Physicochemical and microbiological parameters during the manufacturing of a beer-type fermented beverage using selenized Saccharomycesboulardii

Selenium is an essential trace element in human health. However, it has been considered a widespread selenium deficiency worldwide, although the recommended daily intake is very low (55 μg per day). Strategies have been implemented to comply with the recommended doses, for example, through bioavailable selenium such as selenoamino acids. Thus, this research aimed to elaborate on a beer-type fermented beverage produced with previously selenized Saccharomyces boulardii. For this, the yeast was selenized by adding a minimum inhibitory concentration of Na2SeO3 (74 ppm) to YPD media. Subsequently, barley must fermentations were carried out for 120 h. Kinetic parameters of the fermentation and physicochemical parameters and selenium content of the beverage were measured. The yeast accumulated up to 25.12 mg/g of dry cell. Furthermore, selenization affected the fermentation rate, but the beverage's physicochemical parameters were not different from those of the control. Due to the final concentration of selenium in the beverage (0.378 mg/kg), it is considered a process that confers advantages for the safe intake of selenium with bioavailable potential. In conclusion, fermented beverages enriched with organic selenium could be produced through cell selenization to produce functional beverages and food.

Compliance with Nutritional Recommendations and Gut Microbiota Profile in Galician Overweight/Obese and Normal-Weight Individuals

Different research studies have identified specific groups or certain dietary compounds as the onset and progression of obesity and suggested that gut microbiota is a mediator between these compounds and the inflammation associated with pathology. In this study, the objective was to evaluate the dietary intake of 108 overweight (OW), obese (OB), and normal-weight (NW) individuals and to analyze their gut microbiota profile to determine changes and associations with Body Mass Index (BMI) and diet. When individuals were compared by BMI, significant differences in fiber and monounsaturated fatty acids (MUFAs) intake were observed, showing higher adequacy for the NW group. The analysis of gut microbiota showed statistical differences for 18 ASVs; Anaerostipes and Faecalibacterium decreased in the OW/OB group, whereas the genus Oscillospira increased; the genus was also found in the LEFSe analysis as a biomarker for OW/OB. Roseburia faecis was found in a significantly higher proportion of NW individuals and identified as a biomarker for the NW group. Correlation analysis showed that adequation to nutritional recommendation for fiber indicated a higher abundance of Prevotella copri, linearly correlated with F. prausnitzii, Bacteroides caccae, and R. faecis. The same correlation was found for the adequation for MUFAs, with these bacteria being more abundant when the intake was adjusted to or below the recommendations.

Effects of Unconventional Work and Shift Work on the Human Gut Microbiota and the Potential of Probiotics to Restore Dysbiosis

The work environment is a factor that can significantly influence the composition and functionality of the gut microbiota of workers, in many cases leading to gut dysbiosis that will result in serious health problems. The aim of this paper was to provide a compilation of the different studies that have examined the influence of jobs with unconventional work schedules and environments on the gut microbiota of workers performing such work. As a possible solution, probiotic supplements, via modulation of the gut microbiota, can moderate the effects of sleep disturbance on the immune system, as well as restore the dysbiosis produced. Rotating shift work has been found to be associated with an increase in the risk of various metabolic diseases, such as obesity, metabolic syndrome, and type 2 diabetes. Sleep disturbance or lack of sleep due to night work is also associated with metabolic diseases. In addition, sleep disturbance induces a stress response, both physiologically and psychologically, and disrupts the healthy functioning of the gut microbiota, thus triggering an inflammatory state. Other workers, including military, healthcare, or metallurgy workers, as well as livestock farmers or long-travel seamen, work in environments and schedules that can significantly affect their gut microbiota.

ACE-Inhibitory Activity of Whey Proteins Fractions Derived of Fermentation by Lacticaseibacillus rhamnosus GG and Streptococcus thermophilus SY-102

Many studies have reported the benefits of probiotic microorganisms and the production of angiotensin-converting enzyme (ACE) inhibitors. Determining the proteolytic and ACE inhibition capacities during whey fermentation was the goal of the study. Lacticaseibacillus rhamnosus GG, Streptococcus thermophilus SY-102, and both bacteria together were initially inoculated into whey, reaching an initial concentration of 10⁸ CFU per milliliter in each fermentation system. Through the use of TNBS, SDS-PAGE, and SEC-HPLC methods, the proteolytic profile was examined. An in vitro investigation was performed to test the ACE inhibition capacity. With S. thermophilus, the logarithmic phase of microbial development was shorter than with L. rhamnosus (6 and 12 h, respectively). The logarithmic phase in the co-culture fermentation, however, was extended to 24 h. There were no significant differences in pH between the fermentations. However, the co-culture had a greater concentration of protein hydrolysis (453 ± 0.06 μg/mL), as indicated by the amount of free amino groups. Similarly, this fermentation produced more low molecular weight peptides. The higher inhibition activity, which increased at the conclusion of the fermentation with the co-culture and reached 53.42%, was influenced by the higher peptide synthesis. These findings highlighted the significance of creating useful co-culture products.

The Human Gut Virome and Its Relationship with Nontransmissible Chronic Diseases

The human gastrointestinal tract contains large communities of microorganisms that are in constant interaction with the host, playing an essential role in the regulation of several metabolic processes. Among the gut microbial communities, the gut bacteriome has been most widely studied in recent decades. However, in recent years, there has been increasing interest in studying the influences that other microbial groups can exert on the host. Among them, the gut virome is attracting great interest because viruses can interact with the host immune system and metabolic functions; this is also the case for phages, which interact with the bacterial microbiota. The antecedents of virome-rectification-based therapies among various diseases were also investigated. In the near future, stool metagenomic investigation should include the identification of bacteria and phages, as well as their correlation networks, to better understand gut microbiota activity in metabolic disease progression.

Potential prebiotic effect of two Atlantic whole brown seaweeds, Saccharina japonica and Undaria pinnatifida, using in vitro simulation of distal colonic fermentation

Two brown seaweeds (Saccharina japonica and Undaria pinnatifida) were characterized in terms of their nutritional and mineral composition, as well as their potential to modify the human gut microbiota. Nutritional analysis of these seaweeds showed that they comply with the criteria set out in European legislation to be labeled "low fat," "low sugar," and "high fiber." Mineral content analysis showed that 100 g of seaweed provided more than 100% of the daily Ca requirements, as well as 33-42% of Fe, 10-17% of Cu, and 14-17% of Zn requirements. An in vitro human digest simulator system was used to analyze the effect of each seaweed on the human colonic microbiota. The gut microbiota was characterized by 16S rRNA amplicon sequencing and short-chain fatty-acid analysis. Seaweed digestion and fermentation showed beneficial effects, such as a decrease in the phylum Firmicutes and an increase in the phyla Bacteroidetes and Actinobacteria. At the species level, seaweed fermentation increased the proportion of beneficial bacteria such as Parabacteroides distasonis and Bifidobacterium. Regarding of metabolic pathways, no significant differences were found between the two seaweeds, but there were significant differences concerning to the baseline. An increase in short-chain fatty-acid content was observed for both seaweeds with respect to the negative control, especially for acetic acid. Given of the obtained results, S. japonica and U. pinnatifida intake are promising and could open new opportunities for research and application in the fields of nutrition and human health.

Swine Production: Probiotics as an Alternative to the Use of Antibiotics

Animal food production is one of the most powerful European economic sectors; however, this sector is facing new challenge due to the development of bacteria with resistant genes, and consequently, restriction on the administration of antibiotics. Limitation, at the moment, is focused on those antibiotics employed in human medicines. Therefore, it is necessary to improve as much as possible animals’ health and reduce diseases. Among others, alternatives include adequate animal handling, hygienic facilities, quality food, or vaccines. Probiotics also arise as a good alternative due to their already known properties as intestinal microbiota modulators, improving the immune functions and reducing the risk and the development of illness. Significant data can found scientific literature that demonstrates probiotics benefits when they are administrated to the animals through diet. However, to be able to apply all these findings in a specific animal species, at a particular production animal life stage and at a industrialize scale, it is necessary to compile and organize reported information. This chapter presents the most recent and relevant finding on the use of probiotics in swine production.

Nutritional composition, heavy metal content and in vitro effect on the human gut microbiota of Talitrus saltator, an underutilized crustacean from the Atlantic coast

In this study, an undervalued marine crustacean (Talitrus saltator) was characterized in terms of nutritional and heavy metal composition and its potential to affect human gut microbiota. Nutritional analysis of this crustacean revealed that it complies with the criteria established in European legislation to include nutritional claims in their labeling, such as "source of fiber," "low in fat," "low in sugars" and "high in protein." The analysis of the heavy metal content did not reveal any risk derived from the presence of Cd, Hg, or Pb, whereas essential metals contained in 100 g exceeded the minimum daily requirements recommended in Europe for Zn (19.78 mg/kg), Cu (2.28 mg/kg), and Fe (32.96 mg/kg). Using an in vitro system, the effect of T. saltator on the human colonic microbiota shows some beneficial effects, such as fermentation-maintained populations of Bifidobacterium or Lactobacillus, did not increase Firmicutes phylum counts, decreased the Firmicutes/Bacteroidetes ratio, and stimulated 11 metabolic pathways with respect to baseline. These results are unusual in a high protein content-food. However, negative effects were also found in gut microbiota relative proportions, such as an increase in the Proteobacteria phylum and especially some opportunistic bacteria from this phylum, probably due to the antimicrobial effect of chitin on other groups more sensitive to its effect. This work shows for the first time the effect of T. saltator on human colonic microbiota using and in vitro system. The presence of chitin in its composition could provide some beneficial effects by modulating the microbiota, but as T. saltator is a high-protein food, more studies should be carried out showing these benefits.

Changes in lifestyle behaviors during COVID-19 isolation in Argentina: A cross-sectional study

OBJECTIVE

Our aim was to identify changes in population habits induced by COVID-19 confinement in Argentina.

METHODS

An internet-based cross-sectional survey was conducted among adults in Argentina on December 2020, requesting possible changes occurring during the COVID-19 outbreak. It included 26 questions regarding general information (age, gender, location), eating habits, desire/anxiety for food or to eat between meals, weight gain, physical activity, and hours of sleep. We ran a descriptive statistical analysis of changes in habits and lifestyle during the confinement, followed by a logistic regression analysis to explore the relation between these changes and weight gain. Results: Out of 1536 survey participants, 57.1% were female, aged 38.8 ± 13.1 years. Data showed that during the outbreak, people experienced significant changes in food intake, physical activity, nutritional supplement consumption, anxiety, and sleeping disorders. These changes in behavior resulted in an elevated percentage of people (39.7%) that gained weight (average 4.8 ± 2.8 kg). Weight gain was associated with more food consumption (OR: 9.398), increased snacking between meals (OR: 1.536), anxiety about food (OR: 3.180), less practice of physical activity (OR: 0.586) and less consumption of nutritional supplements (OR: 0.762). Conclusions: COVID-19 outbreak was associated with unhealthy lifestyle changes and body weight increase. These adverse side effects could be prevented by active promotion of nutritional advice and physical activity, implementing virtual activities associated with regular mass promotion campaigns.

Evaluation of the potential prebiotic effect of Himanthalia elongata, an Atlantic brown seaweed, in an in vitro model of the human distal colon

Until now, although different studies have shown the potential prebiotic effect of seaweed carbohydrates, no studies with the whole seaweeds have been carried out. In addition, the prebiotic effect throughput sequencing remains poorly investigated since most of the published works used qPCR or FISH to estimate bacterial changes. In this work, an in vitro model of the human distal colon was used to determine, for the first time, the potential prebiotic effect of a brown whole seaweed Himanthalia elongata. The whole seaweed was characterized in basis of its nutritional and mineral composition and submitted to the entire gastrointestinal digestion. The prebiotic effect was evaluated by the microbial modulation through 16S rRNA amplicon sequencing, qPCR and short-chain fatty acid analysis. The obtained results indicated that the colonic fraction of H. elongata was used selectively by the Bacteroides genus, more specifically by the specie Bacteoides ovatus, whereas inulin was used mainly by the Parabacteroides genus, being Parabacteroides distasonis the most abundant identified specie. Selective use of inulin by P. distasonis is, therefore, reported by the first time. qPCR analysis shown no significative differences in Bifidobacterium population and a decrease in Lactobacillus along the fermentation assays with both substrates. Regarding to the short-fatty acid production, maximal concentration, 56.11 ± 20.48 mM, was achieved for H. elongata, at 24 h of fermentation whereas for inulin total acid production was 93.66 ± 21.82 mM at 48 h of assay. The metabolic pathways associated with bacterial genera were not significantly different between the two tested substrates. Although more studies are necessary to elucidate the prebiotic character of H. elongata, the results presented in this work are promissory and could open new opportunities of research and application in the area of Nutrition and Food Chemistry.

Development and Validation of Multi-Residue Method for Drugs Analysis in Human Feces by Liquid Chromatography-Tandem Mass Spectrometry

The use of veterinary drugs in animal production is a common practice to secure animal and human health. However, residues of administrated drugs could be present in animal food products. Levels of drugs in food of animal origin are regulated within the European Union. In recent years, residues have been detected not only in food, but also in the environmental elements such as water or soil, meaning that humans are involuntarily exposed to these substances. This article presents a multiclass method for the analysis of various therapeutic groups of pharmaceuticals in human feces. Pharmaceuticals are extracted from feces with an acid extraction solvent, and after filtration the extract was analyzed by HPLC-MS/MS. A limit of detection of 10 ng/g was achieved for 9 pharmaceuticals, with linearity over 0.99 and repeatability and reproducibility lower than 20%. The method was satisfactorily applied in 25 feces samples of individuals that had declared not to be under medical treatment for the last two months. Results indicate the presence of six different compounds at concentration between 10 and 456 ng/g. This preliminary study showed the involuntary exposure of human gut microbiota to active substances such as pharmaceuticals.

Probiotic Effects against Virus Infections: New Weapons for an Old War

This review aimed to gather the available literature investigating the effects of probiotics against the most common viral infections using in vitro trials in cell lines and in vivo clinical trials in both experimental animals and humans. Probiotics were employed to prevent and reduce symptoms of infections caused by common viruses, especially respiratory tract viruses, but also for viral digestive infections (such as rotavirus, coronavirus, or norovirus) and other viral infections (such as viruses that cause hepatitis, human papillomavirus, human immunodeficiency virus, and herpes simplex virus). Different probiotics have been studied to see their possible effect against the abovementioned viruses, among which different Lactobacillus species, Bifidobacterium, Clostridium, Enterococcus, and Streptococcus can be highlighted. In many cases, mixtures of various probiotic strains were used. Although the results obtained did not show similar results, in most cases, probiotic supplementation improved both barrier and biochemical immune responses, decreased susceptibility to viral infections, and enhanced the effects of concomitant vaccines. Works collected in this review show a beneficial effect of probiotics in the prevention and treatment of different viral infections. We found interesting results related to the prevention of viral infections, reduction of the duration of diseases, and decrease of symptoms.

Influence of the Intestinal Microbiota on Diabetes Management

In recent decades, there has been a very rapid increase in the prevalence of diabetes globally, with serious health and economic implications. Although today there are several therapeutic treatments for this disease, these do not address the causes of the disease and have serious side effects, so it is necessary to seek new treatments to replace or complement the existing ones. Among these complementary treatments, a strong link between the intestinal microbiota and diabetes has been demonstrated, which has focused attention on the use of biotherapy to regulate the function of the intestinal microbiota and, thus, treat diabetes. In this way, the main objective of this work is to provide a review of the latest scientific evidence on diabetes, gathering information about new trends in its management, and especially, the influence of the intestinal microbiota and microbiome on this pathology. It is possible to conclude that the relationship between the intestinal microbiota and diabetes is carried out through alterations in energy metabolism, the immune system, changes in intestinal permeability, and a state of low-intensity systemic inflammation. Although, currently, most of the experimental work, using probiotics for diabetes management, has been done on experimental animals, the results obtained are promising. Thus, the modification of the microbiota through biotherapy has shown to improve the symptoms and severity of diabetes through various mechanisms related to these alterations.

Potential Use of Marine Seaweeds as Prebiotics: A Review

Human gut microbiota plays an important role in several metabolic processes and human diseases. Various dietary factors, including complex carbohydrates, such as polysaccharides, provide abundant nutrients and substrates for microbial metabolism in the gut, affecting the members and their functionality. Nowadays, the main sources of complex carbohydrates destined for human consumption are terrestrial plants. However, fresh water is an increasingly scarce commodity and world agricultural productivity is in a persistent decline, thus demanding the exploration of other sources of complex carbohydrates. As an interesting option, marine seaweeds show rapid growth and do not require arable land, fresh water or fertilizers. The present review offers an objective perspective of the current knowledge surrounding the impacts of seaweeds and their derived polysaccharides on the human microbiome and the profound need for more in-depth investigations into this topic. Animal experiments and in vitro colonic-simulating trials investigating the effects of seaweed ingestion on human gut microbiota are discussed.

Influence of food consumption patterns and Galician lifestyle on human gut microbiota

The proportion of different microbial populations in the human gut is an important factor that in recent years has been linked to obesity and numerous metabolic diseases. Because there are many factors that can affect the composition of human gut microbiota, it is of interest to have information about what is the composition of the gut microbiota in different populations in order to better understand the possibilities for improving nutritional management. A group of 31 volunteers were selected according to established inclusion and exclusion criteria and were asked about their diet history, lifestyle patterns, and adherence to the Southern European Atlantic Diet. Fecal samples were taken and subsequently analyzed by real-time PCR. The results indicated different dietary patterns for subjects who consumed a higher amount of fruits, vegetables, legumes, and fish and a lower amount of bakery foods and precooked foods and snacks compared to Spanish consumption data. Most participants showed intermediate or high adherence to Southern European Atlantic Diet, and an analysis of gut microbiota showed high numbers of total bacteria and Actinobacteria, as well as high amounts of bacteria belonging to the genera Lactobacillus spp. and Bifidobacterium spp. A subsequent statistical comparison also revealed differences in gut microbiota depending on the subject's body weight, age, or degree of adherence to the Southern European Atlantic Diet.

Food additives, contaminants and other minor components: effects on human gut microbiota-a review

Gut bacteria play an important role in several metabolic processes and human diseases, such as obesity and accompanying co-morbidities, such as fatty liver disease, insulin resistance/diabetes, and cardiovascular events. Among other factors, dietary patterns, probiotics, prebiotics, synbiotics, antibiotics, and non-dietary factors, such as stress, age, exercise, and climatic conditions, can dramatically impact the human gut microbiota equilibrium and diversity. However, the effect of minor food constituents, including food additives and trace contaminants, on human gut microbiota has received less attention. Consequently, the present review aimed to provide an objective perspective of the current knowledge regarding the impacts of minor food constituents on human gut microbiota and consequently, on human health.

Chitosan-based silver nanoparticles: A study of the antibacterial, antileishmanial and cytotoxic effects

Silver nanoparticles have been studied as an alternative for treatment of microbial infections and leishmaniasis, without promoting induction of microbial or parasite resistance. In this study, chitosan-based silver nanoparticles were synthesized from silver nitrate (AgNO3), sodium borohydride as a reducing agent, and the biopolymer chitosan as a capping agent. The chitosan-based silver nanoparticles were characterized by ultraviolet–visible, Fourier transform infrared, dynamic light scattering, zeta potential, atomic force microscopy, and transmission electron microscope. The antibacterial assay was performed by determination of the minimum inhibitory concentration. The antileishmanial and the cytotoxic effects induced by AgNO3, chitosan, and chitosan-based silver nanoparticles were analyzed by resazurin and MTT colorimetric assays, respectively. AgNO3, chitosan, and chitosan-based silver nanoparticles induced a marked activity against all bacterial strains and promastigote forms of Leishmania amazonensis at minimum inhibitory concentrations ranging from 1.69 to 3.38 µg Ag/mL. Interestingly, the chitosan-based silver nanoparticles presented less cytotoxicity than the AgNO3 alone and were more active against L. amazonensis than solely chitosan. Furthermore, the cytotoxic concentrations (CC50) of both chitosan and chitosan-based silver nanoparticles against macrophages were significantly higher than the IC50 against promastigotes. Thus, the chitosan-based silver nanoparticles represent a promising alternative for the treatment of microbial infections and leishmaniasis.

Topical application of probiotics in skin: adhesion, antimicrobial and antibiofilm in vitro assays

AIMS

When skin dysbiosis occurs as a result of skin disorders, probiotics can act as modulators, restoring microbial balance. Several properties of selected probiotics were evaluated so that their topical application could be considered.

METHODS AND RESULTS

Adhesion, antimicrobial, quorum sensing and antibiofilm assays were carried out with several probiotic strains and tested against selected skin pathogens. All tested strains displayed significant adhesion to keratin. All lactobacilli with the exception of Lactobacillus delbrueckii, showed antimicrobial activity against skin pathogens, mainly due to organic acid production. Most of them also prevented biofilm formation, but only Propioniferax innocua was able to break down mature biofilms.

CONCLUSIONS

This study demonstrates that although all tested probiotics adhered to human keratin, they showed limited ability to prevent adhesion of some potential skin pathogens. Most of the tested probiotics successfully prevented biofilm formation, suggesting that they may be successfully used in the future as a complement to conventional therapies in the treatment of a range of skin disorders.

SIGNIFICANCE AND IMPACT OF STUDY

The topically used probiotics may be a natural, targeted treatment approach to several skin disorders and a complement to conventional therapies which present many undesirable side effects.

Synthesis of Oligosaccharides Derived from Lactulose (OsLu) Using Soluble and Immobilized Aspergillus oryzae β-Galactosidase

β-Galactosidase from Aspergillus oryzae offers a high yield for the synthesis of oligosaccharides derived from lactulose (OsLu) by transgalactosylation. Oligosaccharides with degree of polymerization (DP) ≥ 3 have shown to possess higher in vitro bifidogenic effect than di- and tetrasaccharides. Thus, in this work, an optimization of reaction conditions affecting the specific selectivity of A. oryzae β-galactosidase for synthesis of OsLu has been carried out to enhance OsLu with DP ≥ 3 production. Assays with β-galactosidase immobilized onto a glutaraldehyde–agarose support were also carried out with the aim of making the process cost-effective and industrially viable. Optimal conditions with both soluble and immobilized enzyme for the synthesis of OsLu with DP ≥ 3 were 50 °C, pH 6.5, 450 g/L of lactulose, and 8 U/mL of enzyme, reaching yields of ca. 50% (w/v) of total OsLu and ca. 20% (w/v) of OsLu with DP 3, being 6′-galactosyl-lactulose the major one, after a short reaction time. Selective formation of disaccharides, however, was favored at 60 °C, pH 4.5, 450 g/L of lactulose and 8 U/mL of enzyme. Immobilization increased the enzymatic stability to temperature changes and allowed to reuse the enzyme. We can conclude that the use, under determined optimal conditions, of the A. oryzae β-galactosidase immobilized on a support of glutaraldehyde–agarose constitutes an efficient and cost-effective alternative to the use of soluble β-galactosidases for the synthesis of prebiotic OsLu mixtures.

Goat sausages containing chitosan towards a healthier product: microbiological, physico-chemical textural evaluation

Goat meat is extensively known for its interesting nutritional value and for being an important source of protein with high quality.

Development of a low fat fresh pork sausage based on chitosan with health claims: impact on the quality, functionality and shelf-life

A low fat fresh pork sausage based on chitosan was developed with the objective of obtaining a new functional meat product with improved properties and health claims promoting cholesterol reduction. Sausages were formulated with chitosan (2%, w/w) and different fat levels (5%, 12.5% and 20%, w/w). The results indicated that incorporation of 2% chitosan into produced pork sausages with health claims of reduction of cholesterol is technologically feasible. In addition, the chitosan reduced the microbial growth, revealing interesting fat and water absorption capacities, reduced lipid oxidation, provided greater stability in terms of colorimetric parameters and promoted positive firmer texture and gumminess. The reduction of fat content to levels of 5% was positively achieved with the incorporation of chitosan. Sensorial analysis showed that panelists did not detect any significant difference in taste and any unfavorable effect on the sausage appearance as a consequence of chitosan addition and variation of fat.

Improving Properties of a Novel β-Galactosidase from Lactobacillus plantarum by Covalent Immobilization

A novel β-galactosidase from Lactobacillus plantarum (LPG) was over-expressed in E. coli and purified via a single chromatographic step by using lowly activated IMAC (immobilized metal for affinity chromatography) supports. The pure enzyme exhibited a high hydrolytic activity of 491 IU/mL towards o-nitrophenyl β-D-galactopyranoside. This value was conserved in the presence of different divalent cations and was quite resistant to the inhibition effects of different carbohydrates. The pure multimeric enzyme was stabilized by multipoint and multisubunit covalent attachment on glyoxyl-agarose. The glyoxyl-LPG immobilized preparation was over 20-fold more stable than the soluble enzyme or the one-point CNBr-LPG immobilized preparation at 50 °C. This β-galactosidase was successfully used in the hydrolysis of lactose and lactulose and formation of different oligosaccharides was detected. High production of galacto-oligosaccharides (35%) and oligosaccharides derived from lactulose (30%) was found and, for the first time, a new oligosaccharide derived from lactulose, tentatively identified as 3'-galactosyl lactulose, has been described.

Intestinal anti-inflammatory effects of oligosaccharides derived from lactulose in the trinitrobenzenesulfonic acid model of rat colitis

Intestinal microbiota modulation is becoming an interesting approach to manage inflammatory bowel disease and can be achieved by the administration of prebiotics. Previous studies showed the intestinal anti-inflammatory effects of the prebiotic lactulose. The aim of the present study was to test the preventative effects of oligosaccharides derived from lactulose with prebiotic properties (OsLu) in the trinitrobenzenesulfonic acid model of rat colitis and compare them with those of lactulose. Both treatments modified bacterial profile in intestinal contents, increasing the bifidobacteria and lactobacilli counts and up-regulating the production of short-chain fatty acids, although OsLu generated a larger amount. OsLu also inhibited to a greater extent different pro-inflammatory markers such as interleukins (IL) 1, 6, 12, and 23 and chemokines (MCP-1 and CINC-1). However, both prebiotics equally restored colonic epithelial integrity, evaluated both with a histological score (OsLu, 9.8 ± 2.2; and lactulose, 12.1 ± 2.1, vs colitic control, 27.3 ± 3.3) and by measuring several key proteins of the mucosal barrier (MUC-2, MUC-3, and TTF-3). OsLu effect was also associated with an inhibition of iNOS expression and a reduction of Th17 cell activity in the inflamed tissue that facilitated the intestinal mucosa barrier recovery. In conclusion, OsLu showed a better anti-inflammatory profile than lactulose in this model of experimental colitis.

A comprehensive study into the impact of a chitosan mouthwash upon oral microorganism's biofilm formation in vitro

Modern dentistry emphasizes the importance of dental plaque control to improve oral health. To that end the development of oral care formulations has been geared toward the incorporation of antiplaque agents that may play a crucial role in oral health maintenance. In later years the research into antiplaque agents has led to the discovery of compounds with significant capability to affect biofilm formation. Among these compounds was chitosan, a polysaccharide which showed great ability to interfere with Streptococcus mutans biofilm formation. As such the aim of this work was to incorporate chitosan into a mouthwash matrix and assess its effect upon biofilm formation of oral microorganisms. This assessment was performed via study of the impact the mouthwash upon microbial adherence, biofilm formation and mature biofilms. Additionally, the action of the chitosan mouthwash was compared with two commercially available mouthwashes. The results here obtained show that only the chitosan containing mouthwash was capable of interfering with all microorganisms' adherence, biofilm formation and mature biofilms while at the same time showing vastly superior activity than both commercial mouthwashes assayed. As such a chitosan mouthwash shows great potential as a natural and efficient alternative to traditional mouthwashes.

Evaluation of oligosaccharide synthesis from lactose and lactulose using β-galactosidases from Kluyveromyces isolated from artisanal cheeses

The β-galactosidase activity of 15 Kluyveromyces strains isolated from cheese belonging to Kluyveromyces lactis and Kluyveromyces marxianus species was tested for the production of oligosaccharides derived from lactose (GOS) and lactulose (OsLu). All Kluyveromyces crude cell extracts (CEEs) produced GOS, such as 6-galactobiose and 3'-, 4'-, and 6'-galactosyl-lactose. At 4 h of reaction, the main trisaccharide formed was 6'-galactosyl-lactose (20 g/100 g of total carbohydrates). The formation of OsLu was also observed by all CEEs tested, with 6-galactobiose, 6'-galactosyl-lactulose, and 1-galactosyl-lactulose being found in all of the reaction mixtures. The synthesis of trisaccharides predominated over other oligosaccharides. K. marxianus strain O3 produced the highest yields of GOS and OsLu after 4 h of reaction, reaching 42 g/100 g of total carbohydrates (corresponding to 80% lactose hydrolysis) and 45 g/100 g of total carbohydrates (corresponding to 87% lactulose hydrolysis), respectively. Therefore, the present study contributes to a better insight into dairy Kluyveromyces β-galactosidases and shows the feasibility of these enzymes to transglycosylate lactose and lactulose, producing high yields of prebiotic oligosaccharides.

In vitro fermentation of lactulose-derived oligosaccharides by mixed fecal microbiota

Fermentation properties of oligosaccharides derived from lactulose (OsLu) and lactose (GOS) have been assessed in pH-controlled anaerobic batch cultures using lactulose and Vivinal-GOS as reference carbohydrates. Changes in gut bacterial populations and their metabolic activities were monitored over 24 h by fluorescent in situ hybridization (FISH) and by measurement of short-chain fatty acid (SCFA) production. Lactulose-derived oligosaccharides were selectively fermented by Bifidobacterium and lactic acid bacterial populations producing higher SCFA concentrations compared to GOS. The highest total SCFA production was from Vivinal-GOS > lactulose > OsLu > GOS. Longer incubation periods produced a selective fermentation of OsLu when they were used as a carbon source reaching the highest selective index scores. The new oligosaccharides may constitute a good alternative to lactulose, and they could belong to a new generation of prebiotics to be used as a functional ingredient for improving the composition of gut microflora.

Detailed kinetic model describing new oligosaccharides synthesis using different β-galactosidases

The production of prebiotic galactooligosaccharides (GOS) from lactose has been widely studied whereas the synthesis of new prebiotic oligosaccharides with improved properties as those derived from lactulose is receiving an increasing interest. Understanding the mechanism of enzymatic oligosaccharides synthesis from lactulose would help to improve the quality of the products in a rational way as well as to increase the production efficiency by optimally selecting the operating conditions. A detailed kinetic model describing the enzymatic transgalactosylation reaction during lactulose hydrolysis is presented here for the first time. The model was calibrated with the experimental data obtained in batch assays with two different β-galactosidases at various temperatures and concentrations of substrate. A complete system identification loop, including model selection, robust estimation of the parameters by means of a global optimization method and computation of confidence intervals was performed. The kinetic model showed a good agreement between experimental data and predictions for lactulose conversion and provided important insights into the mechanism of formation of new oligosaccharides with potential prebiotic properties.

Characterization of galactosyl derivatives obtained by transgalactosylation of lactose and different polyols using immobilized beta-galactosidase from Aspergillus oryzae

The synthesis of novel galactosides is interesting because of their important role in several biological processes. Their properties greatly depend upon the configuration and type of galactoside. Therefore, to study biological activity, it is essential to elucidate the structure of the products. Glycosidases are capable of catalyzing glycosidic linkages with absolute stereoselectivity of the anomeric center. We report the enzymatic synthesis of galactosyl-ethylene glycol, galactosyl-glycerol, and galactosyl-erythritol by immobilized beta-galactosidase from Aspegillus oryzae. The obtained galactosides were isolated and fully characterized by an extensive nuclear magnetic resonance (NMR) study. Complete structure elucidation and full proton and carbon assignments were carried out using 1D ((1)H and (13)C) and 2D (gCOSY, TOCSY, multiplicity-edited gHSQC, and gHMBC) NMR experiments. The beta-galactosidase from A. oryzae showed a strong preference for primary alcohols. For galactosyl-glycerol and galactosyl-erythritol, this preference generated one and two chiral centers, respectively, and a mixture of stereoisomers was obtained as a consequence.

Isomerization of lactose-derived oligosaccharides: a case study using sodium aluminate

Galactooligosaccharides (GOS) obtained during the enzymatic hydrolysis of lactose contain large amounts of glucose, galactose, and unreacted lactose, which do not have prebiotic properties and increase the calorific value of the product. In this work, the isomerization of the GOS mixture by the action of sodium aluminate has been studied. During the reaction, lactose, glucose, and galactose were isomerized to lactulose, fructose, and tagatose, respectively, and in addition allolactose, 6-galactobiose, and 6'-galactosyl-lactose were also converted to the corresponding keto-sugars. The effect of time, temperature, and aluminate/initial lactose ratio has been studied. After 9 h at 40 degrees C and molar ratio aluminate/lactose 3:1, the isomerization yield was >60%, and the amount of final carbohydrates was close to 90% of the initial product. This process considerably decreases the amount of lactose, glucose, and galactose.

Synthesis of oligosaccharides derived from lactulose and pectinex ultra SP-L

The beta-galactosidase activity of the commercial enzymatic preparation Pectinex Ultra SP-L derived from Aspergillus aculeatus has been used to hydrolyze and transgalactosylate the prebiotic carbohydrate lactulose. During this reaction, new oligosaccharides derived from lactulose have been detected by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The presence of the trisaccharide 6'-galactosyl-lactulose, the major compound formed, has been confirmed by NMR. In addition, disaccharides and other oligosaccharides with higher retention times have been also detected. The effect of transgalactosylation conditions such as time, temperature, pH, and initial lactulose and enzyme concentrations, as well as product inhibition on oligosaccharide synthesis, has been studied. The optimal conditions for the formation of tri and higher oligosaccharides were 60 degrees C, pH 6.5, 450 g/L lactulose, 16 units/mL of enzyme, and 7 h of reaction. Selective formation of disaccharides was achieved under the same conditions with the exception of pH (4.5). The present work provides additional knowledge on the synthesis of new oligosaccharides with potential prebiotic properties.

Enzymatic synthesis and identification of two trisaccharides produced from lactulose by transgalactosylation

The enzymatic transgalactosylation during lactulose hydrolysis was studied using the beta-galactosidase from Kluyveromyces lactis and an initial lactulose concentration of 250 g/L. During hydrolysis of lactulose, the formation of two novel trisaccharides was followed by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). A maximum trisaccharide yield of 14.05% was observed at 91.9% of lactulose hydrolysis. The two novel trisaccharides obtained by transglycosylation of lactulose were isolated and fully characterized by an extensive nuclear magnetic resonance (NMR) study. Complete structure elucidation and full proton and carbon assignment were carried out using 1D ( 1H, 13C, and 1D TOCSY) and 2D (gCOSY, TOCSY, ROESY, gHSQC, and gHMBC) NMR experiments. The trisaccharides were shown to be lactulose-based structures; the main one has a Gal unit linked to C-6 of the galactose moiety, and the other one has a Gal unit linked to C-1 of the fructose moiety. Transglycosylation of lactulose allows for the obtention of galacto-oligosaccharides with new glycosidic structures and would open new routes to the synthesis of prebiotics.

Assessment of initial stages of Maillard reaction in dehydrated onion and garlic samples

The initial steps of the Maillard reaction in freshly laboratory-freeze-dried and commercial dehydrated onion and garlic samples have been assessed by quantitative determination of 2-furoylmethylamino acids, obtained after acid hydrolysis of the corresponding Amadori compound. In freshly prepared samples, hardly any presence of 2-furoylmethylamino acids was detected, whereas in commercial samples, onion contained much more important levels of 2-furoylmethylamino acids as compared to garlic species. 2-Furoylmethyl-gamma-aminobutyric acid (1), 2-furoylmethyl-lysine (furosine; 2), and 2-furoylmethylarginine (3) were identified in all commercial dehydrated onion samples, with compound 3 being the most abundant. All garlic samples presented slightly higher levels of 2 than 3 with no presence of 1. The observed differences between onion and garlic commercial samples may be due to their very different content of reducing sugars. Moreover, some variations found in 2-furoylmethyl derivatives within both onion and garlic species could be also attributed to different processing and storage conditions during the manufacture of these products. The findings of this study show the first evidence of important levels of Amadori compounds in dehydrated garlic and onion samples, as well as the usefulness of 2-furoylmethyl derivatives as quality indicators for the early detection of the Maillard reaction in onion and garlic products.