Solid-state characterization of spray-dried ice cream mixes

Area of Science:

• Food science and technology
• Dairy science
• Powder technology

Background:

• Spray-dried ice cream mixes are complex emulsions with varying fat content.
• Understanding physicochemical properties is crucial for product quality and processing.
• Factors like emulsifiers and sucrose can influence powder characteristics.

Purpose of the Study:

• To analyze the physicochemical properties of spray-dried ice cream mixes.
• To investigate the impact of milk fat content, emulsifiers, and sucrose on powder properties.
• To determine the role of different casein types in fat encapsulation.

Main Methods:

• Analysis of surface composition, wettability, flowability, and microstructure.
• Measurement of surface free-fat using solvent extraction.
• Surface fat coverage analysis using electron spectroscopy for chemical analysis (ESCA).

Main Results:

• Wettability correlated with surface free-fat content.
• Sodium caseinate demonstrated superior co-encapsulation of fat compared to micellar casein.
• Emulsifiers reduced surface protein content by lowering interfacial tension.
• Surface fat led to overestimated particle size due to caking.
• Powders exhibited poor flowability attributed to caking and small particle size.

Conclusions:

• Surface fat significantly impacts the wettability and perceived particle size of spray-dried ice cream powders.
• Sodium caseinate is a more effective encapsulant for milk fat than skim milk in these formulations.
• Emulsifiers play a role in modifying surface composition by reducing protein adsorption.
• Poor flowability is a key challenge, linked to both fat caking and fine particle size.