Production Of Protein Hydrolysates Research Articles

Protein hydrolysates derived from superworm (Zophobas morio): Composition, bioactivity, and techno-functional properties.

This study aimed to produce protein hydrolysates from superworm (Zophobas morio) flour using the enzymes alcalase (HA), protamex (HP), or flavourzyme (HF), and to characterize their nutritional composition, techno-functional properties, bioactive capacity, and bioaccessibility index. The enzymatic process increased the total amino acid and crude protein contents of the hydrolysates by approximately 36% and 46%, respectively, generating better foaming capacity, oil retention, and emulsification capacity, when compared to raw flour. Although 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical capture was similar between the hydrolysates, HA (1479,66μM FeSO4/g) and HP (1514,66μM FeSO4/g) showed greater antimicrobial and iron reducing power (FRAP) activity, while HF has a higher scavenging efficiency for the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (27.53%). The best antimicrobial activity was observed for HA against Vibrio corallilyticus (400mg/mL), and HP showed a better antioxidant response scavenging for DPPH radical. The antioxidant capacity against ABTS radical after in vitro simulation of gastrointestinal digestion (GID) was as follows: HA (79.07±1.53%), HP (74.65±5.85%), and HF (57.95±8.31%). Therefore, insect flour is a promising ingredient for the production of protein hydrolysates and their application in animal and human feeds.

Production of alpha-and beta-chitin, chitosan and protein hydrolysate from seafood processing wastes using an integration of lactic acid and digestive protease from fish viscera as alternative green extraction

Production of alpha-and beta-chitin, chitosan and protein hydrolysate from seafood processing wastes using an integration of lactic acid and digestive protease from fish viscera as alternative green extraction

Enzymatic Hydrolysis Systems Enhance the Efficiency and Biological Properties of Hydrolysates from Frozen Fish Processing Co-Products.

Co-products from the frozen fish processing industry often lead to financial losses. Therefore, it is essential to transform these co-products into profitable goods. This study explores the production of fish protein hydrolysates (FPH) from three co-products: the heads and bones of black scabbardfish (Aphanopus carbo), the carcasses of gilthead seabream (Sparus aurata), and the trimmings of Nile perch (Lates niloticus). Four enzymatic hydrolysis systems were tested: an endopeptidase (Alcalase, A), an exopeptidase (Protana, P), two-stage hydrolysis with an endopeptidase followed by an exopeptidase (A + P), and a single stage with endo- and exopeptidase (AP). The results show that combined enzymatic treatments, especially single-stage Alcalase and Protana (AP), achieved high protein yields (80%) and enhanced degrees of hydrolysis (34 to 49%), producing peptides with lower molecular weights. FPH exhibited significant antioxidant activity, in 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, with EC50 values below 5 mg/mL. Additionally, AP hydrolysates demonstrated over 60% angiotensin-converting enzyme (ACE) inhibition at 5 mg/mL, indicating potential antihypertensive applications. Antidiabetic and anti-Alzheimer activities were present, but at relatively low levels. AP hydrolysates, especially from gilthead seabream, proved to be the most promising. This study highlights the value of fish co-products as sources of functional peptides, contributing to waste reduction, and their potential applications in food, agriculture, and nutraceuticals.

Production of protein hydrolysate from overripe tempeh catalyzed by bromelain

Solid-state fermentation is an important food processing technology, often utilized in the food industry because of its production of secondary metabolites, amino acids, organic acids, and enzymes. Prolonged solid-state fermentation of tempeh can increase the protein and free amino acid content in it. By using bromelain, the production of overripe tempeh protein hydrolysate (OTPH) as a food ingredient may be possible. Bromelain was extracted from pineapple core and its’ optimum temperature and pH for its activity were determined. OTPH is made from soybeans that were fermented for 2, 3, 4, and 5 days, added with crude bromelain enzyme of 0.10, 0.15, 0.20, 0.25% (v/w), and incubated at the optimum condition obtained from the preliminary stage. A longer fermentation time and higher concentration of enzyme added resulted in significant increases in the protein content (ranging from 45.96% to 50.87%), water-soluble amino acids content (ranging from 14.55% to 39.86%), and total amino acid content with 0.25% crude bromelain produced the highest total amino acid content amounting to 36682.002 mg/100 g. These results showed the potential for the application of bromelain to produce protein hydrolysate from overripe tempeh.

Assessing the Plant Growth-Promoting Potential of Diverse Feather Protein Hydrolysates Produced by Keratinolytic Bacteria

Poultry slaughterhouses generate substantial quantities of feather waste, posing potential environmental pollution. These feathers can be degraded by microorganisms, yielding amino acid-rich protein hydrolysates. This research aims to assess and compare the microbial degradation rates of feathers from chickens (CK), guinea fowls (GF), and pigeons (PG) for generating amino acid-rich hydrolysates for cowpea growth promotion. Feather-degrading bacteria were isolated from diverse sources, and their capacity to degrade feathers was evaluated by examining keratinase yields, degradation rate, and amino acid composition. Physico-chemical conditions were optimised using a one-factor-at-a-time approach to enhance keratinase yield, while the growth-promoting potential of the different hydrolysates on cowpea was assessed in a pot experiment in a screen house. The results revealed that Lysinibacillus sp., from the soil of a slaughterhouse dumpsite, completely degraded 1g/L of GF within 7 days, followed by CK and PG within 8 days. Following optimisation, the keratinase yield improved to 190 U/ml after the degradation of 2g/L of feathers under optimal conditions of pH 8 and temperature of 40°C. The hydrolysate derived from CK exhibited higher amino acid content compared to that from GF and PG, with the exception of alanine, which was more abundant in the GF hydrolysate. All the hydrolysates contained eight essential amino acids, which significantly enhanced various growth parameters of cowpeas, including root length, shoot length, root nodules, leaf area, chlorophyll and leaf numbers after four weeks of planting. The study suggests that Lysinibacillus sp. is a promising isolate for efficiently degrading feathers to produce protein hydrolysates, potentially aiding the growth of cowpeas.

Antioxidant Activity and DPP-IV Inhibitory Effect of Fish Protein Hydrolysates Obtained from High-Pressure Pretreated Mixture of Rainbow Trout (Oncorhynchus mykiss) and Atlantic Salmon (Salmo salar) Rest Raw Material.

The use of fish rest raw material for the production of fish protein hydrolysates (FPH) through enzymatic hydrolysis has received significant interest in recent decades. Peptides derived from fish proteins are known for their enhanced bioactivity which is mainly influenced by their molecular weight. Studies have shown that novel technologies, such as high-pressure processing (HPP), can effectively modify protein structures leading to increased biological activity. This study investigated the effect of various HPP conditions on the molecular weight distribution, antioxidant activity, and dipeptidyl-peptidase IV (DPP-IV) inhibitory effect of FPH derived from a mixture of rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar) rest raw material. Six different treatments were applied to the samples before enzymatic hydrolysis; 200 MPa × 4 min, 200 MPa × 8 min, 400 MPa × 4 min, 400 MPa × 8 min, 600 MPa × 4 min, and 600 MPa × 8 min. The antioxidant and DPP-IV inhibitory effects of the extracted FPH were measured both in vitro and at cellular level utilizing human intestinal Caco-2 cells. The results indicated that low and moderate pressures (200 and 400 MPa) increased the proportion of larger peptides (2-5 kDa) in the obtained FPH, while treatment at 600 MPa × 4 min resulted in a higher proportion of smaller peptides (1-2 kDa). Furthermore, HPP led to the formation of peptides that demonstrated increased antioxidant activity in Caco-2 cells compared to the control, whereas their potential antidiabetic activity remained unaffected.

Production and fractionation of protein hydrolysate produced from fish sausage (Keropok Lekor) by-products by Lactobacillus casei fermentation: Optimisation and impact of peptide molecular weight on antioxidant and functional properties

Production and fractionation of protein hydrolysate produced from fish sausage (Keropok Lekor) by-products by Lactobacillus casei fermentation: Optimisation and impact of peptide molecular weight on antioxidant and functional properties

Thermal aggregation and gelation behaviors of glucono-δ-lactone-induced soy protein hydrolysate gels: Effects of protein and coagulant concentrations.

In this study, a novel acid-induced heat-set soy protein hydrolysate (SPH) gel was successfully developed. The effects of protein (7 and 8wt%) and glucono-δ-lactone (GDL, 4, 6, 8, and 10wt%) concentrations on its aggregation and gelation behaviors were investigated by evaluating the structural, rheological, textural, and physical properties of the SPH gel. The structural properties revealed that GDL promoted the formation of SPH aggregates and gels, primarily via disulfide bonds and hydrophobic interactions, which were closely related to the unfolding of the protein structure, exposed hydrophobic groups, decreased protein solubility, and increased particle size and turbidity during the heating process. Subsequently, the gelling properties demonstrated that acidification with GDL (4-8wt%) significantly improved the viscosity, viscoelasticity, water-holding capacity, and stiffness of the network structures, decreased their hardness and springiness, and facilitated the formation of well-supported, soft-stiff gels, particularly for those made with 8wt% protein. In addition, the changes in relaxation time measured via low-field nuclear magnetic resonance and magnetic resonance imaging confirmed that the SPH gels effectively retained water that was trapped in the gel network by strengthening the binding between water and protein molecules. The research could provide useful gelling technique for the protein hydrolysate products.

Enzymatization of Nila Fish (Oreochromis Niloticus) Protein Hydolysate by Combination of Bromelin and Pepsin Enzymes

Nile Tilapia (Oreochromis niloticus) is a freshwater fish with better nutritional content compared to other freshwater fish, making it suitable for use as a source for protein hydrolysate production. Protein hydrolysate is the result of the breakdown of protein into short-chain compounds through hydrolysis. This research aims to hydrolyze the minced Nile tilapia meat using a combination of bromelain and pepsin enzymes at a concentration of 5% and pH 7 conditions for 5-6 hours. The hydrolysis results using the combination of bromelain and pepsin enzymes (B100: P0) have a yield value of 12.68%, ash content of 2.94%, protein of 57.25%, water 2.65%, and fat 10.25% with a degree of hydrolysis of 61.46%. The hydrolysate has antibacterial properties against Staphylococcus aureus and Escherichia coli bacteria with inhibition zones of approximately 8.3 mm and 8.5 mm, respectively, at a concentration of 1 (mg/µL), contains 15 types of amino acids with the highest composition being lysine 5.12% and the highest non-essential amino acid being aspartic acid 5.75%.

Selection of Proteolytic Lactic Acid Bacteria with Probiotic Properties for Fish Protein Hydrolyzate Production

This study aimed to select a proteolytic LAB with probiotic properties that can be applied to manufacture protein hydrolysate from fish heads. Tests on 20 isolates of LAB showed that nine isolates were proteolytic and non-pathogenic. A total of 5 isolates could grow well at 0.5% bile salt stress, and 3 of them could grow at pH 3. These three isolates had antagonistic ability against Salmonella bacteria, and one isolate was sensitive to the antibiotic tested. Molecular identification of the selected LAB isolates showed a 100% sequence similarity with Pediococcus pentosaceus with accession number MT515895.1. The LAB isolate has high proteolytic activity since it can increase the soluble fraction of fish meal powder from 32.10% to 88.38% in 48 hr. Production of protein hydrolysate using tuna waste was carried out for 30 days. Tuna waste protein hydrolysate had a medium antioxidant activity of 25.57 ± 0.93%. The hydrolyzed protein comprised 17 amino acids, including nine non-essential and eight essential amino acids, and is dominated by glutamic acid. Selected LAB isolate is potentially used in protein hydrolysate production, especially for flavor enhancers. Keywords: antagonistic, amino acid, Pediococcus pentosaceus

Antioxidative, Glucose Management, and Muscle Protein Synthesis Properties of Fish Protein Hydrolysates and Peptides.

The marine environment is an excellent source for many physiologically active compounds due to its extensive biodiversity. Among these, fish proteins stand out for their unique qualities, making them valuable in a variety of applications due to their diverse compositional and functional properties. Utilizing fish and fish coproducts for the production of protein hydrolysates and bioactive peptides not only enhances their economic value but also reduces their potential environmental harm, if left unutilized. Fish protein hydrolysates (FPHs), known for their excellent nutritional value, favorable amino acid profiles, and beneficial biological activities, have generated significant interest for their potential health benefits. These hydrolysates contain bioactive peptides which are peptide sequences known for their beneficial physiological effects. These biologically active peptides play a role in metabolic regulation/modulation and are increasingly seen as promising ingredients in functional foods, nutraceuticals and pharmaceuticals, with potential to improve human health and prevent disease. This review aims to summarize the current in vitro, cell model (in situ) and in vivo research on the antioxidant, glycaemic management and muscle health enhancement properties of FPHs and their peptides.

One-step purification and characterization of a haloprotease from Micrococcus sp. PC7 for the production of protein hydrolysates from Andean legumes.

The high content and quality of protein in Andean legumes make them valuable for producing protein hydrolysates using proteases from bacteria isolated from extreme environments. This study aimed to carry out a single-step purification of a haloprotease from Micrococcus sp. PC7 isolated from Peru salterns. In addition, characterize and apply the enzyme for the production of bioactive protein hydrolysates from underutilized Andean legumes. The PC7 protease was fully purified using only tangential flow filtration (TFF) and exhibited maximum activity at pH 7.5 and 40°C. It was characterized as a serine protease with an estimated molecular weight of 130kDa. PC7 activity was enhanced by Cu2+ (1.7-fold) and remained active in the presence of most surfactants and acetonitrile. Furthermore, it stayed completely active up to 6% NaCl and kept ̴ 60% of its activity up to 8%. The protease maintained over 50% of its activity at 25°C and 40°C and over 70% at pH from 6 to 10 for up to 24h. The determined Km and Vmax were 0.1098mg mL-1 and 273.7 U mL-1, respectively. PC7 protease hydrolyzed 43%, 22% and 11% of the Lupinus mutabilis, Phaseolus lunatus and Erythrina edulis protein concentrates, respectively. Likewise, the hydrolysates from Lupinus mutabilis and Erythrina edulis presented the maximum antioxidant and antihypertensive activities, respectively. Our results demonstrated the feasibility of a simple purification step for the PC7 protease and its potential to be applied in industrial and biotechnological processes. Bioactive protein hydrolysates produced from Andean legumes may lead to the development of nutraceuticals and functional foods contributing to address some United Nations Sustainable Development Goals (SDGs).

Bioactivities of black soldier fly larvae protein hydrolysate

One of the potential insects for feed and food sources is the Black Soldier Fly (BSF) (Hermetia illucens). The BSF originated in South America and has now spread to many tropical countries. The BSF larvae (BSFL) had attracted much attention due to their good nutrient content and were recently reported as having useful bioactivities. BSFL has been widely used as feed and has been found to reduce bad smells associated with the growth of pathogenic microbes. The high protein content in BSFL is advantageous in the production of bioactive peptides. This research aimed to extract and hydrolyze the protein from BSFL with protease enzyme to produce protein hydrolysate or peptides with antioxidant and antibacterial activities. The antioxidant activity was measured using DPPH and FRAP, while the antibacterial was analyzed using the agar well diffusion method. BSFL was hydrolyzed with bromelain extracted from pineapple or commercial enzyme (Enzyplex). The IC50 shown by protein hydrolysate was 9.43±0.84% (v/v) or 0.72 mg/mL. The FRAP value was 521.21±264.53 µM for BSFL protein without enzyme addition, 792.14±291.02 for BSFL with the addition of bromelain, and 5,352.114±861.99 µM for BSFL with the addition of Enzyplex. The addition of bromelain increased the FRAP value 1.2 times, while the addition of Enzyplex increased the FRAP value 10.2 times. The antibacterial activity indicated that protein hydrolysate with phosphate buffer pH 8 at 50℃ and 24 hrs incubation showed the highest antibacterial activity to the lowest are Vibrio cholerae, Bacillus cereus and Staphylococcus aureus, respectively. The results suggest that BSFL has antibacterial and antioxidant bioactivities using bromelain extracted from pineapple and Enzyplex, a commercial enzyme that contains protease, lipase and amylase. Using Enzyplex as an enzyme to hydrolyze BFSL shows a very high antioxidant capacity compared to bromelain as an enzyme. This suggests that more protein and other macromolecules contribute to the antioxidant capacity. Using bromelain as an enzyme to hydrolyze BSFL, shows that BSFL peptide has higher antibacterial activity in gramnegative bacteria.

Optimization of the autolysis of rainbow trout viscera for amino acid release using response surface methodology

Background Due to the huge amounts of their production in Europe, their environmental impact, and the difficulty in processing them, there is a clear necessity for the valorization of rainbow trout viscera. Considering that the production of fishmeal with viscera can be problematic, and in order to make viscera more profitable, the production of fish protein hydrolysates has been considered. Although silage and enzymatic hydrolysis are the most common methods for obtaining hydrolysates, autolysis has emerged as an alternative method that uses endogenous enzymes of the viscera. Methods Considering the stability and characteristics of the enzymes, a factorial design was carried out using three variables: pH, temperature, and water content. The design resulted in 15 experiments, and the results were analyzed using response surface methodology. The optimum parameters were validated by comparing the predicted outcomes with experimental results. Additionally, a kinetics study was conducted to shorten the autolysis time. Results from autolysis were compared with those from silage and enzymatic hydrolysis in a previous study. Results The optimal conditions for achieving the highest degree of hydrolysis and yield of free amino acids (FAAs) per 100 g of viscera and per total protein were determined to be a pH of 8, a temperature of 40 ºC, and a water content of 6.85%. The pH and content of the added water were found to be significant variables during autolysis (p < 0.05). The kinetic study showed that 7 h was still required to be effective. Conclusions Autolysis achieved a lower degree of hydrolysis than silage; however, as it solubilized more protein, the global yield of free amino acids per 100 g of viscera was slightly higher. It was concluded that endogenous alkaline proteases could be used in an autolytic process to obtain a free amino acid-rich hydrolysate from trout viscera.

Nanobiocatalyst based on covalent immobilization of proteases onto functionalized nanocellulose for efficient production of sunflower meal protein hydrolysates

This study aimed to engineer bio-based and environmentally friendly nanobiocatalyst systems using commercially available protease preparations, Alcalase® 2.4L (Alcalase) and Flavourzyme® (Flavourzyme), along with functionalized cellulose nanocrystals (CNC). The study highlights the advantageous properties of the obtained glutaraldehyde-activated amino-modified CNC support (GA-amino-CNC), characterized as nanorods with dimensions ranging between 100-800 nm in length and 40-60 nm in width, particularly for protease immobilization. Maximum specific activity of immobilized Alcalase (15 IU/mg of proteins) was achieved at an initial enzyme concentration of 52 mg/g of support after 3 hours, with 80% of covalently attached enzyme molecules. In the case of Flavourzyme, maximum exo-hydrolytic activity of 21 L-pNAU/g of support was observed after 20 min, while a higher yield of covalently bound enzyme molecules (53%) detected after 1 hour. The covalently bound proteases on glutaraldehyde-activated amino-modified cellulose nanocrystals were evaluated for their efficacy in producing high-quality sunflower-based protein hydrolysates suitable for food and feed applications. Sequential hydrolysis of sunflower meal protein isolate (SMPI) using the developed nanobiocatalysts yielded a maximum hydrolysis degree of 20%. In addition, more than 80% of the initial activity of nanobiocatalysts were retained after 3 reuses, suggesting that these protease nanobiocatalysts have potential application in production of SMP hydrolysates.

Content and Bioaccessibility of Minerals and Proteins in Fish-Bone Containing Side-Streams from Seafood Industries.

With the aim to upcycle fish side-streams, enzymatic hydrolysis is often applied to produce protein hydrolysates with bioactive properties or just as a protein source for food and feed. However, the production of hydrolysates generates a side-stream. For underutilized fish and fish backbone this side-stream will contain fish bones and make it rich in minerals. The aim of this study was to assess the relative bioaccessibility (using the standardized in vitro model INFOGEST 2.0) of minerals in a dietary supplement compared to bone powder generated after enzymatic hydrolysis of three different fish side-streams: undersized whole hake, cod and salmon backbones consisting of insoluble protein and bones. Differences in the bioaccessibility of protein between the powders were also investigated. The enzyme hydrolysis was carried out using different enzymes and hydrolysis conditions for the different fish side-streams. The content and bioaccessibility of protein and the minerals phosphorus (P), calcium (Ca), potassium (K) and magnesium (Mg) were measured to evaluate the potential of the powder as an ingredient in, e.g., dietary supplements. The bone powders contained bioaccessible proteins and minerals. Thus, new side-streams generated from enzymatic hydrolysis can have possible applications in the food sector due to bioaccessible proteins and minerals.

Optimization of the Refining Process for a Fraction Rich in Crude Common Pony Fish (Leiognathus equulus) Oil as a By-product of Fish Protein Hydrolysate Processing Using The Response Surface Method

The production of fish protein hydrolysate from common pony fish yields a fraction rich crude fish oil as a by-product. To utilize this by-product, refining is necessary to obtain common pony fish oil. This research aims to use a fraction rich crude fish oil from fish protein hydrolysate by-products to obtain fish oil and to determine the optimal conditions for the refining process using the response surface method (RSM) in the degumming, neutralization, and bleaching processes. The experimental design used was the Box–Behnken design, with the responses used to determine the optimum conditions at the degumming stage were water content and total dissolved solids. The response used to determine the optimum conditions at the neutralization stage was the refining factor, and at the bleaching stage was color (L, a*, b*). Parameters studied for each purification process include heating temperature (50-80°C), contact time between fraction rich crude fish oil with auxiliary materials (10-20 minutes) and the length of time for centrifugation (5-15 minutes) with a rotation speed of 10,062 G. The optimal conditions obtained in the degumming, neutralization, and bleaching processes for heating temperature, contact time between fraction rich crude fish oil with auxiliary materials, and centrifugation time, respectively, were 50°C, 10 min, 5 min; 50°C, 20 min, 5 min; and 80°C, 10 min, 15 min. Verification of the optimum conditions resulted in a free fatty acid value of 8.25% ± 0.01%, an acid value of 1.87 ± 0.02 mg KOH/g oil, a peroxide value of 1.04 ± 0.01 meq/Kg, an anisidine value of 11.11 ± 0.01 meq/Kg, a total oxidation value of 13.21 ± 0.01 meq/Kg and water content 6.052 ± 0.02 %. These results indicate a reduction in free fatty acids, acid number, peroxide number, anisidine number and water content by 66%, 90%, 73.5%, 61%, 63%, and 92% respectively. Our results showed that the purified fraction rich crude fish oil has met the SNI standards in parameter acid number, peroxide number, iodine number, anisidine number, and total oxidation value. The purification process that has been carried out can improve the quality fraction rich crude fish oil, but further processing still needs to be carried out to reduce water content and free fatty acid value

Enhancement of Antibacterial Activity from Chicken Head Protein Hydrolysate Using Dual-Enzyme Hydrolysis

The chicken head is one of the by-products with a high protein content. Therefore, chicken heads can be used as raw materials to produce protein hydrolysates containing bioactive peptides that have biological activities, such as antibacterial, anti-inflammatory, and antioxidant activities. This research aimed to evaluate the use of the combined ratio of papain and bromelain enzymes to produce chicken head protein hydrolysate that has antibacterial activity. The research method used in this study was a laboratory experiment using a completely randomized design (CRD) with four treatments and five replications. Statistical significance was done using one-way analysis of variance (ANOVA) followed by Duncan’s multiple range test (DMRT). The inhibition zones of chicken head protein hydrolysate using a combination of papain enzymes against Lactobacillus casei, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhimurium were 1.72-2.68, 1.19-4.47, 0.93-1.45, 1.64-2.46, and 1.01-3.62 mm, respectively. The result showed that the highest antibacterial activities against Lactobacillus casei, Escherichia coli, and Staphylococcus aureus were in A1 (hydrolysis using papain 75% and bromelain 25%), the highest antibacterial activities against Pseudomonas aeruginosa was in A3 (hydrolysis using papain 25% and bromelain 75%), and the highest antibacterial activity against Salmonella typhimurium was in A2 (hydrolysis using papain 50% and bromelain 50%). However, all the hydrolysate didn’t exhibit antibacterial activity against Bacillus subtilis. Chicken head protein hydrolysate had the potential to be an antibacterial agent against pathogenic bacteria.

Emulsifying and Lipid Peroxidation Inhibitory Activities of Chicken Head Protein Hydrolysate Using a Combination of Papain and Bromelain Enzymes

Protein hydrolysis is a method used to produce protein hydrolysates containing simple peptides and free amino acids. The chicken head is one of the by-products that contain a high protein concentration so it can be use as a raw material for protein hydrolysate with functional properties and as a lipid peroxidation inhibitor. The aim of this research was determination to determine the emulsifying and lipid peroxidation inhibitory properties in chicken head protein hydrolysate using a combination of papain and bromelain enzymes. The method used in this research was a laboratory experiment using a completely randomized design (CRD) consisting of 4 treatments and 5 replications, consisting of T1 (without hydrolysis), T2 (75% papain enzyme and 25% bromelain enzyme), T3 (papain enzyme 50% and bromelain enzyme 50%), and T4 (papain enzyme 25% and bromelain enzyme 75%). The difference in the concentration ratio of papain enzyme and bromelain enzyme in chicken head protein hydrolysate gave a very significant difference (P<0.01) in Electrical conductivity (EC), a significant difference (P<0,05) in lipid peroxidation inhibitory activity and emulsion activity, and no significant difference (P>0,05) in emulsion stability. Chicken head protein hydrolysate shows potential as an emulsifier and lipid peroxidation inhibitor.

Production of protein hydrolysate from four plant sources and its optimization with α-pinene and tea seed saponin to control olive fruit fly

Types, source of production and optimization with some attractive compounds are the main requirements to produce a commercially efficient protein hydrolysate. The current study was designed to produce protein hydrolysate for the first time from Camelia sinensis (Tea) seeds, Cyamopsis tetragonoloba (Guar) seeds, Cucurbita pepo (Summer squash) seeds, Glycine max (Soybean) seeds and Olea europaea Kernels (Olive) optimized with α-pinene and Camelia sinensis saponin (CSS) aiming to availability of the products from the sources with low economic value and more attractance. Results revealed the highest extracted protein from Guar while the highest inhibition of DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) and hydroxyl radicals were recorded in the protein hydrolysates extracted from Summer squash, Soybean and Olive. The highest reduction potential of Fe3+ ion and radical scavenging activity were found in the protein hydrolysate extracted from Olive and Soybean, respectively. Exposure of protein hydrolysates extracted from plant sources were determined in choice and no choice assays. In choice experiment, the highest amount of ingestion was recorded on Tea, Guar and Summer squash but the adults ingested the most protein hydrolysate extracted from tea optimized with α-pinene. In no choice experiment, the highest ingestion was recorded on Guar while optimization with α-pinene caused the highest ingestion on both Tea and Guar. Bioassay of C. sinensis saponin against the adults of B. oleae demonstrated the LC50 and LT50 values of 0.35% and 1.41 days, respectively. Also, CSS decreased activities of digestive enzymes in B. oleae except for TAG-lipase and trypsin. The adults of B. oleae fed on protein hydrolysate containing CSS showed elevated activity of antioxidant enzymes including catalase, peroxidase, superoxide dismutase and ascorbate peroxidase except for glucose-6-phosphate dehydrogenase. Results of the present study showed that protein hydrolysate can be extracted from plant sources that have little commercial value like tea seeds and olive kernels. In addition, their optimization with compounds that are attractive to the olive fruit fly can provide products with the higher efficiency than the products available in the market.