전처리 방법에 따른 흰점박이꽃무지 유충 분말의 단백질 함량과 열변성 특성 변화

Abstract

Purpose: The objective of this study was to evaluate changes in protein content and thermal denaturation properties of white-spotted flower chafer (Protaetia brevitarsis) larvae, powdered using different pretreatment methods. Methods: White-spotted flower chafer larvae powders were prepared by applying the following three methods: oven-dried larvae powder (OLP), oven-dried at 100ºC for 16 hr without any pretreatment process; frozen and oven-dried powder (FOLP), frozen at -20ºC for 24 hr and oven-dried at 100ºC for 16 hr; and frozen and freeze-dried larvae powder (FFLP), frozen at -70ºC for 24 hr and freeze-dried (-45ºC, 0 m Torr) for 5 days. Results: No differences were observed in the moisture content and crude ash content among the larvae powders (p>0.05). However, FFLP exhibited lower crude protein and crude fat contents compared to OLP and FOLP treatments (p<0.05). The order of protein solubility in the white-spotted flower chafer larvae powder was determined to be FFLP (95.66%) > FOLP (76.20%) > OLP (68.71%) (p<0.05). Moreover, the results from differential scanning calorimetry (DSC) analysis showed that FFLP had significantly lower onset and peak temperatures, but higher ΔH than OLP and FOLP treatments. The results from protein SDS-PAGE indicate that although larvae powders prepared with the oven-drying process (OLP and FOLP treatments) present decreased intensity of protein bands (< 50 kDa), a new protein band (70~100 kDa) was also observed. Conclusion: The results of this current study indicate that freeze-drying could be an excellent pre-treatment method to produce white-spotted chafer larvae powder with minimizing the protein denaturation. Moreover, if oven-drying conditions (time and temperature) are fixed, freezing prior to oven-drying reduces the extent of protein denaturation in white-spotted flower chafer larvae powder as compared to direct oven-drying of the raw ingredient.