An assessment of voltammetry on disposable screen printed electrodes to predict wine chemical composition and oxygen consumption rates.

The present work aimed at determining the applicability of linear sweep voltammetry coupled to disposable carbon paste electrodes to predict chemical composition and wine oxygen consumption rates (OCR) by PLS-modeling of the voltammetric signal. Voltammetric signals were acquired in a set of 16 red commercial wines. Samples were extensively characterized including SO2, antioxidant indexes, metals and polyphenols measured by HPLC. Wine OCRs were calculated by measuring oxygen consumption under controlled oxidation conditions. PLS-Regression models were calculated to predict chemical variables and wine OCRs from first order difference voltammogram curves. A significant number of fully validated models predicting chemical variables from voltammetric signals were obtained. Interestingly, monomeric and polymerized anthocyanins can be differently predicted from the first and second wave of the first derivative of voltammograms, respectively. This fast, cheap and easy-to-use approach presents an important potential to be used in wineries for rapid wine chemical characterization.

SO-PLS as an alternative approach for handling multi-dimensionality in modelling different aspects of consumer expectations.

In the development of sensory and consumer science, data are often collected in several blocks responding to different aspects of consumer experience. Sometimes the task of organizing the data and explaining their relation is non-trivial, especially when considering structural (casual) relationship between data sets. In this sense, PLS path modelling (PLS-PM) has been found as a good tool to model such relations, but this approach faces some issues regarding the assumption of uni-dimensionality of consumers' data blocks. Sequential Orthogonalised PLS path modelling (SO-PLS-PM) has been proposed as an alternative approach to handle the multi-dimensionality and to explain the relations between the original data blocks without any preprocessing of the data. This study aims at comparing the efficacy of SO-PLS-PM and PLS-PM (together with splitting blocks into uni-dimensional sub-blocks) for handling multi-dimensionality. Data sets from two satiety perception studies (yoghurt, biscuit) have been used as illustrations. The main novelty of this paper lies in underlining and solving a major, but little studied problem, related to the assumption of one-dimensional blocks in PLS-PM. The findings from the comparisons indicated that the two approaches (PLS-PM and SO-PLS-PM) highlighted the same main trends for the less complex samples (yoghurt samples): liking was the essential driver of satiation perception and portion size selection; while satiation mainly predicted satiety perception. For the more complex data set - from a sensory perspective - (biscuit samples), the relations between data blocks in PLS-PM model was difficult to interpret, whereas they were well explained by SO-PLS-PM. This underlines the ability of SO-PLS-PM to model multi-dimensional data sets without requiring any preprocessing steps.

Sample-Specific Prediction Error Measures in Spectroscopy.

In applied spectroscopy, the purpose of multivariate calibration is almost exclusively to relate analyte concentrations and spectroscopic measurements. The multivariate calibration model provides estimates of analyte concentrations based on the spectroscopic measurements. Predictive performance is often evaluated based on a mean squared error. While this average measure can be used in model selection, it is not satisfactory for evaluating the uncertainty of individual predictions. For a calibration, the uncertainties are sample specific. This is especially true for multivariate calibration, where interfering compounds may be present. Consider in-line spectroscopic measurements during a chemical reaction, production, etc. Here, reference values are not necessarily available. Hence, one should know the uncertainty of a given prediction in order to use that prediction for telling the state of the chemical reaction, adjusting the process, etc. In this paper, we discuss the influence of variance and bias on sample-specific prediction errors in multivariate calibration. We compare theoretical formulae with results obtained on experimental data. The results point towards the fact that bias contribution cannot necessarily be neglected when assessing sample-specific prediction ability in practice.

Application of sequential and orthogonalised-partial least squares (SO-PLS) regression to predict sensory properties of Cabernet Sauvignon wines from grape chemical composition.

The current study determined the applicability of sequential and orthogonalised-partial least squares (SO-PLS) regression to relate Cabernet Sauvignon grape chemical composition to the sensory perception of the corresponding wines. Grape samples (n = 25) were harvested at a similar maturity and vinified identically in 2013. Twelve measures using various (bio)chemical methods were made on grapes. Wines were evaluated using descriptive analysis with a trained panel (n = 10) for sensory profiling. Data was analysed globally using SO-PLS for the entire sensory profiles (SO-PLS2), as well as for single sensory attributes (SO-PLS1). SO-PLS1 models were superior in validated explained variances than SO-PLS2. SO-PLS provided a structured approach in the selection of predictor chemical data sets that best contributed to the correlation of important sensory attributes. This new approach presents great potential for application in other explorative metabolomics studies of food and beverages to address factors such as quality and regional influences.

Projective mapping based on choice or preference: An affective approach to projective mapping.

This work explores a new affective approach to projective mapping, based on consumers' choices or preferences. Two sessions, one week apart, were performed with the same consumers, using whole bread as a case study. Overall liking ratings (OL) were gathered in blind conditions and samples were also profiled by a trained panel using generic descriptive analysis. Three projective mapping tests were performed in different scenarios. Consumers' categorization and product descriptions were explored when consumers based their positioning on the products' similarities and differences (analytical approach, "classic napping") both in blind and informed conditions, and when consumers were focusing on their preference or choice (affective approach). The affective approach to projective mapping successfully revealed consumers' drivers of liking and choice from a holistic perspective, where consumers summarized their main drivers for categorizing products as they would do when choosing in real life situations, based on their preferences.

Exploration of consumer perception of Sauvignon Blanc wines with enhanced aroma properties using two different descriptive methods.

The aim of this study was to evaluate consumers' perception of a complex set of stimuli as aromatically enriched wines. For that, two consumer based profiling methods were compared, concurrently run with overall liking measurements: projective mapping based on choice or preference (PM-C), a newly proposed method, and check-all-that-apply (CATA) questions with an ideal sample, a more established, consumer-based method for product optimization. Reserve bottling and regular bottling of Sauvignon Blanc wines from three wineries were aromatically enriched with natural aromas collected by condensation during wine fermentation. A total of 144 consumers were enrolled in the study. The results revealed that both consumer-based highlighted the positive effect of aromatic enrichment on consumer perception and acceptance. However, PM-C generated a very detailed description, in which consumers focused less on the sensory aspects and more on the usage, attitudes, and reasons behind their choices. Providing a deeper understanding of the drivers of liking/disliking of enriched Sauvignon Blanc wines.

Validation of projective mapping as potential sensory screening tool for application by the honeybush herbal tea industry.

Honeybush herbal tea is produced from the endemic South African Cyclopia species. Plant material subjected to a high-temperature oxidation step ("fermentation") forms the bulk of production. Production lags behind demand forcing tea merchants to use blends of available material to supply local and international markets. The distinct differences in the sensory profiles of the herbal tea produced from the different Cyclopia species require that special care is given to blending to ensure a consistent, high quality product. Although conventional descriptive sensory analysis (DSA) is highly effective in providing a detailed sensory profile of herbal tea infusions, industry requires a method that is more time- and cost-effective. Recent advances in sensory science have led to the development of rapid profiling methodologies. The question is whether projective mapping can successfully be used for the sensory characterisation of herbal tea infusions. Trained assessors performed global and partial projective mapping to determine the validity of this technique for the sensory characterisation of infusions of five Cyclopia species. Similar product configurations were obtained when comparing results of DSA and global and partial projective mapping. Comparison of replicate sessions showed RV coefficients >0.8. A similarity index, based on multifactor analysis, was calculated to determine assessor repeatability. Global projective mapping, demonstrated to be a valid method for providing a broad sensory characterisation of Cyclopia species, is thus suitable as a rapid quality control method of honeybush infusions. Its application by the honeybush industry could improve the consistency of the sensory profile of blended products.

Making sense of the "clean label" trends: A review of consumer food choice behavior and discussion of industry implications.

Consumers in industrialized countries are nowadays much more interested in information about the production methods and components of the food products that they eat, than they had been 50years ago. Some production methods are perceived as less "natural" (i.e. conventional agriculture) while some food components are seen as "unhealthy" and "unfamiliar" (i.e. artificial additives). This phenomenon, often referred to as the "clean label" trend, has driven the food industry to communicate whether a certain ingredient or additive is not present or if the food has been produced using a more "natural" production method (i.e. organic agriculture). However, so far there is no common and objective definition of clean label. This review paper aims to fill the gap via three main objectives, which are to a) develop and suggest a definition that integrates various understandings of clean label into one single definition, b) identify the factors that drive consumers' choices through a review of recent studies on consumer perception of various food categories understood as clean label with the focus on organic, natural and 'free from' artificial additives/ingredients food products and c) discuss implications of the consumer demand for clean label food products for food manufacturers as well as policy makers. We suggest to define clean label, both in a broad sense, where consumers evaluate the cleanliness of product by assumption and through inference looking at the front-of-pack label and in a strict sense, where consumers evaluate the cleanliness of product by inspection and through inference looking at the back-of-pack label. Results show that while 'health' is a major consumer motive, a broad diversity of drivers influence the clean label trend with particular relevance of intrinsic or extrinsic product characteristics and socio-cultural factors. However, 'free from' artificial additives/ingredients food products tend to differ from organic and natural products. Food manufacturers should take the diversity of these drivers into account in developing new products and communication about the latter. For policy makers, it is important to work towards a more homogenous understanding and application of the term of clean label and identify a uniform definition or regulation for 'free from' artificial additives/ingredients food products, as well as work towards decreasing consumer misconceptions. Finally, multiple future research avenues are discussed.

Influence of consumers' cognitive style on results from projective mapping.

Projective mapping (PM), one of the most holistic product profiling methods in approach, is increasingly being used to uncover consumers' perception of products and packages. Assessors rely on a process of synthesis for evaluating product information, which would determine the relative importance of the perceived characteristics they use for mapping them. Individual differences are expected, as participants are not instructed on the characteristics to consider for evaluating the degree of difference among samples, generating different perceptual spaces. Individual differences in cognitive style can affect synthesis processes and thus their perception of similarities and differences among samples. In this study, the influence of the cognitive style in the results of PM was explored. Two consumer studies were performed, one aimed at describing intrinsic sensory characteristics of chocolate flavoured milk and the other one looking into extrinsic (package only) of blueberry yogurts. Consumers completed the wholistic-analytic module of the extended Verbal Imagery Cognitive Styles Test & Extended Cognitive Style Analysis-Wholistic Analytic Test, to characterize their cognitive style. Differences between wholistic and analytic consumers in how they evaluated samples using projective mapping were found in both studies. Analytics separated the samples more in the PM perceptual space than wholistic consumers, showing more discriminating abilities. This may come from a deeper analysis of the samples, both from intrinsic and extrinsic point of views. From a sensory perspective (intrinsic), analytic consumers relied on more sensory characteristics, while wholistic mainly discriminated samples according to sweetness and bitterness/chocolate flavour. In the extrinsic study however, even if analytic consumers discriminated more between packs, they described the products using similar words in the descriptive step. One important recommendation coming from this study is the need to consider higher dimensions in the interpretation of projective mapping tasks, as the first dimensions could underestimate the complexity of the perceptual space; currently, most applications of PM consider two dimensions only, which may not uncover the perception of specific groups of consumers.

Maternal psychological responses during pregnancy after ultrasonographic detection of structural fetal anomalies: A prospective longitudinal observational study.

In this longitudinal prospective observational study performed at a tertiary perinatal referral centre, we aimed to assess maternal distress in pregnancy in women with ultrasound findings of fetal anomaly and compare this with distress in pregnant women with normal ultrasound findings. Pregnant women with a structural fetal anomaly (n = 48) and normal ultrasound (n = 105) were included. We administered self-report questionnaires (General Health Questionnaire-28, Impact of Event Scale-22 [IES], and Edinburgh Postnatal Depression Scale) a few days following ultrasound detection of a fetal anomaly or a normal ultrasound (T1), 3 weeks post-ultrasound (T2), and at 30 (T3) and 36 weeks gestation (T4). Social dysfunction, health perception, and psychological distress (intrusion, avoidance, arousal, anxiety, and depression) were the main outcome measures. The median gestational age at T1 was 20 and 19 weeks in the group with and without fetal anomaly, respectively. In the fetal anomaly group, all psychological distress scores were highest at T1. In the group with a normal scan, distress scores were stable throughout pregnancy. At all assessments, the fetal anomaly group scored significantly higher (especially on depression-related questions) compared to the normal scan group, except on the IES Intrusion and Arousal subscales at T4, although with large individual differences. In conclusion, women with a known fetal anomaly initially had high stress scores, which gradually decreased, resembling those in women with a normal pregnancy. Psychological stress levels were stable and low during the latter half of gestation in women with a normal pregnancy.

Reduced risk of pre-eclampsia with organic vegetable consumption: results from the prospective Norwegian Mother and Child Cohort Study.

OBJECTIVE: Little is known about the potential health effects of eating organic food either in the general population or during pregnancy. The aim of this study was to examine associations between organic food consumption during pregnancy and the risk of pre-eclampsia among nulliparous Norwegian women. DESIGN: Prospective cohort study. SETTING: Norway, years 2002-2008. PARTICIPANTS: 28 192 pregnant women (nulliparous, answered food frequency questionnaire and general health questionnaire in mid-pregnancy and no missing information on height, body weight or gestational weight gain). MAIN OUTCOME MEASURE: Relative risk was estimated as ORs by performing binary logistic regression with pre-eclampsia as the outcome and organic food consumption as the exposure. RESULTS: The prevalence of pre-eclampsia in the study sample was 5.3% (n=1491). Women who reported to have eaten organic vegetables 'often' or 'mostly' (n=2493, 8.8%) had lower risk of pre-eclampsia than those who reported 'never/rarely' or 'sometimes' (crude OR=0.76, 95% CI 0.61 to 0.96; adjusted OR=0.79, 95% CI 0.62 to 0.99). The lower risk associated with high organic vegetable consumption was evident also when adjusting for overall dietary quality, assessed as scores on a healthy food pattern derived by principal component analysis. No associations with pre-eclampsia were found for high intake of organic fruit, cereals, eggs or milk, or a combined index reflecting organic consumption. CONCLUSIONS: These results show that choosing organically grown vegetables during pregnancy was associated with reduced risk of pre-eclampsia. Possible explanations for an association between pre-eclampsia and use of organic vegetables could be that organic vegetables may change the exposure to pesticides, secondary plant metabolites and/or influence the composition of the gut microbiota.

Paternal psychological response after ultrasonographic detection of structural fetal anomalies with a comparison to maternal response: a cohort study.

BACKGROUND: In Norway almost all pregnant women attend one routine ultrasound examination. Detection of fetal structural anomalies triggers psychological stress responses in the women affected. Despite the frequent use of ultrasound examination in pregnancy, little attention has been devoted to the psychological response of the expectant father following the detection of fetal anomalies. This is important for later fatherhood and the psychological interaction within the couple. We aimed to describe paternal psychological responses shortly after detection of structural fetal anomalies by ultrasonography, and to compare paternal and maternal responses within the same couple. METHODS: A prospective observational study was performed at a tertiary referral centre for fetal medicine. Pregnant women with a structural fetal anomaly detected by ultrasound and their partners (study group,n=155) and 100 with normal ultrasound findings (comparison group) were included shortly after sonographic examination (inclusion period: May 2006-February 2009). Gestational age was >12 weeks. We used psychometric questionnaires to assess self-reported social dysfunction, health perception, and psychological distress (intrusion, avoidance, arousal, anxiety, and depression): Impact of Event Scale. General Health Questionnaire and Edinburgh Postnatal Depression Scale. Fetal anomalies were classified according to severity and diagnostic or prognostic ambiguity at the time of assessment. RESULTS: Median (range) gestational age at inclusion in the study and comparison group was 19 (12-38) and 19 (13-22) weeks, respectively. Men and women in the study group had significantly higher levels of psychological distress than men and women in the comparison group on all psychometric endpoints. The lowest level of distress in the study group was associated with the least severe anomalies with no diagnostic or prognostic ambiguity (p < 0.033). Men had lower scores than women on all psychometric outcome variables. The correlation in distress scores between men and women was high in the fetal anomaly group (p < 0.001), but non-significant in the comparison group. CONCLUSION: Severity of the anomaly including ambiguity significantly influenced paternal response. Men reported lower scores on all psychometric outcomes than women. This knowledge may facilitate support for both expectant parents to reduce strain within the family after detectionof a fetal anomaly.

The relationships between consumer liking, sensory and chemical attributes of Vitis vinifera L. cv. Pinotage wines elaborated with different Oenococcus oeni starter cultures.

BACKGROUND: Malolactic fermentation (MLF) mediated by lactic acid bacteria (LAB) has been shown to modulate chemical and sensory attributes of wine. This study investigated the relation between consumer liking, chemical and sensory attributes of Vitis vinifera L. cv. Pinotage wines that were made over two vintages by four different lactic acid Oenococcus oeni starter cultures as well as a control treatment where MLF was prevented. RESULTS: Descriptive analysis showed that the sensory attributes buttery, caramel, vegetative flavour, fruity and nutty aroma differed significantly between the wines. These effects on the wines were not the same for the two vintages tested. Preference mapping results showed that the sensory attributes influenced the average consumer liking. The main chemical and sensory correlations found for MLF-treated wines were related to 2,3-butanedione (diacetyl) with the buttery character and various esters with fruity aromas. CONCLUSION: Although the direct effect of the bacterial starter cultures on wine sensory attributes is difficult to establish, and subject to variation over vintage, the present work suggests that the contribution of LAB starter cultures to wine sensory attributes can influence consumer liking. Selection of an MLF starter culture can thus potentially be used to develop specific wine styles.

Food patterns and dietary quality associated with organic food consumption during pregnancy; data from a large cohort of pregnant women in Norway.

BACKGROUND: Little is known about the consumption of organic food during pregnancy. The aim of this study was to describe dietary characteristics associated with frequent consumption of organic food among pregnant women participating in the Norwegian Mother and Child Cohort Study (MoBa). METHODS: The present study includes 63 808 women who during the years 2002-2007 answered two questionnaires, a general health questionnaire at gestational weeks 15 and a food frequency questionnaire at weeks 17-22. The exploration of food patterns by Principal component analyses (PCA) was followed by ANOVA analyses investigating how these food patterns as well as intake of selected food groups were associated with consumption of organic food. RESULTS: The first principal component (PC1) identified by PCA, accounting for 12% of the variation, was interpreted as a 'health and sustainability component', with high positive loadings for vegetables, fruit and berries, cooking oil, whole grain bread and cereal products and negative loadings for meat, including processed meat, white bread, and cakes and sweets. Frequent consumption of organic food, which was reported among 9.1% of participants (n = 5786), was associated with increased scores on the 'health and sustainability component' (p < 0.001). The increase in score represented approximately 1/10 of the total variation and was independent of sociodemographic and lifestyle characteristics. Participants with frequent consumption of organic food had a diet with higher density of fiber and most nutrients such as folate, beta-carotene and vitamin C, and lower density of sodium compared to participants with no or low organic consumption. CONCLUSION: The present study showed that pregnant Norwegian women reporting frequent consumption of organically produced food had dietary pattern and quality more in line with public advice for healthy and sustainable diets. A methodological implication is that the overall diet needs to be included in future studies of potential health outcomes related to consumption of organic food during pregnancy.

Lamb meat--importance of origin and grazing system for Italian and Norwegian consumers.

The objective of this study was to evaluate the importance of geographic origin and grazing system for Norwegian and Italian consumers' probability of buying lamb meat. The study consisted of a qualitative part with focus groups followed up with a quantitative survey in each country. Included in the survey was a conjoint design with origin of the meat (Norway, Italy and New Zealand) and pasture (lowland pasture and mountain pasture) as factors, plus questions about consumers' motives underlying selection of food. Results from the study shows that country of origin is important for consumers' buying probability of lamb meat, in both countries domestic meat was preferred. In addition, a higher probability of buying meat from lamb grazing on mountain pasture than from lamb grazing on lowland pasture was identified. It is important for producers of lamb meat to increase the communication of these elements in a competitive national and international food market.

The relation of psychological distress to salivary and serum cortisol levels in pregnant women shortly after the diagnosis of a structural fetal anomaly.

OBJECTIVE: To examine the association between psychological distress and levels of salivary cortisol (SalC) and the ratio of serum cortisol to cortisol-binding globulin (SC/CBG) in pregnant women shortly after the diagnosis of a structural fetal anomaly. DESIGN. A prospective, observational study. SETTING: Tertiary referral center for fetal medicine. POPULATION: Pregnant women with (study group, n=126) and without a fetal structural anomaly (comparison group, n=106) were included. Gestational age (GA) was >12weeks. METHODS: Psychological distress was assessed by Impact of Event Scale (IES-22), General Health Questionnaire (GHQ-28) and Edinburgh Postnatal Depression Scale (EPDS). Salivary cortisol was measured in the evening and SC/CBG in the morning. MAIN OUTCOME MEASURES. Levels of SalC (in nanomoles per liter) and SC/CBG. RESULTS: Median (range) GA at assessment was 19 (12-38) and 19 (13-22)weeks in the study and the comparison group, respectively. The study group had significantly higher psychological distress levels (p≤0.001) than the comparison group in all outcome measures. Salivary cortisol correlated with GA in both groups (p<0.004). In subanalyses including only women with GA 18-22 weeks, and excluding smokers or women with chronic diseases or medication which might interfere with cortisol levels, there were no relations of SalC or SC/CBG with the psychometric variables in the study group. CONCLUSIONS. Women with detected fetal malformation had high psychological distress scores. The lack of association between psychological distress and SalC or SC/CBG suggests a blunted response of the hypothalamic-pituitary-adrenal axis following recent psychological stress activation in the second trimester of pregnancy.

Consumers' acceptance of innovations in traditional cheese. A comparative study in France and Norway.

This study explores consumers' acceptance of innovations in traditional cheese in France (n=120) and Norway (n=119). The respondents were presented with 16 photographs of a traditional cheese from their respective countries, varying according to six factors: pasteurisation, organic production, omega-3, packaging, price and appropriateness. For each of the scenarios the consumers indicated their willingness to buy the cheese on a nine-point scale. Results show that consumers' willingness to buy traditional cheese is highly driven by price, appropriateness and pasteurisation in both countries. However, on average consumers in the French sample prefer buying raw milk cheese, while consumers in the Norwegian sample prefer buying pasteurised cheese. These general trends are led by a pro-raw milk segment in France and a pro-pasteurised milk segment in Norway. Several interaction effects involving appropriateness are detected, indicating the importance of the consumption context on the acceptance of innovations in traditional cheese. On a general level, the results indicate that well-accepted innovations in traditional cheese are those that reinforce the traditional and authentic character of the product.

Consumers liking of private labels. An evaluation of intrinsic and extrinsic orange juice cues.

The objective of this article is to compare product quality and brand choice for private labels (PL) and national brands (NB). Over the past two decades, PL have gained larger and larger share of grocery sales, and nowadays PL play a crucial part in the European food retail sector. Since it is stated that most PL have moved on from being mostly low cost me-too products to become also premium products, we want to investigate if objective and perceived quality of PL fits the quality of NB. Four hypotheses are stated and tested on orange juice data from Norway. A trained sensory panel and consumers (n=105) evaluated six juice samples that vary according to three factors. These factors were (1) Brand (PL and NB), (2) Treatment (Gentle heat treatment and Pasteurized) and (3) Pulp (with and without). Principal component analysis, two-way ANOVA, and PLS regression were conducted, and the results indicate that variation in quality exists both among PL and NB, there is a large discrepancy between blind liking and brand choice, and that consumers with a positive attitude towards PL are more likely to choose a PL instead of a NB.

Motivation for choice and healthiness perception of calorie-reduced dairy products. a cross-cultural study.

Understanding consumers' motives for selecting calorie-reduced dairy products are important to provide targeted communication to different consumer segments. The aim of this study was to identify motives for consumption of calorie-reduced dairy products among young consumers, and to identify how these consumers perceive the healthiness of such products compared to other food products. Consumers, aged 18-30 years, from Norway (n=118), Denmark (n=125), and California (n=127) participated in this cross-cultural study. The respondents sorted 24 statements referring to motives for choosing calorie-reduced yoghurt and cheese. The study also assessed the aspect of perceived healthiness of these products in comparison with a selection of other food products using a two-step ranking procedure. The data were analysed using chi-square analysis, Friedman's test and Principal Component Analysis (PCA). The results show that fat content, healthiness and taste were the most important motivators for choice of the calorie-reduced dairy products. In all three countries salmon was perceived as the healthiest among the products presented. The calorie-reduced dairy products were ranked as relatively healthy, with yoghurt ranked as healthier than cheese. Although cross-cultural differences existed in motives for choice and perceived healthiness of the products, the similarities between the countries were evident in this study.

Unveiling an abundant core microbiota in the human adult colon by a phylogroup-independent searching approach.

The potential presence of widespread and stable bacterial core phylogroups in the human colon has promoted considerable attention. Despite major efforts, no such phylogroups have yet been identified. Therefore, using a novel phylogroup- and tree-independent approach, we present a reanalysis of 1,114,722 V2 region and 71,550 near full-length 16S rRNA sequences from a total of 210 human beings, with widespread geographic origin, ethnic background and diet, in addition to a wide range of other mammals. We found two highly prevalent core phylogroups (cores 1 and 2), belonging to the clostridial family Lachnospiraceae. These core phylogroups showed a log-normal distribution among human individuals, while non-core phylogroups showed more skewed distributions towards individuals with low levels compared with the log-normal distribution. Molecular clock analyses suggest that core 2 co-evolved with the radiation of vertebrates, while core 1 co-evolved with the mammals. Taken together, the stability, prevalence and potential functionality support the fact that the identified core phylogroups are pivotal in maintaining gut homeostasis and health.