Heterotrigona Itama Bee Bread Extracts: Effect of Solvent Polarity on Extraction Yield, Chemical Characteristics and Antioxidant Activity

The stingless bee bread formation in the beehives occurs via lactic acid fermentation of the pollen mixed with nectar and bee salivary enzymes. The lack of research and studies about the effect of different extraction solvents in retaining the chemicals and the antioxidant activity of stingless bee bread were noticed. Hence, the objectives of this study were to determine the chemical contents and DPPH scavenging activity of different extracts of Heterotrigona itama stingless bee bread. The bee bread sample was macerated with four different extraction solvents including 95% ethanol (95EE), 70% ethanol (70EE), dichloromethane (DE) and hexane (HE). The chemicals analyses were proximate analysis, resorcinol-sulfuric acid assay and fourier transform infrared (FTIR) spectroscopy, while antioxidant activity was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. As a result, the bee bread of H. itama was found to contain 46.88% carbohydrates, 24.72% moisture content, 21.10% crude proteins, 3.41% crude fats, 2.32% ash and 1.75% crude fibers. The highest yield of extract was recorded by 70EE (41.1%, w/w). Resorcinol-sulfuric acid assay revealed that 70EE contained more total carbohydrates (842.585 mg/mL) compared to 95EE (738.178 mg/mL). In addition, intense FTIR signals at 3100–3600 cm-1 were found in 95EE and 70EE, indicating the presence of hydroxyl group, while strong 2800–3000 cm-1 signals found in HE revealed the presence of aliphatic group, and an intense carbonyl group signal at 1550–1750 cm-1 were detected in DE. Furthermore, 70EE also showed the strongest antioxidant activity compared to other extracts with IC50 value of DPPH radicals scavenging was 0.5173 mg/mL. Thus, these findings would provide the information about chemical composition and antioxidant activity of bee bread, as well as help in promoting the bee bread as a healthy functional food.