Why is it important to understand the nature and chemistry of tannins to exploit their potential as nutraceuticals?

Tannins comprise a large group of polyphenols that can differ widely in chemical composition and molecular weight. The use of tannins dates back to antiquity, but it is only in recent years that their potential use as nutraceuticals associated with the human diet is beginning to be exploited. Although the biological effects of these phytocomplexes have been studied for many years, there are still several open questions regarding their chemistry and biotransformation. The vastness of the molecules that make up the class of tannins has made their characterisation, as well as their nomenclature and classification, a daunting task. This review has been written with the aim of bringing order to the chemistry of tannins by including aspects that are sometimes still overlooked or should be updated with new research in order to understand the potential of these phytocomplexes as active ingredients or technological components for nutraceutical products. Future trends in tannin research should address many questions that are still open, such as determining the exact biosynthetic pathways of all classes of tannins, the actual biological effects determined by the interaction of tannins with other molecules, their metabolization, and the best extraction methods, but with a view to market requirements.

Cronobacter spp. in foods of plant origin: occurrence, contamination routes, and pathogenic potential

Cronobacter is an emerging bacterial pathogen associated with infections such as necrotizing enterocolitis, sepsis, and meningitis in neonates and infants, related to the consumption of powdered infant formula. In addition, this bacterium can also cause infections in adults by the ingestion of other foods. Thus, this review article aims to report the occurrence and prevalence of Cronobacter spp. in foods of plant origin, as well as the possible sources and routes of contamination in these products, and the presence of pathogenic strains in these foods. Cronobacter was present in a wide variety of cereal-based foods, vegetables, herbs, spices, ready-to-eat foods, and foods from other categories. This pathogen was also found in cultivation environments, such as soils, compost, animal feces, rice and vegetable crops, as well as food processing industries, and domestic environments, thus demonstrating possible contamination routes. Furthermore, sequence types (ST) involved in clinical cases and isolates resistant to antibiotics were found in Cronobacter strains isolated from food of plant origin. The identification of Cronobacter spp. in plant-based foods is of great importance to better elucidate the vehicles and routes of contamination in the primary production chain and processing facility, until the final consumption of the food, to prevent infections.

Plant-based diet indices and lipoprotein particle subclass profiles: A cross-sectional analysis of middle- to older-aged adults

BACKGROUND AND AIMS

Plant-based diets (PBDs) are associated with favourable lipid profiles and cardiometabolic outcomes. However, limited data regarding PBD indices (PDIs) and lipoprotein subclasses exist. We examined overall PDI, healthful PDI (hPDI) and unhealthful PDI (uPDI) associations with lipid and lipoprotein profiles.

METHODS

This cross-sectional analysis includes 1,986 middle- to older-aged adults from the Mitchelstown Cohort. The PDI, hPDI and uPDI scores were calculated from validated food frequency questionnaires. Higher PDI, hPDI and uPDI scores indicate a more PBD, healthful PBD and unhealthful PBD, respectively. Lipoprotein particle size and subclass concentrations were measured using nuclear magnetic resonance spectroscopy. Relationships between PDIs and lipid and lipoprotein profiles were examined via correlation and regression analyses adjusted for covariates.

RESULTS

In fully adjusted regression analyses, higher PDI scores were associated with lower high-density lipoprotein (HDL) cholesterol concentrations and more triglyceride-rich lipoprotein and small very low-density lipoprotein (VLDL) particles. Higher hPDI scores were negatively associated with non-HDL cholesterol concentrations, large VLDL and small HDL particles, the Lipoprotein Insulin Resistance Index (LP-IR) score and VLDL particle size. Higher uPDI scores were associated with lower HDL cholesterol and greater triglyceride concentrations and more medium and large VLDL, total LDL, small LDL and total non-HDL particles, less large LDL and large HDL particles, a greater LP-IR score, greater VLDL particle size and smaller LDL and HDL particle size.

CONCLUSIONS

This study provides novel evidence regarding associations between PBD quality and lipoprotein subclasses. A more unhealthful PBD was robustly associated with a more pro-atherogenic lipoprotein profile.

Enhancement of Antioxidant Properties of the Medicinal Plant, Costus Pictus by Optimization of its Drying and Extraction Criteria

Antioxidants act as major protective factors against different infections and diseases. The search for natural antioxidants has gained significant momentum due to its associated health benefits. It prompted the investigation of the antioxidant properties of widely recognized medicinal plants, considering their prominent role in conventional medicine. The incorporation of natural antioxidants derived from medicinal plants into food products has the potential to enhance their health benefits. The present investigation is the first study on the optimization of drying and extraction techniques in Costus pictus leaves. C. pictus leaves were dried under varying conditions (40, 50 and 60 °C) and dried powders were subjected to various solvents, namely water, ethanol, methanol and ethyl acetate. The leaves dried at 60 °C and treated with ethanol showed improved activities and were subsequently selected for further extraction. Among the various extraction methods, ultrasound-assisted extraction demonstrated superior antioxidant properties and increased phytochemical contents, making it the optimal technique for our study. Fourier transform infrared spectroscopy (FTIR) reports also substantiated these quantitative results. The extraction process played a significant role in enhancing the desirable attributes and properties of the leaf extracts, surpassing the results obtained from both dried and fresh leaves. The application of liquid chromatography-mass spectrometry (LC-MS) analysis to the leaf extracts facilitated the identification of phenolic compounds and flavonoids, presenting a comprehensive insight into the composition of the extract. Exploration of antioxidant properties, phenolic compounds and flavonoids would validate the benefits and expand the applications of C. pictus in functional foods and nutraceuticals.

Development, optimization, and validation of a method for detection of cartap, thiocyclam, thiosultap-monosodium, and thiosultap-disodium residues in plant foods by GC-ECD

A method was developed for the simultaneous determination of four nereistoxin-related pesticides, viz. cartap, thiocyclam, thiosultap-monosodium, and thiosultap-disodium, in 20 plant foods. The samples were extracted using a hydrochloric acid solution containing cysteine hydrochloride, derivatized to nereistoxin under alkaline conditions, and analyzed by gas chromatography with electron capture detector. The average recoveries of the method were 72-108%, with relative standard deviations (RSDs) of 0.3-14.7% (n = 1200, p < 0.05). The intermediate precision and reproducibility experiments using established methods were also carried out. All the results passed the Cochrane and Grubbs tests (n = 2400, p < 0.05). The RSDs of intermediate precision and RSDs of reproducibility among laboratories were in the ranges 1.7-10.9% and 2.4-15.3% (n = 2400, p < 0.05), respectively, indicating that the accuracy and precision of the method are satisfactory. This method can be used to detect nereistoxin-related pesticides in plant foods.

Hemp and buckwheat are valuable sources of dietary amino acids, beneficially modulating gastrointestinal hormones and promoting satiety in healthy volunteers

Purpose

This study evaluated the postprandial effects following consumption of buckwheat, fava bean, pea, hemp and lupin compared to meat (beef); focussing on biomarkers of satiety, gut hormones, aminoacids and plant metabolites bioavailability and metabolism.

Methods

Ten subjects (n = 3 men; n = 7 women; 42 ± 11.8 years of age; BMI 26 ± 5.8 kg/m²) participated in six 1-day independent acute interventions, each meal containing 30 g of protein from buckwheat, fava bean, pea, hemp, lupin and meat (beef). Blood samples were collected during 24-h and VAS questionnaires over 5-h.

Results

Volunteers consumed significantly higher amounts of most amino acids from the meat meal, and with few exceptions, postprandial composition of plasma amino acids was not significantly different after consuming the plant-based meals. Buckwheat meal was the most satious (300 min hunger scores, p < 0.05).Significant increase in GLP-1 plasma (AUC, iAUC p = 0.01) found after hemp compared with the other plant-based meals. Decreased plasma ghrelin concentrations (iAUC p < 0.05) found on plant (hemp) vs. meat meal. Several plasma metabolites after hemp meal consumption were associated with hormone trends (partial least squares-discriminant analysis (PLS-DA): 4-hydroxyphenylpyruvic acid, indole 3-pyruvic acid, 5-hydoxytryptophan, genistein and biochanin A with GLP-1, PYY and insulin; 3-hydroxymandelic acid and luteolidin with GLP-1 and ghrelin and 4-hydroxymandelic acid, benzoic acid and secoisolariciresinol with insulin and ghrelin. Plasma branched-chain amino acids (BCAAs), (iAUC, p < 0.001); and phenylalanine and tyrosine (iAUC, p < 0.05) were lower after buckwheat comparison with meat meal.

Conclusion

Plants are valuable sources of amino acids which are promoting satiety. The impact of hemp and buckwheat on GLP-1 and, respectively, BCAAs should be explored further as could be relevant for aid and prevention of chronic diseases such as type 2 diabetes.

Study registered with clinicaltrial.gov on 12th July 2013, study ID number: NCT01898351.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02711-z.

Why interindividual variation in response to consumption of plant food bioactives matters for future personalised nutrition

Food phytochemicals are increasingly considered to play a key role in the cardiometabolic health effects of plant foods. However, the heterogeneity in responsiveness to their intake frequently observed in clinical trials can hinder the beneficial effects of these compounds in specific subpopulations. A range of factors, including genetic background, gut microbiota, age, sex and health status, could be involved in these interindividual variations; however, the current knowledge is limited and fragmented. The European network, European Cooperation in Science and Technology (COST)-POSITIVe, has analysed, in a systematic way, existing knowledge with the aim to better understand the factors responsible for the interindividual variation in response to the consumption of the major families of plant food bioactives, regarding their bioavailability and bioefficacy. If differences in bioavailability, likely reflecting differences in human subjects' genetics or in gut microbiota composition and functionality, are believed to underpin much of the interindividual variability, the key molecular determinants or microbial species remain to be identified. The systematic analysis of published studies conducted to assess the interindividual variation in biomarkers of cardiometabolic risk suggested some factors (such as adiposity and health status) as involved in between-subject variation. However, the contribution of these factors is not demonstrated consistently across the different compounds and biological outcomes and would deserve further investigations. The findings of the network clearly highlight that the human subjects' intervention studies published so far are not adequate to investigate the relevant determinants of the absorption/metabolism and biological responsiveness. They also emphasise the need for a new generation of intervention studies designed to capture this interindividual variation.

Contribution of plant food bioactives in promoting health effects of plant foods: why look at interindividual variability?

Purpose

Research has identified plant-based diets as the most protective for our health; it is now essential to focus on good food associations and the beneficial constituents in plant foods. From a growing body of evidence, some categories of food phytochemicals are increasingly considered to play a crucial role in the cardiometabolic health effects associated with plant food consumption. However, the heterogeneity in responsiveness to plant food bioactive intake that is frequently observed in clinical trials can hinder the identification of the effects of these compounds in specific subpopulations and likely lead to underestimating their actual contribution to the health effects of their food sources.

Results

The magnitude and the main factors responsible for this between-subject variation in response to the consumption of the major families of food phytochemicals have been poorly documented so far. Thus, research efforts in this area must be developed. More importantly, capturing the interindividual variability in response to plant food bioactive intake, together with identifying the main determinants involved, is a crucial step that will enable the development and production of plant food products, thereby satisfying the nutritional needs and conferring benefits to different categories of populations.

Conclusion

The development of a science-based personalised nutrition approach focusing on plant foods rich in specific bioactive compounds could contribute to alleviating the dramatic burden of metabolic and cardiovascular diseases.

Plant food bioactives represent a tremendous potential for innovation in the field of food, nutrition, and health.

The role of phytochemicals in the health benefits of plant-based foods has been underestimated so far.

A full consideration of plant food bioactives in future preventive strategies implies research that tackles the factors responsible for interindividual variability.

A better understanding of interindividual variability in response to plant food bioactives is needed to:

Refine dietary recommendations towards foods that are particularly rich in specific bioactives.

Broaden perspectives for the food industry to develop strategies for future personalised food products targeted to specific consumer groups.

Metabolic engineering of aroma components in fruits

Plants have the ability to produce a diversity of volatile metabolites, which attract pollinators and seed dispersers and strengthen plant defense responses. Selection by plant breeders of traits such as rapid growth and yield leads, in many cases, to the loss of flavor and aroma quality in crops. How the aroma can be improved without affecting other fruit attributes is a major unsolved issue. Significant advances in metabolic engineering directed at improving the set of volatiles that the fruits emit has been aided by the characterization of enzymes involved in the biosynthesis of flavor and aroma compounds in some fruits. However, before this technology can be successfully applied to modulate the production of volatiles in different crops, further basic research is needed on the mechanisms that lead to the production of these compounds in plants. Here we review the biosynthesis and function of volatile compounds in plants, and the attempts that have been made to manipulate fruit aroma biosynthesis by metabolic engineering. In addition, we discuss the possibilities that molecular breeding offers for aroma enhancement and the implications of the latest advances in biotechnological modification of fruit flavor and aroma.

Mediterranean diet adherence and self-reported psychological functioning in an Australian sample

Given the reported health benefits of a Mediterranean diet (MedDiet) and delay in cognitive decline, we aimed to determine the level of adherence to a MedDiet using an 11-point scale and examine relationships with cognitive function and psychological well-being. Cross-sectional analyses were undertaken on data from 1183 Australian adults, aged 40-65. Food frequency questionnaires were used to calculate mean intakes of foods included in a MedDiet and foods typically consumed in an Australian diet. Outcome measures included self-reported cognitive failures, memory, anxiety, stress, self-esteem, general health and physical function. The majority of Australians (71.7%) had a medium adherence to a MedDiet pattern. Overall MedDiet adherence was not related to cognitive function. However, intakes of plant foods associated with a MedDiet were positively associated with physical function and general health, and negatively associated with trait anxiety, depression and perceived stress. A substantial proportion of the diet in this Australian sample came from foods not typically consumed in a MedDiet. This is a major limitation when attempting to compare MedDiet adherence in different populations. Global standardisation of serving sizes and food groups are required for adequate comparison.