Improvement of functional properties and antioxidant activities of cuttlefish (Sepia officinalis) muscle proteins hydrolyzed by Bacillus mojavensis A21 proteases

Leg muscles of migratory locust (Locusta migratoria) as a protein source: Extraction, protein composition and foaming properties

Migratory locust (Locusta migratoria) is an edible insect species that is usually consumed at the adult developmental stage and represents a valuable source of proteins. Locusts can be processed into food ingredients or directly consumed after removal of legs and wings. Legs represent a unique matrix, which comprises a chitin-based exoskeleton typical for insects and muscle tissues commonly occurring also in other animals. Muscle proteins can be easily extracted from traditional animal sources, but the efficiency of these methods for locust legs as well as the functional characteristics of the resulting protein extracts have not been previously explored. This study first compared protein extraction methods at acid, alkaline, and salt-assisted conditions. All three methods resulted in a significantly higher extraction yield from locust leg muscles (0.465-0.595 g/g) than from whole locusts (0.061-0.125 g/g). Shotgun proteomics of the protein fraction extracted at alkaline conditions assigned 310 muscle proteins, comprising components assigned to energy and carbon metabolism, as well as to skeletal, protein folding, membrane trafficking, and cell adhesion functions. The techno-functional potential of locust leg muscles was assessed by a foamability assay. Foam stability of locust leg extracts varied as a function of pH extraction and re-solubilization conditions and was significantly higher (58.3-70.8 %) than for whey proteins taken as a benchmark (38.3-51.7 %); foam capacity at t = 0 h was in the range of 48.6-68.8 %. This study demonstrates that locust legs, which can be a by-product of locust consumption or processing, should be considered a rich source of muscle proteins with promising technological functionality.

Screening and Activity Analysis of α-Glucosidase Inhibitory Peptides Derived from Coix Seed Prolamins Using Bioinformatics and Molecular Docking

Hydrolysates of coix seed prolamins (CHPs) have an excellent hypoglycemic effect and can effectively inhibit α-glucosidase, which is the therapeutic target enzyme for type 2 diabetes mellitus. However, its hypoglycemic components and molecular mechanisms remain unclear, and its stability in food processing needs to be explored. In this study, four potential α-glucosidase inhibitory peptides (LFPSNPLA, FPCNPLV, HLPFNPQ, LLPFYPN) were identified and screened from CHPs using LC-MS/MS and virtual screening techniques. The results of molecular docking showed that the four peptides mainly inhibited α-glucosidase activity through hydrogen bonding and hydrophobic interactions, with Pro and Leu in the peptides playing important roles. In addition, CHPs can maintain good activity under high temperatures (40~100 °C) and weakly acidic or weakly alkaline conditions (pH 6.0~8.0). The addition of glucose (at 100 °C) and NaCl increased the inhibitory activity of α-glucosidase in CHPs. The addition of metal ions significantly decreased the inhibitory activity of α-glucosidase by CHPs, and their effects varied in magnitude with Cu2+ having the largest effect followed by Zn2+, Fe3+, K+, Mg2+, and Ca2+. These results further highlight the potential of CHPs as a foodborne hypoglycemic ingredient, providing a theoretical basis for the application of CHPs in the healthy food industry.

A review on processing methods and functions of wheat germ-derived bioactive peptides

Wheat germ protein is a potential resource to produce bioactive peptides. As a cheap, safe, and healthy nutritional factor, wheat germ-derived bioactive peptides (WGBPs) provide benefits and great potential for biomedical applications. The objective of this review is to reveal the current research status of WGBPs, including their preparation methods and biological functions, such as antibacterial, anti-tumor, immune regulation, antioxidant, and anti-inflammatory properties, etc. We also reviewed the information in terms of the preventive ability of WGBPs to treat serious infectious diseases, to offer their reference to further research and application. Opinions on future research directions are also discussed. Through the review of previous research, we find that there are still some scientific issues in the basic research and industrialization process of WGBPs that deserve further exploration. Firstly, based on current complex enzymolysis, the preparation and production of WGBPs need to be combined with other advanced technology to achieve efficient and large-scale production. Secondly, studies on the bioavailability, biosafety, and mechanism against different diseases of WGBPs need to be carried out in different in vitro and in vivo models. More human experimental evidence is also required to support its industrial application as a functional food and nutritional supplement.HighlightsThe purification and identification of wheat germ-derived bioactive peptides.The main biological activities and potential mechanisms of wheat germ hydrolysates/peptides.Possible absorption and transport pathways of wheat germ hydrolysate/peptide.Wheat germ peptide shows a variety of health benefits according to its amino acid sequence.Current food applications and future perspectives of wheat germ protein hydrolysates/peptide.

Stability and structural properties of bee pollen protein hydrolysate microencapsulated using maltodextrin and whey protein concentrate

In this research, the bee pollen protein hydrolysate was microencapsulated by spray drying using maltodextrin (MD), whey protein concentrate (WPC) and a mixture of both compounds. For this purpose, the bee pollen was hydrolysed by alcalase (enzyme concentration of 1.5%) at 50 °C and pH 8 during 3.95 h, and then freeze-dried. The hydrolysed protein and wall materials were used in ratio of 1:10 (w/w). The wall materials included maltodextrin 2%, WPC 2%, as well as maltodextrin and WPC mixtures with 3:1 ratio. The resulting capsules were exposed to UV radiation for 48 h to accelerate the oxidation. The results showed that the capsule prepared using maltodextrin and WPC mixture showed the highest DPPH radical scavenging during exposure to UV radiation. Based on the FTIR spectroscopy results, the wall containing maltodextrin and WPC mixture showed the best performance in maintaining the chemical structure of hydrolysed protein. The SEM results indicated that the microcapsules prepared with WPC and maltodextrin mixture as wall material showed uniform and smoother wall than those prepared with maltodextrin alone. Finally, it was found that the maltodextrin and WPC mixture was the best wall with an appropriate protective capability for the microencapsulation of hydrolysed proteins and their protection against UV radiation.

Physical and oxidative stability of chicken oil-in-water emulsion stabilized by chicken protein hydrolysates

The emulsifying and antioxidant properties of chicken protein hydrolysates for the physical and oxidative stabilization of chicken oil-in-water emulsion were investigated. The chicken protein pepsin hydrolysates obtained at reaction temperature of 33℃, 1.8% enzyme addition, liquid-solid ratio of 5:1, and reaction time of 4h, showed the DPPH radical scavenging rate of 92.12% and emulsion stability index of 0.07. The hydrolysate exerted significantly improved antioxidant activity and emulsion ability compared to the native chicken protein. The amino acid composition analysis indicated that the contents of hydrophobic amino acids including tyrosine, phenylalanine, and tryptophan were increased after hydrolysis, which contributed to the higher hydrophobicity and antioxidant activity of chicken hydrolysates. The results suggested that the chicken protein hydrolysates could be used as an alternative protein emulsifier for the production of oxidatively stable chicken oil-in-water emulsion.

Identification and synthesis of multifunctional peptides from wheat germ hydrolysate fractions obtained by proteinase K digestion

Wheat germ protein hydrolysate (WGPH) was obtained by proteinase K digestion, in order to produce bioactive antioxidant and antihypertensive peptides. Response surface methodology (RSM) was used to optimize hydrolysis conditions (enzyme-to-substrate ratio, time, and temperature) for antioxidant activity of hydrolysates. The crude WGPH produced in this way significantly inhibited angiotensin-I converting enzyme (ACE) in a concentration-dependent manner. It was next fractionated by reversed-phase semi-preparative High Performance Liquid Chromatography (HPLC) into 12 fractions that were examined for antioxidant and antihypertensive activities. Fractions with antioxidant and ACE-inhibitory activities were then submitted to further analysis by nano-LC-ESI-MS-MS. Among the various peptides identified, MDATALHYENQK (IC₅₀ : 293.3 ± 6.5 µg/ml) and SGGSYADELVSTAK (IC₅₀ : 265.5 ± 8.3 µg/ml) displayed antioxidant activity and VALTGDNGHSDHVVHF (IC₅₀ : 189.3 ± 4.05 µg/ml), VDSLLTAAK (IC₅₀ : 159.7 ± 0.33 µg/ml), MDATALHYENQK (IC₅₀ : 303.6 ± 2.47 µg/ml), IGGIGTVPVGR (IC₅₀ : 125.7 ± 2.3 µg/ml) and SGGSYADELVSTAK (IC₅₀ : 128.2 ± 1.17 µg/ml) showed good ACE-inhibitory activity. PRACTICAL APPLICATIONS: Wheat milling industries produce massive amounts of wheat germ as by-product that can be converted into valuable compounds. The present research indicates that proteinase K is useful to hydrolyze wheat germ proteins in a search for bioactive peptides with antioxidant and ACE-inhibitory properties. The identified peptides can be regarded as functional food additives, or nutraceuticals to improve human health.

Health Implications of Bioactive Peptides: A Review

Abstract. Today, due to immobility, improper food habits, and changes in lifestyle, communities are faced with an increase in health problems such as blood pressure, cholesterol, diabetes, and thrombosis. Bioactive peptides are considered as being the main products of protein hydrolysis which exert high effects on the nervous, immune, and gastrointestinal systems. Unlike synthetic drugs, bioactive peptides have no side effects and this advantage has qualified them as an alternative to such drugs. Due to the above-mentioned properties, this paper focuses on the study of health-improving attributes of bioactive peptides such as anti-oxidative, anti-hypertensive, immunomodulatory, anti-microbial, anti-allergenic, opioid, anti-thrombotic, mineral-binding, anti-inflammatory, hypocholesterolemic, and anti-cancer effects. We also discuss the formation of bioactive peptides during fermentation, the main restrictions on the use of bioactive peptides and their applications in the field of functional foods. In general, food-derived biologically active peptides play an important role in human health and may be used in the development of novel foods with certain health claims.

Neuroprotective Effect of Taurine-Rich Cuttlefish (Sepia officinalis) Extract Against Hydrogen Peroxide-Induced Oxidative Stress in SH-SY5Y Cells

Oxidative stress mediates the cell damage in several neurodegenerative diseases, some of which are Alzheimer's disease (AD), multiple sclerosis and Parkinson's disease (PD). In this study, we investigated whether the taurine-rich cuttlefish extract could exert a protective effect on damaged human neuroblastoma SH-SY5Y cells induced by hydrogen peroxide (H2O2). Our results revealed that pre-treatment with cuttlefish extract effectively increased the cell viability by protecting the cells from intracellular reactive oxygen species (ROS) induced by H2O2 exposure. Furthermore, apoptosis related proteins Bcl-2 and Bax were investigated by western-blot analysis and results indicated that cuttlefish extract promoted the expression of anti-apoptotic Bcl-2 protein while inhibiting the expression of pro-apoptotic Bax protein. Therefore, cuttlefish extract containing the ability of scavenging excessive ROS, the capacity of anti-oxidative stress, could be employed in neurodegenerative disease prevention. In conclusion, the results suggest that cuttlefish extract could be used as a potential candidate for preventing several human neurodegenerative and other disorders caused by oxidative stress.

Antioxidant properties of porcine liver proteins hydrolyzed using Monascus purpureus

In this study, the antioxidant activities of porcine liver proteins, hydrolyzed using Alcalase^®, papain, pepsin, or a microbial suspension of Monascus purpureus (APLH, PaPLH, PePLH, and MPLH, respectively), were investigated. The results indicated that the yield and degree of hydrolysis (DH) of hydrolysates increased with hydrolysis time. The highest yield and peptide content were obtained from APLH, whereas the DH of PaPLH was higher than that of the others. MPLH exhibited the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power, whereas APLH and PaPLH exhibited the higher ferrous ion-chelating ability than that of the MPLH. The molecular weights of all the hydrolysates were <10 kDa. The PaPLH exhibited the highest contents of total amino acids and hydrophobic amino acids. Fifteen antioxidant fractions obtained from MPLH contained one or more of the following amino acids in their sequences: Tyr, Trp, Ala, Pro, Met, Lys, Asp, Cys, Val, Leu, and His.

Spouted bed drying efficiency of bovine hydrolyzed collagen

Summary Bovine hydrolyzed collagen (BHC) is an important food supplement normally consumed in the form of capsules or powder in order to stimulate the synthesis of collagen, promote health and assist in esthetics. The transformation of liquid foods into powders by drying is a difficult operation due to the complex physical and chemical changes resulting from the use of high temperatures, which may result in low drying efficiency and unwanted physicochemical and nutritional characteristics in the final product. In this work, a process engineering approach was used aiming to maximize the drying efficiency and investigate the potential of using a spouted bed on the drying performance of BHC. The effects of feed mode, type of inert material and use of an adjuvant on powder production efficiency were analyzed using a 23 factorial experimental design. A statistical analysis showed significant effects of all the independent variables on drying performance. The maximum powder production efficiencies were achieved using polypropylene as the inert material and atomization as the feed mode. Under the optimal process conditions, up to 85% efficiency was obtained, demonstrating that the spouted bed is a technically viable equipment for drying BHC.

Antiproliferative, ACE-inhibitory and functional properties of protein hydrolysates from rohu (Labeo rohita) roe (egg) prepared by gastrointestinal proteases

Previously, we have reported the chemical composition, molecular mass distribution and antioxidant activity of rohu roe protein hydrolysates. In the current study, antiproliferative, angiotensin-converting enzyme (ACE)-inhibitory activities and functional properties of protein hydrolysates from rohu (Labeo rohita) roe proteins, prepared by gastrointestinal proteases (pepsin and trypsin), were investigated. Antiproliferative activity was evaluated against human colon cancer cell line Caco-2. The results showed that the pepsin hydrolysate possessed dose dependent inhibitory effect on Caco-2 cell line. Pepsin and trypsin hydrolysates displayed ACE-inhibitory activity in vitro. The ACE-inhibitory activity of the hydrolysate generated by pepsin (47 ± 1.7 %, at 1 mg/ml) is higher than that obtained by trypsin (36 ± 3.2 %). Additionally, the undigested rohu roe proteins and its hydrolysates exhibited functional properties. Solubilities of the hydrolysates were above 81 ± 9.2 % at all pH values tested. Pepsin and trypsin hydrolysates showed good foaming capacity (45-211 %) and emulsification activity (4-29 m(2)/g). The foaming abilities and emulsifying activity index (EAI) were affected by pH. The results suggest that protein hydrolysates from rohu roe could be useful in food industry for various applications.

Antioxidant activity and functional properties of enzymatic protein hydrolysates from common carp (Cyprinus carpio) roe (egg)

Previously, we have reported the composition, molecular mass distribution and in vivo immunomodulatory effects of common carp roe protein hydrolysates. In the current study, antioxidative activity and functional properties of common carp (Cyprinus carpio) roe (egg) protein hydrolysates, prepared by pepsin, trypsin and Alcalase, were evaluated. The three hydrolysates showed excellent antioxidant activities in a dose dependent manner in various in vitro models such as 2,2 diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzthiazoline-6)-sulfonic acid (ABTS(+)) radical scavenging activity, ferric reducing antioxidant power (FRAP) and ferrous ion (Fe(2+)) chelating ability. Enzymatic hydrolysis significantly increased protein solubility of the hydrolysates to above 62 % over a wide pH range (2-12). Carp roe hydrolysates exhibited good foaming and emulsification properties. The results suggest that bioactive carp roe protein hydrolysates (CRPHs) with good functional properties could be useful in health food/nutraceutical/pharmaceutical industry for various applications.

The influence of the extent of enzymatic hydrolysis on antioxidative properties and ACE-inhibitory activities of protein hydrolysates from goby (Zosterisessor ophiocephalus) muscle

Antioxidant properties and angiotensin-converting enzyme (ACE) inhibitory activities of protein hydrolysates from goby (Zosterisessor ophiocephalus) muscle, with different degrees of hydrolysis (DH) from 5 to 25%, prepared by treatment with crude proteases extract from smooth hound intestines, were investigated. Goby protein hydrolysates (GPHs) are rich in Gly and Thr, which accounted for 14.1-15% and 11.6-13.2% of the total amino acids, respectively. The antioxidant activities of GPHs were investigated by using several in vitro assay systems. All GPHs exhibited significant metal chelating activity and DPPH free radical-scavenging activity, and inhibited linoleic acid peroxidation. For the ACE-inhibitory activity, as the DH increased, the activity of GPHs increased. The obtained results revealed that antioxidant and ACE-inhibitory activities of GPHs were influenced by the degree of hydrolysis. A medium degree of enzymatic hydrolysis was appropriate to obtain GPHs with good antioxidant activity, while small peptides were essential to obtain high ACE inhibitory activity.