396: Optimization of a Mealworm Defatting Process With Supercritical CO2 Using a Box-Behnken Design to Obtain a Protein Extract With Enhanced Functional Properties

Introduction

Emerging extraction technologies are increasingly replacing traditional defatting methods in biological matrices. In particular, the use of supercritical CO2 (SC-CO2) is providing good results for fat separation, also offering environmental benefits, as CO2 is a not-toxic and not-polluting substance. In addition, the SC-CO2 processing is an easy and low-cost recovery method. In this study, fat was removed from Tenebrio molitor larva with SC-CO2, and a Box-Behnken experimental design was followed to determine the optimum levels of the parameters governing the process to maximize protein concentration in the final extract, while observing the impact on the functional properties of the extract.

Methods

Dehydrated and ground mealworms were kindly supplied by a local company. A fixed amount of 80 g was extracted using a SC-CO2 equipment (model 101-500-AF) with a flow rate of 8 kg/h for each of the experiments performed. Pressure, temperature, and time were chosen as independent variables and introduced into a Box-Behnken design, taking the following values: 250, 325, and 400 bar, 41, 48, and 55ºC, and 45, 75, and 105 min. Thus, 17 runs were carried with 3 central points, employing Design-Expert (Stat-Ease 360) software to run the statistical analysis. Protein concentration and several techno-functional properties (protein solubility, emulsifying capacity, emulsion activity and stability, water holding capacity-WHC, and oil holding capacity-OHC) were determined.

Results

The statistical models provided by the Box-Behnken design showed a significant (P<0.05) impact of processing factors only in three of all the dependent variables analyzed, these are protein concentration, WHC, and OHC; where only temperature was significant (P<0.05), showing a linear correlation with the three responses affected. According to the experimental conducted design, the optimized extraction conditions were as follows: pressure = 400 bar, temperature = 53.8ºC, and time = 45 min, obtaining a protein extract with theoretical values for protein content, WHC, and OHC of 59.75% (w/w), 2.06 g/g, and 1.72 g/g, respectively.

Significance

Modeling SC-CO2 fat extraction from food matrices, such as mealworm, using the advanced Box-Behnken experimental design technique could help to obtain an adequate response to industry interests, creating in this case a sustainable extract potentially suitable for food production purposes.

Authors: Rubén Agregán, Noemí Echegaray, Carlos Álvarez, Mirian Pateiro, Jose Angel Perez-Alvarez, Juana Fernández-Lopez, Roberto Bermúdez, Ruben Dominguez-Valencia, and José Manuel Lorenzo