Production Of Protein Hydrolysates Research Articles

The Hydrolysis of Fish Protein from Giant Mudskipper (Periophthalmodon Schlosseri) using Alcalase Enzyme

Giant mudskippers (Periophthalmodon schlosseri) are amphibious fish and considered as endemic fish, so it can not be found in any other place and they live in a typical habitat in a tidal area with the mud of mangroves. Mudskipper These fish is relatively untapped as food source. This research aims to obtain the optimum conditions of enzyme concentration, pH, temperature, and hydrolysis incubation time on the degress of hydrolysis of alcalase enzyme in giant mudskipper (P. schlosseri). The production of fish protein hydrolysate was conducted by varying one parameter at a time to determine its effect without considering interactions with other parameters. The results obtained optimum hydrolysis at 1.5% alcalase concentration of protein weight, pH 7.5, temperature 50°C, and the duration of hydrolysis 2 hours. The degree of hydrolysis produced at the optimum condition was 67.44%.

Autolysis of rainbow trout (Oncorhynchus mykiss) by-products: Enzymatic activities, lipid and protein oxidation, and antioxidant activity of protein hydrolysates

Autolysis (at fixed temperatures (40, 50, 60 °C) or gradually increasing temperatures (40-60 °C) with different times) was used to produce protein hydrolysates from rainbow trout processing by-products. Total proteolytic and trypsin activities with fixed temperatures was higher than gradually increasing temperatures, decreased with increasing autolysis time and temperature with fixed temperatures (P ≤ 0.05). TCA-soluble peptides decreased with increasing autolysis times from 1 to 3 h (P ≤ 0.05). Autolysis increased peroxide value and thiobarbituric acid-reactive substances in both lipids and hydrolysates, particularly with gradually increasing temperatures (P ≤ 0.05) and was associated with oxidation of polyunsaturated fatty acids. Sulfhydryl groups decreased, while protein carbonyls and solubility were increased with fixed temperatures at higher temperatures (50 and 60 °C) or with gradually increasing temperatures at longer autolysis time (P ≤ 0.05). Free radical scavenging activity and the metal chelating ability of hydrolysates were governed by autolysis times and temperatures. Results of size exclusion chromatography-high performance liquid chromatography indicated that autolysis for 1 h at lower temperature (40 °C) was sufficient to produce autolysates rich in small peptides from rainbow trout by-products. Autolytic hydrolysis might be useful for production of such protein hydrolysates.

Two-stage selective enzymatic hydrolysis generates protein hydrolysates rich in Asn-Pro and Ala-His for enhancing taste attributes of soy sauce

This study demonstrated the contribution of peptides to umami soy sauce taste. Asn-Pro and Ala-His with remarkable umami taste and umami-enhancing capacity were found in original soy sauce, possessing umami thresholds of 175 and 160 mg/L and umami-enhancing thresholds of 10 and 13 mg/L, respectively. Firstly, an industrially viable two-stage hydrolysis at 55 °C (a 12-h hydrolysis with the neutral protease, then a 12-h hydrolysis with the aminopeptidase) was established to produce protein hydrolysates rich in umami-tasting and umami-enhancing peptides (e.g. Asn-Pro and Ala-His) from non-soy sauce protein preparations (soy protein isolate, rice proteins, wheat proteins, peanut proteins or pea proteins). The soy protein isolate hydrolysate produced via the two-stage hydrolysis had Asn-Pro and Ala-His contents 3.32 and 1.15 times higher than those produced via the one-stage hydrolysis using the neutral protease only. Adding the hydrolysate to original soy sauce at 5% w/v significantly increased umami and reduced bitterness.

Isolation of Keratinolytic Microorganism Streptomyces chartreusis strain ISP 5085 from the Soil Sample: Characterization, Degradation and Microbial Identification using 16S rDNA Region

Keratinolytic microorganisms have a broad significance in feather waste degradation and it can be used for advancement of livestock feed and production of protein hydrolysates. Production of keratin into the environment in different forms is very high which leads to setback for its degradation. An approach for degradation of keratin based wastes through potential microorganism with higher efficiency can be attained. The study shows that maximum DFD% i.e. Degree of Feather (keratin) Degradation, through the isolates is achieved, when nutrient medium is kept at temperature 30 °C and pH-8.5 supplemented with dehydrated powdered form of chicken feathers as keratin source for 72 h – 120 h. Chicken feathers acts as a better substrate and source of keratin content. A molecular approach was necessary therefore; phylogenetic trees of the isolate were constructed with neighbour-joining method through the Microbial Identification using 16S rDNA Region, which showed that sequence exhibited a high level of homology with Streptomyces chartreusis strain ISP 5085. The present study deals with identification of isolates that play a significant role in the degradation of chicken feather waste as well as keratin degradation ability of the isolates and optimum conditions required for it.

Optimization of the Enzymatic Protein Hydrolysis of By-Products from Seabream (Sparus aurata) and Seabass (Dicentrarchus labrax), Chemical and Functional Characterization.

Valorization of seabass and seabream by-products is becoming increasingly relevant, as marketing of these species moves from selling whole fish to filleting for convenience products. With this aim, we optimized for the first time the production of fish protein hydrolysates (FPH) by enzymatic hydrolysis from filleting by-products of these commercially relevant aquaculture species, isolating fish oil at the same time. On the whole, both fish yielded similar amounts of protein, but frames and trimmings (FT) were the best source, followed by heads and viscera. In vitro antioxidant and antihypertensive activities showed similar figures for both species, placing FPHs from FT as the most active. Molecular weights ranged from 1381 to 2023 Da, corresponding to the lowest values of FT, in line with the higher hydrolysis degrees observed. All FPHs reached high digestibility (>86%) and displayed an excellent amino acid profile in terms of essential amino acids and flavor, making them suitable as food additives and supplements.

Exploring the Milk-Clotting and Proteolytic Activities in Different Tissues of Vallesia glabra: a New Source of Plant Proteolytic Enzymes.

Proteolytic enzymes are widely distributed in nature, playing essential roles in important biological functions. Recently, the use of plant proteases at the industrial level has mainly increased in the food industry (e.g., cheesemaking, meat tenderizing, and protein hydrolysate production). Current technological and scientific advances in the detection and characterization of proteolytic enzymes have encouraged the search for new natural sources. Thus, this work aimed to explore the milk-clotting and proteolytic properties of different tissues of Vallesia glabra. Aqueous extracts from the leaves, fruits, and seeds of V. glabra presented different protein profiles, proteolytic activity, and milk-clotting activity. The milk-clotting activity increased with temperature (30-65°C), but this activity was higher in leaf (0.20 MCU/mL) compared with that in fruit and seed extracts (0.12 and 0.11 MCU/mL, respectively) at 50°C. Proteolytic activity in the extracts assayed at different pH (2.5-12.0) suggested the presence of different types of active proteases, with maximum activity at acidic conditions (4.0-4.5). Inhibitory studies indicated that major activity in V. glabra extracts is related to cysteine proteases; however, the presence of serine, aspartic, and metalloproteases was also evident. The hydrolytic profile of caseins indicated that V. glabra leaves could be used as a rennet substitute in cheesemaking, representing a new and promising source of proteolytic enzymes.

Optimal Production of Protein Hydrolysates from Monkfish By-Products: Chemical Features and Associated Biological Activities.

The aim of this work was the recovery of protein substrates from monkfish waste (heads and viscera) generated in the on-board processing of this species. Initially, the effect of pH, temperature, and protease concentration was studied on mixtures of a 1:1 ratio (w/v) of monkfish heads/water. The optimal conditions of proteolytic digestion were established at 57.4 °C, pH 8.31, [Alcalase] = 0.05% (v/w) for 3 h of hydrolysis. Later on, a set of hydrolysis at 5L-pH-stat reactor were run under the aforementioned conditions, confirming the validity of the optimization studies for the head and viscera of monkfish. Regarding the chemical properties of the fish protein hydrolysates (FPH), the yield of digestion was higher than 90% in both cases and the degrees of hydrolysis and the soluble protein content were not especially large (<20% and <45 g/L, respectively). In vitro digestibility was higher than 90% and the percentage of essential amino acids ranged from 40 to 42%. Antioxidant activities were higher in viscera FPH, and antihypertensive ability was superior in head FPH. The values of number average molecular weights (Mn) of monkfish hydrolysates were 600 Da in the viscera and 947 Da in the head. The peptide size distribution, obtained by size-exclusion chromatography, indicated that the largest presence of peptides below 1000 Da and 200 Da was observed in the viscera FPH.

Production of whey protein hydrolysates with angiotensin-converting enzyme-inhibitory activity using three new sources of plant proteases

Abstract Production of functional/bioactive components by whey protein hydrolysis using new plant proteases represents an innovative area in food processing and functional foods. The present study evaluated the potential use of plant crude extracts from Citrus aurantium flowers, trompillo (Solanum elaeagnifolium) berries (TE) and melon (Cucumis melo) fruit (ME) for production of whey protein hydrolysates. The hydrolytic patterns of whey proteins (i.e., β-lactoglobulin, α-lactalbumin, serum albumin, and immunoglobulins) at pH 3.5 and 6.5, at 0, 3, 6, 9, and 24 h, were monitored by HPLC and SDS-PAGE analysis. Maximum proteolytic action on the major whey proteins (i.e., β-lactoglobulin and α-lactalbumin) was obtained using ME and TE at pH 6.5. Whey hydrolysates that presented more hydrolysis of β-lactoglobulin showed the highest angiotensin-converting enzyme inhibitory activities (75–90% inhibition). The use of these new plant proteases offers potential in the production of hydrolysates with bioactive properties for the development of functional foods.

Ultrasound microwave-assisted enzymatic production and characterisation of antioxidant peptides from sweet potato protein

Herein, we investigated the effects of ultrasound microwave (UM)-assisted hydrolysis using Alcalase (ALC), Flavourzyme (FLA), and their combination (ALC + FLA), on the production of sweet potato protein hydrolysates (SPPH). UM-assisted enzymatic hydrolysis significantly increased the degree of hydrolysis of SPPH compared with untreated (UN) samples. Fractions with differences in molecular weight (MW) of >10, 3–10, and < 3 kDa in SPPH from UM-assisted ALC, FLA, and ALC + FLA hydrolysis displayed higher antioxidant activities than those from UN samples. MW < 3 kDa fractions of SPPH from UM-assisted ALC and ALC + FLA hydrolysis treatments presented much stronger Fe2+-chelating activity (98.48% and 98.59%), ·OH scavenging activity (67.11% and 60.06%), and higher ORAC values (110.32 and 106.32 µg TE/mL), from which diverse peptides with potential antioxidant activities were obtained by semi-preparative HPLC and LC-MS/MS. All identified peptide sequences exhibited at least three potential antioxidant amino acids. Additionally, changes in peptide conformational structure and antioxidant amino acid composition were revealed by structure–activity relationship analysis. Thus, ultrasound microwave treatment has great potential in antioxidant peptides production.

Chemical and Cellular Antioxidant Activities of In Vitro Digesta of Tilapia Protein and Its Hydrolysates.

Production of protein hydrolysate as nutraceuticals is typically based on the activity of the hydrolysate, which might not yield the optimal activity under physiological condition due to structural modification of peptides upon gastrointestinal (GI) digestion. This study systematically compared the chemical and cellular antioxidant activities of the in vitro digesta of tilapia protein and its hydrolysates prepared with various degree of hydrolysis (DH) by Alcalase. The enzymes used in the in vitro GI digestion analysis significantly contributed to the peptide content, Trolox equivalent antioxidant capacity (TEAC), and oxygen radical absorbance capacity (ORAC). Proteins and all hydrolysates were slightly digested by pepsin but hydrolyzed extensively by pancreatin. Both hydrolysate and digesta predominantly scavenged free radicals via hydrogen atom transfer (HAT). The antioxidant activities of the hydrolysates increased with the increasing DH up to 16 h of hydrolysis. However, the digesta of 10-h hydrolysate displayed the highest chemical and HepG2 cellular antioxidant activities, while the protein digesta displayed the lowest. Principal component analysis (PCA) showed that the TEAC of the digesta was positively correlated with the cellular antioxidant activity (CAA). Therefore, the production of protein hydrolysate should be optimized based on the activity of the hydrolysate digesta rather than that of hydrolysates.

Effects of ultrasonic, microwave, and combined ultrasonic-microwave pretreatments on the enzymatic hydrolysis process and protein hydrolysate properties obtained from Chinese sturgeon (Acipenser sinensis).

Degree of hydrolysis (DH), yield, amino acid profile, protein solubility, and antioxidant activity of Chinese sturgeon protein hydrolysates, as influenced by thermal pretreatment, ultrasonic (US), microwave (MW), and combined US-microwave pretreatments were investigated. Initially, the samples were subjected to thermal pretreatments in order to measure their effect on DH, which increased at 55°C. The DH recorded 7.63, 5.55, and 6.02% for US, MW, and combined US-MW pretreatment (US+MW), respectively, at the optimal time (8min). The enzymatic hydrolysis (EN) of pretreated samples increased the DH to 19.41, 14.18, and 16.91% for US+EN, MW+EN, and US+MW+EN, respectively. The US+EN treatment was most effective for obtaining higher DH and yield, which were 19.41% and 18.62%, respectively. The use of US+EN also resulted in an increase in the percentage of molecular weights (≤1,000Da), amino acid content and protein solubility, which reached 89.24, 80.08, and 98.58%, respectively. While, US+MW+EN pretreatment has achieved the highest antioxidant activities by IC50 of 1,1-diphenyl-2-picrylhydrazyl and 2,2-Azinobis (3-ehtylbenzothiazoli- 6-sulfnic acid), which were 3.01 and 1.85mg/ml, respectively, in addition to the reducing power assay, which was 0.528 at a protein concentration of 5mg/ml. Therefore, US and combined US-MW techniques can play a promising role in the production of protein hydrolysates and the improvement of their antioxidant properties. PRACTICAL APPLICATIONS: Nowadays, interest in Chinese sturgeon production has increased as a promising source of protein and antioxidant peptides. The optimal thermal pretreatment can be used to enhance the degree of hydrolysis. The results indicated that the use of ultrasound as a pretreatment enhanced the degree of hydrolysis, which could be useful in the preparation of protein hydrolysate with higher yields. The use of combined US-MW significantly improved the antioxidant properties of the protein hydrolysate. The combined US-MW technique is a novel method for obtaining valuable peptides and protein hydrolysates that can be applied as antioxidant constituents in the food products.

Biochemical Properties of a Partially Purified Protease from Bacillus sp. CL18 and Its Use to Obtain Bioactive Soy Protein Hydrolysates.

Microbial proteases are relevant biocatalysts with diverse applications. Production of protein hydrolysates is recently focused, since they might display biological activities. Therefore, the extracellular protease from Bacillus sp. CL18 was partially purified through ammonium sulfate precipitation (25-50% saturation) and gel filtration chromatography, with a 60.7-fold purification (40,593 U/mg protein) and 21.3% recovery. The partially purified protease (PPP) was characterized as a serine protease, with optimal activity at 51-59 °C and pH 7.4-8.8 and low thermal stability. Thermal inactivation followed first-order kinetics. PPP depended on Ca2+ for higher thermal stability, depicted by increases in half-lives (t1/2), activation energy (Ea), and free energy (ΔG#) for kinetic inactivation. PPP preferentially hydrolyzed casein > soy protein isolate (SPI) >>> keratinous materials. SPI hydrolysis by PPP was further investigated, and the obtained hydrolysates exhibited increased in vitro bioactivities. Hydrolysates displayed antioxidant capacities through the scavenging of synthetic organic radicals and Fe3+-reducing ability. In addition, hydrolysates inhibited the activities of dipeptidyl peptidase IV (DPP IV) and angiotensin-converting enzyme (ACE), suggesting antidiabetic and antihypertensive potentials, respectively. From its biochemical properties, PPP might be used to produce protein hydrolysates with multifunctional bioactivities. Both PPP and SPI hydrolysates can find applications in food biotechnology.

Production of protein hydrolysate from Protaetia brevitarsis seulensis (Kolbe) larvae by enzyme treatment under high pressure.

To improve the industrial use of health-functional materials based on edible insects, the objective of this study was to establish optimal conditions for improving the quality of Protaetia brevitarsis seulensis larval (PBSL) hydrolysates. PBSL was extracted using four methodologies: atmospheric pressure 50°C-water extraction, atmospheric pressure 95°C-water extraction, atmospheric pressure 50°C-water enzymatic hydrolysis, and enzyme treatment under high pressure (HPE). The quality characteristics of soluble solid content, extraction yield, total protein content, protein yield, protein content with low molecular weight (LMW) (< 1kD), and the amino acid composition of hydrolysates were compared based on the different methods. All of the quality characteristics were found to be higher for HPE extracts than for the other extracts. Under optimized HPE conditions, extraction yield, protein yield, protein content with LMW, amino acid content and the content of essential amino acids increased by 3.4, 4.4 1.4 1.5, and 1.3 times respectively, compared to the other methods.

Physicochemical and sensory properties of deep fried battered squid containing Brownstripe red snapper (Lutjanus vitta) protein hydrolysate

Deep-fried food is a fast and convenient way to prepare food that imparts desirable sensory characteristics of colour, flavour and in particular, a smooth texture, yet has been labelled as not healthy by consumers. Incorporation of other ingredients in the formulation of the batter could reduce the fat absorption in deep-fried foods. This research was aimed to determine the physicochemical and sensory properties of Brownstripe red snapper protein hydrolysate (BRSPH) and its utilisation in reducing the oil intake of deep-fried foods. The BRSPH were extracted using the enzymatic method utilizing Alcalase® as the working enzyme. Batter formulations were prepared by adding 0%, 2%, 4%, 6% and 8% of BRSPH into the sample mixtures. Addition of BRSPH into the batter was found to increase hardness and crispness of deep-fat fried battered squids. The fat content of the deep-fat fried battered squids with 8% BRSPH powder was found to be the lowest compared to those added with 2%, 4% and 6%, while sample without BRSPH powder was the highest (30.15%). Deep-fat fried squids with 4% of BRSPH powder showed the best acceptability scores in terms of crispness, taste and overall acceptability, but no significant differences were determined in the crispness between deep-fat fried squids with and without BRSPH. The findings indicate that enzymatic hydrolysis using Alcalase® has the potential to yield BRSPH with a high degree of hydrolysis (98.19%), low molecular weight (10-15 kDa), and low oil binding capacity (2.38 g oil/ g protein). Enzymatic hydrolysis proved to be a viable technique to produce protein hydrolysate which able to reduce the oil uptake and healthier with high acceptability of the end products. Research on how to optimize the use of BRSPH with a high economic, nutritional and industrial potential of understated resources would allow for the implementation of manufacturing practices to enhance the use of resources and increase the value of the by-product. This approach will offer the potential use of BRSPH for the production of batter formulation which is efficient in the reduction of oil uptake

Development of Technology for Obtaining Protein Hydrolysate from Camel Offal using Enzymatic Hydrolysis

The research is devoted to the creation of protein hydrolysate from camel wool offal. Protein deficiency in diets leads to the search for additional sources of protein. In this regard, protein hydrolysates are a promising reserve for enriching food products with proteins, the problems of obtaining which attract the attention of researchers. The quality and properties of protein hydrolysates are determined by the raw material, the method of hydrolysis and subsequent processing of the resulting product. The total protein content in offal can be from 19.5% (camel's legs with a put joint) to 21.2% (pork's legs), fat-from 3.2% (camel's legs with a put joint) to 21.0% (pork's legs). Data analysis shows that the fat content in camel offal is 2.25 times lower than in beef offal and in pork offal- 6.5 times, which will allow obtaining protein hydrolysate with higher storage capacity. It was found that the maximum degree of hydrolysis, the highest yield of protein hydrolysate in dry form was achieved at a temperature of 45°C with a hydrolysis duration of 8 h with the addition of 15% pancreatic suspension. As a result of the conducted research, the possibility of using camel offal in the production of protein hydrolysate is justified, optimal modes of obtaining protein hydrolysate are established and its nutritional value is evaluated.

Enzymatic Hydrolysis of Fish Waste as an Alternative to Produce High Value-Added Products

Fish waste was studied as a raw material for the simultaneous production of protein hydrolysates, collagen and fish oil. Enzymatic hydrolysis was selected for recovering these by-products with high value-added. Alcalase 2.4 L was used to hydrolyze fish waste in a batch reactor under controlled conditions (180 min, 50 °C and pH 8). The influence of hydrolysis degree on by-products recovery was analyzed for different enzyme and substrate concentrations. Results suggested that the enzyme/substrate ratio was the main factor controlling the hydrolysis rate. Linear relationships were found between the degree of hydrolysis and the amount of each of the obtained by-products. From these relationships, the amounts of by-products with high added value can be predicted by only knowing the degree of hydrolysis reached. In optimal conditions (DH = 25%), 430 g of protein hydrolysate, 10 g of collagen and 350 g of oil could be obtained from 1000 g of fish waste. The use of fish waste as raw material for by-product fabrication resulted in a 79% reduction of waste disposed to landfill. Therefore, this study shows the enzymatic hydrolysis of fish waste as a feasible solution to obtain high value-added products and an alternative to landfilling disposal.

Production, Characterization, and Bioactivity of Fish Protein Hydrolysates from Aquaculture Turbot (Scophthalmus maximus) Wastes.

The valorization of wastes generated in the processing of farmed fish is currently an issue of extreme relevance for the industry, aiming to accomplish the objectives of circular bioeconomy. In the present report, turbot (Scophthalmus maximus) by-products were subjected to Alcalase hydrolysis under the optimal conditions initially defined by response surface methodology. All the fish protein hydrolysates (FPHs) showed a high yield of digestion (>83%), very remarkable degrees of hydrolysis (30–37%), high content of soluble protein (>62 g/L), an excellent profile of amino acids, and almost total in vitro digestibility (higher than 92%). Antioxidant and antihypertensive activities were analyzed in all cases, viscera hydrolysates being the most active. The range of average molecular weights (Mw) of turbot hydrolysates varied from 1200 to 1669 Da, and peptide size distribution showed that the hydrolysate of viscera had the highest content of peptides above 1000 Da and below 200 Da.

Effectiveness of Toothpony (Gazza minuta) protein hydrolysate on reducing oil uptake upon deep-frying

Toothpony (Gazza minuta) is not typically used for human consumption due to its small size and low meat content, which is widely used as a fish meal. It is stated to be high in protein content and may be suitable for fish protein hydrolysate (FPH) production. Deepfat fried foods contain significant amounts of fat, in some cases up to one-third of the total food weight after frying. Toothpony FPH with low oil-binding ability may reduce the amount of oil consumed by deep-fried products. The objective of this research was to measure the physicochemical properties of Toothpony FPH and its utilisation in reducing the oil intake of deep-fried food. Toothpony FPH was obtained using the enzymatic method successfully. Batter formulations are prepared by adding 0%, 2%, 4%, 6% and 8% of Toothpony FPH into the sample mixtures. The present study indicates the degree of hydrolysis of Toothpony FPH determined by trichloroacetic acid (TCA) method was found to be 98.02%. Toothpony FPH's molecular weight distributions ranged from 7 to 175kDa and FTIR's transmission spectrum indicated the presence of amide I and amide II compounds (1654 and 1535cm-1 ). Oil binding capacity of Toothpony FPH was found to be low, which was 1.9 g oil/ g protein. This study indicated that 4% of Toothpony FPH produced the optimum amount to be incorporated in batter in order to best reduce oil uptake. In sensory evaluation, deep-fat-fried squid incorporated with 8% of Toothpony FPH showed the highest acceptance in all attributes, which were colour, crispness, oiliness, taste and overall acceptability. This approach offers the potentials use of Toothpony fish FPH for the production batter formulation which is efficient in the reduction of oil uptake.

Optimization of the porcine liver enzymatic hydrolysis conditions

AbstractWorldwide porcine slaughterhouses produce significant amounts of by‐products, such as porcine liver, daily. Even though the liver presents a very restricted market demand when raw, this product is composed of an exceptional nutritional content, with emphasis on protein, being, therefore, characterized as a potential raw material to produce protein hydrolysates. This article aimed to study the production of protein hydrolysate using the commercial enzymes Alcalase 2.4L™ and Novo Pro‐D™. For the development of this research, a central composite rotatable design with 4 axial points was applied for each enzyme. The factors evaluated were protein/water and enzyme/substrate ratios. The best hydrolysis results indicate average percentages of hydrolysis degree of 27.5% for both enzymes. The presence of low‐molecular‐weight peptides was also evidenced by the electrophoresis technique. It is, therefore, concluded that there is positive viability for the use of hydrolyzed porcine liver in differentiated food applications with an aggregate market value.Practical ApplicationsAt present, the worldwide growing dissemination of food scarcity has become a stimulus for the food industry to rethink the efficient use of raw materials to avoid waste and maximize the use of existing nutritional resources. A potential way of exploiting the nutritional value of the protein by‐products with no commercial applications is their transformation into protein hydrolysates by means of enzymatic processes. Protein hydrolysates have been in focus in the scientific community with industrial applications as beneficial products to the ingesting body, for acting as either nutraceuticals or functional bioactive foods. Commercialization of this type of product has become a growing market niche. Thus, this research, which presents an investigation regarding the conditions of the porcine liver hydrolysis, fits within current issues, with innovative potential of obtainment of bioactive peptides from by‐products.

Whey Protein Concentrate as a Novel Source of Bifunctional Peptides with Angiotensin-I Converting Enzyme Inhibitory and Antioxidant Properties: RSM Study.

Whey protein concentrate (WPC) is a unique source of protein with numerous nutritional and functional values due to the high content of branched-chain amino acid. This study was designed to establish the optimum conditions for Alcalase-hydrolysis of WPC to produce protein hydrolysates with dual biofunctionalities of angiotensin-I converting enzyme (ACE) inhibitory and antioxidant activities via response surface methodology (RSM). The results showed that the optimum conditions were achieved at temperature = 58.2 °C, E/S ratio = 2.5%, pH = 7.5 and hydrolysis time = 361.8 min in order to obtain the maximum DH (89.2%), ACE-inhibition (98.4%), DPPH• radical scavenging activity (50.1%) and ferrous ion chelation (73.1%). The well-fitted experimental data to predicted data further validates the regression model adequacy. Current study demonstrates the potential of WPC to generate bifunctional hydrolysates with ACE inhibition and antioxidant activity. This finding fosters the use of WPC hydrolysate as a novel, natural ingredient for the development of functional food products.