Control questions

1. Determining the completeness of filling.

2. Determination of mass concentration of total extract by refractometric method.

3. Determination of mass concentration of sugar by method of direct titration.

4. Determination of mass concentration of acid.

5. Method of electrometric titration

Laboratory work # 14. Determining how falsification of food raw materials and products

Purpose of the work: to identify flour to determine its grade

Theoretical part:

Flour is a powdery product obtained by repeated grinding of various grains with subsequent separation of individual fractions. Depending on the kind of used grains flour is: wheat, rye, meslin, barley, oats, corn, rice, buckwheat, soybean, pea etc.

The main types of falsification of flour – qualitative and quantitative, is much less common product.

Falsification assortment of flour occurs due to the substitution of one of the other flours; flour derived from this grain to others.

The most common assortment falsification of wheat flour is selling flour of 1 class under the guise of flour. To distinguish between a fake and color, but a more accurate conclusion can be made on the basis of physico-chemical parameters: the contents of cellulose, pentosan, calcium, phosphorus, iron. Also found the substitution of a more expensive rye flour – wheat in southern Russia and on the contrary, wheat – rye.

Falsification assortment – mix for wheat flour, corn, pea and other cheaper types detected by the laundering of gluten. In addition, this falsification can be detected by microscopy, as the starch-grains of wheat flour are peculiar to certain shape and size (small round grains).

Qualitative falsification of flour can be achieved through the following techniques: adding other types of flour; adding foreign additives is not food (chalk, lime, fly ash), food (bran); introduction of food additives, flour improvers.

The most common method of adulteration of flour - re-grading.

While partial or complete replacement of high-grade flour low can be identified by color: the lower the grade of flour, the darker it is. The most accurate measure of flour grade is the ash content. This is because the ash content of individual anatomical parts of the grain varies. The highest ash content of the shells and the aleurone layer, some less - germ and the endosperm.The lower the grade of flour, the more particles of shells having high ash content, the higher ash content of the flour. Flour, which is a pure endosperm, has a low ash content.

The standard requires that the flour of a particular variety must have

mass fraction of ash not higher than the prescribed percentage: flour wheat flour – no more than 55%; 1C - not more than 0.75%; 2 – not more than 1.25%. Mass fraction of ash in rye seeded flour should be 0,75%; for flour -1,45%, for the Wallpaper is 2%, but not less than 0.77 is lower than in the grain before cleaning.

Quantitative falsification of flour (underweight) – this is consumer fraud at the expense of considerable deviations of the parameters of the product (mass) exceeding the maximum permissible limits of deviations. To detect such falsification simply by measuring pre-measuring the mass of attorneys measures of weight.

Information falsification flour is the deception of the consumer with inaccurate or distorted information about the product. This type of fraud by misrepresentation in commodity-accompanying documents, marking of the goods. When falsifying information about the flour quite often distorted or inaccurately specify the following information:

- Product name;

- Grade flour;

- The amount of flour.

Also may be a substitution of certificates, opinions grain testing laboratories, etc.

Identification of flour starts with the determination of its appearance - color. Followed by determination of ash content of flour and the amount of wet gluten (gluten laundering). Then determine the presence of flour non-food additives.