基于低场核磁-近红外二维相关光谱技术研究加热温度对牛肉水分的影响

Effect of heating temperature on beef moisture by two-dimensional correlation spectroscopy based on low-field nuclear magnetic resonance and near-infrared spectroscopy

该文利用低场核磁共振技术(low-field nuclear magnetic resonance,LF-NMR)和近红外光谱(near-infrared spectroscopy,NIR)技术对牛肉在不同温度(60~120℃)受热15 min的特征波谱进行了解析,并结合二维相关光谱技术研究了牛肉熟化过程水分迁移及分子振动规律。结果显示,牛肉中含有3个水分群,熟化过程中半结合水转换为游离水。随着加热温度的升高,不易流动水(T_(22))峰峰高逐渐降低,峰值面积减少;自由水(T_(23))峰峰高逐渐升高,宽度变大并显著左移。二维相关分析揭示牛肉熟化过程中官能团变化时序为:O—H→C—H→N—H→S—H。此外,加热温度对牛肉分子结构的影响呈非线性,并分为2个阶段。温度达到70℃后,热敏感的结构发生变化,水分开始迁移;100~110℃时蛋白质空间结构被进一步破坏。该文利用低场核磁-近红外二维相关光谱技术揭示了低温/高温肉制品生产中温度选择的合理性,为肉品热加工技术提供了理论支撑。

In this paper,the spectral characteristics of beef heated at different temperatures(60-120℃)for 15 min were analyzed by low-field nuclear magnetic resonance(LF-NMR)and near-infrared spectroscopy(NIR).Combined with two-dimensional correlation spectroscopy,the water migration and molecular vibration laws during beef cooking were studied.Results showed that beef contained three water groups and the semi-bound water was converted into free water during the heating process.With the increase in heating temperature,the peak height of T_(22)gradually decreased and the peak area decreased,the peak height of T_(23)gradually increased,and the width became larger and shifted to the left significantly.Two-dimensional correlation analysis revealed that the sequence of functional group changes during beef cooking was O—H→C—H→N—H→S—H.In addition,the effect of heating temperature on the molecular structure of beef was nonlinear and divided into two stages.When the temperature reached 70℃,the heat-sensitive structure changed and water started to migrate;the spatial structure of the protein was further damaged at 100-110℃.This paper revealed the rationality of temperature selection in the production of low-temperature/high-temperature meat products by two-dimensional correlation spectroscopy based on low-field nuclear magnetic resonance and near-infrared spectroscopy and provided theoretical support for meat thermal processing technology.