Commercial Casein Research Articles

Evaluation of the multifunctional dipeptidyl-peptidase IV and angiotensin converting enzyme inhibitory properties of a casein hydrolysate using cell-free and cell-based assays.

The objective of the study was the evaluation of the potential pleiotropic effect of a commercial casein hydrolysate (CH). After an analysis of the composition, the BIOPEP-UWM database suggested that these peptides contained numerous sequences with potential inhibitory activities on angiotensin converting enzyme (ACE) and dipeptidyl-peptidase IV (DPP-IV). The anti-diabetic and anti-hypertensive effects of these peptides were thus assessed using either cell-free or cell-based assays. In the cell-free system, CH displayed inhibitory properties against DPP-IV (IC50 value equal to 0.38 ± 0.01 mg/mL) and ACE (IC50 value equal to 0.39 ± 0.01 mg/mL). Further, CH reduced the DPP-IV and ACE activities expressed by human intestinal Caco-2 cells by 61.10 ± 1.70% and 76.90 ± 4.47%, respectively, versus untreated cells, after 6 h of treatment at the concentration of 5 mg/mL. This first demonstration of the multifunctional behavior of this material suggests that it may become an anti-diabetic and/or anti-hypertensive ingredient to be included in the formulation of different functional food or nutraceutics.

Modulatory Effects of A1 Milk, A2 Milk, Soy, and Egg Proteins on Gut Microbiota and Fermentation

Milk can be divided into A1 and A2 types according to β-casein variants, and there is a debate about whether A1 milk consumption exacerbates gut environments. This study examined the cecum microbiota and fermentation in mice fed A1 casein, A2 casein, mixed casein (commercial casein), soy protein isolate, and egg white. The cecum acetic acid concentration was higher, and the relative abundances of Muribaculaceae and Desulfovibrionaceae were greater in mice fed A1 versus A2 casein. The other parameters of cecum fermentation and microbiota composition were similar among the mice fed A1, A2, and mixed caseins. The differences were more distinctive among the three caseins, soy, and egg feedings. Chao 1 and Shannon indices of the cecum microbiota were lowered in egg white-fed mice, and the microbiota of mice fed milk, soy, and egg proteins were separately grouped by principal coordinate analysis. Mice fed the three caseins were characterized by a high abundance of Lactobacillaceae and Clostridiaceae, those fed soy were characterized by Corynebacteriaceae, Muribaculaceae, and Ruminococcaceae, and those fed egg white were characterized by Eggerthellaceae, Rikenellaceae, and Erysipelatoclostridiaceae. Thus, although several differences can arise between A1 and A2 caseins in terms of their modulatory effects on gut environments, the differences between milk, soy, and egg proteins can be more distinctive and are worth further consideration.

Food fortification with anticariogenic agents: A comprehensive review

Several nutrients have been added to food and drink products around the world, as public health measures and as cost-effective ways of ensuring the nutritional quality of the food supply. Food fortification is a process of adding micronutrients which are necessary to prevent micronutrients deficiency, diseases related to it. Cariogenicity is one of the most common disease found in oral cavity all over the world irrespective of age group. So, to overcome this dental issue in mass population food fortification with anticariogenic agent is one of the amiable method. Anticariogenic agents like calcium sucrose phosphate ions, calcium glycerophosphate, sodium dihydrogen phosphate, casein phosphopeptide and amorphous calcium phosphate (CPP-ACP), commercial casein hydrolysate, etc. are used in food fortification. Food items like flour, soft drinks, salt, milk, sugar, chewing gum, bread, hard cheese, etc. are fortified with anticariogenic agents. This study is done to understand the importance, the methods and the agents of food fortification.

Nutritional, Biochemical and Haematological Indices of White Albino Rats Fed Complementary Diets Developed from Selected Cereals and Legumes

Background: Childhood malnutrition is a common public health problem in Ethiopia. This animal study aims to evaluate the haematological, biochemical, and nutritional indices of weanling albino rats fed on complementary diets developed from selected cereals and legumes. Methods: The nutritional qualities of the formulated blends were assessed biologically by feeding white albino rats in order to determine feed intake, the growth rate, protein quality parameters, biochemical and haematological properties. The commercial weaning diet (cerifam) and casein were used as control diets. On the 28th day, blood samples were collected from three randomly selected rats by decapitation. Full blood count analysis was carried out using the Automated Haematologic Analyzer to determine haematological parameters. All the biochemical parameters were determined using Mindray diagnostic kits. Results and Discussion: The food intake pattern showed that animals placed on diet 3, diet 4, casein, and cerifam consumed more food than those fed on diet 1, diet 2, and diet 7. The mean growth rate of animals fed on diet 3 and diet 4 was significantly (p<0.05) higher than those placed on diet 1, diet 2, and diet 7 but similar to those fed with commercial diet and casein. The protein quality evaluation of the diets showed that the protein efficiency ratio ranged from 1.20 to 2.43 while the biological value was in the range of 54.53 to 69.48%. The net protein utilization and true digestibility were 65.62 to 70.21% and 59.01 to 64.01%, respectively. Serum total protein, albumin, and globulin levels in rats given diet 3 and diet 4 were comparable to the controls and within the normal range. Comparatively, the creatinine and urea levels of rats fed on the control and formulated diets were within the normal range. The serum alanine aminotransferase values of rats fed on the control and formulated diets ranged from 22.03 IU/L in diet 2 to 37.76 IU/L in diet 4 and were not significantly different from each other. In this study, the packed cell volume and haemoglobin values of the control and formulated diets were within the recommended range. Evidently, diet 3 and diet 4 gave the best growth performance after the feeding trials. Conclusion: The haematological and biochemical indices indicate that these diets can support effective growth and development in rats, and consumption of these diets has no detrimental effects on the liver and renal function.

Performance of particleboards based on annual plant byproducts bound with bio-adhesives

Because the timber market is more and more competitive, the particleboard manufacturers are looking for new sources of plant raw material. In the same time, the use of healthier, safer and more environmentally friendly materials becomes a priority in the building sector. In this context, using bio-based adhesives to bond the particles instead of the synthetic ones is an interesting alternative. In the same time agricultural byproducts as annual plant stems can be a sustainable alternative raw material. These resources are abundant, renewable and safe raw material. Moreover, their porous structure gives them interesting properties for building materials such as lightness and thermal insulation capacity. Two agricultural byproducts abundant in France have been studied: flax shives and sunflower bark. Particleboards were made at laboratory scale by thermocompression of the plant raw particles to a target density of 500 kg m−3. The plant particles were bond by different methods:- * without addition of any adhesive. In that case water was sprayed on the plant particles before the forming process and was evaporated during the thermocompression. It leads to extraction of soluble and lignocellulosic compounds from the agroresources that can act as adhesives.- * with addition of a biobased adhesive based on casein, the protein from bovine milk, or based on a commercial caseinate, added at different ratios to the plant particles.- The effect of the type of agroresources, the particle size, the formulation of the biosourced adhesive, and its application are evaluated testing the physico-chemical properties of the particleboards: mechanical properties (bending test and internal bond), thermal properties, and behavior towards water and fire. Using a biobased adhesive improves the mechanical properties of the particleboards significantly compared to the version without added adhesive. Panels made with flax shives generally showed better properties than with sunflower bark, so flax shives seem more suitable for particleboard manufacturing. But after optimization of the formulation and the process, both raw materials could be used with casein-based adhesive yielding efficient and fully biobased particleboards for applications such as furniture or door panels.

Flammability Characteristics and Mechanical Properties of Casein Based Polymeric Composites.

Even though casein has an intrinsic potential ability to act as a flame retardant (FR) additive, the research regarding the FR performance of casein filled polymeric composites has not been thoroughly conducted. In the present work, two commercial casein products, such as lactic casein 720 (LAC) and sodium casein 180 (SC), were chosen to investigate their effects on the performances of the polypropylene (PP) composites. The melt compounding and compression moulding processes were employed to fabricate these casein-based composites. Ammonium polyphosphate (APP) was also selected to explore its combined effects in conjunction with casein on the composite’s flammability. The cone calorimeter results showed that the addition of casein significantly reduced (66%) the peak heat release rate (PHRR) of the composite compared to that of neat PP. In particular, the combination of LAC and APP led to the formation of more compact and rigid char compared to that for SC based sample; hence, a further reduction (80%) in PHRR and self-extinguishment under a vertical burn test were accomplished. Moreover, the tensile modulus of the composite improved (23%) by the combined effects of LAC and APP. The overall research outcome has established the potential of casein as a natural protein FR reducing a polymer’s flammability.

Comparison of the Effects of the Alcalase-Hydrolysates of Caseinate, and of Fish and Bovine Gelatins on the Acidification and Textural Features of Set-Style Skimmed Yogurt-Type Products.

Commercial caseinate and two gelatins from bovine and fish skin were hydrolyzed by alcalase, and used at 2 g/kg in skimmed bovine milk that was then fermented with a commercial direct vat set starter, to clarify different effects of these hydrolysates on acidification and textural attributes of set-style yogurt samples. Compared with the fermentation of the yogurt sample without hydrolysate addition, the two gelatin hydrolysates in the yogurt samples endowed lower titratable acidity but higher pH values and thus delayed yogurt fermentation, while the caseinate hydrolysate showed an effect opposite to the two gelatin hydrolysates. The two gelatin hydrolysates induced worse quality attributes for the resultant yogurt samples, including higher syneresis extent, smaller hysteresis loop areas, and lower values in these textural indices like hardness, adhesiveness, apparent viscosity, elastic and viscous moduli. However, the caseinate hydrolysate led to improved quality attributes. Moreover, bovine gelatin hydrolysate always had a greater negative effect than fish gelatin hydrolysate on yogurt acidification and texture. It is concluded that these gelatin hydrolysates could confer the yogurt with intended bio-activities of gelatin hydrolysates but negatively impact yogurt acidification and texture, while the caseinate hydrolysate might be helpful for yogurt processing by shortening fermentation time and improving yogurt texture.

Effect of Indigenously Developed Nano-Hydroxyapatite Crystals from Chicken Egg Shell on the Surface Hardness of Bleached Human Enamel: An In Vitro Study.

Objective:The objective was to evaluate the effect of nano-hydroxyapatite (nHA) derived from chicken eggshell on bleached human enamel in comparison with commercial casein phophopeptide-amorphous calcium phosphate (CPP-ACP) paste using Vickers microhardness test.Materials and Methods:nHA powder was prepared from chicken eggshell using combustion method. nHA slurry was prepared by mixing 1.8 g of nHA powder with 0.3 ml of distilled water. Forty intact maxillary anterior teeth were collected and decoronated, and the crowns were embedded in acrylic mold with the labial enamel surfaces exposed. Baseline microhardness evaluation was done (T0). The specimens were randomly divided into the following four groups (n = 10) based on the surface treatment of enamel: Group 1: no bleaching treatment; Group 2: bleaching with 30% hydrogen peroxide (HP) solution; Group 3: bleaching followed by the application of CPP-ACP; and Group 4: bleaching followed by the application of nHA. The specimens were stored in artificial saliva at 37°C for 2 weeks, after which they were subjected to Vickers microhardness test (T14). One-way ANOVA and Tukey's post hoc multiple comparison tests were used for statistical analysis (P < 0.05).Results:Bleaching with HP significantly decreased the enamel microhardness. CPP-ACP and nHA derived from chicken eggshell increased the enamel microhardness significantly. There was no significant difference in microhardness values among the CPP-ACP and nHA groups.Conclusion:Nano-hydroxyapatite sourced from chicken eggshell was as effective as CPP-ACP in remineralizing and restoring the lost microhardness of bleached enamel.

Peptidomic study on in vitro and in vivo phosphopeptide release during the chewing of gum fortified with a commercial casein hydrolysate

The kinetics of phosphopeptide release from gum fortified with a commercial casein hydrolysate in artificial and human saliva was studied. Using mass spectrometry techniques, the caseinophosphopeptide (CPP) composition of the commercial casein hydrolysate compared with a standard tryptic casein digest from whole raw cow milk was determined. In in vitro trials, the amount of CPPs released was always the same for each chewing time; in contrast, during in vivo chewing, a decrease of peptide levels was detected, from 10% after 5 min to 0.1% at 20 min, due to physiological swallowing. It is concluded that gums are a useful vehicle for CPP intake, owing to their functional role in bone health. However, their use is less satisfactory for prevention of dental caries, due to the brief contact with the enamel surface. Moreover, more calcium would need to be added to enrich the CPP fraction of the commercial hydrolysate.

Sequential hydrolysis of commercial casein hydrolysate by immobilized trypsin and thermolysin to produce bioactive phosphopeptides

Most reports only focus on the preparation of one specific peptide, while simultaneous preparation of various peptides is rarely investigated. A commercial preparation of casein hydrolysate from bovine milk was used as a source to obtain highly valuable bioactive peptides. A tailor-made protocol to immobilize trypsin and thermolysin in highly activated glyoxyl agarose was used to obtain heterogeneous protease biocatalysts. The intense multipoint covalent immobilization and the subsequent improvement of the thermal-stabilization enabled the reuse of the catalyst for three reaction cycles. The sequential hydrolysis with immobilized trypsin and thermolysin leads to an increase of 12% in the degree of hydrolysis (DH) starting from the commercial hydrolysate. After sequential hydrolysis, casein phosphopeptides (CPPs) were obtained with a high purity by selective precipitation using Ca2+/ethanol at pH 8. Consequently, chemical analysis of these hydrolysates revealed an increase in the content of phosphorous and calcium by 39 and 30%, respectively, with regard to the original sample. Sequential hydrolysis and selective precipitation yielded interesting bioactive peptides with 29 phosphorylation sites. These peptides, identified by LC-MS/MS shared common sequences with known peptides that show biological activities such as opioid agonists, immunostimulants, mineral carriers, antioxidant, bifidogenic, antihypertensives, antithrombotic, as well as peptides that show gastrointestinal mucosal protection activity.

Characterization of Casein Fractions – Comparison of Commercial Casein and Casein Extracted from Cow’s Milk

Biopolymer casein was isolated from cow’s milk by acid coagulation, which was initiated by acetic acid and sodium acetate in the first, and hydrochloric acid in the second process. The casein isolated by acid coagulation, i.e. by first process, and commercial casein were separated on α-, β-, (α+κ)- and κ casein by urea fractionation. The aim of this study was to compare various properties of commercial casein fractions with casein fractions isolated from cow’s milk. The structure of casein and casein fraction samples were monitored by Fourier transform infrared spectroscopy (FTIR), and the obtained vibrational bands showed structural differences between isolated and commercial casein (presence of various amino acids), as well as their fractions. Differential scanning calorimetry (DSC) was used to determine glass transition temperature. The results showed that the glass transitions of the isolated and commercial casein were below room temperature (Tg = 2–30 °C) due to the destruction of the samples structure that provides molecules mobility and leads to a phase transition. Thermal degradation obtained by thermogravimetric analysis (TGA) of all samples occurred in multiple steps. From the results, it is evident that 5 mass % of the each sample degraded at significantly different temperatures (T95), and it can be concluded that isolated casein and its fractions showed better heat stability than commercial casein and its fraction.

Preparation of peptone from chicken bone residue by using natural pancreas as catalyst

BACKGROUND The cost of peptone is often a major contributor to costs in the fermentation industry. A novel method for preparation of peptone from chicken bone residue by using natural pancreas as catalyst was developed in this study, aiming to provide a way to convert waste into valuable peptone. RESULTS The molecular weight of chicken bone extract (CBE) hydrolyzed with pancreas or its combination with trypsin ranges between 100 and 1000 Da after 4 h of hydrolysis. CBE hydrolyzed with pancreas (5%, w/w) for 4 h shows higher degree of hydrolysis (DH) (23.60%) than that of 0.5% trypsin, and higher polypeptides and free amino acids content than that of 0.5% trypsin and 1% pancreas. Thus, it was selected for yeast, bacteria and fungi incubation, with commercial casein peptone as a control. Saccharomyces cerevisiae shows a similar growth curve in both media during 36 h incubation. Although Bacillus subtilis shows a longer lag phase (14 h) in chicken bone hydrolysate (CBH) than in the control (6 h), significantly higher OD600 in CBH was obtained after 24 h incubation (P<0.05). Both Escherichia coli and Aspergillus oryzae grew better in CBH than in the control. CONCLUSION The proposed process for inexpensive peptone production provides an effective way to utilize animal bone wastes, and the alternative peptone has widespread application in fermentation industry. © 2016 Society of Chemical Industry

Collaborative Interlaboratory Studies for the Validation of ELISA Methods for the Detection of Allergenic Fining Agents Used in Wine According to the Criteria of OIV Resolution 427–2010 Modified by OIV–Comex 502–2012

The clarification or fining of wine removes undesired substances (mainly proteins, phenols, and tannins), which would roil the wine and cause bitterness and astringency. A common fining agent, egg white, can be directly added to wine through the inlet of a circulating pump, but more typically egg white comes as commercial preparation in powdered form (commercially named egg albumin). Skimmed milk or more frequently purified caseinates are used to remove bitterness and hardness of white wine and sherry. Both egg white and caseinates are fining agents with optimal enological properties, but their residues could represent a risk for subjects suffering from food allergy. The rules for allergen labeling were detailed in Directives 2003/89/EC, and Directive 2005/26/EC established a list of food ingredients provisionally excluded from labeling, that included wine fining agents. Extended till June 2012, wine labeling exemption can be now maintained only if (1) egg and milk derivatives are not used and cross-contamination is under control; and (2) wine clarified with such products is negative for the presence of residues using techniques with detection and quantification limits of 0.25 and 0.5 ppm, respectively. Analytical requirements were defined in the OIV resolution 427–2010 (OIV 2010) modified by OIV/COMEX 502–2012 (OIV 2012). On the basis of a previous experience, an interlaboratory collaborative trial was organized to validate a commercial ELISA kit designed to measure allergenic residues in red wine fined with egg white proteins. In the meantime, the performance of the commercial caseinate ELISA kit for white wine was rechecked according to the new limit of detection and limit of quantification values, recommended by OIV in 2012. The collaborative interlaboratory studies showed that both ELISA kits had good reproducibility, repeatability, and robustness in detecting residues of allergenic fining agents in wine, in good agreement with the requirements of the OIV resolution 427–2010 modified by OIV/COMEX 502–2012.

Rheological, gelling and emulsifying properties of a glycosylated and cross‐linked caseinate generated by transglutaminase

SummaryThe impacts of oligochitosan glycosylation and cross‐linking on some properties of a commercial caseinate were investigated in this study. The glycosylated and cross‐linked caseinate with glucosamine content of 4.74 g kg−1 protein was generated by transglutaminase (TGase) and oligochitosan at pH 7.5 and 37 °C, with fixed substrate molar ratio of 1:3 (acyl donor to glucosamine acceptor), caseinate content of 50 g L−1, TGase of 10 kU kg−1 protein and reaction time of 3 h, respectively. In comparison with the caseinate, the glycosylated and cross‐linked caseinate had decreased reactable amino groups (0.58 vs. 0.51 mol kg−1 protein), higher apparent viscosity, decreased emulsifying activity index (about 14.5%) and statistically unchanged emulsion stability index (92.6 vs. 90.5%). Based on the mechanical spectra of the acid‐induced gels, the glycosylated and cross‐linked caseinate showed shorter gelation time (95 vs. 200 or 220 min) than the caseinate or cross‐linked caseinate. The gels prepared from the glycosylated and cross‐linked caseinate also had enhanced hardness, springiness and cohesiveness. The results indicated that TGase‐mediated oligochitosan glycosylation and cross‐linking has the potential to obtain new protein ingredients.

Viability of the microencapsulation of a casein hydrolysate in lipid microparticles of cupuacu butter and stearic acid

Solid lipid microparticles produced with a mixture of cupuacu butter and stearic acid were used to microencapsulate a commercial casein hydrolysate (Hyprol 8052). The composition of the lipid matrix used for the production of the lipid microparticles was chosen according to data on the wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) of bulk lipid mixtures, which indicated that the presence of 10 % cupuacu butter was sufficient to significantly change the crystalline arrangement of pure stearic acid. Preliminary tests indicated that a minimum proportion of 4 % of surfactant (polysorbate 80) was necessary to produce empty spherical lipid particles with average diameters below 10 mm. The lipid microparticles were produced using 20 % cupuacu butter and 80 % stearic acid and then stabilized with 4 % of polysorbate 80, exhibiting an encapsulation efficiency of approximately 74 % of the casein hydrolysate. The melting temperature of the casein hydrolysate-loaded lipid microparticles was detected at 65.2 °C, demonstrating that the particles were solid at room temperature as expected and indicating that the incorporation of peptides had not affected their thermal behavior. After 25 days of storage, however, there was a release of approximately 30 % of the initial amount of encapsulated casein hydrolysate. This release was not thought to have been caused by the liberation of encapsulated casein hydrolysate. Instead, it was attributed to the possible desorption of the adsorbed peptides present on the surface of the lipid microparticles.

Viability of the microencapsulation of a casein hydrolysate in lipid microparticles of cupuacu butter and stearic acid

Solid lipid microparticles produced with a mixture of cupuacu butter and stearic acid were used to microencapsulate a commercial casein hydrolysate (Hyprol 8052). The composition of the lipid matrix used for the production of the lipid microparticles was chosen according to data on the wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) of bulk lipid mixtures, which indicated that the presence of 10 % cupuacu butter was sufficient to significantly change the crystalline arrangement of pure stearic acid. Preliminary tests indicated that a minimum proportion of 4 % of surfactant (polysorbate 80) was necessary to produce empty spherical lipid particles with average diameters below 10 mm. The lipid microparticles were produced using 20 % cupuacu butter and 80 % stearic acid and then stabilized with 4 % of polysorbate 80, exhibiting an encapsulation efficiency of approximately 74 % of the casein hydrolysate. The melting temperature of the casein hydrolysate-loaded lipid microparticles was detected at 65.2 °C, demonstrating that the particles were solid at room temperature as expected and indicating that the incorporation of peptides had not affected their thermal behavior. After 25 days of storage, however, there was a release of approximately 30 % of the initial amount of encapsulated casein hydrolysate. This release was not thought to have been caused by the liberation of encapsulated casein hydrolysate. Instead, it was attributed to the possible desorption of the adsorbed peptides present on the surface of the lipid microparticles.

Fractionated and Recombined Casein Superplasticizer in Self-Leveling Underlayments

Individual casein biopolymers have been fractionated out of the whole bovine casein, and characterized with respect to their specific dispersing performance in cement based self-leveling underlayments (SLUs). In contrast to β- and κ-caseins, α-casein provided excellent dispersing effectiveness as well as unique self-healing effect on the surface of the grout. In order to reproduce the bovine casein, a reconstituted casein sample was prepared by blending the individual biopolymers. Using fast protein liquid chromatography (FPLC), the biochemical composition of recombined casein was determined. Compared with the commercial casein, the reproduced casein superplasticizer exhibited improved dispersing power in SLU paste at the flow time of 0 – 20 min. Furthermore, atomic force microscope (AFM) images revealed the morphology of commercial casein and reproduced casein in alkaline environments. The latter was found to form smaller structure, which explained the improved initial flow of SLU paste. This study suggests that the performance of casein superplasticizer can be modified by recombining the individual casein biopolymers. SLU pastes with different properties may be further achieved by adjusting the biochemical composition of the recombined casein superplasticizer.

Effect of milk hydrolysates on inflammation markers and drug-induced transcriptional alterations in cell-based models1

Nonsteroidal anti-inflammatory drugs (NSAID) are associated with gastrointestinal inflammation and subsequent damage to the intestinal tissue. Earlier studies in our laboratory have found that specific casein hydrolysates (CH) might be useful in the treatment of gastrointestinal wounds. The underlying mechanisms that support inflammation and wound healing are not completely understood, but transcriptional alterations may be used as markers for inflammation and wound healing. The bioactivity of 3 CH prepared by treatment of commercial casein with pepsin (60 min) followed by corolase (0, 10, or 60 min) were investigated in intestinal epithelial cells treated with the NSAID indomethacin. The bioactivity was evaluated as transcriptional alterations of transforming growth factor-β1 (TGF-β1), cyclooxygenase-2 (COX-2), peroxisome proliferator-activated receptor-γ (PPAR-γ) and nuclear factor κB (NFκB) by real-time PCR. Furthermore, the effect of CH on lipopolysaccharide-induced inflammation was evaluated in macrophages by measuring PG E(2) levels. Casein hydrolysates treated with corolase for 10 or 60 min after pepsin treatment downregulated transcription of TGF-β1 and NFκB (P < 0.05) compared with the hydrolysate treated with pepsin only. Hydrolysate prepared by corolase treatment for 60 min after pepsin hydrolysis downregulated transcription of COX-2 (P < 0.05) compared with hydrolysate treated with corolase for only 10 min whereas transcription of PPAR-γ was not affected (P > 0.05). Additionally, the hydrolysate prepared by pepsin treatment only (0 min corolase) had a pro-inflammatory effect on macrophages via PG E(2) stimulation (P < 0.05). In conclusion, CH produced by a combination of pepsin and corolase treatments downregulated the transcription levels of TGF-β1, COX-2, and NFκB.

Absorption of Casein Antihypertensive Peptides through an In Vitro Model of Intestinal Epithelium

A commercial casein hydrolysate, which contains peptides RYLGY and AYFYPEL as active molecules, has shown antihypertensive effects after acute and long-term administration. This study examines transepithelial absorption of RYLGY and AYFYPEL and derived digestion fragments using Caco-2, HT29-MTX−6 and co-culture 75 % Caco-2/25 % HT29-MTX−6 as predictive models and RP-HPLC–MS as analytical tool. Peptides RYLGY and AYFYPEL were absorbed intact through cell monolayers, although RYLGY was partly hydrolyzed by intestinal peptidases. Co-culture 75 % Caco-2/25 % HT29-MTX−6 exhibited intermediate properties, with regard to transepithelial electrical resistance, peptide hydrolysis, and absorption of the studied peptides, between Caco-2 and HT29-MTX−6 pure cultures. Interestingly, mucus layer that covered completely HT29-MTX−6 and co-culture monolayers was not a barrier for the absorption of the studied peptides. The apparent permeability values for absorptive transport across Caco-2 monolayers for RYLGY (0.22 × 10−6 cm/s) and AYFYPEL (0.26 × 10−6 cm/s) were similar. These findings highlight that in vivo absorption of antihypertensive peptides RYLGY and AYFYPEL may occur partially as intact peptides.

Characterization of lyophilized liposomes produced with non-purified soy lecithin: a case study of casein hydrolysate microencapsulation

A commercial casein hydrolysate was microencapsulated in liposomes produced with non-purified soy lecithin, cryoprotected with two different disaccharides and lyophilized. The encapsulation efficiency of casein hydrolysate ranged from 30 to 40%. The powders were analyzed by differential scanning calorimetry (DSC), scanning electron micrography (SEM), infrared spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). DSC data revealed the presence of an exothermal transition in empty lyophilized liposomes, which was ascribed to the presence of a quasicrystalline lamellar phase (intermediary characteristics between the Lβ and Lc phases). The addition of peptides to the liposomal system caused the disappearance of this exothermic phenomenon, as they were located in the polar headgroup portion of the bilayer, causing disorder and preventing the formation of the quasicrystalline phase. Infrared data indicated the presence of the peptides in the lyophilized formulations and showed that the cryoprotectants interacted effectively with the polar heads of phospholipids in the bilayer.