The food and drink industry deals with the greatest diversity of materials encountered in any single production activity. Food producers are committed to providing food and drinks of consistent quality and uncompromising safety. Consumers will accept nothing less.
Malvern Instruments provides particle measurement products and services to help food producers deliver on that commitment. Our instruments are used throughout the food production chain, from the inspection of raw materials and ingredients to new product formulation and development, quality control and packaging.
Many characteristics of food stuffs are determined by the dynamic mechanical properties of their constituent materials or in the end product which influences the rheological properties of the bulk product. The particle charge of food emulsions and suspensions (sauces, dairy products, cream soups, cream liqueurs etc) will affect shelf life. Low particle charges will lead to agglomeration and coalescence which causes changes in particle size and rheological properties.
The taste and feel of chocolate for example, the dissolution rates of milk and coffee, the stability of cream liqueurs and the viscosity of emulsions are all influenced by particle size and charge and, these in turn influence the rheological properties. Particle size, particle charge and rheology also characterize other processes such as the emulsification of mayonnaise and the crystallization of sugar. They can be an indicator of unwanted processes like creaming and phase separation and are critical QC parameters
Introduction
In the food and beverage industry, the physical properties of food constituents affect the taste, appearance, stability, processing behaviour and function of the final product. The measurement of key physical properties such particle size is therefore of great importance in assuring consistently safe and high quality food products.
For example, knowledge of the basic physical properties of milk is of great importance in determining the usefulness of its constituents in food formulations and the quality attributes and acceptability of foods containing these components. The analysis of milk samples with the qNano is shown in the examples below.
qNano Analysis of Standard Milk and Trim Milk
Analysis of Milk on the qNano
Milk powder generally consists of a continuous mass of amorphous lactose and other components, including fat globules, casein micelles, and serum proteins. The particles also contain vacuoles of occluded air where particle surfaces are not in contact. Particle size is an important physical property of milk which can affect appearance, reconstitution from powder and flow characteristics.
qNano is a useful tool for the study of key physical properties of naturally occuring particles, including milk, with particle-by-particle detail.
qNano Analysis of Standard Milk and Trim Milk
Standard "blue-top" milk and Trim "green-top" milk were analysed on the qNano (Figures 1 & 2). Particle-by-particle measurement shows the difference in particle size distribution between the two samples. Standard milk (blue) shows a higher content of of larger sized particle constituents, in comparison to Trim milk (green). This is as expected as Trim milk contains fewer high-volume constituents, such as fat globules, that are present and in Standard milk.
Figure 1. Particle Size Distribution for Trim and Standard Milk
Figure 2. Particle Size vs Blockade Duration for Trim and Standard Milk
Individual data points represents the detection individual particles from the of milk samples. Blockade Baseline Duration is an indicator of relative surface charge of particles. The distribution of Blockade Baseline Duration (Time of Flight) in the milk samples were quite consistent between samples, and did not vary significantly.
Conclusions
qNano provides rapid, particle-by-particle analysis of milk which is useful for:
- Examining differences in quality attributes during production processes.
- Ensuring consistent product quality - the food industry is increasingly concerned with ensuring well-defined, reliable physical properties to facilitate automated formulations of food products.
- Examining implications of substitution of ingredients or simulation of traditional foods.
