Application of preliminary high-pressure processing for improving bioactive characteristics and reducing antigenicity of whey protein hydrolysates.

This study investigated the use of Novo Pro-D® (NPD) and Ficin (FC) as alternative proteases for the production of bioactive peptides with reduced allergenicity from whey protein concentrate (WPC). In addition, the use of high hydrostatic pressure processing as pre-treatment of WPC and its impact on the final characteristics of hydrolysates were also evaluated. NPD treatments generated hydrolysates with a 98% reduction of soluble proteins, greater in vitro antioxidant capacity, and less immunoreactivity when compared to FC ones. However, pre-treatment was an essential tool to improve WPC hydrolysis when FC was used, resulting in hydrolysates with less soluble proteins, enhanced antioxidant capacity, and less allergenicity compared with conventional hydrolysis. As for NPD, the pre-treatment of WPC improved the in vitro antioxidant capacity and resulted in a 100% reduction in immunoreactivity to ß-lactoglobulin in a shorter processing time. Importantly, bioactive peptides generated by FC displayed an improved ability to induce in vitro arterial relaxation, compared with those obtained from NPD process. Therefore, this study provides innovative evidence regarding how the proteases used for production of whey hydrolysates can improve its biological effects, and discloses the use of high hydrostatic pressure combined with enzymatic hydrolysis as a promising alternative to produce hydrolysates with improved properties.

Effect of high hydrostatic pressure on the antioxidant capacity and peptic hydrolysis of whey proteins / Efeito da alta pressão hidrostática na hidrólise péptica das proteínas do soro de leite e na capacidade antioxidante

ABSTRACT: The effect of high hydrostatic pressure (HHP) application on whey protein concentrate was evaluated both before (pre-treatment - PT) and during (hydrolysis assisted - HA) hydrolysis processes. A factorial design 22 with 3 central points was used with pressure (100, 250, 400 MPa) and time (5, 20 and 35 minutes) as independent variables. The hydrolysis was evaluated and monitored by soluble protein, aromatic amino acid contents and RP-HPLC. ABTS and ORAC tests were used to evaluate the in vitro antioxidant capacity. The reduction of soluble protein content was approximately 20% for conventional hydrolysis and for all PT treatments up to 4 h of reaction, while HHP assisted hydrolysis at 100 MPa showed a 35% protein reduction after 35 minutes of reaction. In addition, pressurization favored peptic hydrolysis of β-lactoglobulin by up to 98% and also improved the in vitro antioxidant capacity of the hydrolysates, which increased from 34.25 to 60.89 μmoles TE g-1 of protein in the best treatment. The results suggest that the use of HHP assisted hydrolysis favored the peptic hydrolysis, with a reduction in hydrolysis time and increased antioxidant activity.

RESUMO: Neste estudo, o efeito da aplicação de alta pressão hidrostática (HHP) sobre o concentrado proteico de soro de leite foi avaliado antes (pré-tratamento - PT) e durante os processos de hidrólise (assistida por hidrólise - HA). Utilizou-se o delineamento fatorial 22 com três pontos centrais, onde as variáveis independentes foram pressão (100, 250, 400 MPa) e tempo (5, 20 e 35 minutos). A hidrólise foi avaliada pelo conteúdo de proteínas solúveis e aminoácidos aromáticos, além do perfil peptídico por RP-HPLC. As análises de ABTS e ORAC foram utilizadas para avaliar a capacidade antioxidante in vitro. A redução do teor de proteína solúvel foi de aproximadamente 20% para a hidrólise convencional e para todos os pontos de PT até 4h de reação, enquanto a hidrólise assistida por HHP a 100 MPa mostrou uma redução de 35% de proteína em 35 minutos de reação. Além disso, a pressurização favoreceu a hidrólise péptica da β-lactoglobulina em até 98% e também melhorou a capacidade antioxidante in vitro dos hidrolisados, que aumentaram de 34,25 para 60,89 μmoles de TE g-1 de proteína no melhor tratamento. Os resultados sugerem que o uso da hidrólise assistida por HHP favoreceu a hidrólise péptica, com redução no tempo de hidrólise e aumento da atividade antioxidante.

The Influence of Peptidases in Intestinal Brush Border Membranes on the Absorption of Oligopeptides from Whey Protein Hydrolysate: An Ex Vivo Study Using an Ussing Chamber.

For many years, it was believed that only amino acids, dipeptides, and tripeptides could be absorbed and thus reach the bloodstream. Nowadays, the bioavailability of oligopeptides is also considered possible, leading to new research. This pilot study investigates the activity of brush border enzymes on undigested whey protein hydrolysate (WPH) and on simulated intestinal digested (ID) whey hydrolysate and the subsequent absorption of resultant peptides through the proximal jejunum of a 7-week old piglet setup in an Ussing chamber model. Amongst all samples taken, 884 oligopeptides were identified. The brush border peptidase activity was intense in the first 10 min of the experiment, producing several new peptides in the apical compartment. With respect to the ID substrate, 286 peptides were detected in the basolateral compartment after 120 min of enzyme activity, originating from ß-lactoglobulin (60%) and ß-casein (20%). Nevertheless, only 0.6 to 3.35% of any specific peptide could pass through the epithelial barrier and thus reach the basolateral compartment. This study demonstrates transepithelial jejunum absorption of whey oligopeptides in an ex vivo model. It also confirmed the proteolytic activity of brush border enzymes on these oligopeptides, giving birth to a myriad of new bioactive peptides available for absorption.

Gastrointestinal digestion enhances the endothelium-dependent vasodilation of a whey hydrolysate in rat aortic rings.

Whey proteins present encrypted biofunctional peptides that need to be released from the native protein to exert their biological activity. Antihypertensive whey peptides are the most studied ones, which can be explained by high prevalence of this chronic degenerative disease. The present study investigated whether the molecular changes occurred during the gastrointestinal digestion of a whey protein hydrolysate could modulate its vasorelaxant potential in rat aortic rings. Spectrophotometric data and SDS-PAGE gel showed a small degree of hydrolysis during the gastric phase and intense intestinal proteolysis. RP-HPLC revealed the formation of a large peptide profile. During the simulated digestion, 198 peptides were generated and identified and, left-shifted the concentration-response curve of the endothelium-dependent vasorelaxation, as recorded for the digested hydrolysates. In conclusion, gastrointestinal digestion of the whey hydrolysate leads to the generation of bioactive peptides with enhanced vasodilatory potency, reinforcing the relevance of whey-derived products in blood pressure regulation.

Effects of regular and decaffeinated roasted coffee (Coffea arabica and Coffea canephora) extracts and bioactive compounds on in vitro probiotic bacterial growth.

The aim of this study was to investigate the effects of coffee species, roast degree and decaffeination on in vitro probiotic bacterial growth, and to identify the major coffee compounds responsible for such effects. Six C. arabica and C. canephora extracts (regular medium and dark roasted and decaffeinated medium roasted), and five bioactive compounds (chlorogenic acid, galactomannan, type 2 arabinogalactan, caffeine and trigonelline) were individually incorporated into a modified low-carbon broth medium-(mMRS), at different concentrations (0.5 to 1.5% soluble coffee and 0.05 to 0.8 mg mL-1 standard solutions). Inulin and fructooligosaccharides (FOS) were used as prebiotic references. MRS and mMRS were used as rich and poor medium controls, respectively. The growth of Lactobacillus rhamnosus GG ATCC 53103-(GG), L. acidophilus LA-5-(LA), Bifidobacterium animalis DN-173010-(BA) and B. animalis subsp. lactis BB12-(BB12), as well as the growth inhibition of non-probiotic Escherichia coli ATCC 25922 were evaluated. Differences in growth between mMRS and treatments (Δlog CFU mL-1) were compared by ANOVA and Tukey's test, and considered when p ≤ 0.05. Overall, after 48 h incubation, the medium roasted arabica coffee extract increased the growth of GG, LA and BA (range: Δlog CFU mL-1 = 0.5 to 1.8), while the dark roasted arabica coffee extract increased BB12 growth (range: Δlog CFU mL-1 = 0.9 to 1.7), in a dose dependent manner. Improved performances of GG, LA and BA were promoted by higher polysaccharides and CGA concentrations, with better performance for Lactobacillus sp. The tested coffee bioactive compounds promoted the poor growth of BB12. Plain caffeine did not promote Bifidobacterium sp. growth and limited the growth of Lactobacillus sp. Regular C. arabica and C. canephora extracts inhibited the growth of E. coli, while the decaffeinated extracts promoted its growth. The present results show that coffee consumption can selectively improve the growth of probiotic strains, thus exerting a prebiotic effect, and show that coffee roasting and decaffeination affect this property and that different strains utilize different coffee components to grow.

Whey hydrolysate-based ingredient with dual functionality: From production to consumer's evaluation.

The aim of the present study concerns the development, characterization and sensory evaluation of a dual-functional whey hydrolysate. Four concentrations of commercial pepsin (0.48%, 0.95%, 1.43%, 1.91% w/w) were evaluated. The hydrolyses curves and the Reversed-Phase High Performance Liquid Chromatography analyses showed a direct relationship between enzyme concentration and degree of hydrolysis. Through mass spectrometry 21 peptides were identified and 5 of them have never been described in the literature before. The hydrolysate produced (PC3) induced a vascular relaxation of 65.02% in phenylephrine-contracted rat aortic rings. PC3 powder presented a homogeneous aspect with a mean particle size of 86.39 µm, high water solubility (>92%) in a wide pH range (1-12) and an increase of 33% in oil absorption capacity, when compared to the unhydrolyzed product. Sensory analysis showed a high acceptance (7.6 in a 9-point hedonic scale) of the hydrolysate among 100 consumers. The results brought the possibility of developing a whey hydrolysate with high vasorelaxant activity, great technological properties and sensory appeal, as an interesting dual-functional ingredient to be incorporated into food products.

Grape seed pomace as a valuable source of antioxidant fibers.

BACKGROUND: Grape seed pomace is a valuable by-product from winery/oil extraction industries and a potential source of bioactive compounds. Hot water extraction is the most widely used technology for polysaccharide recovery from plant and seed sources. To obtain an antioxidant fiber-rich extract (AFE) from defatted grape seed pomace, seed:water ratio (1:10-1:20) and extraction temperature (70-90 °C) effects on extraction yield, total sugars, total phenolic compounds and condensed tannins were investigated. RESULTS: The best extraction results were achieved at the highest seed:water ratio and temperature. At these conditions, the extraction yield and total sugar content of the freeze-dried AFE were 100.1 g kg-1 and 725.3 g kg-1 , respectively. The AFE presented high total phenolic content (16.2 g GAE kg-1 ), condensed tannins (515.1 mg CAT kg-1 ), soluble (219.1 g kg-1 ) and insoluble fibers (132.4 g kg-1 ), besides protein (171.1 g kg-1 ) and ash (152.6 g kg-1 ). The antioxidant capacity of the AFE was 382.7, 823.7 and 1439.4 µmol Trolox g-1 for DPPH, ABTS and ORAC methods. CONCLUSION: The AFE was shown to be not only an interesting source of fiber with antioxidant capacity, which could become a potential foodstuff, but also an ecofriendly and sustainable alternative to use grape seed pomace. © 2019 Society of Chemical Industry.

Enzymatic production of xylooligosaccharides from Brazilian Syrah grape pomace flour: a green alternative to conventional methods for adding value to agricultural by- products.

BACKGROUND: The aim of this work was to determine the most favorable conditions for the production of xylooligosaccharides (XOS) from Brazilian Syrah grape pomace. Chemical processes were performed using a rotatable central composite design where the concentration of sulfuric acid or sodium hydroxide and the grape pomace flour/solvent mass ratio were the dependent variables. Enzymatic production was also evaluated using xylanase produced by Aspergillus niger 3T5B8 and Viscozyme® enzymatic commercial cocktail. RESULTS: Chemical extraction allowed to recover 21.8-74.6% and 5.2-96.3% of total XOS for acidic and alkaline processes respectively. Enzymatic production extracted up to 88.68 ± 0.12% of total XOS using xylanase and up to 84.09 ± 2.40% with Viscozyme® . CONCLUSION: The present study demonstrated different feasible methods to produce high-added-value molecules, i.e. XOS, from Syrah grape pomace flour, valorizing this major by-product. The use of enzymatic cocktails demonstrated to be an alternative to the conventional methods, allowing to obtain an eco-friendly and sustainable grape pomace extract. © 2018 Society of Chemical Industry.

Hot topic: Holder pasteurization of human milk affects some bioactive proteins.

The aim of this research was to investigate the effect of Holder pasteurization (HoP; 62.5°C, 30 min) on the protein profile and activities of glutathione peroxidase (GPx) and lysozyme (LZ) in human milk. Over 6 mo of lactation, human milk samples were analyzed before (raw) and after HoP for GPx and LZ activity and electrophoresis protein profile. Holder pasteurization reduced human milk lactoferrin, immunoglobulin fractions, and GPx activity. In addition, GPx activity, which is high in colostrum and transitional milk, was naturally reduced over the 6-mo lactation period. In contrast, HoP did not affect human milk LZ activity. Besides its critical cellular antioxidant role in protecting the organism from oxidative damage, GPx decreases the redox potential of milk, stimulating the growth of anaerobic microorganisms, such as the probiotic Bifidobacterium. Considering the role of lactoferrin in infant health, we conclude that an important part of its function has been inactivated by pasteurization. These compounds should be replaced by human milk banks after the HoP step to recover lost functionality. Otherwise, an alternative technology to HoP that better retains human milk properties should be used by milk banks to eliminate the risk of transmission of infectious agents.

Towards integral utilization of grape pomace from winemaking process: A review.

Grape is the main fruit crop in several countries. Although many grape-based food products can be found in the market, studies have shown that around 75% of the world grape production is destined for the wine industry. Grape pomace is an abundant by-product from the wine industry, which consists of the remaining skin, seeds and stalks and represents around 25% of total grape weight used in the winemaking process. In countries such as Italy, France and Spain, where wine production is more relevant, the annual grape pomace generation can reach nearly 1200 tonnes per year. In order to reach a sustainable winemaking process there is a need of a waste reduction policy. Several studies explore this subject using grape pomace as a source of healthy and technological compounds that could be applied in animal feed, pharmaceutical, cosmetic or food industry to improve stability and nutritional characteristics, and in cosmetic industry, where grape seeds oil is widely used. This review aims to approach the recent winemaking scenario and the benefits achieved when a waste management policy is implemented, as well as to compare available extractive technologies and a wide alternative of uses for grape pomace.

Antioxidant dietary fibre recovery from Brazilian Pinot noir grape pomace.

Brazilian grape pomace was extracted in hot water, and a factorial experiment was used to evaluate polysaccharide recovery. The dependent variables were the temperature, particle size and solute:solvent ratio. Polysaccharide yields varied from 3% to 10%, and the highest sugar content was observed when extraction was carried out at 100 °C from finely sized particles (⩽249 µm) in a 1:12 solute:solvent ratio. The monosaccharide composition of extracts obtained from flours were, on average, Rha:Ara:Xyl:Man:Gal:Glc:GalA in a 3:32:2:13:11:20:19 M ratio, with varying Glc:GalA ratios. (13)C NMR and HSQC spectra confirmed the presence of pectic- and glucose-based polysaccharides in the extracts. Phenolic compounds were found after pomace extraction, and catechin, gallic acid and epicatechin were the principal compounds identified. The extracts also had ABTS radical scavenging capacity (from 8.00 to 46.60 mMol Trolox/100 g pomace). These findings indicate that these grape pomace flours are rich in antioxidant dietary fibre and have a potential use as food ingredients.

Coupling of ultrafiltration and enzymatic hydrolysis aiming at valorizing shrimp wastewater.

The objective of this work was to obtain a protein hydrolysate from the wastewater generated during shrimp cooking, by coupling ultrafiltration and enzymatic hydrolysis processes. Initially, the effluent was concentrated by ultrafiltration, reaching a protein concentration factor of 3.2. The concentrated effluent was then enzymatically hydrolyzed, aiming at obtaining peptides with antioxidant capacity. The effects of some process variables--temperature (55-75 °C), pH (7-9) and enzyme/substrate (E/S) ratio (0.1-2.5%)--on the degree of hydrolysis and the antioxidant capacity were evaluated. The increase in temperature and pH resulted in lower degree of hydrolysis and higher antioxidant capacity. The conditions selected as the most suitable were: temperature of 75 °C, pH of 9.0 and E/S ratio of 0.1%. The hydrolysates produced at these conditions were also evaluated for total amino acid content and electrophoretic profile, showing a suitable amount of essential amino acids that covers the recommended daily needs.

Isolation of a gastroprotective arabinoxylan from sugarcane bagasse.

After industrial processing, one-third of sugarcane culms is converted into residual bagasse. The xylan-rich hemicellulose components of the bagasse were extracted with hot aqueous alkali (AX-CRUDE). Approximately 82% of the extracted hemicelluloses was precipitated with ethanol (AX-PET). Both AX-CRUDE and AX-PET contained an arabinoxylan as confirmed by 13C NMR and methylation analysis. Fraction AX-PET was fed to female Wistar rats with ethanol-induced gastric lesions. Oral administrations of 30, 100, and 300 mg/kg reduced the gastric lesion area by over 50%, and replenished ethanol-induced depletion of glutathione. The polysaccharide also increased mucus production by over 70%, indicating its cytoprotective action on experimentally induced gastric ulcers. These findings are significant, since a biologically active compound can be extracted in high yields from an abundant, readily available residue.