Effect of two defatting processes on the physicochemical and flow properties of <i>Hermetia illucens</i> and <i>Tenebrio molitor</i> larvae powders
Sophie Laurent, Vanessa Jury, Marie de Lamballerie, Francine Fayolle
Abstract
The use of defatted insect powders as sustainable alternative ingredients has recently stirred great interest in the Western food industry. In this context, a variety of downstream processes involving a fat removal step has been developed for their manufacture. However, little is known about the influence of such treatments on the characteristics of powders. The aim of this study was to evaluate the impact of two defatting processes, namely centrifugal defatting (CD) and supercritical carbon dioxide defatting (SCO2D), on the proximate composition, color, grain size distribution, and flow properties of the resulting insect powders. Two species were used as follows: larvae of Hermetia illucens and Tenebrio molitor. Blanching, a common larvae pretreatment step, was performed before defatting. The conditions for the centrifugal defatting step were 4000 g centrifuge force and 5 min centrifuge time at 80°C, whereas the supercritical CO2 defatting step was performed at a pressure of 300 bar, a temperature of 45°C, and a duration of 180 min. For both species, the best defatting performance was obtained for supercritical CO2 defatting, leading to HI and TM powders with protein contents of, respectively, 64% and 79% and fat contents of, respectively, 6% and 3%. The color and the particle size distribution were both significantly different between the processes, resulting in SCO2D powders with lighter colors and higher average particle size. Regarding flow properties, the flowability and floodability indices were significantly higher for SCO2D powders, except in the case of HI powders for which the differences between flowability indices were not significant. Practical application Insect powders are a novel and trendy food ingredient with huge potential that could be used in the preparations of foods like biscuits, burgers, bars, etc. The high amounts of fat of certain insect species often require a defatting step in the powder manufacture process. European legislation is beginning to change and three species are now allowed as a novel food. The aim of this work was to consider two processing pathways involving either a centrifugal defatting or a supercritical carbon dioxide defatting to produce defatted powder from Hermetia illucens and Tenebrio molitor and to investigate the effect of these two processing approaches on the physicochemical and flow properties of the resulting powders. Industrial users willing to introduce insect powder will then be able to verify that the properties of these powders are close enough to the traditional ingredients they use in order not to change their process.