Reverse Engineering to Design Food Processes for the New Generation of Healthy Foods
University of California, Davis, CA, USA and Riddet Institute, Massey University, New Zealand
R. Paul Singh and Gail Bornhorst
Reverse engineering is commonly used to develop an understanding of a device, machine, or a computer program by systematically disassembling it and then analyzing each component to determine how it works. The knowledge gained in such a process may be later used for a variety of purposes including design of improved devices. In designing new generation of healthy foods, our research is aimed at investigating how various food processes may influence food material properties that play an important role in food digestion in the human gastro-intestinal tract. In designing food processes when the end product is a functional food, it is necessary to understand the modifications that occur within the food matrix due to changes in its physical and chemical properties. Those properties can have significant influence on the subsequent digestion of foods within the human body. In a novel approach, we have considered various processes taking place in the human gastro-intestinal (GI) tract as analogous to process engineering operations as shown in Figure 1. The knowledge of how a functional food undergoes changes within the GI tract due to size reduction, mixing, reaction kinetics, nanoscale mass transfer of nutrients into the blood stream is important in selecting processing conditions during the food manufacturing operations. Using the reverse engineering approach, we considered the state of the bioactive (such as a nutrient) just prior to its release into the blood stream. All major mechanical and biological steps occurring in the GI tract that help create the unique state of the bioactive are then comprehensively studied to get new insights relevant to manufacturing novel and innovative foods for health. For example, the release of beta-carotene from sweet potatoes (Figure 2) is examined by observing all processing steps such as boiling, frying, and steaming that a potato matrix may undergo during its manufacturing and later in the GI tract. In another example, the role of milling of rice was studied to determine how it changes the properties of brown versus white rice. The milling process was found to have major influence on rice breakdown within the stomach as observed from vivo trials conducted with pigs. Food breakdown has a profound influence on the stomach emptying time that has major implications related to several human health issues. Quantitative information obtained from these studies regarding the kinetics of the concerned processes, and the knowledge of the in situ rheological properties, are useful to rice processors in creating new foods where rice in its various forms is incorporated to meet specific health benefits for the consumer.