CN103149205A

CN103149205A - On-site rapid detection kit for protein adulteration

Info

Publication number: CN103149205A
Application number: CN2013100627583A
Authority: CN
Inventors: 方邢有; 路东琪; 马青; 邵秋荣; 丁晓
Original assignee: SHUNDE ENTRY-EXIT INSPECTION AND QUARANTINE
Current assignee: SHUNDE ENTRY-EXIT INSPECTION AND QUARANTINE
Priority date: 2013-02-07
Filing date: 2013-02-07
Publication date: 2013-06-12

Abstract

The invention discloses an on-site rapid detection kit for protein adulteration, which is used for detecting whether fresh milk, liquid milk products and powdered milk are adulterated with 'false protein' of urea or ammonium salt and belongs to the field of food rapid detection. The detection comprises the steps of: adding reagents A, B, C and D in liquid milk or powdered milk solution; and after chemical reaction, comparing the color development results with a urea mixing color chart and an ammonium salt mixing color chart, thereby determining the content ranges of urea and ammonium salt mixed in a sample. The kit is low in cost, simple in operation step, good in color development effect, and applicable to qualitative and semi-quantitative detection on site, and the lower limits of urea and ammonium salt detection are respectively 0.05%.

Description

Protein is mixed pseudo-field quick detection kit

Technical field

The invention belongs to food fast detecting field, be specifically related to a kind of quick detection kit of mixing false protein urea and ammonium salt in fresh milk, liquid milk products and the milk powder.

Background technology

The important indicator of protein food nutrition is connected by the peptide bond bonding by amphoteric amino acids, and its chief component element is C, H, O, N, S, though kinds of protein is many, its nitrogen content is more approaching, average out to 16%.The Ruzhong adds the nitrogen substances such as urea, can improve the content of nonprotein nitrogen, the illusion that causes protein to increase, and can improve proportion, and mix mouthfeel and local flavor that the nitrogen substance such as urea not only affects finished milk, change the solubleness of milk, also can damage the healthy of consumer, even cause poisoning.Feed is the material base of developing animal husbandry, and nutriment and objectionable impurities contained in feed directly affect the quality of animal products, and then affect human health.

As everyone knows, Kjeldahls method is the classical way of measuring total organic nitrogen, has advantages of that applicability is strong, good reproducibility.But the evaluation to Protein in Food has certain limitation, and the method is measured and comprised that nonprotein nitrogen, fake producer utilize the limitation of method of protein measurement to fake just, and the nitrogen substances such as Determining Methods for Carbamide, ammonium salt improve " protein " content in product.No matter be Determining Methods for Carbamide or ammonium salt, on the impact of sample protein matter content all clearly, Determining Methods for Carbamide and amounts of ammonium salt are higher, and be larger on the impact of protein determination result, often mixes 1% urea, and the protein determination amount on average increases by 2.7%; Often mix 1% ammonium nitrate, the protein determination amount on average increases by 1.34%.At present, offer report although there are the nitrogen substances such as urea, ammonium salt to detect dispatch, also there is no quick detection kit.

Summary of the invention

The invention provides a kind of simple to operate, be applicable to on-the-spot sxemiquantitative ground and detect the kit that mixes false protein urea and ammonium salt in fresh milk and milk powder etc.

For achieving the above object, the technical solution used in the present invention is:

1) get many parts of liquid milk of 2ml or milk powder lysate, mix respectively urea and the ammonium salt of variable concentrations in every part of blank liquid milk or the milk powder lysate, make and contain the sample that urea and ammonium salt concentration ladder increase.

2) contain in the sample that the urea concentration ladder increases to this and add 10 0.05% sodium nitrites and 10 concentrated sulphuric acids, reaction 3min adds reagent in little spoon (0.3g) lattice after lather collapse, place 10min, observes change color.According to the different colours that manifests, that urea content in the fresh milk sample is corresponding with color, be prepared into colorimetric card.

3) add 3 of Mayer's reagents in the sample that increases to this ammonium salt-containing concentration ladder, place approximately 10s, observe change color.According to the different colours that manifests, that amounts of ammonium salt in the fresh milk sample is corresponding with color, be prepared into colorimetric card.

4) get testing sample, detect according to above-mentioned steps 2 and 3, the colorimetric card for preparing in colour developing result and step 2 and 3 of reaction is compared, obtain the content range of Determining Methods for Carbamide and ammonium salt in sample.

Protein is mixed pseudo-quick detection kit, comprising:

A reagent: Griess reagent

B reagent: 0.05% sodium nitrite

C reagent: sulfuric acid

D reagent: alkaline mercuric iodixde reagent

Mix the urea colorimetric card

Mix the ammonium salt colorimetric card

Described kit also comprises the plastic suction pipe that the kit series products is often joined, glass color comparison tube, little medicine spoon, milk powder sample spoon etc.

The invention has the advantages that:

1. made up the blank of this series products on market.

2. the colour developing color range is obvious, and vision is intuitively effective, and sensitivity is good.

3. simple to operate, fast, the departments such as quality inspection, industry and commerce, market surveillance that are adapted at apply.

Embodiment

Detect the preparation of liquid

A reagent: Griess reagent tartrate 89g, sulfanilic acid 10g, a-naphthylamines 1g mixed grinding are even

B reagent: 0.05% sodium nitrite

C reagent: sulfuric acid

D reagent: alkaline mercuric iodixde reagent mercuric iodixde 22.7g and potassium iodide 17.5g are dissolved in 50ml distilled water, get potassium hydroxide 56g and are dissolved in 250ml water, and above-mentioned two kinds of solution are merged, and are settled to 500ml.

The kit operation steps

Sample pre-treatments: if the solid samples such as milk powder or soymilk powder with milk powder sampling bale-out one scoop sample product (approximately 2 grams), are put into color comparison tube, add 5ml water, shake well, all dissolvings, dissolved solution for later use.If fresh milk or other liquid milk samples do not need pre-treatment.

1. directly get 2ml liquid milk or milk powder lysate in the glass color comparison tube, add 10 B reagent and 10 C reagent, reaction 3min adds little spoon (0.3g) A reagent after lather collapse, and reaction 10min observes change color.

2. the result that will develop the color with mix the urea colorimetric card and compare, determine the content range of Determining Methods for Carbamide in sample.

3. directly get 2ml liquid milk or milk power solution in the glass color comparison tube, slowly add 3 of Mayer's reagents, place approximately 10s, observe change color.

4. the result that will develop the color with mix the ammonium salt colorimetric card and compare, determine to mix in sample the content range of ammonium salt.

Claims

1. a protein is mixed pseudo-field quick detection kit, it is characterized in that: fresh milk, in liquid milk products and milk powder, frequent Determining Methods for Carbamide and ammonium salt are to be used for doing " false protein ", affect nitrite and the reaction of Griess reagent generation azo according to urea, ammonium salt and potassium mercuric iodide generate the principle of brown complex was in alkaline solution, add respectively A in sample, B, C reagent and D reagent, after chemical reaction, mix the urea colorimetric card and mix the ammonium salt colorimetric card and compare what colour developing result and this kit were made, determine the content range of Determining Methods for Carbamide and ammonium salt in sample.

2. protein as claimed in claim 1 is mixed pseudo-field quick detection kit, it is characterized in that: described A reagent is Griess reagent.

3. protein as claimed in claim 1 is mixed pseudo-field quick detection kit, it is characterized in that: described B reagent is 0.05% sodium nitrite.

4. protein as claimed in claim 1 is mixed pseudo-field quick detection kit, it is characterized in that: described C reagent is sulfuric acid.

5. protein as claimed in claim 1 is mixed pseudo-field quick detection kit, it is characterized in that: described D reagent is alkaline mercuric iodixde reagent.

6. protein as claimed in claim 1 is mixed pseudo-field quick detection kit, it is characterized in that: also comprise mix the urea colorimetric card, mix the ammonium salt colorimetric card, plastic suction pipe, glass color comparison tube, little medicine spoon, milk powder sample spoon.

7. protein as claimed in claim 1 is mixed the using method of pseudo-field quick detection kit:

1) directly get 2ml liquid milk or milk powder lysate in the glass color comparison tube, add 10 B reagent and 10 C reagent, reaction 3min adds little spoon (0.3g) A reagent after lather collapse, and reaction 10min observes change color.

2) will develop the color result with mix the urea colorimetric card and compare, determine the content range of Determining Methods for Carbamide in sample.

3) directly get 2ml liquid milk or milk power solution in the glass color comparison tube, slowly add 3 of Mayer's reagents, place approximately 10s, observe change color.

4) will develop the color result with mix the ammonium salt colorimetric card and compare, determine to mix in sample the content range of ammonium salt.