RESUMO
BACKGROUND: Human milk is a vehicle for bioactive compounds and beneficial bacteria which promote the establishment of a healthy gut microbiome of newborns, especially of preterm infants. Pasteurized donor human milk (PDHM) is the second-best option when preterm mother's own milk is unavailable. Since pasteurization affect the microbiological quality of donor milk, PDHM was inoculated with different preterm milk samples and then incubated, in order to evaluate the effect in terms of bacterial growth, human milk microbiome and proteolytic phenomena. METHODS: In an in-vitro study PDHM was inoculated at 10% v/v using ten preterm milk samples. Microbiological, metataxonomic and peptidomic analyses, on preterm milk samples at the baseline (T0), on PDHM and on inoculated milk (IM) samples at T0, after 2 h (T1) and 4 h (T2) of incubation at 37 °C, were conducted. RESULTS: IM samples at T2 showed a Total Bacterial Count not significantly different (p > 0.01) compared to preterm milk samples. At T2 lactic acid bacteria level was restored in all IM. After inoculation, metataxonomic analysis in IM samples showed that Proteobacteria remained the predominant phylum while Firmicutes moved from 3% at T1 to 9.4% at T2. Peptidomic profile of IM resembled that of PDHM, incubated for the same time, in terms of number and type of peptides. CONCLUSION: The study demonstrated that inoculation of PDHM with mother's own milk could restore bacterial growth and personalize human milk microbiome in PDHM. This effect could be beneficial because of the presence of maternal probiotic bacteria which make PDHM more similar to mother's own milk.
Assuntos
Leite Humano , Mães , Feminino , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro , Pasteurização , Doadores de TecidosRESUMO
Polysaccharides derived from plant foods are major components of the human diet, with limited contributions of related components from fungal and algal sources. In particular, starch and other storage carbohydrates are the major sources of energy in all diets, while cell wall polysaccharides are the major components of dietary fiber. We review the role of these components in the human diet, including their structure and distribution, their modification during food processing and effects on functional properties, their behavior in the gastrointestinal tract, and their contribution to healthy diets.
Assuntos
Parede Celular/metabolismo , Carboidratos da Dieta/metabolismo , Fibras na Dieta/metabolismo , Digestão , Ingestão de Energia , Modelos Biológicos , Plantas Comestíveis/química , Carboidratos/biossíntese , Carboidratos/química , Doença Crônica/epidemiologia , Doença Crônica/prevenção & controle , Temperatura Baixa/efeitos adversos , Carboidratos da Dieta/efeitos adversos , Carboidratos da Dieta/uso terapêutico , Fibras na Dieta/efeitos adversos , Fibras na Dieta/análise , Fibras na Dieta/uso terapêutico , Manipulação de Alimentos , Índice Glicêmico , Temperatura Alta/efeitos adversos , Humanos , Desnutrição/epidemiologia , Desnutrição/metabolismo , Desnutrição/prevenção & controle , Estrutura Molecular , Plantas Comestíveis/efeitos adversos , Plantas Comestíveis/metabolismo , Fatores de Risco , Resposta de Saciedade , Amido/efeitos adversos , Amido/química , Amido/metabolismo , Amido/uso terapêuticoRESUMO
Strachitunt, a blue-veined Italian cheese, received the Protected Designation of Origin (PDO) label in 2014. Its unique technological feature is represented by the dual-curd method of production. Strachitunt is produced from raw bovine milk with or without the inoculation of natural starter cultures of lactic acid bacteria, and the addition of secondary cultures of mold spores is not permitted by the product specification. Physico-chemical properties, proteolysis, and volatile profile of Strachitunt were investigated in 10 cheese samples (ripened for 75 d) made throughout spring 2015 and provided by the main cheese maker. Overall, composition parameters showed a large variability among samples. Cheese was characterized by an acid paste (pH 5.46) and a lower extent of proteolysis compared with other blue-veined varieties. The main chemical groups of volatile organic compounds were alcohols and esters, whereas ketones represented only a minor component. The erratic adventitious contamination by mold spores of the cheese milk, the unique dual-curd method of cheese-making, and the large time variability between the piercing time and the end of ripening could be highlighted as the main causes of both the distinctive analytical fingerprint and the scarce standardization of this blue-veined cheese.
Assuntos
Queijo , Proteólise , Animais , Bovinos , Manipulação de Alimentos , Cetonas , Leite/química , Compostos Orgânicos VoláteisRESUMO
Twenty-nine strains of mastitis pathogens were used to study the antibacterial activity of the cell-free supernatants (CFS) of 25 strains of Lactococcus lactis ssp. lactis. Out of the tested strains, only the CFS of L. lactis LL11 and SL153 were active, inhibiting and killing most of the pathogens. By means of ultra-performance liquid chromatography/high resolution mass spectrometry, they were shown to produce nisin A, a class I bacteriocin. A variable sensitivity to nisin A-containing CFS was observed among Streptococcus uberis and Enterococcus faecalis strains. Nonetheless, Streptococcus agalactiae, Strep. uberis, and E. faecalis displayed high minimum inhibitory concentration values, reaching 384 arbitrary units/mL. Interestingly, the minimum inhibitory values and the bactericidal concentrations were almost identical among them for each of the 2 stains, LL11 and SL153. Staphylococci were, on average, less sensitive than streptococci, but the 2 CFS inhibited and killed, at different dilutions, strains of methicillin-resistant Staphylococcus aureus. The immune response to nisin A-containing CFS was tested using the bovine mammary epithelial cell line BME-UV1. Application of CFS did not damage epithelial integrity, as demonstrated by the higher activity of N-acetyl-ß-d-glucosaminidase (NAGase) and lysozyme inside the cells, in both treated and control samples. On the other hand, the increase of released NAGase after 15 to 24h of treatment with LL11 or SL153 live cultures demonstrated an inflammatory response of epithelial cells. Similarly, a significantly higher lysozyme activity was detected in the cells treated with LL11 live culture confirming the stimulation of lysosomal activity. The treatment of epithelial cells with SL153 live culture induced a significant tumor necrosis factor-α downregulation in the cells, but did not influence IL-8 expression. The control of tumor necrosis factor-α release could be an interesting approach to reduce the symptoms linked to clinical intramammary infections. Due to their antibacterial activity and to the stimulation of lysosomal activity of mammary epithelial cells, the L. lactis strains SL153 and LL11 could be of interest for the development of alternative intramammary treatments to control cow mastitis.
Assuntos
Bactérias/efeitos dos fármacos , Bacteriocinas/farmacologia , Imunomodulação/efeitos dos fármacos , Lactococcus lactis/química , Mastite Bovina/imunologia , Animais , Antibacterianos/farmacologia , Bovinos , Técnicas de Cultura de Células , Sistema Livre de Células , Cromatografia Líquida de Alta Pressão/veterinária , Células Epiteliais/efeitos dos fármacos , Feminino , Imunidade Inata/efeitos dos fármacos , Espectrometria de Massas/veterinária , Mastite Bovina/microbiologiaRESUMO
We studied the thermostable proteolytic activity of Pseudomonas fluorescens PS19 isolated from raw bovine milk. The heat-treated cell-free supernatant (HT-CFS) contained a thermostable protease of approximately 45 kDa, as revealed by casein zymography. We assigned this enzyme to P. fluorescens AprX metalloprotease (UniProtKB Acc. No. C9WKP6). After concentration by ultrafiltration at 10 kDa, the HT-CFS showed 2 other thermostable proteolytic bands on zymogram, with molecular masses of approximately 15 and 25 kDa. The former resulted a fragment of the AprX protease, whereas the 25-kDa protease was not homologous to any known protein of Pseudomonas spp. Subsequently, we assessed the proteolytic activity of the HT-CFS on bovine αS-, ß-, and κ-casein during in vitro incubation at 7 or 22°C. By means of ultra-performance liquid chromatography-tandem mass spectrometry we identified the released peptides (n=591). Some of them resisted proteolysis during the whole incubation period at both incubation temperatures and, therefore, they could be assumed as indicators of the proteolytic action of P. fluorescens PS19 on bovine caseins.
Assuntos
Caseínas/metabolismo , Leite/microbiologia , Animais , Bovinos , Endopeptidases/metabolismo , Pseudomonas/metabolismo , Pseudomonas fluorescens/isolamento & purificaçãoRESUMO
The occurrence of 8 bovine casein-derived peptides (VPP, IPP, RYLGY, RYLG, AYFYPEL, AYFYPE, LHLPLP, and HLPLP) reported as angiotensin converting enzyme-inhibitors (ACE-I) was investigated in the 3-kDa ultrafiltered water-soluble extract (WSE) of Parmigiano Reggiano (PR) cheese samples by ultra-performance liquid chromatography coupled to high-resolution mass spectrometry via an electrospray ionization source. Only VPP, IPP, LHLPLP, and HLPLP were revealed in the WSE, and their total amount was in the range of 8.46 to 21.55 mg/kg of cheese. Following in vitro static gastrointestinal digestion, the same ACE-I peptides along with the newly formed AYFYPEL and AYFYPE were found in the 3 kDa WSE of PR digestates. Digestates presented high amounts (1,880-3,053 mg/kg) of LHLPLP, whereas the remaining peptides accounted for 69.24 to 82.82 mg/kg. The half-maximal inhibitory concentration (IC50) values decreased from 7.92 ± 2.08 in undigested cheese to 3.20 ± 1.69 after in vitro gastrointestinal digestion. The 3-kDa WSE of digested cheeses were used to study the transport of the 8 ACE-I peptides across the monolayers of the Caco-2 cell culture grown on a semipermeable membrane of the transwells. After 1h of incubation, 649.20 ± 148.85 mg/kg of LHLPLP remained in the apical compartment, whereas VPP, IPP, AYFYPEL, AYFYPE, and HLPLP accounted in total for less than 36.78 mg/kg. On average, 0.6% of LHLPLP initially present in the digestates added to the apical compartment were transported intact to the basolateral chamber after the same incubation time. Higher transport rate (2.9%) was ascertained for the peptide HLPLP. No other intact ACE-I peptides were revealed in the basolateral compartment. For the first time, these results demonstrated that the ACE-I peptides HLPLP and LHLPLP present in the in vitro digestates of PR cheese are partially absorbed through an in vitro model of human intestinal epithelium.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/metabolismo , Queijo , Mucosa Intestinal/metabolismo , Animais , Células CACO-2 , Caseínas/química , Bovinos , Digestão , Trato Gastrointestinal/metabolismo , Humanos , Concentração Inibidora 50RESUMO
The aromatic profile of wine determines its overall final quality, and among the volatile molecules that define it, varietal thiols are responsible for shaping the distinctive character of certain wine varieties. In grape must, these thiols are conjugated to amino acids or small peptides in a non-volatile form. During wine fermentation, yeasts play a principal role in expressing these aromatic compounds as they internalise and cleavage these precursors, releasing the corresponding free and aroma-impacting fraction. Here, we investigate the impact of three wine yeasts (Saccharomyces cerevisiae, Torulaspora delbrueckii and Lachancea thermotolerans) on thiol releasing in synthetic grape must fermentations supplemented with different cysteinylated (Cys-4MSP and Cys-3SH) and glutathionylated (GSH-4MSP and GSH-3SH) precursors. We demonstrate higher consumption levels of cysteinylated precursors, and consequently, higher amounts of thiols are released from them compared to glutathionylated ones. We also report a significant impact of yeast inoculated on the final thiols released. Meanwhile T. delkbrueckii exhibits a great 3SHA releasing capacity, L. thermotolerans stands out because of its high 3SH release. We also highlight the synergic effect of the co-inoculation strategy, especially relevant in the case of S. cerevisiae and L. thermotolerans mixed fermentation, that has an outstanding release of 4MSP thiol. Although our results stem from a specific experimental approach that differs from real winemaking situations, these findings reveal the potential of unravelling the specific role of different yeast species, thiol precursors and their interaction, to improve wine production processes in the context of wine aroma enhancement.
RESUMO
A capillary zone electrophoresis method for the determination of Na in milk and milk products was developed and compared with an International Organization for Standardization/International Dairy Federation standard method that is based on flame atomic absorption spectrometry. The adoption of a background electrolyte consisting of 10 mM imidazole adjusted to pH 3.75 by the addition of oxalic acid allowed baseline separation of Na from other milk cations and from Li ion, which was adopted as an internal standard. Method validation was performed and the results for linearity, precision, limit of detection, limit of quantification, and recovery are presented. The procedure was tested on commercial milk samples differing in fat content (whole, semiskimmed, and skimmed) and processing conditions (pasteurization, UHT sterilization, and microfiltration). The reliability of the method was confirmed for different varieties of cheese and other milk products. The method enables the routine measurement of Na content by a rapid and accurate capillary zone electrophoresis procedure.
Assuntos
Laticínios/análise , Eletroforese Capilar/métodos , Leite/química , Sódio/análise , Animais , Bovinos , Concentração de Íons de Hidrogênio , Sensibilidade e Especificidade , Espectrofotometria Atômica , TemperaturaRESUMO
This study investigated the changes in chemical and microbiological properties of fresh goat milk cheese stored in an open deck refrigerated display cabinet (6 ± 2°C) or in a dark cold room (4 ± 1°C). The effects of partial-vacuum packaging and fluorescent lighting were studied during the cheese shelf life (45 d) and 15 d after. Storage conditions did not affect the pH values (4.3), whereas a slight decrease in moisture (ca. 1%) and in water activity (<0.01 units) was recorded. Proteolysis monitored by Kjeldahl determination increased significantly during storage of all samples. The highest increase from 8.5 to 13.0% of soluble nitrogen (expressed as percentage of total nitrogen) was measured in cheese packaged in the presence of air and stored in a lighted cabinet. The proteolytic trend was also studied through capillary zone electrophoresis by monitoring the degradation of the main casein fractions and the formation of new peptides. In particular, 2 indices, based on peak area ratio of new-formed peptides and casein fractions were related to cheese age. Lipolysis, measured by solid-phase microextraction gas chromatography coupled to mass spectrometry of volatile fatty acids, was unaffected by air or light and did not proceed through storage. As expected, hexanal formed mainly in cheeses stored under light and packaged in air. Evaluation of sensorial quality, performed using a hedonic scale, showed significantly lower scores of cheeses kept under light compared with those kept in the dark, both at 45 and 60 d storage. Overall, the microbiological and chemical results suggested that the shelf life of soft goat milk cheese would be extended from 45 to 60 d. Such conclusion was supported also by the sensory quality evaluation.
Assuntos
Queijo/análise , Aldeídos/análise , Animais , Queijo/microbiologia , Ácidos Graxos Voláteis/análise , Qualidade dos Alimentos , Armazenamento de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Cabras , Leite , Proteólise , Fatores de TempoRESUMO
OBJECTIVE: Grana Padano, an Italian protected designation of origin (PDO) semi-fat cheese, undergoes a long ripening period during which the proteolysis carried out by natural starter lactic acid bacteria releases peptides having sustained angiotensin-converting enzyme (ACE)-inhibitory activity. The length (generally 3-8 amino acid residues) and the sequence of these peptides are responsible for their ability to elicit ACE-inhibitory activity. The aim of this study has been the evaluation of the effect of a daily dietary supplement consisting in a small amount (30 g/day) of Grana Padano cheese, in terms of the lowering of the blood pressure (BP) of mild-moderate hypertensive subjects. PATIENTS AND METHODS: Thirty mild-moderate hypertensive patients, with BP values not on target (> 140 and/or > 90 mmHg) after at least 3 months of stable treatment were considered in this randomized, double-blind placebo-controlled cross-over study. All patients randomly received a dietary integration (30 g/day) of Grana Padano cheese or a placebo (made from flavored grated bread mixed with fats and salts in concentrations equal to those of the cheese). BP was evaluated at baseline and at the end of the active and placebo treatments (2 months each) by: - Office BP (OBP); - Automated Office BP (AOBP) using the BpTRU®, an automated oscillometric device that provides the average of multiple (n=6) blood pressure measurements; - Ambulatory Blood Pressure (ABP) 24 hour monitoring. RESULTS: Dietary integration with Grana Padano cheese resulted in a significant decrease in Office, Automated Office and Ambulatory BP. The mean decrease (vs. placebo) for 24-hour ABP was -3.5 mmHg for systolic and -2.4 mmHg for diastolic BP (p = 0.0063 and p = 0.0065, respectively). CONCLUSIONS: Daily dietary integration with 30 g of Grana Padano DOP cheese effectively reduces BP and may help mild-to-moderate hypertensive patients to reach a target BP.
Assuntos
Queijo , Hipertensão/dietoterapia , Adulto , Monitorização Ambulatorial da Pressão Arterial , Estudos Cross-Over , Suplementos Nutricionais , Método Duplo-Cego , Feminino , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Projetos PilotoRESUMO
Residues of lysine-substituted AGEs (advanced glycosylation end-products) arising from the Maillard reaction and containing the carbon backbone of lactose or maltose, thus deriving from 1-desoxy-ketose degradation, were produced when casein was heated in the presence of the corresponding U14C labelled disaccharides. The enzymatic hydrolysates of the washed casein were purified by SPE and submitted to HPLC on a C18 column flushed with diluted acetic acid. A specific chromatographic peak (lambda max, 288.1 nm; MW, 416.2 Da) with a different retention time was obtained for each disaccharide reacted. On the basis of the value of the specific radioactivity, the two compounds appeared to contain the whole carbon backbone of the parent sugar. Analyses by MS/MS and NMR performed on the same two compounds extracted at preparative scale from lysine-lactose and lysine-maltose model systems allowed the structure assignment of 6-[2-acetyl-3-(beta-D-galactopyranosyloxy)-1-pyrrolyl] 2-amino hexanoic acid and 6-[2-acetyl-3-(alpha-D-glucopyranosyloxy)-1-pyrrolyl] 2-amino hexanoic acid, respectively. Both compounds submitted to enzymatic deglycosylation by specific alpha- or beta-glucosidases produced the lysine-derived acetyl pyrrole 6-(2-acetyl-3-hydroxy-1-pyrrolyl) 2-amino hexanoic acid (lambda max, 288.1 nm; MW, 254.1 Da). Galactosyl- and glucosyl-isomaltoles, extracted from the lysine-containing systems, identified with the reference molecules and heated in the presence of lysine under slightly alkaline conditions, gave the expected lysine-derived glycosyl pyrroles as identified above. The HPLC conditions were optimized by adjusting the composition of the eluting solvent and temperature of the column to achieve the best separation and identification of the AGEs in mixtures such as foods with possible interfering molecules like Trp and lysyl pyrrole aldehyde. Because of the reported presence of the two precursors isomaltol glycosydes in some foods, the corresponding lysine-derived glycosyl pyrroles can occur as both protein bound and in free form.