Method for determining the amount of oat flour addition in compound flours and noodles

Patent metadata

Field	Value
Publication number	US-9518973-B1
Application number	US-201514975554-A
Country	US
Kind code	B1
Filing date	Dec 18, 2015
Priority date	Oct 13, 2015
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

The invention relates to a method for determining the amount of oat flour addition in compound flours and noodles, and it belongs to the field of food detection technology. Based on the similarity of the fatty acid composition between oat and wheat, the quantitative analysis index used for measuring the oat flour addition was determined. Based on the differences of fatty acid contents in oat and wheat, the relationship between the changing trend of fatty acid composition and oat flour content in compound powders or noodles is employed to quantitatively determine the amount of oat added to these compound flours or noodles. The invention provides a highly sensitive and feasible method for safety monitoring and quality control of oat flours and oat noodles.

First claim

What is claimed is:

1. A method for determining the amount of oat flour addition in unknown compound wheat-oat flour or compound wheat-oat noodle, comprising the steps of:
a). Mixing oat and wheat flours of different varieties and from different production areas to make compound powders with different levels of oat flours according to a balanced incomplete block design;
b). Analyzing fatty acid compositions of the wheat flours, the oat flours and the compound powders by gas chromatography;
c). Analyzing similarities and differences of contents of palm acid, oleic acid and linoleic acid in the wheat flours, the oat flours and the compound powders;
d). Establishing a 3D graph of discriminant analysis model and Fisher linear discriminant functions based on correlations of contents or paired ratios of palm acid, oleic acid and linoleic acid and amounts of oat flour added in the compound powders;
e). Determining quantitatively the amount of oat flour addition in unknown compound wheat-oat flour using the 3D graph of discriminant analysis model and the Fisher linear discriminant functions established in step d);
f). Calculating coefficients of variation of fatty acids in a compound noodle as compared to the compound powder that is used to make the compound noodle, and using the coefficients of variation to adjust corresponding values of contents or ratios of fatty acids in unknown wheat-oat compound noodle; and
g). Applying adjusted values of fatty acids to the 3D graph of discriminant analysis model and the Fisher linear discriminant functions to quantitatively determine the amount of oat added in unknown wheat-oat compound noodles.

2. The method of claim 1 , wherein, in step a), oat and wheat flours are mixed to make compound powders containing 0%-30% oat flour;
wherein, in step d), the 3D graph of discriminant analysis model and the Fisher linear discriminant functions use contents of palm acid, oleic acid and linoleic acid, or ratios of oleic acid/linoleic acid, palm acid/oleic acid, and palm acid/linoleic acid as independent variables, Wilks' principle of λ minimum statistics is used to analyze contribution of each independent variable to the discriminant analysis model and establish Fisher linear discriminant functions, and sample back tests are carried out to further verify the discriminant analysis model;
wherein, in step e), contents of palm acid, oleic acid and linoleic acid, or ratios of oleic acid/linoleic acid, palm acid/oleic acid, and palm acid/linoleic acid in unknown compound wheat-oat flour are applied in the 3D graph of discriminant analysis model and the Fisher linear discriminant functions established in step d) to calculate the amount of oat flour added in the unknown wheat-oat compound flour; and
wherein, in step g), the contents of palm acid, oleic acid and linoleic acid, or the ratios of oleic acid/linoleic acid, palm acid/oleic acid, and palm acid/linoleic acid in the unknown compound wheat-oat flour are adjusted by the coefficients of variation of fatty acids, and adjusted contents or ratios of fatty acids are applied in the 3D graph of discriminant analysis model and the Fisher linear discriminant functions established in step d) to calculate the amount of oat flour added in the unknown compound wheat-oat noodle.

3. The method of claim 2 , wherein 30 to 50 oat varieties and 30 to 50 wheat varieties are mixed in step a), and wherein the fatty acid composition of the wheat flours, the oat flours and the compound powders are pretreated with methyl esterification before the gas chromatography analysis in step b).

4. The method of claim 3 , wherein 48 oat varieties and 40 wheat varieties are mixed in step a).

5. The method of claim 3 , wherein the fatty acid compositions are extracted by Soxhlet extraction method in step d).

6. The method of claim 3 , wherein the methyl esterification method in step b) comprises the following steps:
1). adding 20 mg fatty acid sample into a 10 ml centrifuge tube;
2). adding 2 mL 0.5 mol/L NaOH—CH 3 OH solution as a methyl esterification reagent into the 10 ml centrifuge tube, vortexing and reacting at 65° C. for 30 min until fatty acids are completely dissolved;
3). adding 2 mL 25% BF 3 —CH 3 OH into the 10 ml centrifuge tube after it is mixed, and letting it stand cool for 5 min; and then vortexing it and reacting at 65° C. for 20 min, and letting it stand cool again;
4). adding 2 ml hexane into the 10 ml centrifuge tube and vortexing it;
5). adding 2 ml saturated NaCl solution into the 10 ml centrifuge tube and vortexing it;
6). removing upper organic phase into a dry vial, after centrifugation at a speed of 3000 r/min for 15 min, adding 0.35 g anhydrous Na 2 SO 4 to the organic phase to remove trace moisture, and storing final products at 4° C. for gas chromatography.

7. The method of claim 3 , wherein conditions of gas chromatography in step b) are as follows: PEG-20M capillary column; gas: nitrogen; purge flow: 3 mL/min; injection volume: 1 μL; split ratio: 100:1; inlet temperature: 250° C.; temperature program: initial temperature is 80° C., 3 min, increase the temperature to 215° C. at a speed of 15° C./min, keep the temperature at 215° C. for 16 min, and solvent delay time is 1.5 min.

8. The method of claim 2 , wherein levels of the oat flours added to the compound powders in step a) are 0%, 5%, 10%, 15%, 20%, 25% and 30%.

Assignees

• Zhang Hui
• Wang Chaoqun
• Qi Xiguang
• Wang Li
• Qian Haifeng
• Univ Jiangnan

Inventors

• Zhang Hui
• Wang Chaoqun
• Qi Xiguang
• Wang Li
• Qian Haifeng

Classifications

• G01N33/02

  Food · CPC title

• G01N33/92

  involving lipids, e.g. cholesterol {, lipoproteins, or their receptors (steroid hormones G01N33/743)} · CPC title

• Y10T436/25

  including sample preparation · CPC title

• G01N33/10 Primary

  Starch-containing substances, e.g. dough · CPC title