Protein By-products Research Articles

Antioxidant and Enzyme Inhibitory Activities of Metapenaeus monoceros By-Product Hydrolysates Elaborated by Purified Alkaline Proteases

This study investigated the antioxidant potential and enzymatic inhibitory power of shrimp by-product protein hydrolysates (hyd) prepared using two purified serine alkaline proteases namely; alkaline protease from Anoxybacillus kamchatkensis strain M1V (SAPA) and alkaline protease from Aeribacillus pallidus strain VP3 (SPVP). The characterization of their molecular weights showed the presence of peptides less than 15 kDa. SAPA-hyd displayed the highest reducing power activity. Likewise, SAPA-hyd was found to be active against angiotensin I-converting enzyme (ACE), tyrosinase (Tyr), and amylase (Amy) enzymes with IC50 values of 10.01, 6.13, and 4.11 µg/mL, respectively. SPVP-hyd revealed the highest radical scavenging power, β-carotene protection, and ferrous chelating activity with EC50 values of 11.79, 3.69, and 0.61 µg/mL, respectively. After fraction nation, all fractions displayed a high inhibitory potential against ACE. Only fractions F2 and F3 from SAPA-hyd showed the highest anti-tyrosinase activity with IC50 values of 25.10 and 12.5 ng/mL, respectively. These results suggest that a simple, clean, economic, and controllable bioprocess for the utilization of shrimp by-product was investigated. This study gives an unprecedented report on the anti-Tyr activity of the protein hydrolysate from fish bio-waste. Additionally, two peptide hydrolysates with multifunctional biological activities were elaborated from Metapenaeus monoceros by two bacterial purified proteases.

Improvement of physicochemical, mechanical, thermal and surface properties of anchovy by-product protein films by addition of transglutaminase, and the correlation between secondary structure and mechanical properties

Abstract In this study, improvement of some properties of anchovy by-product protein (ABP-P) films by addition of transglutaminase (TGase), and the correlation between secondary structural results and mechanical properties were investigated. The solubility and water vapor permeability of films improved by the TGase treatment at low concentrations. The highest tensile strength value was obtained in films containing 5 % TGase, and the elongation at break values decreased with the TGase concentration increasing. Glass transition temperature (Tg) of films decreased depending on TGase concentration and the lowest Tg was observed from 5 % TGase treated film. Fourier transform infrared spectra of films displayed similar backbone structures with different band intensities. The secondary structure of films from Amide-I band was significantly affected by TGase addition and the results were well correlated with mechanical properties. TGase addition modified the film surface structure and 3 % concentration caused the lowest surface roughness. These results revealed that mechanical, barrier and surface properties of ABP-P films could be modified with 3 % TGase treatment.

Prevention of protein and lipid oxidation in freeze-thawed bighead carp (Hypophthalmichthys nobilis) fillets using silver carp (Hypophthalmichthys molitrix) fin hydrolysates

Conversion of aquatic by-products into value-added food ingredients has gained great interest worldwide, and enzymatic hydrolysis is one of the most accepted methods for the recovery of by-product proteins. In our study, fins from silver carp (Hypophthalmichthys molitrix) were hydrolyzed by four enzymes (trypsin, alcalase, papain, and neutrase) and the antioxidant activity of the derived fin hydrolysates was evaluated both in vitro and in freeze-thawed bighead carp (Hypophthalmichthys nobilis) fillets. The results showed that fin hydrolysates by trypsin and alcalase exhibited strong in vitro scavenging activity against 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals and chelating activity to ferrous ions. Freeze-thaw-induced protein oxidation (the formation of carbonyls and disulfide bonds) and degradation (the loss of Ca2+-ATPase activity) were significantly (P < 0.05) inhibited by fin hydrolysates. In addition, fin hydrolysates reduced lipid oxidation as evidenced by decreased free fatty acid content, peroxide value, thiobarbituric acid reactive substances (TBARS), and fluorescent compounds after multiple freeze-thaw cycles. Therefore, fin hydrolysates by trypsin and alcalase could be potential natural antioxidants in preservation of fish fillets.

Antiproliferative activity of protein hydrolysates derived from fish by-products on human colon and breast cancer cells.

AbstractThe consumption of fish is encouraged in dietary guidelines because of its association with health benefits; however, fish processing generates by-products (gills, bones, skin, head), which can rise up to 50–60% of fish weight after filleting. The investigation of bioactivity of fish by-products and subsequent utilization for the development of high added-value food ingredients and/or supplements will reduce waste and create new products of high nutritional value. We studied the antiproliferative activity of fish by-product protein hydrolysates (FPH) on human colon and breast cancer cells. A total of 6 Meagres “Argirosomus Regius” (1256.45 ± 232.32g) and 16 Gilthead Sea Breams “Sparus Aurata” (403.47 ± 72.92g) were obtained by HCMR Institute in Crete, Greece. The fins, skin, bones, head, and gills were isolated, lyophilized, homogenized and stored separately at -80oC. The protein hydrolysates from each byproduct were prepared using a pH extraction method. Human colorectal adenocarcinoma cells (COLO320 cells) and human breast adenocarcinoma cells (MCF7A cells) were treated with different FPH for 48 hours, and cellular proliferation was measured using the MTT assay. Results are given as mean percentage of triplicate independent analyses. Statistical significance of growth inhibition was estimated following Wilcoxon Signed-Ranks test with α = 0.05. In COLO320 cells, FPH induced a the significant antiproliferative activity at 0.5g/L. Specifically, FPH from bones, gills and skin of Meagre showed a growth inhibition of 23.7%, 9.9% and 26.4%, respectively, after 48 h of treatment. The inhibition by the same by-products from the Gilthead Sea bream was 24.6%, 21.9% and 26.4%, respectively after 48 h. In MCF7A cells, FPH exerted a significant growth inhibition at 1g/L. The skin and fins of Meagre induced a growth inhibition of 25.5% and 39.0% respectively; the gills, skin and fins of Gilthead Sea Bream showed a growth inhibition of 28.5%, 47.1% and 39.6%, respectively, after 48 h. These values were in the same range with etoposide (reference anticancer molecule) in the concentration of 3.1μM for COLO320 cells and 50μM for MCF7A. These preliminary data suggest that certain fish by-products could represent a source of anticancer peptides and may cause growth inhibition of human cancer cells. The isolation of responsible bioactive peptides from fish byproducts and the integration of them into food supplements can have beneficial effects on human health.

Effects of pressure-assisted enzymatic hydrolysis on functional and bioactive properties of tilapia (Oreochromis niloticus) by-product protein hydrolysates

Fish by-product protein can be converted into valuable food and nutraceutical ingredients via proteolysis. The existing process suffers from many limitations such as extended reaction time and nonselective hydrolysis. In this study, protein from tilapia fish by-products was transformed into functional peptides using pressure-assisted enzymatic hydrolysis. Proteins were extracted from the tilapia by-products by isoelectric solubilization and precipitation method. The effects of pressure (38–462 MPa) and hydrolysis time (6–35 min) on the properties of the hydrolysates were investigated using a central composite design. Pressure enhanced protein hydrolysis with a maximum trichloroacetic acid-solubility index (TCA-SI) of 23% obtained at 250 MPa for 35 min. Pressure and time were also vital in improving soluble protein content (5.7 mg/mL), reducing power (44 μg AAE/g), and solubility (71%) of the hydrolyzed products. Improved antioxidant activity, indicated by a significant decrease in IC50 values from 653 μg/mL to 304 μg/mL, was recorded. The combined process facilitated the release of low-molecular-weight peptides and essential amino acids. However, water and oil holding capacities were found to be decreased. Pressure-assisted enzymatic hydrolysis could provide an effective approach for recovering bioactive peptides from fish by-products for industrial applications.

GROWTH PERFORMANCE, NUTRIENTS DIGESTIBILITY AND CARCASS MEASUREMENTS OF GROWING RABBITS FED DIETS INCORPORATED WITH LENTIL OR CHICKPEA SCREENING BY-PRODUCTS.

This work aimed to study the influence of replacement 15 or 30% of soybean meal protein by either lentil screening by-products protein (LSBP) or chickpea screening by-products protein (CSBP) on performance, nutrients digestibility, plasma parameters, carcass measurements and economic profitability of growing rabbits. Sixty New Zealand White (NZW) growing rabbits, six weeks of age, were divided to five experimental groups. Each group included four replicates (three rabbits each) as follow: control group fed basal diet without LSBP or CSBP; the 2nd, 3th, 4th and 5th groups of rabbits fed 15% LSBP, 30% LSBP, 15% CSBP and 30% CSBP diets, respectively. Results showed that LSBP has lower DM, OM and EE contents than CSBP. Meanwhile, LSBP has higher CP, CF, ash% and GE (kcal/kg) contents compared to CSBP. LSBP was higher in arginine, threonine, isoleucine, and lysine. Meantime, CSBP had higher contents in leucine, methionine and phenylalanine as predominant essential amino acids. Inclusion of LSBP and CSBP insignificantly improved FBW, BWG and FCR. However, average daily feed intake of rabbits fed 15% CSBP was higher (P<0.05) than those fed 30% CSBP. No significant differences were observed in all nutrients digestibility (DM, OM, CP, EE and NFE) and nutritive values expressed as DCP%, TDN% and DE Kcal/kg between groups of rabbits fed LSBP and CSBP diets and those fed the control diet. Meanwhile, group of rabbits fed 30% LSBP had higher (P<0.05) CP digestibility. Conversely, group of rabbits fed 30% CSBP recorded the lowest (P<0.05) CP digestibility. Significant higher (P<0.05) values of plasma total protein and albumin concentrations were recorded for rabbits fed diets contained 30% LSBP, 15 or 30% CSBP than the control group. Moreover, there were insignificant differences in globulin and uric acid among all the experimental groups. Regarding liver functions (AST and ALT), there was a significant decrease (P<0.05) in AST levels with rabbits fed 30% LSBP and 15 or 30% CSBP compared to the control group. No significant differences in most carcass measurements were found between rabbits fed different levels of LSBP and CSBP diets and those fed the control diet except heart, kidneys weights and total edible parts %. The inclusion of LSBP at a level of 15% significantly decreased (P<0.05) total edible parts % compared with the inclusion of 30% CSBP and the control group. The net revenue improved by 4.16, 7.75, 3.43 and 9.52% for 15% LSBP, 30% LSBP, 15% CSBP and 30% CSBP, respectively. The best net revenue and economical efficiency were recorded by 30% CSBP diet followed by 30%LSBP, 15%LSBP, 15% CSBP diets and the lowest one was the control group. In conclusion, lentil or chickpea screening by-products protein could be used up to 30% substitution level for soybean meal protein without any detrimental effects on performance, nutrient digestibility, plasma parameters and carcass measurements of growing rabbits.

Preparation Protein Hydrolysates from Fish by-product and Study Effected on Lettuce (Lactuca sativa L.) Growth, Yield, Quality and Enhanced Salt Tolerance

The experiment was carried out during the winter season 2019-2018 in Al-Hartha district, Basrah Governorate to study the effects of fish by-product prepared by Alcalase and Flavourzyme enzyme as a foliar application on lettuce (Lactuca sativa L.) yield and quality grown under salinity conditions. Fish by-product protein hydrolysate was spray-applied (3 and 6ml. L-1) additional to control treatment (spraying with water) referred to (T0-T4) at four (S4), six(S6) times after 20 days transplanting at10-day intervals. Randomized Complete Block Design (R.C.B.D.) was used as factorial experiment. Treatment means were compared by using Least Significant Differences (L.S.D.) at a probability of 0.05. The results showed that spraying with protein hydrolysates had a significant effect on most studied characters compared to control treatment. Results showed that foliar application with (T2) significantly increased the total leaves number, leaves area, carbohydrate ,proline, shoot fresh weight of plant, dry matter, total soluble solids (TSS %) and total yield additional to significantly decreased in nitrate contents, while foliar application with (T4) significantly increased in the plant height and stem height. The results showed that spraying six times (S6) were significant increases in these growth characters comparing with four sprays (S4). The interaction between treatments and spraying number show significantly increased in some characters, the (T2 S6) had the highest value shoot fresh weight 762.5g and total yield 17.899 tone.donum-1.

Insect larvae, Hermetia illucens in poultry by-product meal for barramundi, Lates calcarifer modulates histomorphology, immunity and resistance to Vibrio harveyi

This study investigated the effects of replacement of fishmeal (FM) with poultry by-product (PBM) protein, supplemented with black soldier fly, Hermetia illucens (HI) larvae on growth, histomormhology, immunity and resistance to Vibrio harveyi in juvenile barramundi. Two hundred and twenty five barramundi averaging 3.51 ± 0.03 g were randomly allocated into three groups and fed isonitrogenous and isocalorific diets containing different levels of PBM supplemented with HI as follows: Control (FM based diet), 45PBM + HI (45% PBM supplemented with 10% HI), and 90PBM + HI (90% PBM supplemented with 10% HI) for 6 weeks. Results showed that dietary inclusion of 45PBM + HI significantly improved the growth performance than control whereas growth inhibition occurred in the 90PBM + HI. The 45PBM + HI groups demonstrated significant increases in histometric measurements (villus and enterocyte width, and microvilli height) and acidic mucins. The impaired growth in 90PBM + HI groups was further associated with multifocal necrosis in the liver, an upregulation of the stress related genes (HSP70 and HSP90) and increase in the levels of liver enzymes. When 45PBM + HI was fed, survival against V. harveyi increased significantly and also an increase in serum immunity and immune-related genes in the head kidney was observed after infection.

Amino acid composition and digestible amino acid content in animal protein by-product meals fed to growing pigs1.

An industry survey and animal experiment were conducted to evaluate the amino acid (AA) compositional variability and standardized ileal digestibility (SID) of AA in animal protein by-products fed to growing pigs. Animal protein by-product meals (212) were categorized into 8 groupings (blood meal, chicken by-product meal, chicken meal, feather meal, meat and bone meal, meat meal, poultry by-product meal, and poultry meal) and analyzed for total AA. Amino acid analysis among (e.g., Lys in blood meal averaged 9.20% compared with 2.31% for feather meal, DM basis) and within (e.g., Lys range of 1.54% in blood meal and 1.44% in feather meal, DM basis) the by-product classifications varied as expected, but on average the total AA values were similar to that reported in the literature. For the determination of the SID of AA, 15 barrows (average initial and final BW of 31.6 and 78.7 kg, respectively) were fitted with a T-cannula in the distal ileum and allotted to 15 diets over nine 7-d periods, resulting in 9 replications per diet. Pigs were fed a basal diet based on soybean meal and dehulled-degermed corn, 13 diets containing 17.5% animal protein by-product meal to partially replace a portion of the soybean meal and dehulled-degermed corn in the basal diet, or a N-free diet. Pigs were re-allotted to diets based on minimizing the number to times that the N-free diet would precede or follow feeding either of the blood or feather meal diets because of concern with inadequate diet consumption, as well as to prevent diets from being re-fed to the same pig during the next or subsequent periods. Values for the apparent ileal AA digestibility of each diet were determined, adjusted to SID based upon the endogenous AA losses determined by feeding the N-free diet, and the SID of AA in each animal protein by-product meal calculated using the difference procedure. The SID of AA varied among (e.g., SID of Lys averaged 91% in chicken meal but 47% in feather meal) and within (e.g., SID of Lys in three meat and bone meals was 80%, 71%, and 54%) the animal protein by-product meals, as would be expected and are consistent with variation reported in the literature. Overall, the data provide total AA composition for 212 samples and SID of AA for 13 samples of animal protein by-product meals, including data on their variability, which is critical for their use in feed formulation programs.

Wheat bread enriched with raspberry and strawberry oilcakes: effects on proximate composition, texture and water properties

Oilcakes from the oilseed industry are rich in dietary fibre and protein by-products. We assessed the impact of wheat flour replacement with raspberry and strawberry oilcakes on the proximate composition of bread, colour, texture and water behaviour. The substitution influenced the ash, fat and protein content causing an increase in the content of each of the analysed macronutrients. The crumb colour components (CIE L*a*b*) were shifted toward red while the saturation of yellow decreased. Texture analysis showed that the hardness and chewiness of crumb with oilcakes increased as well as springiness decreased. It was found that flour substitution with oilcakes limited significantly water transport and also influenced the molecular dynamics of water in the bread crumb. 1H NMR measurement results of relaxation times demonstrated that the free water in relation to the bound water in the examined systems depended on the amount of the flour replaced by the oilcake, as well as on the botanical origin of the oilcakes.

Functional Properties of White Shrimp (Litopenaeus vannamei) By-Products Protein Recovered by Isoelectric Solubilization/Precipitation

ABSTRACTThe processing of fish in general entails quantities of by-products, such as exoskeleton and cephalothorax of shrimp, which may reach 70%. Protein recovered from by-products has been investigated in recent years for its ability to offer more nutritious foods and improved functional properties. The objective of the present study was the use of the pH shifting process to recover proteins from solubilization and precipitation that are present in the by-products (heads and shells) of white shrimp (Litopenaeus vannamei). The proximal composition of the by-products presented 58.5% protein (d.b). The isoelectric point used to precipitate the protein was defined at pH 4. The protein concentrate presented 73.1% of protein. The yield of the protein concentrate mass resulted in 47.8% (w.b). The greatest solubility found for the protein concentrate was 51.3% at pH 8. The oil and water retention capacity resulted in values of 8.5 and 2.5 mL/g of protein, respectively, and the highest emulsifying capacity was found at pH 8. The by-products and concentrate amino acids profiles confirmed the presence of 16 amino acids. In general, the shrimp protein concentrate obtained showed the potential to be included as an ingredient in food formulations.

Traceability of animal protein byproducts in ruminants by multivariate analysis of isotope ratio mass spectrometry to prevent transmission of prion diseases.

Background:Ruminant feed containing animal byproduct proteins (ABPs) is prohibited in many countries due to its risk of transmitting prion diseases (PD). In most cases the entire herd is sacrificed, which causes great harm to the producer countries by preventing their exportation of ruminant derived-products.Methods:We used stable isotope ratio mass spectrometry (IRMS) of carbon (13C/12C) and nitrogen (15N/14N) to trace the animal protein in the blood of 15 buffaloes (Bubalus bubalis) divided into three experimental groups: 1 - received only vegetable protein (VP) during 117 days; 2 - received animal and vegetable protein (AVP); and 3 - received animal and vegetable protein with animal protein subsequently removed (AVPR). Groups 2 and 3 received diets containing 13.7% bovine meat and bone meal (MBM) added to a vegetable diet (from days 21-117 in the AVP group and until day 47 in the AVPR group, when MBM was removed).Results:On the 36th day, differences were detectable in the feeding profile (p <0.01) among the three experimental groups, which remained for a further 49 days (85th day). The AVPR group showed isotopic rate reversibility on the 110th day by presenting values similar to those in the control group (VP) (p> 0.05), indicating that it took 63 days to eliminate MBM in this group. Total atoms exchange (> 95%) of 13C and 15N was observed through incorporation of the diet into the AVP and AVPR groups.Conclusions:IRMS is an accurate and sensitive technique for tracing the feeding profile of ruminants through blood analysis, thus enabling investigation of ABP use.

Protein concentrates obtained from pig by-products using pH-shifting technique: a preliminary study

ABSTRACT: This study aimed to investigate the extraction and characterization of protein concentrates from pig by-products (heart, liver and kidneys) using the pH-shifting technique. From the solubility profiles (pH 2 to 12), the protein extraction was performed at alkaline pH (10.0 to 11.5), obtaining two fractions: soluble (SC) and insoluble (IC). Higher protein content (71 to 77%) and extractability (214 to 459 mg/g) were observed in heart and liver concentrates; whereas, for water holding capacity (WHC) the highest values (4.20 to 4.54 g water/g protein) were for the heart (SC) and kidney (SC and IC) concentrates. All concentrates had high emulsion stability and higher WHC than commercial protein extenders (whey and soybean). The concentrates obtained from the soluble fraction were redder (higher a* values and lower h values) and darker (lower L* values) than insoluble fraction, especially heart and liver concentrates. Use of concentrates in sausage production slightly altered the color chroma (C*) of samples. It was concluded that the pig by-products protein concentrates had great potential of use as extenders in sausage production.

Identification of Antioxidant Peptides in Enzymatic Hydrolysates of Carp (Cyprinus Carpio) Skin Gelatin

The protein by-products from carp (Cyprinus carpio) are normally discarded as industrial waste during fish processing. The objective of this study was to identify and characterise the peptides with a potential antioxidant activity that are released from carp skin proteins during hydrolysis by the Protamex enzyme mixture. This study shows that a hydrolysate of carp skin gelatin and its reversed-phase chromatography fractions have strong in vitro antioxidant properties. Among these fractions, the alanine-tyrosine (Ala-Tyr) dipeptide was identified as the major compound with high antioxidant potential. The peptide has good stability during in vitro enzymatic digestion assay and can inhibit the angiotensin-converting enzyme (ACE). In conclusion, our study proves that both the unfractionated hydrolysate of carp skin gelatin and the above-mentioned Ala-Tyr dipeptide represents attractive novel compounds for the formulation of antioxidant foods.

PSIII-32 Nutrient and amino acids digestibility of animal protein byproduct in swine, determined using an in vitro model.

PSIII-32 Nutrient and amino acids digestibility of animal protein byproduct in swine, determined using an in vitro model.

Proteolytic susceptibility of food by-product proteins: An evaluation by means of a quantitative index

Abstract A proteolytic susceptibility index was proposed to evaluate the reaction performance of different food by-products with subtilisin. Whey, salmon muscle and feather keratine were hydrolyzed at the same peptide bond concentration at 50 °C and pH 8.0 with different subtilisin concentrations. The logarithmic equation P = 1/b ln(abt+1) was fitted to estimate the kinetic constants a and b. The a/b ratio was proposed as a proteolytic susceptibility index, which was correlated with the chemical structure and conformation of protein sources in increasing order of feather keratin, salmon muscle and whey proteins with corresponding a/b values of 0.1, 8.2 and 14.4 mM2/min, respectively. The methodology proposed in this work can be used to evaluate the proteolytic susceptibility of different protein by-products to different proteases and to evaluate the changes in proteolytic susceptibility after treatment.

Nutrient ileal digestibility evaluation of dried mealworm (Tenebrio molitor) larvae compared to three animal protein by-products in growing pigs.

ObjectiveThis study was to investigate the nutrient ileal digestibility of dried mealworm (Tenebrio molitor) larvae and compare with those of three animal protein by-products in growing pigs.MethodsA total of 12 crossbred ([Landrace×Yorkshire]×Duroc) growing pigs with average body weights of 24.12±0.68 kg were surgically equipped with simple T-cannulas after being deprived of feed for 24 h according to published surgical procedures. These pigs had a recovery period of two weeks. A total of 12 pigs were assigned to individual metabolic crates and allotted to one of four treatments with 3 replicates in a fully randomized design. Dietary treatments included the following: i) Fish meal, corn-vegetable by-product basal diet+9.95% fish meal; ii) Meat meal, corn-vegetable by-product basal diet+9.95% meat meal; iii) Poultry meal, corn-vegetable by-product basal diet+9.95% poultry meal; iv) Tenebrio molitor, corn-vegetable by-product basal diet+9.95% dried Tenebrio molitor larvae.ResultsResults showed that the apparent ileal digestibility (AID) of Lys was higher (p<0.05) in pigs fed Tenebrio molitor diet than that in pigs fed fish meal diet. Pigs fed Tenebrio molitor diet showed increased (p<0.05) AID of His and Arg compared to pigs fed Fish meal or Meat meal diet. The AID of Cys was increased (p<0.05) in pigs fed poultry meal and Tenebrio molitor diets compared to that in pigs fish meal diet. Pigs fed meat meal, poultry meal, and Tenebrio molitor diets showed higher (p<0.05) standardized ileal digestibility (SID) of total energy compared to pigs fed fish meal diet. The SID of Arg was higher (p<0.05) in pigs fed Tenebrio molitor diet than that in pigs fed fish meal or meat meal diet. Furthermore, pigs fed poultry meal or Tenebrio molitor diets showed increased (p<0.05) SID of Cys compared to pigs fed fish meal diet.ConclusionIn conclusion, providing pigs with diets that contained Tenebrio molitor larvae meal improved AID and SID of nutrients as well as essential and non-essential amino acids. The digestibility of dried mealworm larvae protein and its utilization in vivo are also good. Therefore, dried mealworm larvae protein can be used as protein source at 10% level in growing pigs.

Effect of dietary common carp by-product protein hydrolysates on antioxidant status in different organs of zebrafish (Danio rerio)

Effect of dietary common carp by-product protein hydrolysates on antioxidant status in different organs of zebrafish (<i>Danio rerio</i>)

Physicochemical and Biological Properties of Eel By-Products Protein Hydrolysates: Potential Application to Meat Product Preservation

European eel by-products have been hydrolysed in order to produce novel bioactive peptides with antibacterial and antioxidant activity. Protein hydrolysates from Anguilla by-products obtained by treatment with Savinase® (PHAB-s) have high protein content than that produced with Protamex® (PHAB-p). Furthemore, both protein hydrolysates had a high percentage of essential amino acids. In addition, results indicated that PHAB-s and PHAB-p exhibited different degrees of antioxidant activities, evaluated by several antioxidant assays. Thus, PHAB-s displayed high antioxidant activity, in terms of DPPH-radical scavenging effect (IC50 = 5.2 mg/ml), β-carotene bleaching inhibitory effect (CI50 = 4.4 mg/ml) and metal chelating activity. At 10 mg/ml, PHAB-p showed the highest reducing power. Antibacterial activities of PHAB-s and PHAB-p were also evaluated. PHAB-s showed the most important inhibitory effects against seven bacterial species. The application of PHAB-s and PHAB-p on minced meat as preservative reduced the lipid oxidation and inhibited the microbial growth during chilled storage for 11 days.

Production and Identification of Biologically Active Peptides Derived from By-product of Hen Egg-Yolk Phospholipid Extraction

Biologically active peptides derived from food proteins have been increasingly popular due to their therapeutic properties. This paper attempts to utilize a by-product of phospholipid extraction from egg yolk as a source of peptides with antioxidant [radical scavenging capacity, Fe2+ chelating effect, reducing power (FRAP)] and ACE-inhibitory activity. In addition, in this research we analysed the ability to release bio-peptides of a non-commercial proteases obtained from Yarrowia lipolytica yeast. Yeast serine protease exert greater ability to evaluate antioxidant and ACE inhibitory activity than yeast aspartyl protease during degradation of protein by-product. Purification procedures including membrane filtration, gel filtration chromatography and reversed-phase high-performance liquid chromatography led to obtain a decapeptide QSLVSVPGMS with strong DPPH free radical scavenging and ACE inhibitory activities. A new application of the serine protease from Y. lipolytica yeast in the production of bioactive peptides from egg yolk protein by-product was demonstrated.