Cow’s milk as a dietary source of equol and phenolic antioxidants: differential distribution in the milk aqueous and lipid fractions

Using Targeted Metabolomics to Unravel Phenolic Metabolites of Plant Origin in Animal Milk

Milk holds a high nutritional value and is associated with diverse health benefits. The understanding of its composition of (poly)phenolic metabolites is limited, which necessitates a comprehensive evaluation of the subject. This study aimed at analyzing the (poly)phenolic profile of commercial milk samples from cows and goats and investigating their sterilization treatments, fat content, and lactose content. Fingerprinting of phenolic metabolites was achieved by using ultra-high-performance liquid chromatography coupled with triple-quadrupole mass spectrometry (UHPLC-QqQ-MS/MS). Two hundred and three potential microbial and phase II metabolites of the main dietary (poly)phenols were targeted. Twenty-five metabolites were identified, revealing a diverse array of phenolic metabolites in milk, including isoflavones and their microbial catabolites equol and O-desmethylangolensin, phenyl-γ-valerolactones (flavan-3-ol microbial catabolites), enterolignans, urolithins (ellagitannin microbial catabolites), benzene diols, and hippuric acid derivates. Goat's milk contained higher concentrations of these metabolites than cow's milk, while the sterilization process and milk composition (fat and lactose content) had minimal impact on the metabolite profiles. Thus, the consumption of goat's milk might serve as a potential means to supplement bioactive phenolic metabolites, especially in individuals with limited production capacity. However, further research is needed to elucidate the potential health effects of milk-derived phenolics.

Effects of inoculation and dry matter content on microbiome dynamics and metabolome profiling of sorghum silage

Sorghum forage was ensiled for 90 days at two dry matter (DM) contents (27 vs. 39%) without or with Lactiplantibacillus plantarum inoculation. On day 90 of fermentation, silages were sampled to assess the microbial community dynamics and metabolome profile. L. plantarum inoculation improved silage quality, as shown by a lower pH and greater acetic acid concentration. Loss of DM remained unaffected by L. plantarum inoculation but was greater in low- vs. high-DM sorghum silages (14.4 vs. 6.62%). The microbiome analysis revealed that Pseudomonas congelans represented the dominant species of the epiphytic microbiota in both low- and high-DM sorghum forage before ensiling. However, L. buchneri represented the dominant species at the end of ensiling. Ensiling fermentation resulted in distinct metabolic changes in silages with varying DM content. In low-DM silages, ensiling fermentation led to the accumulation of 24 metabolites and a reduction in the relative concentration of 13 metabolites. In high-DM silages, ensiling fermentation resulted in an increase in the relative concentration of 26 metabolites but a decrease in the concentration of 8 metabolites. Compared to non-inoculated silages, L. plantarum inoculation resulted in an increased concentration of 3 metabolites and a reduced concentration of 5 metabolites in low-DM silages. Similarly, in high-DM silages, there was an elevation in the relative concentration of 3 metabolites, while a decrease in 7 other metabolites. Ten metabolites with bio-functional activity were identified, including chrysoeriol, isorhamnetin, petunidin 3-glucoside, apigenin, caffeic acid, gallic acid, p-coumaric acid, trans-cinnamic acid, herniarin, and 3,4-dihydroxy-trans-cinnamate. This study presents a comprehensive analysis of microbiome and metabolome profiling of sorghum forage during ensiling as a function of DM content and L. plantarum inoculation, with a particular emphasis on identifying metabolites that may possess bio-functional properties. KEY POINTS: • DM loss was not different by L. plantarum but higher in low- vs. high-DM silage. • L. buchneri dominated ensiling, regardless of DM level. • 10 metabolites with bio-functional activity were identified.

Development of a functional Greek sheep yogurt incorporating a probiotic Lacticaseibacillus rhamnosus wild-type strain as adjunct starter culture

Greek yogurt is a fermented dairy product of high nutritional value that can be used as a matrix for the delivery of probiotics. The aim of this study was to develop a new probiotic Greek sheep yogurt with upgraded quality and functional characteristics. To do this, yogurt was manufactured by fermenting pasteurized milk with the commercial starter culture (Streptococcus thermophilus (ST), Lactobacillus bulgaricus (LB)) together with a probiotic Lacticaseibacillus rhamnosus (LR) wild-type strain (probiotic yogurt; PY). As a control, yogurt manufactured with only the starter culture (ST, LB) was used (conventional yogurt; CY) The survival of all three lactic acid bacteria (LAB) species (ST, LB, and LR) was monitored throughout the products' shelf life (storage at 4 °C for 25 days), and also following exposure to a static in vitro digestion model (SIVDM). The population dynamics of total aerobic plate count (APC), Enterobacteriaceae, yeasts and molds grown in both yogurts were also determined. The total antioxidant activity (AA) of yogurts was comparatively determined using in parallel two different assays, whereas the Folin-Ciocalteu assay was used to determine their total phenolic content (TPC). At each sampling day, yogurts were also evaluated for their pH, titratable acidity (TA) and main sensory characteristics. The population of probiotic LR remained stable during the shelf life (and above 108 CFU/g). Yogurt starters (ST, LB) were not detected following SIVDM, whereas LR (in PY) presented a reduction of about only one log. The AA and TPC of PY were found significantly higher than that of CY (P < 0.05). At the end of storage (25th day), neither pH nor TA differed significantly between the two yogurt types, while no fungal growth was observed in the PY. Consumer sensory analysis did not reveal important differences between the two yogurt types during their shelf life. To sum up, the novel yogurt was able to deliver to consumers a high number of probiotic cells (>108 CFU/g), presented increased antioxidant power, had an expanded shelf life, and maintained its good sensory attributes.

Antimicrobial potential of kombucha fresh cheese with the addition of sage (Salvia officinalis L.) and its preparations

One of the main challenges in fresh cheese technology is its rather limited shelf life. Prolongation of the shelf life of fresh cheese has been the focus of numerous research studies and different strategies have been thus used. One of the strategies that could prolong the shelf life of fresh cheese, as well as increase its quality is the application of different starter cultures. As the antimicrobial capacity of sage (Salvia officinalis) has been proven, the possibility of reusing its by-product obtained from a tea factory could be a significant step towards the retention of environmental equilibrium and simultaneous production of food with additional functional value. Therefore, the aim of our research was to examine the antimicrobial potential of kombucha fresh cheese with the addition of ground herbal sage, sage essential oil and sage supercritical fluid extract, and compare it with fresh cheese obtained from a commercial starter culture. In order to examine the antimicrobial activity of kombucha fresh cheese produced with the addition of sage preparations, the produced samples were artificially contaminated with common foodborne contaminants: Listeria monocytogenes, Escherichia coli and Staphylococcus aureus. The obtained results revealed that the addition of sage essential oil and herbal ground sage increased the antimicrobial activity during the 30 days of storage against E. coli in kombucha fresh cheese (decrease of 2.9 and 2.5 log CFU g^-1, respectively). Implementation of sage significantly increased the antimicrobial activity of the fresh cheese produced with a commercial XPL-1 starter culture against L. monocytogenes (essential oil - 0.9 log CFU g^-1 and ground sage - 1.2 log CFU g^-1). In the XPL-1 sample, the growth of S. aureus was inhibited by the addition of ground sage - a decrease of 1.4 log CFU g^-1. Analysis of the total phenols revealed their 5-fold higher content in the kombucha fresh cheeses compared to the samples obtained by the XPL-1 starter culture. These results correlate with the higher antimicrobial activity of the kombucha fresh cheese samples compared to the XPL-1 samples. According to our results, industrial waste, obtained as a by-product in sage (Salvia officinalis) filter tea production, can be efficiently used in fresh cheese technology in order to increase the antimicrobial activity against L. monocytogenes, E. coli and S. aureus.

Traditional Mexican Food: Phenolic Content and Public Health Relationship

Phenolic compounds have a positive effect on obesity, diabetes, and cardiovascular diseases because of their antioxidant and anti-inflammatory capacity. The prevalence of these diseases has increased in the last years in the Mexican population. Therefore, the Mexican diet must be assessed as provider of phenolic compounds. To assess this, a survey of phenolic compound intake was validated and applicated to 973 adults (798 females) between 18 and 79 years old. We compared the phenolic compound intake of 324 participants with more diseases (239 females) and 649 participants with healthier condition (559 females). The groups differed in sex, age, and scholarship. Males, older participants, and those with lower schooling reported suffering from more diseases. Regarding phenolic compound intake analyses, the participants with healthier conditions displayed a higher phenolic compound intake than the other group in all foods assessed. In addition, the regression model showed that the phenolic compounds intake of Mexican dishes, such as arroz con frijol or enchiladas, positively affected health status, suggesting that this traditional food is beneficial for the participant’s health condition. However, the weight effect of PCI was different for each disease. We conclude that, although PCI of Mexican food positively affects health conditions, this effect depends on sex, age, and participants’ diseases.

Polyphenols for Livestock Feed: Sustainable Perspectives for Animal Husbandry?

There is growing interest in specialized metabolites for fortification strategies in feed and/or as an antioxidant, anti-inflammatory and antimicrobial alternative for the containment of disorders/pathologies that can also badly impact human nutrition. In this context, the improvement of the diet of ruminant species with polyphenols and the influence of these compounds on animal performance, biohydrogenation processes, methanogenesis, and quality and quantity of milk have been extensively investigated through in vitro and in vivo studies. Often conflicting results emerge from a review of the literature of recent years. However, the data suggest pursuing a deepening of the role of phenols and polyphenols in ruminant feeding, paying greater attention to the chemistry of the single compound or to that of the mixture of compounds more commonly used for investigative purposes.

Microencapsulates by spray of Lacticaseibacillus rhamnosus GG from fermented whole or skimmed cow's milk added with Mexican honeysuckle (Justicia spicigera) extract using mesquite gum as carrier agent

This work aimed to evaluate the effect of the addition 5°Bx Mexican honeysuckle (Justicia spicigera) extract (JSE) in spray dried encapsulates of whole and skimmed unfermented and fermented cow's milk with Lacticaseibacillus rhamnosus (LR). All samples were spray dried at 160 °C. Samples were analyzed in physical properties (moisture content, water activity (a_w), L∗, a∗, b∗, Hue, Chroma color parameters, particle size), LR content, and bioactive compounds (total anthocyanins (TA), total phenolic content (TPC), and antioxidant capacity (AC) using the DPPH assay). Results showed that the load of LR was in the range 6.79–7.44 Log₁₀ (CFU/mL) cycles after fermentation, lower values were obtained when JSE was added before fermentation. In addition, LR remains after drying in fermented samples but decrease about 1 Log₁₀ (CFU/mL) cycle. LR was 4.46 Log₁₀ (CFU/mL) in the fermented skimmed milk-J. spicigera extract powder. All powders had a_w and moisture content below 0.295 and 6.51%, respectively. Color of powders depended on the moment of addition of JSE and fermentation. Powders from fermented milk were pale brownish/orangey/red (Hue = 44.91–59.7) and unfermented and J. spicigera extract-maltodextrin solution (12% w/v) powders were purple (Hue = 314.52–326.68). Higher particle sizes (52.3–104.7 μm) were obtained with whole milk fermented and unfermented powders. On the contrary, skimmed milk and JSE without milk protein had values in the range 15.56–44.0 μm. TPC in powders were higher (16.96–33.81 mg GAE/g powder db) compared with TA (0.27–0.64 mg Peonidin-3,5-diglucoside/g powder db). TPC increased with fermentation and remain after spray drying. The AC and TPCs were highly correlated and had antioxidant capacity of 10.18 mg TE/g powder db. The principal component analysis showed that the type of milk and fermentation separate the powders in four groups, depending on their physical and antioxidant properties. Encapsulated pigments could be used in formulations in the food industry to increase bioactive compounds and pigments in foods.

Occurrence of Polyphenols, Isoflavonoids, and Their Metabolites in Milk Samples from Different Cow Feeding Regimens

In this work, milk samples collected in a cohort of intensive dairy farms of the Po Valley (Italy) were screened for their (poly)-phenolic profile to check the occurrence of phenolic metabolites of biological interest. The selected dairy farms were previously classified on the basis of their cow feeding system, considering the utilization of corn silage as the main ingredient of the rations. Overall, ultra-high-pressure liquid chromatography coupled with mass spectrometry using an Orbitrap analyzer, followed by unsupervised and supervised statistics, allowed identifying clear different phenolic distributions in the milk samples. Accordingly, a great variability in the phenolic profiles of the different milk samples was observed, with two main phenolic clusters outlined by the unsupervised hierarchical clustering approach and not fully correlated to the nutritional strategy considered. The variables’ importance in the projection approach allowed selecting the most important metabolites, resulting in samples’ discrimination. Among the most discriminative compounds, we found phenolic metabolites (such as hippuric acid and 4-hydroxyhippuric acid), followed by lignans (such as enterolactone) and isoflavonoids (such as equol and O-desmethylangolensin). Taken together, our findings suggested that both the feeding systems and the ability of dairy cows to process parent phenolic compounds were the main factors providing the final (poly)-phenolic profile of the milk samples. Future targeted and ad hoc studies appear of great interest to evaluate the potential biological effects of these compounds on cow health.

Effects of lingonberry extract (Vaccinium vitis-idaea L.) on the antioxidant, physicochemical and sensory characteristics of ice cream

In the present work, ice cream mixtures with 5%, 10% and 15% lingonberry extract were studied. The lingonberry (Vaccinium vitis-idaea L.) is a source of anthocyanins and flavonoids, which are the bioactive components with good antioxidant properties. There was a significant increase in antioxidant activity (p<0.05) from 133.3 ± 5.6 mM TE/100 g to 249.8 ± 8.3 mM TE/100 g (ABTS method) with increasing the concentration of the extract from 5% to 15%, respectively. Significant changes (p<0.05) in the acidity and dry matter of the samples with lingonberry extract were recorded. After 30 days of storage, a decrease in the antioxidant properties (p<0.05) of the ice cream samples was observed but higher values (mM TE/100 g) were maintained compared to the sample without extract. The color characteristics of the samples were also influenced by the concentration of the extract used. During storage, the highest stability of the colorimetric index a* (red component) was established, which indicates relative color stability during storage.

Polyphenols in Farm Animals: Source of Reproductive Gain or Waste?

Reproduction is a complex process that is substantially affected by environmental cues, specifically feed/diet and its components. Farm animals as herbivorous animals are exposed to a large amount of polyphenols present in their natural feeding system, in alternative feed resources (shrubs, trees, and agro-industrial byproducts), and in polyphenol-enriched additives. Such exposure has increased because of the well-known antioxidant properties of polyphenols. However, to date, the argumentation around the impacts of polyphenols on reproductive events is debatable. Accordingly, the intensive inclusion of polyphenols in the diets of breeding animals and in media for assisted reproductive techniques needs further investigation, avoiding any source of reproductive waste and achieving maximum benefits. This review illustrates recent findings connecting dietary polyphenols consumption from different sources (conventional and unconventional feeds) with the reproductive performance of farm animals, underpinned by the findings of in vitro studies in this field. This update will help in formulating proper diets, optimizing the introduction of new plant species, and feed additives for improving reproductive function, avoiding possible reproductive wastes and maximizing possible benefits.

In vitro metabolism of red clover isoflavones in rumen fluid

The degradation of red clover isoflavones was studied in vitro using a rumen fluid buffer system. Various amounts of red clover extract (5-75 mg) together with hay or concentrate-rich diet were added to 40 ml of rumen fluid obtained from non-lactating and lactating dairy cows, respectively, and incubated for 0, 3, 6, 12 or 24 hr. Following incubation, concentrations of daidzein, genistein, formononetin, biochanin A and equol were determined in the samples. After 3 hr of incubation, isoflavone metabolism and equol production could be observed. The results obtained indicate that hay diet provides better conditions for isoflavone metabolism, as concentrations of daidzein, formononetin and biochanin A were higher in incubations based on the concentrate-rich diet and the production of equol was higher in incubations based on the hay diet. Furthermore, in incubations with higher amounts of added clover extract, a decrease in equol production was observed. Further studies are needed to clarify the role of adaptation of rumen microflora on isoflavone degradation kinetics and to clarify the interrelationship between various dietary factors, rumen microbiota and isoflavones. The knowledge of isoflavone metabolism kinetics in dependence on studied factors will be useful for the optimization of feeding dose.

Chemical Composition of Commercial Cow's Milk

Bovine milk is a nutritionally rich, chemically complex biofluid consisting of hundreds of different components. While the chemical composition of cow's milk has been studied for decades, much of this information is fragmentary and very dated. In an effort to consolidate and update this information, we have applied modern, quantitative metabolomics techniques along with computer-aided literature mining to obtain the most comprehensive and up-to-date characterization of the chemical constituents in commercial cow's milk. Using nuclear magnetic resonance (NMR) spectroscopy, liquid chromatography-mass spectrometry (LC-MS), and inductively coupled plasma-mass spectrometry (ICP-MS), we were able to identify and quantify 296 bovine milk metabolites or metabolite species (corresponding to 1447 unique structures) from a variety of commercial milk samples. Through our literature analysis, we also found another 676 metabolites or metabolite species (corresponding to 908 unique structures). Detailed information regarding all 2355 of the identified chemicals in bovine milk have been made freely available through a Web-accessible database called the Milk Composition Database or MCDB ( http://www.mcdb.ca/ ).

In vitro and in vivo antioxidant potential of milks, yoghurts, fermented milks and cheeses: a narrative review of evidence

The antioxidant potential (AP) is an important nutritional property of foods, as increased oxidative stress is involved in most diet-related chronic diseases. In dairy products, the protein fraction contains antioxidant activity, especially casein. Other antioxidants include: antioxidant enzymes; lactoferrin; conjugated linoleic acid; coenzyme Q10; vitamins C, E, A and D3; equol; uric acid; carotenoids; and mineral activators of antioxidant enzymes. The AP of dairy products has been extensively studied in vitro, with few studies in animals and human subjects. Available in vivo studies greatly differ in their design and objectives. Overall, on a 100 g fresh weight-basis, AP of dairy products is close to that of grain-based foods and vegetable or fruit juices. Among dairy products, cheeses present the highest AP due to their higher protein content. AP of milk increases during digestion by up to 2·5 times because of released antioxidant peptides. AP of casein is linked to specific amino acids, whereas β-lactoglobulin thiol groups play a major role in the AP of whey. Thermal treatments such as ultra-high temperature processing have no clear effect on the AP of milk. Raw fat-rich milks have higher AP than less fat-rich milk, because of lipophilic antioxidants. Probiotic yoghurts and fermented milks have higher AP than conventional yoghurt and milk because proteolysis by probiotics releases antioxidant peptides. Among the probiotics, Lactobacillus casei/acidophilus leads to the highest AP. The data are insufficient for cheese, but fermentation-based changes appear to make a positive impact on AP. In conclusion, AP might participate in the reported dairy product-protective effects against some chronic diseases.

Multiclass analytical method for the determination of natural/synthetic steroid hormones, phytoestrogens, and mycoestrogens in milk and yogurt

Within this study, a new method enabling monitoring of various estrogenic substances potentially occurring in milk and dairy products was proposed. Groups of compounds fairly differing in physico-chemical properties and biological activity were analyzed: four natural estrogens, four synthetic estrogens, five mycoestrogens, and nine phytoestrogens. Since they may pass into milk mainly in glucuronated and sulfated forms, an enzymatic hydrolysis was involved prior to the extraction based on the QuEChERS methodology. For the purification of the organic extract, a dispersive solid-phase extraction (d-SPE) with sorbent C18 was applied. The final analysis was performed by ultra-high-performance liquid chromatography (UHPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS). Method recovery ranged from 70 to 120% with a relative standard deviation (RSD) value lower than 20% and limits of quantification (LOQs) in the range of 0.02-0.60 μg/L (0.2-6.0 μg/kg dry weight) and 0.02-0.90 μg/kg (0.2-6.0 μg/kg dry weight) for milk and yogurt, respectively. The new procedure was applied for the investigation of estrogenic compounds in 11 milk samples and 13 yogurt samples from a Czech retail market. Mainly phytoestrogens were found in the studied samples. The most abundant compounds were equol and enterolactone representing 40-90% of all estrogens. The total content of phytoestrogens (free and bound) was in the range of 149-3870 μg/kg dry weight. This amount is approximately 20 times higher compared to non-bound estrogens.

Changes in equol and major soybean isoflavone contents during processing and storage of yogurts made from control or isoflavone-enriched bovine milk determined using LC-MS (TOF) analysis

The effect of supplementing a basal diet for dairy cows with "Soybean extract 40" (Biomedica, Prague, Czech Republic), containing 40% soybean isoflavones, on the contents of daidzein, glycitein, genistein, and equol in milk as well as fresh and mature yogurts was estimated. To determine the contents of these isoflavonoids, an efficient analytical LC-MS (TOF) technique was used. The "Soybean extract 40" used in our study contained an especially high proportion of daidzein (307gkg-1). In both milk and yogurt samples, the amounts of daidzein and its metabolite equol were significantly higher in samples obtained from cows that received the isoflavone extract-supplemented diet than from those that received the basal diet, as the precursor daidzein contributed to the increased equol concentrations. Fermentation caused significant changes in the daidzein and glycitein concentrations. With maturation, the concentrations of daidzein and equol were unaffected, while the glycitein concentration decreased significantly.