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 of active chemical compounds from natural products is one of the most important research areas for pharmaceutical and chemical industries. Traditional techniques used for the solvent extraction of natural products are associated with longer extraction times and lower yields, use of large amount of organic solvents and poor extraction efficiency. Ultrasound can be effectively used to improve the extraction rate by increasing the mass transfer rates and possible rupture of cell wall due to formation of microcavities leading to higher product yields with reduced processing time and solvent consumption. The present work presents an exhaustive overview of different aspects of ultrasound assisted extraction (UAE) of various natural products. Mechanism of UAE has been discussed and recommendations for optimum operating conditions have been reported for maximizing the yield. An overview of different applications of UAE has been also presented. Possible intensification of UAE by coupling with traditional solvent and supercritical extraction processes has also been discussed. Overall it appears that ultrasonic irradiations can be effectively used for intensification of the extraction of important constituents from natural products.

Intensification of extraction of natural products using ultrasonic irradiations—A review of current status

Ultrasound-assisted extraction (USAE) is an interesting process to obtain high valuable compounds and could contribute to the increase in the value of some food by-products when used as sources of natural compounds. The main benefits will be a more effective extraction, thus saving energy, and also the use of moderate temperatures, which is beneficial for heat-sensitive compounds. For a successful application of the USAE, it is necessary to consider the influence of several process variables, the main ones being the applied ultrasonic power, the frequency, the extraction temperature, the reactor characteristics, and the solvent–sample interaction. The highest extraction rate is usually achieved in the first few minutes, which is the most profitable period. To optimize the process, rate equations and unambiguous process characterization are needed, aspects that have often been lacking.

/pdf/ultrasound-assisted-extraction-of-natural-products-n3oed0iig2.pdf

Ultrasound-Assisted Extraction of Natural Products

Adhesion ability to the host is a classical selection criterion for potential probiotic bacteria that could result in a transient colonisation that would help to promote immunomodulatory effects, as well as stimulate gut barrier and metabolic functions. In addition, probiotic bacteria have a potential protective role against enteropathogens through different mechanisms including production of antimicrobial compounds, reduction of pathogenic bacterial adhesion and competition for host cell binding sites. The competitive exclusion by probiotic bacteria has a beneficial effect not only on the gut but also in the urogenital tract and oral cavity. On the other hand, prebiotics may also act as barriers to pathogens and toxins by preventing their adhesion to epithelial receptors. In vitro studies with different intestinal cell lines have been widely used along the last decades to assess the adherence ability of probiotic bacteria and pathogen antagonism. However, extrapolation of these results to in vivo conditions still remains unclear, leading to the need of optimisation of more complex in vitro approaches that include interaction with the resident microbiota to address the current limitations. The aim of this mini review is to provide a comprehensive overview on the potential effect of the adhesive properties of probiotics and prebiotics on the host by focusing on the most recent findings related with adhesion and immunomodulatory and antipathogenic effect on human health.

/pdf/adhesion-mechanisms-mediated-by-probiotics-and-prebiotics-57n8ns3kfv.pdf

Adhesion mechanisms mediated by probiotics and prebiotics and their potential impact on human health.

In food processing, the applications of ultrasound can be divided into two categories, namely replacing traditional technologies and assisting traditional technologies In the latter case, the processing efficiency is enhanced and the disadvantageous of traditional technologies during processing are improved These ultrasonic effects can be defined as ultrasonic enhancement of food processes This review is focused on the use of ultrasound to enhance various food processes, including extraction, freezing, thawing, brining, oxidation, filtration, and drying/dehydration The major functions of ultrasound in enhancing these processes and the factors which can affect the ultrasonic enhancement are elucidated In the meantime, the strategies of modeling these processes enhanced by ultrasound are provided Future studies should pay more attention to elucidate the ultrasonic effects during freezing, thawing, brining, oxidation, and filtration processes Furthermore, when it comes to design the ultrasound equipment at the industrial level, it is better to quantify the ultrasonic effects through numerical stimulation

Enhancement of Food Processes by Ultrasound: A Review

Considering food matrix and gastrointestinal effects in enhancing bioactive peptide absorption and bioavailability

Comparison of functional properties and secondary structures of defatted wheat germ proteins separated by reverse micelles and alkaline extraction and isoelectric precipitation

Optimization of ultrasound-assisted extraction of defatted wheat germ proteins by reverse micelles

Microwave treatment increased protein digestibility of pigeon pea (Cajanus cajan) flour: Elucidation of underlying mechanisms

Zein and its derived peptides have been used as nanocarriers for bioactive components. Lutein, as well as other xanthophylls, are characterized by blue light filtering and anti-oxidant properties. However, lutein is unstable and has low water solubility, poor absorption, and low bioavailability. In order to protect lutein from oxidative degradation, and to enhance its solubility and dispersibility, stability and bioactivity, lutein-loaded zein nanoparticles (LLZ-NP) and zein-derived peptide nanoparticles (LLZ-PEP-NP) were prepared by the solvent diffusion method. Compared to LLZ-NP, LLZ-PEP-NP possessed good physicochemical properties, including particle size, polydispersity index, zeta potential, entrapment efficiency and in vitro stability. Specifically, transmission electron microscopy (TEM) images showed that LLZ-PEP-NP had a spherical form with a nanometric size and lutein was efficiently loaded into zein-derived peptides through self-assembly. Dynamic light scattering (DLS) results demonstrated that LLZ-PEP-NP had a narrow size distribution in the range of 200–300 nm and a decreased zeta potential compared to that of LLZ-NP. The lutein entrapment efficiency (EE%) of LLZ-NP and LLZ-PEP-NP was more than 85%, while LUT-PEP-NP showed higher lutein entrapment efficiency because of the better capacity of peptides bound with lutein. Nanoencapsulation of lutein into LLZ-PEP-NP resulted in a significantly higher solubility compared to nanoencapsulation of lutein into LLZ-NP and free lutein. The stabilities of lutein in zein-derived peptide nanoparticles in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were improved. These results suggest that zein-derived peptides have the potential to be used as nanocarriers to enhance the solubility and stability of lutein, which can further improve its bioavailability.

Xiaohong Sun

Papers

Considering food matrix and gastrointestinal effects in enhancing bioactive peptide absorption and bioavailability

Comparison of functional properties and secondary structures of defatted wheat germ proteins separated by reverse micelles and alkaline extraction and isoelectric precipitation

Optimization of ultrasound-assisted extraction of defatted wheat germ proteins by reverse micelles

Microwave treatment increased protein digestibility of pigeon pea (Cajanus cajan) flour: Elucidation of underlying mechanisms

Zein-derived peptides as nanocarriers to increase the water solubility and stability of lutein