|Monday, November 23|
The potential of dominant micro-organisms isolated from the gut of the larvae of Hermetia illucens for microbiological control
* Jeroen De Smet, KU Leuven and Research Foundation Flanders, Belgium
Ellen Gorrens, KU Leuven
Laurence Van Moll, UAntwerp
Paul Cos, UAntwerp
Leen Van Campenhout, KU Leuven
Hermetia illucens is currently the most frequently used insect for the bioconversion of organic waste on an industrial scale. One of the reasons explaining its success is that evolution has enabled the larvae of H. illucens to thrive on a wide range of organic materials, ranging from rotting fruit to carcasses. While these niches can be a rich source of nutrients, they are also known to contain a high microbial load. To defend themselves these larvae express one of the highest number of antimicrobial peptides known to date for insects. Their own defense system might be further strengthened by the larval gut microbiome, because insects that occupy sophisticated ecological niches in some cases depend on their gut microbiota to prevent colonization by invading pathogens taken up with the diet, according to evolution theory predictions. To explore if such complex interactions occur between the larvae of H. illucens and their gut microbes, isolates of abundant bacteria were collected from larvae fed on five nutritionally different diets, containing respectively high levels of lignin, cellulose, hemicellulose, pectin and keratin. A total of 180 isolates were obtained from plates containing the abundant strains present in the larval gut. Using RAPD, 63 unique isolates were retained from this collection and identified using MALDI-TOF. It is worth noting that almost half of the collected isolates consists of merely six unique isolates, which were identified on the different diets. In addition to findings in literature, this is another indication towards the existence of a potential core set of micro-organisms present in the larval gut. In parallel, the antimicrobial activity of all isolates against human pathogens S. aureus, P. aeruginosa, S. enteritidis, B. cereus and C. albicans was assessed using spot tests. Several isolates were found to have antimicrobial activity against the tested micro-organisms and could be micro-organisms that help their host to control its gut microbiota, as hypothesized. Future work will zoom in on this promising isolates to identify their active components and also to explore the potential use of such strains as a supplement in the rearing process to prevent colonization by unwanted micro-organisms.
Influence of processing methods on the techno-functional properties of flours from three edible insects
* Forkwa Tengweh Fombong, KU Leuven, Belgium
Chrysantus Mbi Tanga, International Center of Insect Physiology and Ecology (icipe)
Jozef Vanden Broeck, KU Leuven
John Kinyuru, Jomo Kenyatta University of Agriculture and Technology, Department of Food Science and Technolog
Although insects are a well-known valuable alternative protein source to fish and beef in many countries, consumer acceptability remains a significant challenge, especially in the western world. However, consumer acceptance can be improved through grinding into flour and used as high-quality food ingredients. There is a lack of information on the impact of processing methods on the techno-functional properties of edible insects. The current work was aimed to investigates the influence of oven and freeze-drying methods on the techno-functionality of processed insect flours from three edible insects: Ruspolia differens, Gryllus bimaculatus and Schistocerca gregaria. Fifty (50) percent of the dried ground insect powder was defatted using hexane, while the other portion was not defatted. Selected techno-functional properties (such as water binding, water-holding, foaming capacity and stability and fat absorption capacity) of both samples was evaluated. The acid value, iodine, saponification, and peroxide values of the extracted oils were assessed. Our results revealed that there was no significant difference in the influence of drying method on the techno-functional properties of the insect flours investigated. There was significant variation of most of the afore-mentioned physico-chemical attributes in the protein concentrate and non-defatted portions among the different insect species. Also, peroxide and acid values were significantly influenced by both drying methods and insect oil type. Irrespective of the drying method, there was a clear distinction on the quality of non-defatted insect flours and their protein concentrates which is a direct reflection of the techno-functional properties of the target insects. Our findings demonstrate that both non-defatted and defatted insect powders could serve as a convenient alternative nutrient-rich source of ingredients for inclusion in diets and other food matrices to improve on their functionality.
Insect processing and the insects anatomy
* Catriona Lakemond, Wageningen University and Research, Netherlands
Domenico Azzollini, Wageningen University and Research
Dieke van de Minkelis, Wageningen University and Research
Maryia Mishyna, Wageningen University and Research
Vincenzo Fogliano, Wageningen University and Research
The insect value chain includes processing of reared insects to make them suitable for food or feed purposes as a whole, or to obtain fractions that can be further used as ingredients. Processing is often not evaluated in relation with the insects anatomy. So we present examples of how the insects anatomy is important for I. Softening whole insects using chitinase II. Aqueous extraction of insect protein III. Effective biofractionation into lipid and protein.
Thermo-mechanical and Pulsed Electric Field processing effects on protein quality of insect flours
* Samir Mezdour, AgroParisTech, France
Camille Loupiac, AgroSup Dijon
Houcine Mhemdi, UTC/ESCOM, EA 4297 TIMR
Thermo-mechanical and Pulsed Electric Field processing effects on protein quality of insect flours Samir Mezdoura, Camille Loupiacb and Houcine Mhemdic aParis-Saclay Food and Bioproduct Engineering research unit (Say Food)(Université Paris-Saclay, INRAE, AgroParisTech) 91300 Massy, France bUMR Procédés Alimentaires et Microbiologiques, Equipe de Physicochimie des Aliments et du Vin, AgroSup Dijon-Université de Bourgogne Franche Comté, 21000 Dijon, France cSorbonne Universités, Université de Technologie de Compiègne, Laboratoire Transformations Intégrées de la Matière Renouvelable (UTC/ESCOM, EA 4297 TIMR), Centre de Recherche de Royallieu, CS 60319, 60203 Compiègne Cedex, France email@example.com Without being the only options, it is becoming increasingly clear that insects could offer complementary and credible solutions to the problems faced by conventional protein sources, and also generate products offering a variety of micronutrients. These new sources should be considered in the context of biorefining and a circular economy that integrates the recycling of by-products to limit resource wastage and includes the valorisation of all microconstituents from the source being processed, so that the threshold of economic viability can be reached. The development of dedicated sectors will necessarily mean that account should be taken of the availability of the resource and also design of the production methods and transformation processes to be implemented. This study investigated a fractionation approach to produce protein-enriched and differently composed fractions of mealworm larvae (Tenebrio molitor), as well as Saturniidae caterpillars, in accordance with the bioreffinery concept. One of the objectives was to know how the different steps of a thermo-mechanical process, including freezing, blanching, pressing, grinding, affect the quality of insect flour (colour, chemical composition, amino-acid and fatty acid profiles) as well as the physico-chemical and techno-functional properties of the protein fraction. In order to enhance the pressing kinetics and to increase the extraction yield, pulsed electric fields were applied as pre-treatment. This work allowed for the production of protein-rich insect flours whose protein content ranges from 72 to 75% (bs), with 10-14% (bs) of lipids content and 4% (bh) of water. The amino-acid profile of these flours meets the needs of animal and human nutrition with good protein efficiency. The production yield of 20-25% is similar to that of fishmeal production. Results showed that the application of a pre-treatment before pressing improves the extraction yield and reduces the extraction time. Pulsed electric fields seem to be a very promising technology. In fact, the application of the electrical treatment induces cell membranes permeabilization, thus facilitating the extraction stage at cold temperature and preserving product quality. These results provide insights into physico-chemical and functional properties of proteins affected by treatments. The potential of fractionation techniques for protein enrichment and delivery of a variety of differently composed fractions was demonstrated and may provide an interesting potential to optimize energy consumption during insect fractionation.