Associate Professor University of Nebraska-Lincoln Lincoln, Nebraska, United States
Abstract: This study reports formation of first-of-their-kind composite starch bioaerogels that can be used as clean food ingredients to develop novel oleogels as saturated fat replacers. The process is clean, no toxic chemical/solvent was used, product is food grade and has the potential to improve food quality and human health through diet. Fats provide unique functionalities in many food formulations. However, high intake of solid fats has been a concern among consumers due to negative health effects or high caloric value. With the increasing consumer awareness and health concerns, food industry is searching for alternatives to saturated and trans fats from natural food sources. In this study, an innovative approach based on starch bioaerogels was developed to generate novel saturated fat replacers. Composite nanoporous starch bioaerogels (NSB) were prepared from starch with varying amylose (0, 27, 55, 72%) and chitosan contents (0-0.75 wt.%) by forming a hydrogel, then converting the hydrogel to alcogel by ethanol exchange, and finally removing the ethanol by supercritical carbon dioxide (SC-CO2). These NSB were then employed as oil-absorbing porous templates for structuring liquid oils to develop first-of-their-kind saturated fat replacers. The starch type and the presence of chitosan had significant effects on the macroporosity of the NSB and their oil structuring performance. NSB with higher amylose content showed significantly lower shrinkage and density and higher specific surface area and microporosity (p < 0.05). Chitosan addition substantially decreased the shrinkage of the NSB. NSB from 55 and 72% amylose starch had improved oil structuring capacity compared to the dent starch. Starch-chitosan composite NSB showed superior oil structuring ability than the neat NSB, where solid-like oleogels with strong elastic modulus were developed. This is a novel approach that has the potential to replace saturated fats in many food formulations to reduce the saturated fat and calorie intake in diet.