Mid-infrared imaging applications in agricultural and food sciences

Douglas L. Elmore, Carrie A. Lendon, Sean A. Smith and Chad L. Leverette 

Homogeneous systems, such as cooking oil, exist in thermodynamic equilibrium and the properties of these systems are determined by their chemical composition.1 Heterogeneous systems are not in thermodynamic equilibrium. The properties of these systems are governed by both the chemical composition and the internal framework formed by the spatial arrangement of the individual chemical components present. The formation of steric, electrostatic and covalent forces between these individual components can have a dramatic effect on the properties of the product. Ice cream is a classic example, which is primarily composed of ice cream mix and air. The pure components of ice cream have different structural properties in the mixture than they do in their isolated form. Frozen ice cream has a certain consistency and texture, which is quite different from any of the individual frozen ingredients. 

This band has a more rounded shape than v(OH). 

This band can be used to monitor saturation in fats and oils. 

Large CH2/CH3 intensity ratios suggest long alkyl chains and visa versa. CH stretching features for fatty compounds (and proteins) and carbohydrates are significantly different. Frequencies of the iy,(CH2) and Vs(CH2) bands can be used to qualitatively monitor conformational order. 

---

Mid-infrared imaging applications in agricultural and food sciences... 

---