weight is consistent).
Reduced time and effort: prepASH is a fully automatic drying and ashing machine, no need for multiple weighing after the time consumed cooling down in the desiccator and automatic calculation of results. Working in groups of similar samples in a single run will increase efficiency and optimise time of analysis.
Improved safety and efficiency: No more dangerous analysis with the open flame. The prepASH analysis can be done in different time slots, e.g. at night.
Increased quality up to 20% of each ash determination has to be re-analysed because of faulty/undefined results. prepASH is highly repeatable and reliable!
Detailed analysis reports: Due to the permanent recording of measurements during the entire process and the automatic saving of the final results, all data is retrievable at any moment.
You can download the complete Application Note: Ash and Moisture Determination with prepASH 340 Series for Food Analysis
If you would like to find out more about TGA Analysis we have a excellent range of Thermogravimetric Analysers that could accommodate your needs on our website. Please don’t hesitate to get in touch, someone from our team will be happy to assist you.