The evaluation of the potential of Tenebrio molitor, Blatta lateralis, Blaptica dubia, Hermetia illucens and Naupheta cinerea for human consumption

Wilson Bessa, Leah (2016-12)

Thesis (MSc Food Sc)--Stellenbosch University, 2016.

Thesis

ENGLISH ABSTRACT: The proximate, chemical and microbial analysis of five insect species were evaluated to determine the nutritional significance of consuming insects. Black soldier fly (Hermetia illucens) larvae (BSFL), rated by the European Union as the insect species to have the biggest potential in food and feed, were selected for further analysis to determine its functional properties as an indication of its processing potential. The BSFL were further processed into a vienna-type sausage and compared to a traditional pork vienna sausage in terms of its nutritional composition and perceived texture analysis. The five insect species are a good source of nutrients, where Tenebrio molitor (mealworm) was found to have the highest fat content (35.7 g.100g-1), whilst Blatta lateralis (Turkistan roach) was found to have the highest protein values (101.5 g.100g-1). The insects were considered a good source of energy (averaging 24.12 MJ.kg-1), crude fibre (ranging from 8.7 g.100g-1 to 19.1 g.100g-) and minerals, specifically iron and zinc. The amino acid profile of each insect species compared favourably to the daily requirement for the average adult, with the exception of methionine, which is considered to be the limiting amino acid in all of the insects tested. Oleic acid was the most prominent fatty acid (FA) in all of the insects tested, with values ranging from 11.6 % in H. illucens to 46.2 % in Blaptica dubia (Dubia roach). Linoleic acid was the highest PUFA and ranged from 3.3 % in H. illucens to 13.9 % in B. lateralis. Alpha-linolenic acid, was found in low concentrations, with the exception of B. lateralis (0.9 % - 1.5 % of total FA). In terms of microbial safety, T. molitor and H. illucens contained high total viable counts and unsafe levels of Enterobacteriaceae. Blanching reduced microbial levels to less than 10 cfu.g-1 which was below the recommended amount. Blanching is recommended prior to consumption or processing. The aerobic endospore count was low on both T. molitor (< 10 cfu.g-1) and H. illucens (< 100 cfu.g-1) and Salmonella was not found on either insect species. There was a slight growth of Listeria species, which could pose as a potential risk. BSFL were found to have some functional properties, however, the extent of the functionality of BSFL in a paste form was somewhat limited. BSFL had limited water (± 104 %) and lipid (± 105 %) absorption capacities, and formed a gel that was too weak to retain its shape under pressure. BSFL had a poor emulsifying activity and antioxidant activity. Blanching the BSFL reduced some of the functional properties, but had no effect on water and lipid absorption capacity. Blanching did have a positive effect on the colour retention of the BSFL by preventing enzymatic reactions. BSFL could successfully be processed into vienna-type sausages, however, they were inferior to the pork sausage in terms of moisture, protein content, hardness, gumminess and springiness. From a food safety standpoint, the BSFL sausages are considered safe to eat at day 0 and after 14 days vacuum sealed in refrigerated conditions. Ultimately, BSFL does have the potential to act as a meat alternative in the meat industry.

AFRIKAANSE OPSOMMING: Die chemiese en mikrobiese analise van vyf insek-spesies is beoordeel om die sinvolheid, in voedingswaarde, van die eet van insekte te bepaal. Die larwes van die swartsoldaatvlieg (Hermetia illucens) (beter bekend as black soldier fly larvae of BSFL), wat deur die Europese Unie as die insek-spesie met die grootste potensiaal as voedsel en voer gereken word, is gekies vir verdere analise om die funksionele eienskappe daarvan as ’n indikasie van die verwerkingspotensiaal daarvan te bepaal. Die swartsoldaatvlieg-larwes is verder verwerk tot ’n worsie soortgelyk aan ’n Weense worsie en vergelyk met tradisionele vark- Weense worsies ten opsigte van voedingsamestelling en waargenome tekstuuranalise. Die vyf insek-spesies is ’n goeie bron van voedingstowwe. Van die vyf het Tenebrio molitor (meelwurm) die hoogste vetinhoud (35.7 g.100g-1), terwyl gevind is dat Blatta lateralis (Turkestan-kakkerlak) die hoogste proteïenwaardes het (101.5 g.100g-1). Die insekte is ’n goeie energiebron (met ’n gemiddelde 24.12 MJ.kg-1), ruveselbron (wat strek van 8.7 g.100g-1 tot 19.1 g.100g-1) en mineraalbron, veral van yster en sink. Die aminosuurprofiel van elke insek-spesie het goed vergelyk met die daaglikse voedingsvereiste van die gemiddelde volwassene, met die uitsondering van metionien, wat as die beperkende aminosuur beskou is in al die getoetsde insekte. Oleïensuur was die prominentste vetsuur (VS) in al die insekte wat getoets is, met waardes vanaf 11.6 % in H. illucens tot 46.2 % in Blaptica dubia (Dubia-kakkerlak). Linoleïensuur was die hoogste poli-onversadigde vetsuur en het gestrek vanaf 3.3 % in H. illucens tot 13.9 % in B. lateralis. Alpha-Linoleïensuur, is in lae konsentrasies gevind, met die uitsondering van B. lateralis (0.9 % - 1.5 % van totale VS). Rakende mikrobiese veiligheid, het T. molitor en H. illucens hoë totale lewensvatbare tellings en onveilige vlakke van Enterobacteriaceae bevat. Blansjering het mikrobiese vlakke na minder as 10 cfu.g-1 verminder, wat onder die aanbevole hoeveelheid was, en word aanbeveel voor eet of verwerking. Die aërobiese endospoor-telling was laag in T. molitor (< 10 cfu.g-1) én in H. illucens (< 100 cfu.g-1) en salmonella is nie in een van dié twee insek-spesies gevind nie. Daar was ’n geringe aanwas van die Listeria-spesie, wat ’n potensiële risiko sou kon inhou. Daar is bevind dat BSFL ’n paar funksionele eienskappe het, maar die omvang van die funksionaliteit van BSFL in ’n smeervorm was effens beperk. BSFL het beperkte water-absorpsiekapasiteit (± 104 %) en lipied-absorpsiekapasiteit (± 105 %) gehad, en ’n jel gevorm wat te swak was om sy vorm onder druk te behou. BSFL het ’n swak emulsifiseringsaktiwiteit en antioksidant-aktiwiteit gehad. Blansjering van BSFL het sommige van die funksionele eienskappe verminder, maar nie ’n uitwerking op water- en lipiedabsorpsiekapasiteit gehad nie. Blansjering het wel ’n positiewe uitwerking op die kleurbehoud van die BSFL gehad deur ensiem reaksies te voorkom. BSFL kon suksesvol verwerk word tot worsies soortgelyk aan Weense worsies, maar hulle was minderwaardig teenoor die varkwors in terme van vogtigheid, proteïeninhoud, hardheid, klewerigheid en veerkragtigheid. Uit ’n voedselveiligheid-oogpunt word die BSFL-worsies geag as veilig om te eet by dag 0, en na 14 dae vakuum-verseël in verkoelde toestande. Uiteindelik het BSFL wel die potensiaal om as ’n vleis-alternatief in die vleisbedryf te funksioneer.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/100415
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