Investigation of techno-functional properties of protein rich insect powders obtained from Acheta domesticus & Tenebrio molitor

---

Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Gıda Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2019

Tezin Dili: İngilizce

Öğrenci: BERKAY BOLAT

Asıl Danışman (Eş Danışmanlı Tezler İçin): Halil Mecit Öztop

Eş Danışman: Hami Alpas

Özet:

Edible insects have become one of the most attractive food sources and the most striking concept in recent times all over the world especially in Europe as a potential nutrient supply for the near future. Recently, researches on edible insects have been increasing since they are considered as an environmentally friendly option to livestock. This study is carried out with a purpose of investigating the physical and functional characterization of the protein extracts of two edible insect species; Acheta domesticus and Tenebrio molitor. The insect species include 69.80 and 52.50 % crude protein in granulated form respectively. In the study, the fat content was reduced primarily by defatting procedure with hexane. While defatting, insect powders were also exposed to the high hydrostatic pressure at 500 MPa for 15 minutes at 30oC or 40oC to observe changes in their antioxidant capacities and functionality of protein fractions. Protein content of protein rich insect powders was determined with Kjeldahl method and the results were found as in the range of 72.80-74.50 % and 79.05-81.50 % for mealworm and cricket powders, respectively. Protein solubility in distilled water was determined with Lowry method to get knowledge about hydrophilicity mechanism of insects. Results indicated that, temperature increase from 30 to 40 oC caused a decrease in solubility of both insect proteins. For characterization of gelling ability, NMR T2 relaxometry was used to interpret the relation between polymer and water retention. CaCl2 showed salting out salt property for mealworm proteins while it behaved as salting in salt in the presence of cricket proteins. According to FTIR spectroscopy, the strongest absorbance peaks were absorbed mainly in amide I, amide II and amide III regions in both species. This study aimed to provide a comprehensive solution for more nutritious foods by searching on the functional properties of insect proteins because of the possible food shortage and increasing demand for the nourishing foods in all around the world.