RESUMEN
The angiotensin-I converting enzyme (ACE) plays a pivotal role in hypertension, and while ACE inhibitors are conventional in hypertension management, synthetic medications often carry undesirable side effects. This has spurred interest in alternative ACE inhibitors derived from natural sources, such as edible insects. The silkworm, recognized for its bioactive peptides with potent ACE-inhibitory properties, has emerged as a promising candidate. This study aims to evaluate the acute toxicity and assess the antihypertensive efficacy of crude mature silkworm hydrolysate powder (MSHP) obtained from mature Thai silkworms. Utilizing the commercial protease Alcalase®2.4L, MSHP was administered at various doses, including 50, 100, and 200 mg kg-1, to hypertensive rats. The investigation spans a 14-day period to observe any potential acute toxic effects. Results indicate that MSHP exhibits LD50 values equal to or exceeding 2000 mg kg-1, signifying a low level of acute toxicity. Furthermore, the effective dose for blood pressure reduction in hypertensive rats surpasses 100 mg kg-1 of rat body weight. These findings suggest that MSHP derived from Thai mature silkworms holds promise as a natural antihypertensive food source. The implications of this research extend to the development of functional foods, functional ingredients, and dietary supplements aimed at managing hypertension.
RESUMEN
The mulberry silkworm (Bombyx mori L.) is a common edible insect in many countries. However, the impact of thermal processing, especially regarding Thai silkworm powder, is poorly known. We, therefore, determined the optimum time for treatment in hot water and subsequent drying temperatures in the production of silkworm powder. The silkworms exposed to 90 °C water for 0, 5, 10, 15, and 20 min showed values of Total Phenolic Compounds (TPCs), 2,2-Diphenyl-1-picrylhydrazyl free radical scavenging (DPPH) assay, 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay, and Ferric Reducing Antioxidant Power (FRAP) assay that were significantly (p < 0.05) higher at the 5 min exposure time compared with the other times. The reduction of microorganisms based on log CFU/g counts was ≥3 log CFU/g (99%) at the 5 min treatment. To determine the optimum drying temperature, the silkworms exposed to 90 °C water for 5 min were subjected to a hot-air dryer at 80, 100, 120, and 140 °C. The TPC value was the highest (p < 0.05) at 80 °C. The silkworm powder possessed significantly (p < 0.05) higher DPPH, ABTS radical scavenging ability, and ferric ion reducing capability (FRAP assay) at 80 °C compared with other drying temperatures. This study indicates that shorter exposure times to hot water and a low drying temperature preserve the antioxidant activities. High antioxidant activities (in addition to its known protein and fat content) suggest that silkworms and silkworm powder can make a valuable contribution to human health.