Affiliation:
1. Department of Food Science and Technology, College of Agriculture Isfahan University of Technology Isfahan 84156‐83111 Iran
2. Department of Food Science and Technology, College of Food, Agricultural and Environmental Sciences The Ohio State University Columbus OH 43210 USA
Abstract
SummaryFood waste by‐products contain many bioactive compounds, such as proteins, carbohydrates, polyphenols and carotenoids. The purposes of this study was to extract oleoresin from tomato waste, apply tomato pomace powder (TPP) as a new shell material for encapsulation of oleoresin and to fortify orange juice using the developed microcapsules. Microencapsulation was carried out based on different TPP (2% and 3%) and oleoresin (20% and 30%) concentrations by spray drying at two temperatures (130 and 140 °C). Different features of microcapsules such as the encapsulation load, encapsulation efficiency, moisture content, hygroscopicity, bulk and tapped densities and the Hausner ratio were analysed. Based on properties of microcapsules, samples containing 3% TPP and 30% oleoresin dried at 130 °C were selected as the best treatment and their characteristics such as morphology, chemical structure and thermal behaviour were investigated. Scanning electron microscopy indicated that spherical micron‐size particles were formed and their crack‐free fine surface showed their potential for encapsulation of anti‐oxidants to reduce oxygen diffusion. Microencapsulated oleoresin was then added to the orange juice and the samples' pH, acidity, total soluble solids and colour were evaluated and compared with pure orange juice. Free radical scavenging method was used to investigate the anti‐oxidant properties of orange juice during storage. The results indicated that at the end of the 30 days of storage the fortified orange juice had anti‐oxidant activity equal to pure fresh orange juice on day one. Sensory evaluation results showed no significant differences between appearance, colour, thickness and overall acceptance of fresh and the fortified juices (P < 0.05). The results of this study showed the potential application of food and agricultural waste in production of value‐added ingredients to be used as natural additives in food industries.