Effects of Drying Conditions on Moisture Content, Crude Protein Yield and Functional Group Features of Hermetia illucens Prepupae

¹ Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Malaysia
² Faculty of Science, Universiti Tunku Abdul Rahman, Malaysia
³ Nutrition, Metabolic and Cardiovascular Research Centre, Institute for Medical Research, Malaysia.

^* Corresponding author: leongsy@utar.edu.my

Abstract

This study aims to determine the optimal drying conditions for moisture content and crude protein in Hermetia illucens prepupae and to investigate changes in functional groups of crude protein under different drying conditions using FTIR spectroscopy. Drying experiments were conducted at various temperatures and durations in a range of 60–80°C and 24–48 hours, respectively. A total of 13 sets of drying conditions were generated from the Stat Ease, Design Expert software. The results demonstrated that both temperature and drying time significantly influenced the moisture content and crude protein yield. An inverse relationship was observed between drying conditions on moisture content and crude protein yield. The highest moisture content loss achieved was 63.5% at 80°C and 48 hours, whereas the lowest moisture loss achieved is 58.2% at 55.8°C and 36 hours. However, this came at the cost of protein yield. The highest crude protein yield (33.5%) was obtained at the lowest drying condition (55.8 °C for 36 hours). FTIR analysis of crude protein extracted from Hermetia illucens prepupae revealed significant alterations in the amide I (1700–1600 cm^-1), II (1600–1500 cm^-1), and III (1200–1350cm^-1) bands with increasing drying temperature and time.