Simultaneous imaging of fat crystallinity and crystal polymorphic types by Raman microspectroscopy

Area of Science:

• Food Science
• Analytical Chemistry
• Materials Science

Background:

• Fat crystalline states significantly impact food properties.
• Existing imaging techniques struggle to simultaneously assess fat crystallinity and polymorphism.
• Understanding fat crystal structure is crucial for food quality and stability.

Purpose of the Study:

• To develop and demonstrate a novel Raman microspectroscopy technique for simultaneous imaging of fat crystallinity and crystal polymorphs.
• To quantitatively visualize the hardness-associated β' crystal polymorph and overall crystallinity.
• To detect the presence of the deterioration-associated β crystal polymorph in fats.

Main Methods:

• Utilized Raman microspectroscopy for simultaneous imaging.
• Analyzed key Raman bands to visualize crystallinity and the β' polymorph.
• Employed multivariate curve resolution alternating least squares (MCR-ALS) analysis on full Raman spectra to image the β polymorph.
• Applied the technique to a model fat system (porcine adipose tissue).

Main Results:

• Successfully visualized and quantified fat crystallinity and the β' crystal polymorph.
• Demonstrated the capability to image the emergence of the β crystal polymorph.
• Confirmed the non-destructive, in situ visualization of fat crystalline states at the molecular level.
• Showcased the elimination of laborious sample pretreatments.

Conclusions:

• Raman microspectroscopy provides a powerful tool for simultaneous, non-destructive analysis of fat crystalline states.
• This technique enables detailed molecular-level understanding of fat structure in food products.
• The method facilitates in situ analysis without extensive sample preparation, improving efficiency.