Simulated gastro-intestinal digestion is widely employed in many fields of food and nutritional sciences, as conducting human trials are often costly, resource intensive, and ethically disputable. As a consequence, in vitro alternatives that determine endpoints such as the bioaccessibility of nutrients and non-nutrients or the digestibility of macronutrients (e.g. lipids, proteins and carbohydrates) are used for screening and building new hypotheses. Various digestion models have been proposed, often impeding the possibility to compare results across research teams. For example, a large variety of enzymes from different sources such as of porcine, rabbit or human origin have been used, differing in their activity and characterization. Differences in pH, mineral type, ionic strength and digestion time, which alter enzyme activity and other phenomena, may also considerably alter results. Other parameters such as the presence of phospholipids, individual enzymes such as gastric lipase and digestive emulsifiers vs. their mixtures (e.g. pancreatin and bile salts), and the ratio of food bolus to digestive fluids, have also been discussed at length. In the present consensus paper, within the COST Infogest network, we propose a general standardised and practical static digestion method based on physiologically relevant conditions that can be applied for various endpoints, which may be amended to accommodate further specific requirements. A frameset of parameters including the oral, gastric and small intestinal digestion are outlined and their relevance discussed in relation to available in vivo data and enzymes. This consensus paper will give a detailed protocol and a line-by-line, guidance, recommendations and justifications but also limitation of the proposed model. This harmonised static, in vitro digestion method for food should aid the production of more comparable data in the future.

https://hal.archives-ouvertes.fr/hal-01209876/document

A standardised static in vitro digestion method suitable for food – an international consensus

Extraction and quantification of saponins: A review

Edible flowers: A review of the nutritional, antioxidant, antimicrobial properties and effects on human health

Background Functional foods fortified with antioxidants are gaining more popularity since consumption alone of foods naturally rich in antioxidants is insufficient to reduce oxidative stress associated with various diseases. Despite their beneficial effects, natural antioxidants present in coffee are sensitive to heat, light and oxygen, limiting their application in the food industry. Although microencapsulation is able to protect the antioxidant from degradation, mask its taste and control its release, the process of microparticles incorporation affects the original food properties. Scope and approach A carefully designed delivery system is essential to produce sensory appealing food, guarantee the delivery of the bioactive ingredient, prevent interactions with other food components and overcome problems encountered during food manufacturing and digestion. This review discusses the implementation of microencapsulation as a delivery system for coffee antioxidants, focusing on the critical aspects of microparticles food incorporation. Key findings and conclusions The development of microparticles containing coffee antioxidants for food applications should consider technological issues (such as antioxidant bioavailability, food manufacturing process and product final properties) as well as regulatory standards, economic feasibility and consumer acceptability. Further studies regarding the aforementioned parameters are needed in order to design suitable microparticles for functional foods.

Microencapsulation of natural antioxidants for food application – The specific case of coffee antioxidants – A review

There is increased interest in following a healthy lifestyle and consuming a substantial portion of secondary plant metabolites, such as polyphenols, due to their benefits for the human body. Food products enriched with various forms of fruits and vegetables are sources of pro-health components. Nevertheless, in many cases, the level of their activities is changed in in vivo conditions. The changes are strictly connected with processes in the digestive system that transfigure the structure of the active compounds and simultaneously keep or modify their biological activities. Much attention has focused on their bioavailability, a prerequisite for further physiological functions. As human studies are time consuming, costly and restricted by ethical concerns, in vitro models for investigating the effects of digestion on these compounds have been developed to predict their release from the food matrix, as well as their bioaccessibility. Most typically, models simulate digestion in the oral cavity, the stomach, the small intestine and, occasionally, the large intestine. The presented review aims to discuss the impact of in vitro digestion on the composition, bioaccessibility and antioxidant activity of food polyphenols. Additionally, we consider the influence of pH on antioxidant changes in the aforementioned substances.

Influence of In Vitro Digestion on Composition, Bioaccessibility and Antioxidant Activity of Food Polyphenols-A Non-Systematic Review.

BACKGROUND

Rosa rugosa petals are used for production of teas, jams, wines and juices. Despite the wide availability of rose cultivars, comprehensive information on petal chemical composition and healthful properties is still lacking. Therefore, the aim of this study was analysis of cytotoxic, antioxidant and antimicrobial activity and chemical composition of rugosa rose petals.



RESULTS

Petals of R. rugosa were evaluated for their cytotoxic effect against cervical (HeLa) and breast cancer (T47D) cell lines and for antiradical activity (with DPPH•). As a result, significant cytotoxic (up to 100% of dead cells) and antiradical properties (IC50 1.33–0.08 mg mg−1 DPPH•) were demonstrated. Moreover, notable antimicrobial activity against eight bacterial (i.e. Staphylococcus. epidermidis, S. aureus, Bacillus subtilis, Micrococcus luteus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis) and two yeast strains (Candida. albicans, C. parapsilosis) was shown. Total phenolic, flavonoid, phenolic acid, tannin, carotenoid and polysaccharide content in petals was determined using spectrophotometric methods. Liquid chromatography–electrospray ionization–tandem mass spectrometry was used to thoroughly analyze phenolic acids and flavonoid glycosides in the methanolic extract and fractions obtained after its separation. Five phenolic acids and six flavonoids previously not reported in the plant material were identified.



CONCLUSION

This is the first such detailed report on chemical composition and biological activity of R. rugosa petals. © 2013 Society of Chemical Industry

Cytotoxic, antioxidant, antimicrobial properties and chemical composition of rose petals.

The paper presents the study on possibilities of using green coffee beans (GCB) from Ethiopia, Kenya, Brazil and Colombia as a functional additive. The dominant compound identified was 5-caffeoylquinic acid. Caffeine content was comparable in all samples and averaged from 4.36 mg/g dw to 4.99 mg/g dw. The grinding characteristics of GCB was studied and the sensory properties of bread enriched with GCB flour were evaluated. GCB was characterized by high grinding energy requirements. Phenolics released during simulated digestion were highly bioavailable in vitro. Simulated digestion released phytochemicals acting as chelating and reductive agents, free radical scavengers and lipid-preventers. Results of a preliminary study concerning the proposed functional product indicate that phenolic compounds from bread enriched with powdered GCB were highly mastication-extractable, which may predict their high bioaccessibility and bioavailability. The content of phenolics was strongly correlated with powdered GCB addition. The sensory characteristics linking results indicated that a partial replacement of wheat flour in bread with up to 3% ground GCB powder gives satisfactory overall consumer acceptability. Bread enriched with GCB possessed higher antiradical activity than control samples. The results of our study clearly show that powdered GCB may be used directly, without extract preparation, for food supplementation.

Ground green coffee beans as a functional food supplement – Preliminary study

Lungwort (Pulmonaria officinalis L., Boraginaceae) is considered to possess therapeutic properties and it has been traditionally used as a remedy against various lung disorders in many countries. Nevertheless, very few data concerning its phytochemical composition are available. This research aims to provide a detailed description of specialized metabolites from the aerial parts of lungwort. Nine previously undescribed and 36 known phenolic compounds were detected in the 50% methanolic extract. Following multistep preparative procedures, structures of newly discovered compounds were determined using one- and two-dimensional techniques of NMR spectroscopy. Among the identified compounds were caffeic acid esters with aliphatic hydroxycarboxylic acids, conjugates of dicaffeic acid with rosmarinic acid, and previously unknown isomers of isosalvianolic acid A and yunnaneic acid E, as well as other lignans. Concentrations of all identified phenolic derivatives in the investigated herbal material were estimated using a method based on liquid chromatography with high-resolution mass spectrometry detection. Seasonal changes in the concentration of metabolites were also investigated using targeted and untargeted metabolomics techniques.

https://www.mdpi.com/1420-3049/23/9/2277/pdf

Novel Phenolic Constituents of Pulmonaria officinalis L. LC-MS/MS Comparison of Spring and Autumn Metabolite Profiles

The impact of mild drought stress (3 weeks at 40 % field water capacity) on yield, physiological processes, accumulation of proline and phenolic compounds and forage quality parameters in forage grasses was evaluated in pot experiments. During four different growing periods, the effects of water deficit were assessed in nine varieties from five species (Lolium perenne, Lolium multiflorum, Festuca pratensis, Festuca arundinacea and Festulolium braunii). All measured parameters were affected by drought stress in the different cuts. Photosynthesis, transpiration rate, stomatal conductance and dry matter yield were significantly lower in drought stress than under well-watered conditions in all varieties. Higher water-use efficiency was only observed during the first and fourth drought period, while this was not the case in the second and third. Mild drought stress significantly increased the content of proline, phenolic acid, flavonoids, water-soluble carbohydrates and protein. All tested grasses showed also an increase of organic matter digestibility and cell wall digestibility under drought stress conditions.

Łukasz Pecio

Papers

Cytotoxic, antioxidant, antimicrobial properties and chemical composition of rose petals.

Ground green coffee beans as a functional food supplement – Preliminary study

Novel Phenolic Constituents of Pulmonaria officinalis L. LC-MS/MS Comparison of Spring and Autumn Metabolite Profiles

Mild Drought Stress-Induced Changes in Yield, Physiological Processes and Chemical Composition in Festuca, Lolium and Festulolium

Lipoxygenase inhibitors and antioxidants from green coffee—mechanism of action in the light of potential bioaccessibility