Current research project include:
- Effect of high intensity ultrasound on lipid crystallization
- The role of lipids in flavor and taste perception
- Physics-Based Methods for the Nanoscale Monitoring and Processing of Foods
- Primary roles for secondary compounds: Enhancing the health of soil, plants, herbivores and people
- Relationships between beef flavor attributes, meat quality and consumer acceptance
- Effect of high intensity ultrasound (HIU) on functional properties of whey proteins
- Fortification of cheese with Vitamin D
- Development of a Descriptive Panel for Dairy Application
- Relationship between physiochemical properties of fats and emulsions and sensory characteristics
- Crystallization Kinetics of Fats
- Microstructure of fats
Relationship between physiochemical properties of fats and emulsions and sensory characteristics
As food companies strive to improve taste and nutrition of products while maximizing revenue they are confronted by numerous technical challenges. We hope that our basic research will ultimately lead to new knowledge that enhances the experience of eating food while contributing to healthy diets. Certainly there is significant opportunity for food scientist to improve nutritional value of fat containing foods. Some of these opportunities to include:
- eliminating trans fats
- substituting saturated fats with healthier unsaturated fats
- adding ingredients with high nutritional and nutraceutical qualities
- using healthier functional food oils (e.g. polyunsaturated and monounsaturated fatty acids, fish oils, etc.)
At present we focus on food emulsions such as spreads, margarines, shortenings, dressings, and toppings. We investigate the basic mechanisms that contribute to the physical and sensory stability of emulsions and determine how various ingredients and processing conditions impact stability.
In addition to a research laboratory well equipped for work in this area we are fortunate to have a superb sensory evaluation facility that provides much needed data that describes the sensory experience of the materials we are investigating.
Crystallization Kinetics of Fats
The functional performance and textural quality of fats, and fat-containing products are determined mainly by the balance between the solid and liquid phases and the crystal structures of the solid fats. Fats can crystallize in different forms in a phenomenon called polymorphism. It is known that polymorphism of fats greatly affects the consistency, plasticity, graininess and other physical properties of many products such as butter, lard, margarine, hydrogenated vegetable shortening, and cocoa butter. During storage, there is a tendency for the fat to be transformed into the most stable crystal form, which may or may not be desirable. Therefore, much effort is given to designing the processing, tempering or storage conditions so as to achieve and maintain the desirable crystal forms.
Control of crystallization in foods is an important aspect of food quality. Crystallization may be employed as a separation process (i.e., Sugar refining, fat fractionation, etc.) or to provide a certain texture within a food itself (i.e., ice cream. Fondant, chocolate, etc). The nature of the crystalline dispersion in these products helps to define their organoleptic properties. Furthermore, crystallization may be used for preservation purposes, for example, during freezing of foods. One of the most difficult aspects of controlling crystallization is related to shelf stability. In some foods, (i.e., ice in ice cream and frozen foods, chocolate, etc.) the crystalline dispersion may change its nature during storage to further minimize free energy. These changes can have severe repercussions on the quality of these products. In other foods, the desired product is crystal free, but the thermodynamic driving forces during storage lead to eventual crystallization. Thus, shelf life is limited by the onset of crystallization in these products (i.e., lactose in ice cream, hard candies, un-grained caramels, etc.)
Microstructure of fats
In our lab we are interested in understanding the factors that control lipid crystallization in different food systems. The objective of this area of research is to be able to tailor a food product for a specific application by controlling the crystallization process in the food. To achieve this goal, several variables can be controlled such as:
- crystallization temperature
- cooling rate
- agitation rate
- additives addition
- crystallization induction or inhibition, etc.
When fats crystallize they do so by forming a network of solid fat in a “sea” of liquid oil. Small structures of fat are interconnected resulting in different types of “crystal shapes” or microstructures that give information about the 3-dimensional arrangement of the crystals in the network. Depending on crystallization procedures different microstructures can be obtained, and specific fat networks can be tailored in order to obtain a specific functionality for a certain food product. An important concept about microstructure of fats is that it is highly correlated with the macroscopic properties of a food system such as texture, mouth-feel and appearance. For this reason, the microscopic characteristic of this network is very important when evaluating the factors that control product quality and sensory acceptance.
Our interest in the microstructure of lipid systems is very closely related to crystallization. Different microstructures result from different crystallization procedures and again, microstructure as crystallization properties can be related to a food product functionality. Our lab seeks to understand the factors that affect the microstructure of these systems and correlate their behavior with product development and stability.
In-line real-time ultrasonics for measuring solid fat content in fats and emulsions
New ultrasonic technology shows great promise as a ttool hat will help food producers optimize production processes. Traditionally off-line techniques such as p-NMR have been used to evaluate solid fat content (SFC) in foods. Ultrasonic transducers are easily mounted on process line pipes. An ultrasound generator, receiver, and processor provides real-time measurements of SFC.
We aim to understand how to apply this technique in more complex matrices such as emulsions and systems containing air (e.g. whipped toppings).