Jilin Provincial Key Laboratory of Nutrition and Functional Food College of Food Science and Engineering, Jilin University, Changchun 130062, PR China.
College of Plant Protection, Jilin Agricultural University/Key Laboratory of Soybean Disease and Disease Control, Ministry of Agriculture and Rural Affairs, Changchun 130118, PR China.
Int J Biol Macromol. 2024 Jun;272(Pt 2):132787. doi: 10.1016/j.ijbiomac.2024.132787. Epub 2024 Jun 4.
Insect protein extract is one of the high-quality protein sources and is frequently viewed as a potential nutrition alternative. However, a more precise method for protein measurement is still needed due to protein overestimation by the Kjeldahl method due to the presence of a large amount of chitin in insects. Therefore, we demonstrated the monitoring of chitin and protein extracted from yellow mealworm larvae through the information on molecular vibration obtained using Raman spectroscopy and infrared (IR) spectroscopy. The NH vibration at 3475 cm is the characteristic peak of chitin in defatted product observed in the Raman spectra. The nitrogen-to-protein conversion factor in protein extracted from larvae by the Raman method was determined based on the NH vibration and found to be 5.66 ± 0.01. We also compared these experimental data to theoretical Raman and IR spectra and determined the possible reasons for why nitrogen elements in chitin affect the determination of protein content. The method of sequentially removing fat and protein could provide more accurate quantification of protein and chitin. Raman spectroscopy is feasible for various types of insects with high chitin content. Compared with the Kjeldahl method, the Raman method is a faster and more accurate measurement method. Moreover, it provides the content of impurities, purity, and structural information.
昆虫蛋白提取物是一种高质量的蛋白质来源，常被视为潜在的营养替代品。然而，由于昆虫中大量存在几丁质，凯氏定氮法会导致蛋白质的高估，因此仍需要更精确的蛋白质测量方法。因此，我们通过拉曼光谱和红外（IR）光谱获得的分子振动信息，展示了对黄粉虫幼虫中几丁质和蛋白质的监测。在拉曼光谱中观察到脱油产物中，3475cm 处的 NH 振动是几丁质的特征峰。通过拉曼法从幼虫中提取蛋白质的氮-蛋白质转换因子基于 NH 振动确定，结果为 5.66±0.01。我们还将这些实验数据与理论拉曼和 IR 光谱进行了比较，并确定了几丁质中的氮元素影响蛋白质含量测定的可能原因。依次去除脂肪和蛋白质的方法可以更准确地定量蛋白质和几丁质。拉曼光谱适用于各种高几丁质含量的昆虫。与凯氏定氮法相比，拉曼法是一种更快、更准确的测量方法。此外，它还提供了杂质含量、纯度和结构信息。
