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

Wine production wastes are an interesting source of natural polyphenols. In this work, wine wastes extracts were encapsulated through vibration nozzle microencapsulation using sodium alginate as polymer and calcium chloride as hardening reagent. An experimental design approach was used to obtain calcium-alginate microbeads with high polyphenol content and good morphological features. In this way, the effect of pressure, frequency, voltage and the distance to the gelling bath were optimized for two nozzles of 150 and 300 lm. Long-term stability of the microbeads was studied for 6 months taking into account different storage conditions: temperatures (4 C and room temperature), in darkness and in presence of light, and the addition of chitosan to the gelling bath. Encapsulated polyphenols were found to be much more stable compared to free polyphenols regardless the encapsulation procedure and storage conditions. Moreover, slightly lower degradation rates were obtained when chitosan was added to the gelling bath.

Microencapsulation and Storage Stability of Polyphenols from Vitis Vinifera Grape Wastes

Aim: Microencapsulation of chokeberry extracts was performed in order to improve functionality, stability, and bioavailability of extracted polyphenols.Methods: Chokeberry fruits and juice by-produ...

Chokeberry polyphenols preservation using spray drying: effect of encapsulation using maltodextrin and skimmed milk on their recovery following in vitro digestion.

The encapsulation by spray drying is a common method of encapsulation on the food industry. Many biopolymers are described on the literature as wall materials for this purpose. As different wall materials are applied on spray drying, it is necessary to know their physicochemical characteristics. In view of the different applications for this technology, the objective of the present study is to discuss the physicochemical characteristics of several wall materials used in encapsulation of bioactive compounds by spray drying for human consumption. Among all biopolymers make blends of carbohydrate-based and protein-based biopolymers seems to be the better way to encapsulate bioactive compounds, especially when using vegetable proteins in view of reach a less allergenic product.

Spray-drying wall materials: relationship with bioactive compounds.

Chokeberries, elderberries, blueberries, and blackberries are highly nutritious native fruits in the US Midwest region. Their high moisture content, delicate structure easily leads to fruit loss/waste. This review focuses on different drying methods for whole fruits and juices to preserve their quality and improve their shelf life. Solar drying, hot-air drying, spray drying, freeze-drying, vacuum-drying, electromagnetic drying, and osmotic dehydration are the commonly used dehydrating methods for berries. Berries are photo, heat-sensitive, and rich source of essential nutrients. Texture, flavor, color, water content, phytonutrients, physicochemical properties can be influenced by dryer and processing parameter selection. Drying is a complex dynamic process, due to structural differences among various foods, combined thermal and non-thermal techniques could improve fruit quality. Hence, knowledge of drying behavior and degradation kinetics is vital for optimizing the process parameters to enhance the fruit quality. Freeze drying and spray drying showed better preservation of nutrients. Existing research suggests that chokeberries (Aronia) are underutilized compared to blueberries and blackberries. Aronia fruit has a lot of potentials containing health-promoting compounds and is yet to be explored. Future research suggestions have been put forward for the efficient use of drying techniques and to improve the fruit quality.

Sustainable food processing of selected North American native berries to support agroforestry.

Due to its high content of phenolics, black chokeberry has been proposed as a health-promoting material, especially use of chokeberry extract as a food or pharmaceuticals. Chokeberry extract was spray-dried using gum Arabic as a carrier. The optimal conditions for the efficient microencapsulation of chokeberry extract using spray-drying technique have been investigated. The aim of our study was to obtain microparticles with the best potential to improve functionality and stability of extracted chokeberry polyphenols, and to investigate the possibility of microbeads to protect active compounds during simulated digestion process. Morphological characteristics of microbeads were analyzed using FTIR and SEM techniques. Zeta potential, particle size and moisture content were determined. Released total phenolics and total anthocyanins content as well as concentration of individual anthocyanins were quantified before and after digestion process. Microparticles exhibited high encapsulation efficiency up to 87%, and high content of released polyphenols was achieved. After in vitro simulated digestion phenolic compounds decreased by 11-24%, exhibited higher protective effect of gum Arabic. Our results showed that chokeberry microparticles obtained by spray drying method could be useful supplements or functional food.

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Application of gum Arabic in the production of spray-dried chokeberry polyphenols, microparticles characterisation and in vitro digestion method

In the recent past, bioactive compounds, especially naturally antioxidants, have occupied the main research focus, due to their high biological activity. Plant polyphenols are one of the most potent antioxidants. Encapsulation technique is a promising tool to protect their beneficial properties and to overcome the problems of polyphenols instability and low bioavailability. Micro- and nanohydrogel particles are attractive carriers and have a significant interest because of their unique small size and size-dependent physical properties, which provide many benefits. This chapter is an overview of the current state of the art in encapsulation techniques for polyphenolics with an insight into physicochemical and morphological characteristics of hydrogel–polyphenol systems. Finally, the effect of encapsulation process on biological activity of phenolics will be discussed through the examples available in literature.

Nada Ćujić Nikolić

Papers

Application of gum Arabic in the production of spray-dried chokeberry polyphenols, microparticles characterisation and in vitro digestion method

Potential of encapsulated phytochemicals in hydrogel particles