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BACKGROUND: The general assumption that prebiotics reach the colon without any alterations has been challenged. Some in vitro and in vivo studies have demonstrated that 'non-digestible' oligosaccharides are digested to different degrees depending on their structural composition. In the present study, we compared different methods aiming to assess the digestibility of oligosaccharides synthesized by ß-galactosidase (ß-gal) of Lactobacillus delbruecki subsp. bulgaricus CRL450 (CRL450-ß-gal) from lactose, lactulose and lactitol. RESULTS: In the simulated gastrointestinal fluid method, no changes were observed. However, the oligosaccharides synthesized by CRL450-ß-gal were partially hydrolyzed in vitro, depending on their structure and composition, with rat small intestinal extract (RSIE) and small intestinal brush-border membrane vesicles (BBMV) from pig. Digestion of some oligosaccharides increased when mixtures were fed to C57BL/6 mice used as in vivo model; however, lactulose-oligosaccharides were the most resistant to the physiological conditions of mice. In general ß (1â6) linked products showed higher resistance compared to ß (1â3) oligosaccharides. CONCLUSION: In vitro digestion methods, without disaccharidases, may underestimate the importance of carbohydrates hydrolysis in the small intestine. Although BVMM and RSIE digestion assays are appropriate in vitro methods for these studies, in vivo studies remain the most reliable for understanding what actually happens in the digestion of oligosaccharides. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Digestão , Camundongos Endogâmicos C57BL , Oligossacarídeos , Prebióticos , beta-Galactosidase , Prebióticos/análise , Animais , beta-Galactosidase/metabolismo , beta-Galactosidase/química , Oligossacarídeos/metabolismo , Oligossacarídeos/química , Camundongos , Ratos , Suínos , Masculino , Lactulose/metabolismo , Lactulose/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Intestino Delgado/metabolismo , Intestino Delgado/enzimologia , Lactobacillus/metabolismo , Lactobacillus/enzimologia , Hidrólise , Lactose/metabolismo , Lactose/químicaRESUMO
BACKGROUND: Due to the increasing incidence of obesity and cardiovascular diseases, consumers are demanding products with lower sugar content. In this sense, the reformulation of traditional foods with improved, safe and tasty ingredients is arousing a huge interest. Jams are conventionally produced with elevated amounts of sucrose, which increase the glycaemic index and must be avoided in certain kinds of consumers. RESULTS: This paper describes for the first time the elaboration of strawberry jams using low-methoxyl pectins from sunflower by-products, which allowed the addition of low amounts of sucrose (10-30%). These jams were compared with best-selling commercial samples. An in-depth physicochemical, compositional, sensorial and rheological characterization was carried out. The obtained jams were safe considering aw and pH values; samples presented enough acidity to avoid microorganism development and syneresis. The stabilizing role of sunflower pectin is noteworthy in terms of colour and other physicochemical characteristics. The organoleptic analysis showed that the taste and sweetness of laboratory samples were highly valued, although the presence of pieces of fruits was disliked some panellists. After knowing the content of added sugar used in each jam, the tasters preferred samples with 20% and 30% of sucrose over commercial samples. CONCLUSIONS: The results show the usefulness of sunflower pectin for the elaboration of jams of low glycaemic index. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Fragaria , Helianthus , Frutas , Helianthus/química , Pectinas/química , SacaroseRESUMO
Worldwide there is great interest in producing low lactose milk and drinks, such as soy beverages, suitable for consumption by lactose-intolerant people. These products have different carbohydrate compositions, which affect quality indicators derived from Maillard reaction (furosine and 5-hydroxyl-methyl furfural, HMF). In this study, quality parameters have been determined in 11 commercial samples (8 lactose-hydrolyzed milks and 3 soy beverages). Presence of ß-galactooligosaccharides in milks (22.2-458.1 mg/100 mL) correlating roughly with the remaining lactose content (1.9-357.7 mg/100 mL). Soy beverages contained α-galactosides in concentrations of 30-75 mg/100 mL. HMF and furosine were detected in all milk samples. In addition, powdered milks subjected to controlled storage (40 °C, aw 0.44) showed a furosine increase up to 88%. In conclusion, a great composition diversity was observed in the different products, probably favored by the lack of regulation and underline the importance of controlling processing and storage conditions to preserve product quality.
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BACKGROUND: This study reports the use of low glycemic sunflower pectin gel, elaborated with calcium and without or with sweeteners (sucrose, stevia and saccharin) as an edible coating and its possible combination with two modified atmosphere packaging (MAP), in order to extend shelf life, maintaining the quality, of strawberries during the storage at 4 °C. RESULTS: This pectin coating, formed with only calcium and/or stevia or saccharin, extended the shelf life of strawberries with respect to uncoating fruits, up to 12 days, keeping the microbial load constant, the firmness and less weight loss. With the same edible coatings, the shelf life of strawberries was extended up to 23 days when they were combined with MAP [10% carbon dioxide (CO2 ), 85% nitrogen (N2 ) and 5% oxygen (O2 )], maintaining the quality of strawberries, while the other MAP, with a higher CO2 concentration (20% CO2 , 75% N2 and 5% O2 ), had no effect. CONCLUSIONS: These results highlight the suitability of the combination of edible pectin coating combined with MAP to obtain an important shelf life extension, maintaining the good quality of the fruit. © 2021 Society of Chemical Industry.
Assuntos
Conservação de Alimentos/métodos , Fragaria/química , Frutas/química , Helianthus/química , Pectinas/química , Extratos Vegetais/química , Filmes Comestíveis , Conservação de Alimentos/instrumentação , Armazenamento de Alimentos , Índice GlicêmicoRESUMO
The potential of probiotic bacteria to produce prebiotic oligosaccharides by transgalactosylation has been minimally studied. In this work, we screened the ß-galactosidase (ß-gal) activity of dairy propionibacteria (PAB) isolated from Argentinean foods to select strains for the synthesis of oligosaccharides from lactose (GOS) and lactulose (OsLu). PAB, when grown in a medium with lactose as a carbon source, were disrupted, and the cell-free extracts were assayed for ß-gal activity. Nine strains grew on lactose and showed ß-gal activities from 0.27 to 2.60 U mL-1. Propionibacterium acidipropionici LET 120, the strain with the highest activity, was able to synthesize, using 30% lactose and lactulose at pH 6.5 and 45⯰C, 26.8% of LET 120-GOS and 26.1% of LET 120-OsLu after 24â¯h. When they were tested as carbon sources for growth, P. acidipropionici LET 120 attained higher biomasses, µmax and ß-gal activities at the expense of Aspergillus oryzae-OsLu, Vivinal®-GOS and lactulose compared to lactose or glucose. In addition, LET 120-GOS and LET 120-OsLu synthesized by PAB were prebiotic for some probiotic strains. For the first time, our results show the production of GOS and OsLu by dairy PAB, and these results encourage further studies on the optimization of the synthesis and structure characterization of the obtained oligosaccharides.
Assuntos
Lactose/metabolismo , Lactulose/metabolismo , Oligossacarídeos/biossíntese , Prebióticos , Propionibacterium/metabolismo , Animais , Aspergillus oryzae , Queijo/microbiologia , Meios de Cultura/química , Leite/microbiologia , Oligossacarídeos/química , Probióticos , Propionibacterium/crescimento & desenvolvimento , Propionibacterium/isolamento & purificação , Fatores de Tempo , beta-Galactosidase/metabolismoRESUMO
An optimization of temperature, time, and extracting agent concentration of pectin extraction from sunflower heads using sodium citrate and nitric acid (SP-SC and SP-NA) was carried out. At optimal conditions, the yield of extraction with nitric acid (SPO-NA) was twofold greater than the corresponding with sodium citrate (SPO-SC) (14.3 versus 7.7%, respectively). Regarding pectin structure, the galacturonic acid (GalA) content in both, SPO-SC and SPO-NA, was similar (â¼85%). However, SPO-NA showed lower molecular weight (Mw) (88.9 kDa) and neutral sugar content (4%) than SPO-SC (464 kDa, 9%), indicating that nitric acid deeply degraded pectin structure. These differences derived into dissimilar behavior in their technological functionality. SPO-SC showed higher viscosity and better emulsifying capacity than SPO-NA, although any of them were able to stabilize the oil/water emulsion. Both sunflower pectins formed gels with Ca2+ (75 mg/g of pectin) at pH 3.0. However, when sucrose was added, the gels formed by SP-SC and 20% sucrose presented the same hardness as those of SP-NA with 40% sucrose. These results suggest that the pectin extracted with sodium citrate, an eco-friendly agent, could be a promising ingredient, with good thickening and gelling properties.
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BACKGROUND: Pectin is heteropolysaccharide found in cell walls originating mainly from by-products, as well as citrus peels, apple and sugar beet pulp, and presenting biological and techno-functional properties. In the present study, a general and structural characterisation of industrial citrus pectins was performed together with a study of impact of power ultrasound (US) on their rheological properties, with the aim of using them as edible coatings for fresh strawberries. RESULTS: The results obtained indicated that pure pectin showed a methylesterification degree greater than 50% and galacturonic acid content > 65%, supporting its consideration as additive E-440; such conditions were not achieved in pectin with sugar addition. Furthermore, in the rheological study, pectin gels showed a non-Newtonian flow and pseudoplastic behaviour and presented different viscosity ranges depending on the preparation methods, including power US. Gels were used as edible coatings for fresh strawberries aiming to improve their quality during storage over a period of 5 days, controlling quality characteristics such as humidity loss, acidity and colour parameters (L*, a*, b*, C, h°, ΔE). CONCLUSION: The results obtained demonstrate that US treatments give rise to pectin gels that can improve the quality of strawberries over their lifetime. © 2018 Society of Chemical Industry.
Assuntos
Conservação de Alimentos/métodos , Fragaria/química , Frutas/química , Géis/química , Pectinas/química , Conservação de Alimentos/instrumentação , ViscosidadeRESUMO
BACKGROUND: One of the most promising uses of whey permeate (WP) is the synthesis of prebiotic oligosaccharides. Herein, commercial WP was submitted to chemical isomerization catalysed by sodium borate at an alkaline pH and subsequent purification using anion-exchange resins to remove boron. Subsequently, purified mixtures were used to synthesize prebiotic oligosaccharides using ß-galactosidase from Bacillus circulans. RESULTS: Isomerization of concentrated WP (200 g L-1 lactose) gave rise to levels of lactulose up to 155.5 g L-1 after 30 min of reaction (molar ratio of boron/lactose, 1/1; pH 12; 70 °C). Boron was removed from the isomerized WP (IWP) using the combination of a strong acid (IR-120, H+ ) and a weak base (IRA-743) anion-exchange resins, reducing its level to <1 ppm, without loss of lactulose. During the transglycosylation reaction of purified IWP (lactose/lactulose ratio, 1/2.4) maximum content of prebiotic compounds was achieved, i.e. 690 g kg-1 WP after 3 h of reaction. CONCLUSION: This study shows that combined chemical-enzymatic reactions together with the purification of IWP results in an efficient synthesis of prebiotic oligosaccharides. © 2017 Society of Chemical Industry.
Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/química , Lactulose/química , Oligossacarídeos/química , Prebióticos/análise , Soro do Leite/química , beta-Galactosidase/química , Biocatálise , Isomerismo , Oligossacarídeos/isolamento & purificaçãoRESUMO
In this paper, the quality of bean, chickpea, fava beans, lentil and pea flours from Algeria has been evaluated. Maillard reaction (MR) indicators, modifications in the carbohydrate and protein fractions, antioxidant activity and α-amylase inhibitor of raw, toasted and stored samples were evaluated. Fava beans, beans and peas showed higher content of raffinose family oligosaccharides while chickpeas and lentils showed higher polyol content. Toasting and storage caused slightly change in pulse quality; MR showed slight losses of lysine but increased antioxidant activity. Moreover, inhibition of α-amylase was slightly augmented during processing; this could increase the undigested carbohydrates that reach the colon, modulating the glycemic response. These results point out the suitability of these flours for preparing high-quality foodstuffs intended for a wide spectrum of the population, including hyperglycemic and gluten intolerant individuals.
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OBJECTIVES: The objective of this work was to elucidate the influence of extremely premature birth (gestational age 24-27 weeks) on the microbiological, biochemical, and immunological composition of colostrum and mature milk. METHODS: A total of 17 colostrum and 34 mature milk samples were provided by the 22 mothers of extremely preterms who participated in this study. Bacterial diversity was assessed by culture-based methods, whereas the concentration of lactose, glucose, and myo-inositol was determined by a gas chromatography procedure. Finally, the concentrations of a wide spectrum of cytokines, chemokines, growth factors, and immunoglobulins were measured using a multiplex system. RESULTS: Bacteria were present in a small percentage of the colostrum and milk samples. Staphylococci, streptococci, and lactobacilli were the main bacterial groups isolated from colostrum, and they could be also isolated, together with enterococci and enterobacteria, from some mature milk samples. The colostrum concentrations of lactose and glucose were significantly lower than those found in mature milk, whereas the contrary was observed in relation to myo-inositol. The concentrations of most cytokines and immunoglobulins in colostrum were higher than in mature milk, and the differences were significant for immunoglobulin G3, immunoglobulin G4, interleukin (IL)-6, interferon-γ, interleukin-4 (IL-4), IL-13, IL-17, macrophage-monocyte chemoattractant protein-1 and macrophage inflammatory protein-1ß. CONCLUSIONS: The bacteriological, biochemical, and immunological content of colostrum and mature milk from mothers of extremely preterm infants is particularly valuable for such infants. Efforts have to be made to try that preterm neonates receive milk from their own mothers or from donors matching, as much as possible, the gestational age of the preterm.
Assuntos
Colostro/química , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Positivas/crescimento & desenvolvimento , Lactação/metabolismo , Leite Humano/química , Nascimento Prematuro/metabolismo , Adulto , Carga Bacteriana , Quimiocinas/análise , Colostro/imunologia , Colostro/metabolismo , Colostro/microbiologia , Citocinas/análise , Feminino , Glucose/análise , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Humanos , Imunoglobulinas/análise , Inositol/análise , Peptídeos e Proteínas de Sinalização Intercelular/análise , Lactose/análise , Pessoa de Meia-Idade , Leite Humano/imunologia , Leite Humano/metabolismo , Leite Humano/microbiologia , Período Pós-Parto , Nascimento Prematuro/imunologia , EspanhaRESUMO
ß-Galactosidases from Kluyveromyces lactis and Kluyveromyces marxianus isolated from artisanal ewes' milk cheeses, were used to transgalactosylate lactose from cheese whey permeate (WP). The content of galactooligosaccharides (GOS) obtained by transgalactosylation was comparable with that formed using pure lactose as substrate. In order to obtain a mixture with higher prebiotic oligosaccharide content, isomerisation of the transgalactosylated WP was carried out using sodium aluminate as catalyst. The transgalactosylated mixtures at 6 h of reaction contained amounts of prebiotic carbohydrates (tagatose, lactulose, GOS and oligosaccharides derived from lactulose, OsLu) close to 50 g/100 g of total carbohydrates for all the strains tested, corresponding to 322 g prebiotics/kg whey permeate. Thus, the suitability of this methodology to produce mixtures of dietary non-digestible carbohydrates with prebiotic properties from WP has been demonstrated, which is interesting for the food industry since it increases the value and the applicability of this by-product from cheese manufacture.
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Queijo/microbiologia , Galactose/metabolismo , Kluyveromyces/enzimologia , Lactulose/metabolismo , Oligossacarídeos/biossíntese , beta-Galactosidase/metabolismo , Compostos de Alumínio/química , Animais , Carboidratos da Dieta , Feminino , Isomerismo , Oligossacarídeos/análise , Prebióticos/análise , Ovinos , Compostos de Sódio/química , Soro do Leite/químicaRESUMO
The increasing interest for prebiotic carbohydrates as functional food ingredients has promoted the synthesis of galactooligosaccharides and new lactose derivatives. This review provides a comprehensive overview on the chromatographic analysis, structural characterization, and bioactivity studies of lactose-derived oligosaccharides. The most common chromatographic techniques used for the separation and structural characterization of this type of oligosaccharides, including GC and HPLC in different operational modes, coupled to various detectors are discussed. Insights on oligosaccharide MS fragmentation patterns, using different ionization sources and mass analyzers, as well as data on structural analysis by NMR spectroscopy are also described. Finally, this article deals with the bioactive effects of galacto oligosaccharides and oligosaccharides derived from lactulose on the gastrointestinal and immune systems, which support their consumption to provide significant health benefits.
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Lactose/análogos & derivados , Lactose/farmacologia , Oligossacarídeos/química , Oligossacarídeos/farmacologia , Prebióticos , Animais , Anti-Infecciosos/química , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Cromatografia Gasosa/métodos , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Fatores Imunológicos/química , Fatores Imunológicos/metabolismo , Fatores Imunológicos/farmacologia , Lactose/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Espectrometria de Massas/métodos , Oligossacarídeos/metabolismo , Prebióticos/análiseRESUMO
This work demonstrates that sesame (Sesamum indicum L.) hull, an unexploited food industrial waste, can be used as an efficient source for the extraction of hemicellulose and/or pectin polysaccharides to further obtain functional oligosaccharides. Different polysaccharides extraction methods were surveyed including alkaline and several enzymatic treatments. Based on the enzymatic release of xylose, arabinose, glucose, and galacturonic acid from sesame hull by using different enzymes, Celluclast®1.5 L, Pectinex®Ultra SP-L, and a combination of them were selected for the enzymatic extraction of polysaccharides at 50 °C, pH 5 up to 24 h. Once the polysaccharides were extracted, Ultraflo®L was selected to produce arabinoxylo-oligosaccharides (AXOS) at 40 °C up to 24 h. Apart from oligosaccharides production from extracted polysaccharides, alternative approaches for obtaining oligosaccharides were also explored. These were based on the analysis of the supernatants resulting from the polysaccharide extraction, alongside a sequential hydrolysis performed with Celluclast®1.5 L and Ultraflo®L of the starting raw sesame hull. The different fractions obtained were comprehensively characterized by determining low molecular weight carbohydrates and monomeric compositions, average Mw and dispersity, and oligosaccharide structure by MALDI-TOF-MS. The results indicated that sesame hull can be a useful source for polysaccharides extraction (pectin and hemicellulose) and derived oligosaccharides, especially AXOS.
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Oligossacarídeos , Sesamum , Sesamum/química , Oligossacarídeos/química , Hidrólise , Polissacarídeos/química , Xilanos/química , Xilanos/isolamento & purificação , Pectinas/química , Pectinas/isolamento & purificação , Resíduos Industriais , Arabinose/química , Xilose/químicaRESUMO
BACKGROUND: Lactose from cheese whey permeate (WP) was efficiently isomerised to lactulose using egg shell, a food-grade catalyst, and the subsequent transgalactosylation reaction of this mixture with ß-galactosidase from Bacillus circulans gave rise to a wide array of prebiotic carbohydrates derived from lactose and lactulose. RESULTS: Lactulose obtained by efficient isomerisation of WP (16.1% by weight with respect to the initial amount of lactose) showed great resistance to the hydrolytic action of ß-galactosidase from B. circulans, which preferentially hydrolysed lactose, acting as a galactosyl donor and acceptor. Lactulose had capacity as an acceptor, leading to the formation of lactulose-derived oligosaccharides. The enzymatic synthesis was optimised by studying reaction conditions such as pH, temperature, time, enzyme concentration and carbohydrate concentration. The maximum formation of galactooligosaccharides with degrees of polymerisation from 2 to 4 was achieved after 5 h of reaction at pH 6.5 and 50 °C with 300 g kg(-1) carbohydrates and 3 U mL(-1) ß-galactosidase. CONCLUSION: These findings indicate that the transgalactosylation of isomerised WP with ß-galactosidase from B. circulans could be a new and efficient method to obtain a mixture with 50% of potentially prebiotic carbohydrates composed of lactulose, and galactooligosaccharides derived from lactose and lactulose.
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Queijo , Lactose/metabolismo , Lactulose/metabolismo , Proteínas do Leite , Oligossacarídeos/biossíntese , Prebióticos , beta-Galactosidase/metabolismo , Animais , Bacillus/enzimologia , Carboidratos da Dieta/metabolismo , Casca de Ovo , Proteínas Fúngicas/metabolismo , Galactose/metabolismo , Concentração de Íons de Hidrogênio , Isomerismo , Polimerização , Proteínas do Soro do LeiteRESUMO
Arabinoxylan (AX) and arabinoxylo-oligosaccharides (AXOS) derived therefrom are emergent prebiotics with promising health promoting properties, likely linked to its capacity to foster beneficial species in the human gut. Bifidobacteria appear to be one taxa that is frequently promoted following AX or AXOS consumption, and that is known to establish metabolic cross-feeding networks with other beneficial commensal species. Therefore, probiotic bifidobacteria with the capability to metabolize AX-derived prebiotics represent interesting candidates to develop novel probiotic and synbiotic combinations with AX-based prebiotics. In this work we have deepen into the metabolic capabilities of bifidobacteria related to AX and AXOS metabolization through a combination of in silico an in vitro tools. Both approaches revealed that Bifidobacterium longum and, particularly, B. longum subsp. longum, appears as the better equipped to metabolize complex AX substrates, although other related subspecies such as B. longum subsp. infantis, also hold some machinery related to AXOS metabolization. This correlates to the growth profiles exhibited by representative strains of both subspecies in AX or AXOS enriched media. Based on these results, we formulated a differential carbohydrate free medium (CFM) supplemented with a combination of AX and AXOS that enabled to recover a wide diversity of Bifidobacterium species from complex fecal samples, while allowing easy discrimination of AX metabolising strains by the appearance of a precipitation halo. This new media represent an appealing alternative to isolate novel probiotic bifidobacteria, rapidly discriminating their capacity to metabolize structurally complex AX-derived prebiotics. This can be convenient to assist formulation of novel functional foods and supplements, including bifidobacterial species with capacity to metabolize AX-derived prebiotic ingredients.
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Bifidobacterium longum , Simbióticos , Humanos , Bifidobacterium longum/metabolismo , Bifidobacterium/metabolismo , Xilanos , Oligossacarídeos/metabolismo , PrebióticosRESUMO
Inflammatory bowel disease (IBD) is a public health challenge and the use of pectin for symptom amelioration is a promising option. In this work, sunflower pectin has been extracted without (CHP) and with assistance of ultrasound (USP) using sodium citrate as a food-grade extracting agent. At optimal conditions (64 °C, 23 min) the highest yield was obtained with ultrasound application (15.5 vs. 8.1 %). Both pectins were structurally characterized by 1H NMR, HPSEC-ELSD, FT-IR and GC-FID. Unlike CHP, USP showed a lower molecular weight, higher galacturonic acid, lower degree of methyl-esterification and, overall, higher viscosity. These characteristics could affect the anti-inflammatory activity of pectins, evaluated using DSS-induced IBD model mice. So, USP promoted the defence (ICAM-1) and repair of the gastrointestinal mucosa (TFF3, ZO-1) more effectively than CHP. These results demonstrate the potential amelioration of acute colitis in IBD mice through USP supplementation. Taking into account the biomarkers analysed, these results demonstrate, for the first time, the positive impact of sunflower pectin extracted by ultrasound under very soft conditions on inflammatory bowel disease that might open up new possibilities in the treatment of this serious pathology.
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Helianthus , Doenças Inflamatórias Intestinais , Animais , Camundongos , Pectinas/farmacologia , Pectinas/química , Helianthus/química , Espectroscopia de Infravermelho com Transformada de Fourier , Citrato de Sódio , Doenças Inflamatórias Intestinais/diagnóstico por imagem , Doenças Inflamatórias Intestinais/tratamento farmacológicoRESUMO
OBJECTIVES: The objectives of the present study were to enumerate and characterize the pathogenic potential of the Bacillus population that may survive holder pasteurisation of human milk and to evaluate the nutritional damage of this treatment using the furosine and lactulose indexes. MATERIALS AND METHODS: Milk samples from 21 donors were heated at 62.5°C for 30 minutes. Bacterial counts, lactose, glucose, myoinositol, lactulose, and furosine were determined before and after the heat treatment. Some B cereus isolates that survived after pasteurisation were evaluated for toxigenic potential. RESULTS: Nonpasteurised milk samples showed bacterial growth in most of the agar media tested. Bacterial survival after pasteurisation was observed in only 3 samples and, in these cases, the microorganisms isolated belonged to the species B cereus. Furosine could not be detected in any of the samples, whereas changes in lactose, glucose, and myoinositol concentrations after holder pasteurisation were not relevant. Lactulose was below the detection limit of the analytical method in nonpasteurised samples, whereas it was found at low levels in 62% of the samples after holder pasteurisation. The lactation period influenced myoinositol content because its concentration was significantly higher in transition milk than in mature or late lactation milk samples. CONCLUSIONS: Holder pasteurisation led to the destruction of bacteria present initially in donor milk samples, except for some B cereus that did not display a high virulence potential and did not modify significantly the concentration of the compounds analyzed in the present study.
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Microbiologia de Alimentos , Leite Humano/química , Leite Humano/microbiologia , Pasteurização , Bacillus cereus/genética , Bacillus cereus/isolamento & purificação , Carga Bacteriana , Toxinas Bacterianas/genética , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Glucose/análise , Humanos , Inositol/análise , Lactose/análise , Lactulose/análise , Lisina/análogos & derivados , Lisina/análise , Bancos de Leite Humano , Valor NutritivoRESUMO
The intake of diets rich in carbohydrates with a high-glycaemic load provides excessive energy consumption and low nutritional quality, contributing to cardiovascular diseases, type II diabetes and obesity, among other pathologies. Natural options such as the use of low-methoxyl pectin to develop sugar free formulations is growing since they form gel without sucrose, providing stability and viscosity of numerous foodstuffs. In this paper, we have reviewed the consumer habits of sugar intake and the potential of pectin in the elaboration of low-glycaemic index foods, as well as the structure, applications and sources of pectin. Special attention has been paid on the structure-function relationship of low-methoxyl pectins considering their effects on type I and II diabetes. It has been shown that these pectins reduce the post-prandial glycaemic responses and have an important and recognised potential for the treatment and prevention of diabetes. Rheological behaviour of pectin, impact on intestinal microbiota and on different biomarkers have been postulated as the potential involved mechanisms. As future trends, it is necessary to consider new sources and structures of pectin that present improved functionalities. For this purpose, the obtainment of pectin and derivatives should be placed in a framework of sustainable food systems.
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Diabetes Mellitus Tipo 2 , Pectinas , Dieta , Humanos , Reologia , ViscosidadeRESUMO
The aim of this work was to develop a comprehensive workflow to elucidate molecular features of artichoke pectic oligosaccharides (POS) contributing to high potential prebiotic activity. First, obtainment of artichoke POS by Pectinex® Ultra-Olio was optimised using an artificial neural network. Under optimal conditions (pH 6.86; 1.5 h; enzyme dose 520.5 U/g pectin) POS yield was 624 mg/g pectin. Oligosaccharide structures (Mw < 1.3 kDa) were characterised by MALDI-TOF-MS. Then, conformational analysis of glycosidic bonds was performed by replica exchange molecular dynamics simulations and interaction mechanisms between POS and several microbial glycosidases were proposed by molecular modelling. Chemical information was integrated in virtual simulations of colonic fermentation. Highest hydrolysis rate was obtained for GalA-Rha-GalA trisaccharide, while the presence of partial negative charges and high radius of gyration enhance short chain fatty acid formation in distal colon. Established structure-activity relationships could help the rational design of prebiotics and clinical trials.
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Colo/metabolismo , Cynara scolymus/química , Ácidos Graxos Voláteis/biossíntese , Oligossacarídeos/metabolismo , Pectinas/metabolismo , Prebióticos/análise , Análise Fatorial , Ácidos Graxos Voláteis/química , Fermentação , Concentração de Íons de Hidrogênio , Hidrólise , Simulação de Dinâmica Molecular , Redes Neurais de Computação , Oligossacarídeos/química , Oligossacarídeos/isolamento & purificação , Pectinas/química , Pectinas/isolamento & purificação , Extratos Vegetais/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Relação Estrutura-Atividade , Interface Usuário-ComputadorRESUMO
Three non-conventional extraction techniques (enzyme-assisted with cellulase, citric acid ultrasound-assisted and enzyme-ultrasound-assisted treatment) and conventional citric acid extraction were applied to obtain pectin from raspberry, blueberry, strawberry and redcurrant, and were compared in terms of extraction yields and physicochemical properties of the extracted pectins. Except for pectin from raspberry, conventional citric acid extraction led to the highest extraction yield (~8%) and, for the same berries, the lowest pectin recovery was found for the extraction with cellulase (~4%). Regarding the structural characteristics of pectins, enzymatically extracted pectins from redcurrant and strawberry exhibited the highest levels of galacturonic acid (≥73%) whereas, in general, this monosaccharide was found from 51 to 69% in the rest of samples. Although, ultrasound-assisted extraction did not improve pectin yield, it minimized the levels of "non-pectic" components leading to the obtainment of purer pectin. The different monomeric composition and the wide range of molecular weight of the obtained pectins pointed out their usefulness in different potential food applications (e.g., thickening, gelling ingredients) and biological activities. This has been evidenced by the differences found in their physicochemical and techno-functional characteristics. Finally, it can be considered that the berries here studied are efficient sources of pectin.