Fat Acidity of Milled Cereal Products

The REX Ti-50 Automatic Potential Titrator allows quick and si mple determinations of the fat acidity of milled cereal products.

When cereal products deteriorate in storage, various chemical changes occur. Under ideal storage conditions, these changes progress very slowly, but when storage conditions are unfavorable, they progress more rapidly, reflecting faster deterioration. The breakdown of fats by lipases and the liberations of free fatty acids is the most rapid chemical change during grain products deterioration.

A fat acidity test (ISO 7305) has been developed to estimate the degree of soudness of grain and cereal products. Fat acidity can be an indicator of biochemical changes during storage of cereal products. It therefore provides a sensitive and significant test to characterize the state of conservation and the utilization values of these products. 

A fat acidity test (ISO 7305) describes a method of estimating the quantity of long-chain, non-esterified fatty acids which are liberated by the action of lipase during the storage of milled cereal products.

1. Standard Reference

ISO 7305:2019《Milled cereal products — Determination of fat acidity》

ISO 27107:2008 specifies a method for the determination of the fat acidity of milled cereal products. It is applicable to flours and semolinas obtained from wheat and durum wheat, and to pasta.

2. The Principle  

Dissolution of the acids in ethanol at room temperature, centrifuging and titration of an aliquot portion of the supernatant liquid against sodium hydroxide.

Fat acidity is expressed in milligrams of sodium hydroxide per 100 g of dry matter.

The solvent used for the extraction, 95 % to 96 % ethanol, breaks all the low-energy links where fatty acids are involved, and solubilizes the latter rapidly and quantitatively, with the exclusion of the major part of amino acids and mineral salts.

Observation of the colour change at the end point of the titration is facilitated by the absence of turbidity in the solution.

3. Recommended Configuration

1. Ti-50 Automatic Potential Titrator 
   14. Range：(-2000.00~2000.00) mV
   14. mV Accuracy：±0.03% or ±0.2mV
   14. 1 extra burette driver can be installed (optional).
   14. Replaceable burette with high-accuracy (10 ml or 20 ml selectable).
   14. Support acid-base titration, non-aqueous aqueous phase titration, constant titration, REDOX titration, precipitation titration, complexation titration
   14. Support the following titration modes: DET (dynamic equivalence point titration), MET (monotone equivalence point titration), SET (Preset Endpoint Titration) and MAT (manual titration).
   14. Titration methods, curves and results are displayed in detail.

2. Auxiliary titration unit 20mL
3. Burette valve device 20mL (SC5.461.057)
4. Anti-diffusion capillary
5. Electrodes：982211 Non Aqueous pH Titration Electrode

4. Titration Setting

50. Non-aqueous aqueous phase titration
50. Sample: DET (dynamic equivalence point titration)
50. Blank Sample: MET (monotone equivalence point titration)

5. Titration curve