Chicken Protein Hydrolysates Research Articles

Partial Replacement of Fish Meal with Protein Hydrolysates in the Diet of Penaeus vannamei (Boone, 1934) during the Nursery Phase

The objective was to evaluate the effects of partial replacement of fish meal with protein hydrolysates and a commercial product in the diets of Penaeus vannamei post-larvae on zootechnical performance, proximate chemical composition, digestive enzyme activity, and total hemocyte count. The experiment was conducted in a clear water recirculation system comprising 24 experimental units, each with 30 shrimp with an average weight of 0.2 g. The treatments were control, chicken protein hydrolysate (CPH), enzymatic hydrolysate of chicken feathers, Aquabite®, CPH + maltodextrin, and CPH + yeast, with four replicates each. The inclusion level of the different protein sources evaluated was 6%. At the end of the experiment, all shrimp were counted, weighed, and measured to determine the zootechnical performance. The body and feed chemical compositions, as well as the enzymatic activities of the hepatopancreas and the total hemocyte count in the hemolymph, were analyzed. The data obtained were subjected to ANOVA and Tukey’s test. There was no statistical difference between the treatments in any of the analyzed parameters. The results showed that all the evaluated protein hydrolysates can be used as partial substitutes for fish meal in P. vannamei diets during the nursery phase, maintaining equivalent and adequate digestive enzyme activities, health, growth, and body composition of the shrimp, in addition to being ecologically sustainable ingredients.

Different Protein Hydrolysates Can Be Used in the Penaeus vannamei (Boone, 1934) Diet as a Partial Replacement for Fish Meal during the Grow-Out Phase

This study evaluated the inclusion of protein hydrolysates and a commercial product as a partial replacement for fish meals in the diet of Pacific white shrimp (Penaeus vannamei) during the grow-out phase. A recirculation system with 24 experimental units and a biological filter was used. The experimental design was completely randomized with six treatments: control; chicken protein hydrolysate (CPH); enzymatic hydrolysate of chicken feathers; Aquabite®; CPH + maltodextrin; CPH + yeast; and four replicates. After 50 days, the zootechnical performance and animal welfare parameters, centesimal carcass composition, digestive enzyme activity, and hemocyte count were evaluated. The treatments did not affect the zootechnical performance and total hemocyte count of the animals (p > 0.05). The evaluation of the antenna length indicated that all animals were in good health. The antenna length in treatment T5 was significantly greater (p > 0.05) than that in T4 and similar to that in treatments T3 and T6, demonstrating a positive influence of dietary protein hydrolysates. Concerning animal welfare, dietary protein hydrolysates influenced the length of the antenna (p < 0.05). The antenna length associated with different treatments indicated that the animals were in good welfare conditions in the production environment. With respect to body chemical composition, dry matter, ether extract, and ash were affected by the treatments (p < 0.05). Regarding the analysis of digestive enzymes, the treatments influenced the activities of amylase and trypsin (p < 0.05). The performance of the animals was satisfactory under all treatments, including enzymatic activity, demonstrating the possibility of using hydrolysates.

The effects of hydrolyzed protein on macronutrient digestibility, fecal metabolites and microbiota, oxidative stress and inflammatory biomarkers, and skin and coat quality in adult dogs.

Research on protein hydrolysates has observed various properties and functionalities on ingredients depending on the type of hydrolysate. The objective of this study was to evaluate the effects of hydrolyzed chicken protein that was incorporated into diets on digestibility, gut health, skin and coat health, oxidative stress, and intestinal inflammation markers in healthy adult dogs. Five complete and balanced diets were manufactured: (1) CONd: 25% chicken meal diet; (2) 5% CLHd: 5% chicken liver and heart hydrolysate plus 20% chicken meal diet; (3) CLHd: 25% chicken liver and heart hydrolysate diet; (4) 5% CHd: 5% chicken hydrolysate plus 20% chicken meal diet; (5) CHd: 25% chicken hydrolysate diet. A replicated 5 × 5 Latin square design was used which included 10 neutered adult Beagles. Each of the 5 periods consisted of a 7-d washout time and a 28-d treatment period. All diets were well accepted by the dogs. Fecal butyrate concentration was higher while fecal isovalerate and total phenol/indole were lower in dogs fed CLHd than CONd (P < 0.05). Dogs fed CHd had higher fecal immunoglobulin A concentration when compared with CLHd (P < 0.05); however, both groups were comparable to the CONd. There was no difference among groups in serum cytokine concentrations, serum oxidative stress biomarkers, or skin and coat health analyses (P > 0.05). Fecal microbiota was shifted by CLHd with higher abundance in Ruminococcus gauvreauii group as well as lower Clostridium sensu stricto 1, Sutterella, Fusobacterium, and Bacteroides when compared with CONd (P < 0.05). There was also a difference in beta diversity of fecal microbiota between CLHd and CHd (P < 0.05). In conclusion, chicken protein hydrolysate could be incorporated into canine extruded diets as a comparable source of protein to traditional chicken meal. The test chicken protein hydrolysates showed the potential to support gut health by modulating immune response and microbiota; however, functional properties of protein hydrolysates are dependent on inclusion level and source.

PSXIII-27 Evaluation of Protein Quality of Select Chicken-Based Protein Sources Using the Precision-Fed Cecectomized Rooster Assay

Abstract The objective of this experiment was to determine and compare the standardized amino acid (AA) digestibility of chicken-based protein sources using the precision-fed cecectomized rooster assay. Four ingredients were tested: spray-dried chicken protein hydrolysate (CPH), spray-dried chicken meat (CC), spray-dried chicken broth (CB), and chicken meal (CM). All animal care procedures were approved by the University of Illinois Institutional Animal Care and Use Committee before experimentation. Sixteen cecectomized roosters (4 roosters per substrate) were randomly assigned to the four test substrates. After 24 h of feed withdrawal, roosters were tube-fed 12 g of test substrates and 12 g of corn. Following crop intubation, excreta (urine and feces) were collected for 48 h. Endogenous corrections for AA were made using 5 additional cecectomized roosters. All data were analyzed using the Mixed Models procedure of SAS version 9.4. Generally, CC had the greatest (P &amp;lt; 0.05) standardized digestibility for AA, followed by CPH. Methionine, phenylalanine, and valine had greater (P &amp;lt; 0.05) digestibility in CC and CPH compared with CB and CM. Digestibility of isoleucine and leucine were greater (P &amp;lt; 0.05) in roosters fed CC, followed by CPH, CM, and CB. Greater digestibility (P &amp;lt; 0.05) of lysine was observed in roosters fed CC and CPH, followed by CM and CB. Histidine and threonine had the least digestibility (P &amp;lt; 0.05) in CB compared with all other ingredients. In contrast, digestibility of tryptophan was greatest (P &amp;lt; 0.05) in CC, followed by CPH and CB, while CM had similar (P &amp;gt; 0.05) digestibility to CC and CPH. Amino acid digestibility for most indispensable AA was above 80% for all ingredients, except for histidine, lysine, and threonine, which were exceptions only for CB (68%, 73%, and 74%, respectively). For selected dispensable AA, amino acid digestibility was above 60% for all ingredients, except for aspartic acid in CB and CM, and serine in CB, which were exceptions (43, 68% and 66%, respectively). In general, the least DIAAS values were observed in roosters fed CB, followed by CPH, CM, and greatest in CC. Overall, CC and CPH have comparable indispensable AA digestibility, and tryptophan or phenyl alanine+tyrosine were, generally, the first limiting AA.

PSIX-6 The Effects of Hydrolyzed Protein on Macronutrient Digestibility, Fecal Metabolites, Oxidative Stress and Inflammatory Biomarkers, and Skin and Coat Quality in Adult Dogs

Abstract Research on protein hydrolysates has observed various properties and functionalities of these ingredients depending on the type of hydrolysate. The objective of this study was to evaluate the effects of hydrolyzed chicken protein that was incorporated into diets on digestibility, gut health, skin and coat health, oxidative stress, and inflammation in healthy adult dogs. Five complete and balanced treatment diets were manufactured: 1) CONd: chicken meal diet; 2) 5% CLHd: 5% substitution of chicken liver hydrolysate of chicken meal diet; 3) CLHd: chicken liver hydrolysate diet; 4) 5% CHd: 5% substitution of chicken hydrolysate of chicken meal diet; and 5) CHd: chicken hydrolysate diet. A 5×5 Latin square design was used which included 10 neutered adult beagles. Each of the 5 periods consisted of a 7-d washout time and a 28-d treatment period. All diets were well accepted by the dogs. There was greater (P &amp;lt; 0.05) fecal butyrate (226.8 μmol/g DMB) concentration as well as decreasedr isovalerate (6.8 μmol/g DMB), 4-ethylphenol (1.4 μmol/g DMB), and indole (0.7 μmol/g DMB) in dogs fed CLHd than CONd (149.3, 10.8, 2.5, and 1.5 μmol/g DMB, respectively). Doges fed CHd had greater (P &amp;lt; 0.05) fecal immunoglobulin A concentration (2.86 mg/g) when compared with CLHd (0.91 mg/g); however, both groups were comparable to the control. There was no difference among groups in serum cytokine concentrations, serum oxidative stress biomarkers, or skin and coat health analyses (P &amp;gt; 0.05). In conclusion, chicken protein hydrolysate could be incorporated into canine extruded diets as a comparable source of protein to traditional chicken meal. The test chicken protein hydrolysates may have potential to support gut health by modulating immune response and fermentative activity; however, more research is needed to confirm the effect.

196 The Effect of Hydrolyzed Protein on Fecal Microbiota in Adult Dogs

Abstract Research on protein hydrolysates has observed various properties and functionalities of these ingredients depending on the type of hydrolysate. The objective of this study was to evaluate the effect of hydrolyzed chicken protein that was incorporated into diets on gut health in healthy adult dogs. Five complete and balanced treatment diets were manufactured: 1) CONd: chicken meal diet; 2) 5% CLHd: 5% substitution of chicken liver hydrolysate of chicken meal diet; 3) CLHd: chicken liver hydrolysate diet; 4) 5% CHd: 5% substitution of chicken hydrolysate of chicken meal diet; and 5) CHd: chicken hydrolysate diet. A 5×5 Latin square design was used which included 10 neutered adult beagles. Each of the 5 periods consisted of a 7-d washout time and a 28-d treatment period. All diets were well accepted by the dogs. For fecal metabolites, there was greater fecal butyrate concentration as well as reduced isovalerate, 4-ethylphenol, and indole in dogs fed CLHd than CONd (P &amp;lt; 0.05). Regarding the overall microbiota composition, Firmicutes, Bacteriodota, Fusobacteriota, Actinobacteriota, and Proteobacteria were the top 5 most abundant phyla. At the class level, samples from CHd group had greater relative abundances of Bacteriodia and Fusobacteriia as well as less Bacilli. On the other hand, CLHd group had greater abundances of Bacilli and Actinobacteria with less Fusobacteriia. At the level of order, CHd group had greater Bacteriodales and Fusobacteriales while CLHd group had greater Bifidobacteriales. At the family level, CHd group showed a greater abundance of Muribaculaceae and a decreased abundance of Bifidobacteriaceae when compared with the other groups. Alternatively, CLHd group demonstrated a greater abundance of Bifidobacteriaceae together with reduced abundance of Fusobacteriaceae, Muribaculaceae, Sutterrellaceae, and Ruminococcaceae. Fecal microbiota was shifted by CLHd with greater differential abundance in Ruminococcus gauvreauii group as well as reduced Clostridium sensu stricto 1, Sutterella, Fusobacterium, and Bacteroides compared with CONd (P &amp;lt; 0.05). There was also a difference in beta diversity of fecal microbiota between CLHd and CHd (P &amp;lt; 0.05). However, no difference was observed in alpha diversity among treatment groups (P &amp;lt; 0.05). Fecal butyrate concentration was negatively correlated with the genera Blautia, Phascolarctobacterium, Sutterella, Faecalibacterium, and Bacteriodes. Conversely, Allobaculum and Bifidobacterium were positively correlated with butyrate concentration. In conclusion, the test chicken protein hydrolysates may have potential to support gut health by modulating microbiota.

Plasma Cholesterol- and Body Fat-Lowering Effects of Chicken Protein Hydrolysate and Oil in High-Fat Fed Male Wistar Rats.

Rest raw materials provide a new source of bioactive dietary ingredients, and this study aimed to determine the health effects of diets with chicken protein hydrolysate (CPH) and chicken oil (CO) generated from deboned chicken meat. Male Wistar rats (n = 56) were divided into seven groups in three predefined sub-experiments to study the effects of protein source (casein, chicken fillet, pork fillet, and CPH), the dose-effect of CPH (50% and 100% CPH), and the effects of combining CPH and CO. Rats were fed high-fat diets for 12 weeks, and casein and chicken fillet were used as controls in all sub-experiments. While casein, chicken-, or pork fillet diets resulted in similar weight gain and plasma lipid levels, the CPH diet reduced plasma total cholesterol. This effect was dose dependent and accompanied with the reduced hepatic activities of acetyl-CoA carboxylase and fatty acid synthase. Further, rats fed combined CPH and CO showed lower weight gain, and higher hepatic mitochondrial fatty acid oxidation, plasma L-carnitine, short-chain acylcarnitines, TMAO, and acetylcarnitine/palmitoylcarnitine. Thus, in male Wistar rats, CPH and CO lowered plasma cholesterol and increased hepatic fatty acid oxidation compared to whole protein diets, pointing to potential health-beneficial bioactive properties of these processed chicken rest raw materials.

Hydrolysates and bioactive peptides generated from chicken protein hydrolysis: A systematic review of antihypertensive effects in rats

In recent years, obtaining protein hydrolysates and peptides from food proteins has been widely studied in order to better understand not only their nutritional and functional properties, but also the possibility of their use as ingredients in functional foods. It is known that many dietary proteins have, in their primary structure, peptide sequences that, when released, can be absorbed by enterocytes and modulate specific physiological functions, in addition to providing essential amino acids and contributing to energy metabolism. Therefore, this review aims to carry out a systematic review to assess the effectiveness of these bioactive compounds in controlling blood pressure in rats. In addition, the methodological quality of the published articles was evaluated. Searches in Scopus, ScienceDirect, ISI Web of Science and PubMed databases were focused on studies on the use of hydrolysates and peptides obtained from the enzymatic hydrolysis of various chicken tissues in rats. It was possible to verify that the positive antihypertensive effects were mainly dependent on the enzymatic conditions and enzymatic hydrolysis and the monitoring of vital organ functions is essential for the regulation of blood pressure. Due to their effectiveness and low cost, chicken protein hydrolysates could be an interesting alternative for biotechnology applications. Administration of hydrolysates and peptides derived from chicken proteins to spontaneously hypertensive rats (SHR) exhibit potential antihypertensive activity with likely cardiac protective effects against target organ damage.

Attractivity and palatability of different hydrolysed proteins for the ornamental species Betta splendens (Regan, 1910)

The objective of this study was to define attractivity and palatability of juvenile Betta splendens when fed diets containing tilapia meal (TM) and a 5% inclusion of different protein sources: chicken protein hydrolysate (CPH), porcine liver protein hydrolysate (PLH), feather protein hydrolysate (PHP) and porcine mucosa protein hydrolysate (PMH). Five juveniles were utilized with an average weight of 2.92 ± 0.24 g, and an average length of 3.24 ± 0.39 cm. Feeding management was determined via random drawings of both specimens and feed type, with a feeding schedule of four times per day, in which feeding habits were observed regarding the time of capture of the first pellet, number of pellet rejections, number of approaches without pellet capture and number of pellets consumed. The data were submitted to ANOVA, and, subsequently, Duncan's test was performed with a 5% significance. The greatest index of attractivity and palatability was encountered with PLH at 17.14%. The significant effect (p < 0.05) was observed in the feeding behaviour regarding the consumption of pellets. Thus, PLH may be utilized to effectively increase consumption in Betta splendens juveniles as a substitute to tilapia meal and as a means of reducing feed waste in aquariums of this species.

Sensory Assessment of Fish and Chicken Protein Hydrolysates. Evaluation of NMR Metabolomics Profiling as a New Prediction Tool.

Nuclear magnetic resonance (NMR) metabolomics profiling was evaluated as a new tool in sensory assessment of protein hydrolysates. Hydrolysates were produced on the basis of different raw materials (cod, salmon, and chicken), enzymes (Food Pro PNL and Bromelain), and hydrolysis time (10 and 50 min). The influence of raw material and hydrolysis parameters on sensory attributes was determined by traditional descriptive sensory analysis and 1H NMR spectroscopy. The raw material had a major influence on the attribute intensity and metabolite variation, followed by enzyme and hydrolysis time. However, the formation of bitter taste was not affected by the raw material. Partial least-squares regression (PLSR) on 1H NMR and sensory data provided good models (Q2 = 0.55-0.89) for 11 of the 17 evaluated attributes, including bitterness. Significant metabolite-attribute associations were identified. The study confirms the potential prediction of the sensory properties of protein hydrolysates from cod, salmon, and chicken based on 1H NMR metabolomics profiling.

Ability of chicken protein hydrolysate to lower serum cholesterol through its bile acid binding activity

ABSTRACT In this study, chicken breast meat was hydrolyzed enzymatically to obtain chicken meat hydrolysate with its molecular weight to a large extent (98%) less than 3000 Da. The hydrolysate was capable of binding bile acids dose-dependently. The potential hypolipidemic effect of this hydrolysate was evaluated in high-fat-fed hamsters. Total free amino acids in the hydrolysate were seven times higher than those in the chicken meat. As compared with high-fat control, the inclusion of hydrolysate resulted in decreased concentrations of serum TG (by 16–34%) and TC (by 6–20%). The animals fed hydrolysate at a high dose exhibited 30% lower serum LDL-C levels and maintained a higher ratio of HDL-C/LDL-C (0.54) than those fed casein (0.36). Moreover, higher levels of hydrolysate inclusion were associated with increased outputs of fecal bile acid and total lipid, suggesting an association between hypocholesterolemic potential and bile acid binding capacity of the chicken hydrolysate.

A chicken protein hydrolysate exerts anti-atherosclerotic effect beyond plasma cholesterol-lowering activity in Apoe-/- mice.

Chicken protein hydrolysates (CPHs) generated from rest raw materials through enzymatic hydrolysis using Corolase PP or Alcalase were shown to reduce inflammation and stimulate hepatic mitochondrial fatty acid oxidation in high‐fat‐fed mice. This study investigates the effect of CPH diets in atherosclerosis‐prone apolipoprotein E‐deficient (Apoe−/−) mice. Apoe−/− mice were divided into three groups of 12 animals and fed high‐fat diets with casein (control), Alcalase CPH, or Corolase PP CPH. After 12 weeks, mice were sacrificed, blood samples were collected, and aorta was dissected for subsequent én face analysis. Mice fed Corolase PP CPH but not Alcalase CPH had significantly lower % atherosclerotic plaque area in the aortic arch compared to controls (p = .015 and p = .077, respectively). Plasma and liver cholesterol and triacylglycerol remained constant, but levels of the fatty acid C20:5n‐3 were increased, accompanied by an elevated delta‐5 desaturase index in both CPHs groups. Moreover, a significant reduction of plasma MCP‐1 was detected in Corolase PP CPH compared to control. Overall, our data show that protein hydrolysates from chicken reduced atherosclerosis and attenuated systemic risk factors related to atherosclerotic disorders, not related to changes in the level of plasma cholesterol.

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

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

Purification and identification of kokumi‐enhancing peptides from chicken protein hydrolysate

SummaryThe Maillard reaction products (MRPs) from chicken protein hydrolysate were demonstrated to have intense umami and kokumi‐enhancing effects. To find the main flavour‐enhancing compounds in the chicken protein hydrolysate, the fractions with different molecular weights were obtained by ultrafitration. The evaluation of taste characteristics revealed that the fractions with molecular weights ranging from 1000 to 5000 Da predominantly contributed to the umami and kokumi‐enhancing effects. After further purification by using ultrafiltration, gel filtration chromatography, and ultra‐high performance liquid chromatography‐tandem mass spectrometry (UPLC‐MS/MS) in combination with sensory evaluation, three peptides were identified, an octapeptide (WVNEEDHL), a nonapeptide (NSLEGEFKG) and a decapeptide (KDLFDPVIQD). Sensory evaluation results showed that all three peptides could significantly enhance the meat flavour, umami taste and thickness of the chicken powder solution. The results indicate that the peptides have potential application as effective chicken flavour‐enhancing ingredients in the food industry.

Sensory characteristics of Maillard reaction products from chicken protein hydrolysates with different degrees of hydrolysis

ABSTRACTThe sensory characteristics of Maillard reaction products from chicken protein hydrolysates (MRP-CPHs) at different degrees of hydrolysis (DH) were evaluated using descriptive sensory analysis. Five characteristics (boiled chicken flavor, umami, mouthfulness, continuity and overall acceptance) of the MRP-CPHs were evaluated. In addition, the changes in free amino acid contents and molecular weight distribution of chicken protein hydrolysates (CPHs) were also determined. The results showed that the sensory attributes were affected by DH of the CPHs, there was a distinct difference among the MRP-CPHs of almost all sensory attributes. The Maillard reaction product with a hydrolysis time of 3 h showed the strongest in the mouthfulness, boiled chicken flavor, and overall acceptance. These results indicated that the CPHs with a DH range from 15.80% to 18.64% (hydrolysis time range from 3 to 6 h) might be a desirable precursor for the production of chicken flavor in the food industry.

Chicken Protein Hydrolysates Have Anti-Inflammatory Effects on High-Fat Diet Induced Obesity in Mice.

Background: Studies have shown that dietary source of protein and peptides can affect energy metabolism and influence obesity-associated diseases. This study aimed to investigate the impact of different chicken protein hydrolysates (CPHs) generated from chicken rest raw materials in a mouse obesity model. Methods: Male C57BL/6 mice were fed a high-fat, high-sucrose diet with casein or CPHs generated using Papain + Bromelain, Alcalase, Corolase PP, or Protamex for 12 weeks (n = 12). Body weight, feed intake, and intraperitoneal glucose tolerance was determined, and plasma and liver and adipose tissues were collected at sacrifice. Results: The average feed intake and body weight did not differ between the groups and white adipose tissue depots were unchanged, except for a reduction in the subcutaneous depot in mice fed the Protamex CPH diet. Moreover, the CPH diets did not prevent increased fasting glucose and insulin levels. Interestingly, the hepatic mitochondrial fatty acid β-oxidation was increased in mice fed Alcalase and Corolase PP CPHs. All CPH diets reduced plasma interleukine (IL)-1β, interferon-γ, tumor necrosis factor α, and monocyte chemotactic protein 1 compared to control, indicating anti-inflammatory effects. In addition, Corolase PP and Protamex CPHs significantly reduced plasma levels of IL-1α, IL-2, IL-6, IL-10, and granulocyte macrophage colony-stimulating factor. Conclusions: CPH diets were not able to counteract obesity and glucose intolerance in a mouse obesity model, but strongly reduced inflammatory parameters associated with obesity. Alcalase and Corolase PP CPHs also stimulated mitochondrial fatty acid β-oxidation. The possibility that hydrolysates from chicken rest raw materials could alleviate obesity-associated metabolic disease should be investigated further.

Bioactivity of Cod and Chicken Protein Hydrolysates before and after in vitro Gastrointestinal Digestion.

Bioactivity of cod (Gadus morhua) and chicken (Gallus domesticus) protein hydrolysates before and after in vitro gastrointestinal (GI) digestion was investigated using yeast Saccharomyces cerevisiae as a model organism. Both hydrolysates were exposed to in vitro GI digestion prior to cellular exposure to simulate digestion conditions in the human body and therefore investigate the role of modulations in the GI tract on the cell response. The effect of digested and undigested hydrolysates on intracellular oxidation, cellular metabolic energy and proteome level was investigated. No difference in the effect on intracellular oxidation activity was obtained between cod and chicken hydrolysates, while higher affect on intracellular oxidation was provided by digested hydrolysates, with relative values of intracellular oxidation of cod of (70.2±0.8) and chicken of (74.5±1.4) % than by undigested ones, where values of cod and chicken were (95.5±1.2) and (90.5±0.7) %, respectively. Neither species nor digestion had any effect on cellular metabolic energy. At proteome level, digested hydrolysates gave again significantly stronger responses than undigested counterparts; cod peptides here also gave somewhat stronger response than chicken peptides. The knowledge of the action of food protein hydrolysates and their digests within live cells, also at proteome level, is important for further validation of their activity in higher eukaryotes to develop new functional food ingredients, such as in this case chicken and cod muscle-derived peptides.

Effect of thermal treatment on the enzymatic hydrolysis of chicken proteins

The proteins of chicken breast meat were thermally treated in this work. Treatment temperature and time were chosen to evaluate the effect of thermal treatment. By determination of SH and S-S group levels, the results indicated that the SH and S-S group levels in the chicken proteins without thermal treatment were 65.06 and 12.29 μmol/g. With the increase of treatment temperature, the SH group level decreased, while S-S group level increased gradually. Enzymatic hydrolysis by Alcalase was done to evaluate the nitrogen levels of hydrolysates. A temperature-dependent effect was observed for soluble and formaldehyde nitrogen levels. A slight increase of peptide nitrogen level was found with the increase of temperature. Treatment time had a similar effect to treatment temperature. The molecular weight of chicken protein hydrolysates was analysed by gel permeation chromatography. The chicken protein hydrolysates without thermal treatment showed an apparent peak at 27.5 ml of elution volume and a weak peak at 4.0 ml, which represented fractions with molecular weight of > 10,000 Da and < 2640 Da, respectively. Thermal treatment led to decreases of the fractions with molecular weight of > 10,000 Da, 3500–2640 Da and < 2640 Da, compared with hydrolysate fractions without thermal treatment. Treatment with a temperature higher than 60 °C for 20 min would completely eliminate the > 10,000 Da fraction from chicken protein hydrolysates. The percentage of fraction with molecular weight of 4500–3500 Da increased with the extension of treatment time to 20 min, thereafter decreased. The annual yield of chicken meat in China ranks the second of the world. However, the extensive development of this resource is still limited. In this work, chicken breast meat was thermally treated and then hydrolysed by Alcalase. Effects of treatment temperature and time on the hydrolysates were investigated. The results indicated that thermal treatment could change the levels of soluble nitrogen, formaldehyde nitrogen and peptide nitrogen. The area percentages of fractions with different molecular weight were also changed. This work was helpful to understand the characteristics of bioactive peptides produced from chicken proteins.

Effect of maltodextrin and gum arabic on water sorption and glass transition temperature of spray dried chicken meat hydrolysate protein

The water adsorption isotherm and glass transition temperatures ( T g) of chicken protein hydrolysate powder, with and without maltodextrin or gum Arabic, were studied in order to investigate their stability. The hydrolysate powder, pure and formulated with 10%, 20% and 30% (w/w) of additive, was obtained by spray drying. The sorption isotherm was determined by the gravimetric method. A differential scanning calorimeter was used to determine the T g of samples equilibrated with several water activities. As results, the BET model fitted the data for the sorption isotherm of the protein hydrolysate well. A strong plasticizing effect of water on the T g was found, with a great reduction in this value with increase in water activity. The data for T g versus solids content gave a satisfactory correlation with the Gordon-Taylor model. The addition of carrier agents increased the T g of the hydrolysate, decreasing its hygroscopicity and, consequently, increasing its storage stability.

A method for in vitro evaluation of protein hydrolysates for potential inclusion in veterinary diets

A candidate chicken-protein hydrolysate was subjected to high-performance size-exclusion chromatography to characterize its molecular weight profile. An inhibition ELISA assay was developed to assess the residual antigenicity, using canine serum IgG produced by dogs sensitized to the intact protein. Finally, the hydrolysate was compared to the intact protein through electrophoresis and immunoblotting. The chicken hydrolysate had a suitable molecular weight profile with 96.9% reduced to less than 10 kDa peptides. The inhibition ELISA demonstrated a residual antigenic mass of 1.5% compared with the intact protein. Immunoblotting demonstrated a strong immunoreactive band at 68–70 kDa consistent with chicken serum albumin in the intact protein, which was absent in the hydrolysate. These results demonstrate the suitability of the chicken hydrolysate for use in a protein hydrolysate diet, and provide a basis for the future comparisons of the peptide components of hydrolyzed protein diets so that veterinarians may make more informed decisions in their dietary prescriptions.