Bioactive peptides from Tenebrio molitor: physicochemical and antioxidant properties and antimicrobial capacity.

Recent research has demonstrated the increasing interest in using insects for the extraction of bioactive compounds, particularly peptides. These compounds offer a spectrum of beneficial physiological effects. The aim of this study was to standardize a methodology for obtaining bioactive peptides from Tenebrio molitor and evaluate its physicochemical characterization, antioxidant, and antimicrobial potential. Six assays were carried out to hydrolyse larvae protein, with variations in Alcalase concentration (0.04 to 0.08%) and reaction time (3 to 8 h). The results indicated that the process applied to defatted mealworm flour was effective in reducing lipids by 82.5%. Consequently, it was an observed increase of 38.4% in protein content. Additionally, an increase in glycogen content was found in defatted mealworm flour (177 µmol glucose g-1 sample) and peptides (152.81 µmol glucose g-1 sample). The degree of hydrolysis was higher in assays with longer hydrolysis durations (8.14 - 8.38%). The antioxidant capacity was 12 to 14% lower in assays with an incubation time of 8h. In this sense, the methodology proposed in the present study proved to be efficient in obtaining bioactive peptides from T. molitor.

Efficiency of protein combinations in diets for Rhamdia quelen: growth, digestive and metabolic biochemistry and nutrient deposition.

This study was conducted to determine the best combination of protein sources in diets for jundiá, based on growth, metabolism, and nutrient deposition. Five protein combinations were tested: casein + fish meal (control), casein + gelatin, casein + albumin, casein + albumin + fish meal, and albumin + fish meal, in diets containing 370 g Kg-1 of crude protein and 13.4 MJ Kg-1 of digestible energy. The fish (9.38 ± 0.12 g) were allocated in a water recirculation system at a density of 3.35 g L-1 per experimental unit and fed until apparent satiety for 40 days with the diets. The fish fed with the control diet had the highest final weight, specific growth rate, protein and feed efficiency ratio, protein retention, and best apparent feed conversion. On the other hand, fish that received casein + albumin and albumin + fish meal diets showed worse results in growth and body protein retention, low trypsin and chymotrypsin activity, and high intestinal amylase activity. Therefore, the combination referred to as control (casein + fish meal) conclusively provides the best rhythm for nutrient digestion and metabolism processes, enabling fish to reach greater growth and retention of body protein with low whole-fish fat content.

Growth performance, plasma and hepatic biochemistry of jundiá Rhamdia quelen fed dephytinized rice bran protein concentrate.

A 45-day feeding assay was carried out to evaluate the effects of crescent levels of dephytinized rice bran protein concentrate (DRBPC) on growth performance, nutrient deposition, plasma and liver parameters of jundiá Rhamdia quelen. Five experimental diets were formulated with inclusion of 0 (control), 10, 15, 20, and 30% of DRBPC. In total 500 jundiás (initial body weight 6.28 ± 0.12 g) were allocated in 20 tanks (230 L) to give four groups for each treatment. Fish were fed to apparent satiation for 45 days. Weight gain and specific growth rate were evaluated by cubic regression analysis (P < 0.05) and displayed maximal growth on the inclusion level of 25% of DRBPC. The results indicated that fish fed DRBPC15 and DRBPC30 had lower body protein deposition and hepatosomatic index compared to CONTROL diet, respectively. No significant differences (P > 0.05) were assessed in plasma parameters. The alanine aminotransferase activity was higher in fish fed DRBPC30 compared to CONTROL group. The present study has demonstrated that DRBPC displayed significant nutritional quality for the jundiá. Thus, this new ingredient could be included as a protein source in fish for minimizing the use of fish meal.