Evaluation of Tenebrio molitor protein as a source of peptides for modulating physiological processes

The increasing world population has led to the need to search for new protein sources, such as insects, the harvesting of which can be economical and environmentally sustainable. This study explores the biological activities (angiotensin-converting enzyme (ACE) inhibition, antioxidant capacity, and dipeptidyl peptidase IV (DPP-IV) inhibition) of Tenebrio molitor hydrolysates produced by a set of food-grade pro- teases, namely subtilisin, trypsin, ficin and flavourzyme, and the degree of hydrolysis (DH), ranging from 5% to 20%. Trypsin hydrolysates exhibited the highest ACE inhibitory activity at a DH of 10% (IC50 0.27 mg mL−1) in the experimental series, which was attributed to the release of short peptides containing Arg or Lys residues in the C terminus, and described as the ACE-inhibition feature. The levels of in vitro anti- oxidant activities were comparable to those reported for insect species. Subtilisin and trypsin hydrolysates at a DH of 10% displayed optimal DPPH scavenging and ferric reducing activities, which was attributed to the presence of 5–10-residue active peptides, as reported in the literature. Iron chelating activity was significantly favoured by increasing the DH, attaining a minimal IC50 of 0.8 mg mL−1 at a DH of 20% regardless of the enzymatic treatment. Similarly, in vitro antidiabetic activity was significantly improved by extensive hydrolysis, and, more specifically, the presence of di- and tripeptides. In this regard, the combined treatment of subtilisin–flavourzyme at a DH of 20% showed maximal DPP-IV inhibition (IC50 2.62 mg mL−1). To our knowledge, this is the first study evaluating the DPP-IV activity of Tenebrio molitor hydrolysates obtained from these commercial proteases. We conclude that Tenebrio molitor hydrolysates produced with food-grade proteases are a valuable source of active peptides that can be used as functional ingredients in food and nutraceutical preparations.FEDER CTQ2017-87076-RMinisterio de Economía, Industria y Competitivida

Evaluation of Tenebrio molitor protein as a source of peptides for modulating physiological processes

This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness and by FEDER (project CTQ2017-87076-R). The authors would like to thank MealFoodEurope (Salamanca, Spain) for kindly providing Tenebrio molitor meal.The increasing world population has led to the need to search for new protein sources, such as insects, the harvesting of which can be economical and environmentally sustainable. This study explores the biological activities (angiotensin-converting enzyme (ACE) inhibition, antioxidant capacity, and dipeptidyl peptidase IV (DPP-IV) inhibition) of Tenebrio molitor hydrolysates produced by a set of food-grade proteases, namely subtilisin, trypsin, ficin and flavourzyme, and the degree of hydrolysis (DH), ranging from 5% to 20%. Trypsin hydrolysates exhibited the highest ACE inhibitory activity at a DH of 10% (IC50 0.27 mg mL(-1)) in the experimental series, which was attributed to the release of short peptides containing Arg or Lys residues in the C terminus, and described as the ACE-inhibition feature. The levels of in vitro antioxidant activities were comparable to those reported for insect species. Subtilisin and trypsin hydrolysates at a DH of 10% displayed optimal DPPH scavenging and ferric reducing activities, which was attributed to the presence of 5-10-residue active peptides, as reported in the literature. Iron chelating activity was significantly favoured by increasing the DH, attaining a minimal IC50 of 0.8 mg mL(-1) at a DH of 20% regardless of the enzymatic treatment. Similarly, in vitro antidiabetic activity was significantly improved by extensive hydrolysis, and, more specifically, the presence of di- and tripeptides. In this regard, the combined treatment of subtilisin-flavourzyme at a DH of 20% showed maximal DPP-IV inhibition (IC50 2.62 mg mL(-1)). To our knowledge, this is the first study evaluating the DPP-IV activity of Tenebrio molitor hydrolysates obtained from these commercial proteases. We conclude that Tenebrio molitor hydrolysates produced with food-grade proteases are a valuable source of active peptides that can be used as functional ingredients in food and nutraceutical preparations.Spanish Ministry of Economy, Industry and CompetitivenessEuropean Commission CTQ2017-87076-

Optimization of the Emulsifying Properties of Food Protein Hydrolysates for the Production of Fish Oil-in-Water Emulsions

The incorporation of lipid ingredients into food matrices presents a main drawback—their susceptibility to oxidation—which is associated with the loss of nutritional properties and the generation of undesirable flavors and odors. Oil-in-water emulsions are able to stabilize and protect lipid compounds from oxidation. Driven by consumers’ demand, the search for natural emulsifiers, such as proteins, is gaining much interest in food industries. This paper evaluates the in vitro emulsifying properties of protein hydrolysates from animal (whey protein concentrate) and vegetal origin (a soy protein isolate). By means of statistical modelling and bi-objective optimization, the experimental variables, namely, the protein source, enzyme (i.e., subtilisin, trypsin), degree of hydrolysis (2–14%) and emulsion pH (2–8), were optimized to obtain their maximal in vitro emulsifying properties. This procedure concluded that the emulsion prepared from the soy protein hydrolysate (degree of hydrolysis (DH) 6.5%, trypsin) at pH 8 presented an optimal combination of emulsifying properties (i.e., the emulsifying activity index and emulsifying stability index). For validation purposes, a fish oil-in-water emulsion was prepared under optimal conditions, evaluating its physical and oxidative stability for ten days of storage. This study confirmed that the use of soy protein hydrolysate as an emulsifier stabilized the droplet size distribution and retarded lipid oxidation within the storage period, compared to the use of a non-hydrolyzed soy protein isolate.Spanish Government CTQ2017-87076-

Development of Fish Oil-Loaded Microcapsules Containing Whey Protein Hydrolysate as Film-Forming Material for Fortification of Low-Fat Mayonnaise

The authors are very grateful to Lis Berner for her skillful help with the PV and SVOP measurements of the microcapsules.The influence of the carbohydrate-based wall matrix (glucose syrup, GS, and maltodextrin, MD21) and the storage temperature (4 ◦C or 25 ◦C) on the oxidative stability of microencapsulated fish oil was studied. The microcapsules (ca. 13 wt% oil load) were produced by spray-drying emulsions stabilized with whey protein hydrolysate (WPH), achieving high encapsulation efficiencies (>97%). Both encapsulating materials showed an increase in the oxidation rate with the storage temperature. The GS-based microcapsules presented the highest oxidative stability regardless of the storage temperature with a peroxide value (PV) of 3.49 ± 0.25 meq O2/kg oil and a content of 1-penten-3-ol of 48.06 ± 9.57 ng/g oil after six weeks of storage at 4 ◦C. Moreover, low-fat mayonnaise enriched with GS-based microcapsules loaded with fish oil and containing WPH as a film-forming material (M-GS) presented higher oxidative stability after one month of storage when compared to low-fat mayonnaise enriched with either a 5 wt% fish oil-in-water emulsion stabilized with WPH or neat fish oil. This was attributed to a higher protective effect of the carbohydrate wall once the microcapsules were incorporated into the mayonnaise matrix.Spanish Ministry of Science, Innovation and Universities CTQ2017-87076-R PRE2018-08486

Encapsulation of Bioactive Peptides by Spray-Drying and Electrospraying

Bioactive peptides derived from enzymatic hydrolysis are gaining attention for the production of supplements, pharmaceutical compounds, and functional foods. However, their inclusion in oral delivery systems is constrained by their high susceptibility to degradation during human gastrointestinal digestion. Encapsulating techniques can be used to stabilize functional ingredients, helping to maintain their activity after processing, storage, and digestion, thus improving their bioaccessibility. Monoaxial spray-drying and electrospraying are common and economical techniques used for the encapsulation of nutrients and bioactive compounds in both the pharmaceutical and food industries. Although less studied, the coaxial configuration of both techniques could potentially improve the stabilization of protein-based bioactives via the formation of shell–core structures. This article reviews the application of these techniques, both monoaxial and coaxial configurations, for the encapsulation of bioactive peptides and protein hydrolysates, focusing on the factors affecting the properties of the encapsulates, such as the formulation of the feed solution, selection of carrier and solvent, as well as the processing conditions used. Furthermore, this review covers the release, retention of bioactivity, and stability of peptide-loaded encapsulates after processing and digestion.I+D+i project PID2020-114137RBI00 funded by MCIN/AEI/10.13039/501100011033

Peptides and protein hydrolysates exhibiting anti-inflammatory activity: sources, structural features and modulation mechanisms

Inflammation is the response of the immune system to harmful stimuli such as tissue injury, infection or toxic chemicals, which has the aim of eliminating irritants or pathogenic microorganisms and enhancing tissue repair. Uncontrolled long-lasting acute inflammation can gradually progress to chronic, causing a variety of chronic inflammatory diseases that are usually treated with anti-inflammatory drugs, but most of them are inadequate to control chronic responses and are also associated with adverse side effects. Thus, many efforts are being directed to develop alternative and more selective anti-inflammatory therapies from natural products. One main field of interest is the obtaining of bioactive peptides exhibiting anti-inflammatory activity from sustainable protein sources like edible insects or agroindustry and fishing by-products. This work highlighted the structure–activity relationship of anti-inflammatory peptides. Small peptides with molecular weight under 1 kDa and amino acid chain length between 2 to 20 residues are generally the most active because of the higher probability to be absorbed in the intestine and penetrate into cells when compared with the larger size peptides. The presence of hydrophobic (Val, Ile, Pro) and positively charged (His, Arg, Lys) amino acids is another common occurrence for anti-inflammatory peptides. Interestingly, a high percentage (77%) of these bioactive peptides can be found in alternative sustainable protein sources such as Tenebrio molitor or sunflower, apart from its original protein source. However, not all of these peptides with anti-inflammatory potential in vitro achieve good scores by the in silico bioactivity predictors studied. Therefore, it is essential to implement current bioinformatics tools, in order to complement in vitro experiments with prior prediction of potential bioactive peptides.I + D + i project from the Regional Ministry of Economic Transformation, Industry, Knowledge and Universities of Andalusia (Spain) PY20_0002

Activity, structural features and in silico digestion of antidiabetic peptides

Funding This research was funded by the grant PID2020-114137RB-I00 funded by MCIN/AEI/10.13039/501100011033Food antidiabetic peptides inhibit the enzymes involved in the regulation of the glycemic index (e.g. a-amylase, a-glucosidase and dipeptidyl peptidase-IV (DPP-IV)). This work reviews the antidiabetic peptide sequences reported in the literature, with activity confirmed by using synthetic peptides, and critically discusses their structural features. Moreover, it provides an overview of the potency of in silico analysis tools to predict the in vitro antidiabetic activity of DPP-IV-inhibitory peptides. In addition, the potential degradation of the most active peptides during digestion was evaluated in silico. Therefore, this work advances our understanding on the structure-activity relationship of antidiabetic peptides and provides new insights on their stability during digestion.MCIN/AEI/10.13039/501100011033: PID2020-114137RB-I0

Obtención de hidrolizados de proteínas de leche de cabra con actividad inhibidora de la enzima convertidora de la angiotensina

Tesis Univ. Granada. Departamento de Ingeniería Químic

Antidiabetic Food-Derived Peptides for Functional Feeding: Production, Functionality and In Vivo Evidences

Abstract: Bioactive peptides released from the enzymatic hydrolysis of food proteins are currently a trending topic in the scientific community. Their potential as antidiabetic agents, by regulating the glycemic index, and thus to be employed in food formulation, is one of the most important functions of these peptides. In this review, we aimed to summarize the whole process that must be considered when talking about including these molecules as a bioactive ingredient. In this regard, at first, the production, purification and identification of bioactive peptides is summed up. The detailed metabolic pathways described included carbohydrate hydrolases (glucosidase and amylase) and dipeptidyl-peptidase IV inhibition, due to their importance in the food-derived peptides research field. Then, their characterization, concerning bioavailability in vitro and in situ, stability and functionality in food matrices, and ultimately, the in vivo evidence (from invertebrate animals to humans), was described. The future applicability that these molecules have due to their biological potential as functional ingredients makes them an important field of research, which could help the world population avoid su ering from several diseases, such as diabetes.Spanish Ministry of Science, Innovation and UniversitiesResearch Group Bio-110 from University of Granada CTQ2017-87076-