Method for measuring agar gel strength through low-field NMR (nuclear magnetic resonance)

Abstract

The invention provides a method for measuring agar gel strength through low-field NMR (nuclear magnetic resonance). The method comprises the following steps of: putting a certain number of agar powder samples into a nuclear magnetic tube; putting the nuclear magnetic tube into an NMR analyzer; measuring the spin-spin relaxation time T2 by using a CPMG (carr purcell meiboom gill) array; testing every sample for 3 times repeatedly; performing quick inversion by using inversion software to obtain the spin-spin relaxation time T2, wherein a corresponding linear relationship of the gel strength B and the spin-spin relaxation time T2 is as follows: T2=0.446+3.60*10<-5>B. Compared with a constant-pressure fracturing method and a texture analyzer or rheometer measuring method of the conventional agar measuring method, the defects that a sample preparing process is complicated, the measuring time consumption is high, influence caused by external factors is relatively large and the like are overcome and the method provided by the invention has the advantages of simple sample preparing method, no damage to samples, quick detection, accurate measuring result, good repeatability and the like.

Description

technical field [0001] The invention relates to a method for measuring the strength of agar gel, in particular to a method for measuring the strength of agar gel by using low-field NMR, and belongs to the technical field of agar gel strength detection. Background technique [0002] Gel strength is the most important index to measure the quality of agar. Low-strength gel has excellent protection of the dispersion system, prevents diffusion and improves product texture; high-strength gel has excellent strength, Elasticity, resilience, relative transparency, relative permeability and reversibility, have extremely high application value. Therefore, it is particularly important to accurately and rapidly determine the gel strength of agar. [0003] At present, the gel strength determination methods of agar mainly include: constant pressure rupture method, texture analyzer or rheometer measurement and other methods. Although the constant pressure rupture method is relatively simp...

AI Technical Summary

Problems solved by technology

Although the constant pressure fracturing method is relatively simple and low in cost, it is time-consuming to measure, difficult to control the flow rate of water, the balance vibrates, the external influence is large, and the accuracy and repeatability are poor.

Texture analyzer or rheometer measurement method adopts automatic equipment, overcomes the error of manual operation by controlling the descent speed of the drill bit, and the result is easy to read, but this method still needs to prepare agar sol, the sample preparation process is complicated, and the sample height is high. Significantly affect the measured strength, and the accuracy and repeatability are also poor, so a new method for gel strength determination is urgently needed