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

Obesity and chronic diet-related diseases such as type 2 diabetes, hypertension, cardiovascular disease, cancers, and celiac are increasing worldwide. The increasing prevalence of these diseases has led nutritionists and food scientists to pay more attention to the relationship between diet and different disease risks. Among different foods, rice has received increasing attention because it is a major component of billions of peoples' diets throughout the world. Rice is commonly consumed after polishing or whitening and the polished grain is known a high glycemic food because of its high starch content. In addition, the removal of the outer bran layer during rice milling results in a loss of nutrients, dietary fiber, and bioactive components. Therefore, many studies were performed to investigate the potential health benefits for the consumption of whole brown rice (BR) grain in comparison to the milled or white rice (WR). The objective of this work was to review the recent advances in research performed for purposes of evaluation of nutritional value and potential health benefits of the whole BR grain. Studies carried out for purposes of developing BR-based food products are reviewed. BR safety and preservation treatments are also explored. In addition, economic and environmental benefits for the consumption of whole BR instead of the polished or WR are presented. Furthermore, challenges facing the commercialization of BR and future perspectives to promote its utilization as food are discussed.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-4337.12449

Brown Rice Versus White Rice: Nutritional Quality, Potential Health Benefits, Development of Food Products, and Preservation Technologies.

Background In recent times, research has highlighted the bioactive roles played by non-extractable polyphenols (NEP) in human health, especially from by-products of grains, fruits and vegetables. Most studies have reported on the total phenol content of samples without adequate attention paid to a major class of polyphenols referred to as NEP. This limits the scope of polyphenol studies and the extent of NEP incorporation into medicines, nutraceuticals, cosmetic and foods among other applications. Scope and approach This review introduces NEP and gives an update on recent advances in free and bound polyphenol extraction from plant by-products. Owing to the fact that most researchers are already familiar with the extraction of free polyphenols, this review emphasizes the extraction of NEP and provides a basis for the selection of appropriate techniques and applications for different plant by-product sources. It also presents suggestions for future studies into NEP extraction efficiency from complex plant sources using alternative physical approaches. Key findings and conclusions NEP from by-products have high potential for use in industry, especially in pharmaceutical, nutraceutical and cosmetic applications. To ascertain the total phenol content of extracts, both free and bound phenols must be accounted for with special attention directed at appropriate sample pretreatment and extract hydrolysis. Higher bioactive properties of NEP, coupled with their cheaper by-product sources makes them economically viable and medicinally potent. Also, structure-function relationships and the possibility to use physical means such as slow-freezing-thawing to increase hydrolytic yield of NEP is recommended.

Latest developments in polyphenol recovery and purification from plant by-products: A review

Background Native starches have been modified by employing various methods for desired industrial applications over the last few decades. There have been intense interests to develop novel methods with advantages of high-efficiency, environment-friendly and easy operation for starch modification. Although there is more attention to the functional properties of modified starch for practical applications in the industry, structural changes are the basis of functional changes, hence understanding the structural alteration induced by processing techniques is a fundamental issue towards better utilization of starch and starch modification techniques. Scope and approach The current review mainly presents the effects of several efficient physical processing techniques on the changes in the starch multi-scale structure including molecular structure, crystallinity, lamellae structure, and morphology characteristic. Among these techniques, the influences of high hydrostatic pressure, cold plasma, and microwave treatments are emphasized, and research gaps to better develop these techniques for starch modifications are suggested. Key findings and conclusions Physical processing techniques by means of pressure, heat, radiation or free radicals can affect amylose, amylopectin, and degree of their interactions in the crystalline and amorphous region, as well as the packing mode of the crystal structure, thereby resulting in various functional properties and extensive applications in starch industries. However, the exact mechanisms behind these modification techniques are inconclusive because there are many affecting factors mainly including processing parameters, starch origin, and environment. Exploring new research methods or improving modified equipment to reduce the influence of these interference factors should be a good inspiration to study physical modification.

Effects of novel physical processing techniques on the multi-structures of starch

Whole-grain dietary fiber is rich in bound-form phenolics, and the biological activity of this special structural feature has attracted increasing attention. In this study, rice bran dietary fiber (RBDF) was subjected to in vitro gastrointestinal digestion and colonic fermentation to investigate the liberation of bound phenolics and their potential activities. Bound phenolics were released at a higher ratio during colonic fermentation (27.57%) than gastrointestinal digestion (2.68%). Nine phenolic compounds were detected from the fermentation supernatants. The released phenolics showed radical scavenging activity (DPPH and ABTS assays) and α-glucosidase inhibitory activity (IC50 = 19.11 μg GAE/mL). Compared with phenolics-removed RBDF (PR-RBDF), RBDF had a significantly stronger prebiotic effect on the microbes associated with diabetes (Lactobacillus spp., Akkermansia muciniphila, and Faecalibacterium prausnitzii). These findings indicate that bound phenolics may act as important functional components that could contribute to the health benefits of whole-grain dietary fiber.

Phytochemical Profile, Bioactivity, and Prebiotic Potential of Bound Phenolics Released from Rice Bran Dietary Fiber during in Vitro Gastrointestinal Digestion and Colonic Fermentation

Free and bound phenolic profiles of the bran from different rice varieties and their antioxidant activity and inhibitory effects on ɑ-amylose and ɑ-glucosidase

The influence of high hydrostatic pressure (HHP) treatment at 150, 300, 450, 600 MPa for 25 min on the physicochemical, structural properties and in vitro digestibility of pea starch was studied. Compared to native and pea starch treated at 150-450 MPa, the morphology of pea starch at 600 MPa was completely destroyed and particle size became larger, indicating complete gelatinization. The X-ray diffraction results showed that the native pea starch was gradually changed from C-type into B-type pattern after 150-600 MPa HHP treatment. At 30-70 °C, pea starch treated at 600 MPa had higher water absorption index (p < 0.05), swelling power and solubility than other samples did, but opposite results were obtained at 90 °C. The RVA (Rapid Visco Analyzer) results indicated that pea starch treated with high pressure at 600 MPa showed lower values of peak viscosity, trough, breakdown, final viscosity and setback (p < 0.05), reflecting lower retrogradation. Gelatinization temperatures and enthalpy determined by DSC (Differential Scanning Calorimetry) decreased with increasing pressure. Furthermore, the in vitro digestibility of HHP treated pea starches was lower than native pea starch (p < 0.05). Therefore, it is an effective method for HHP treatment to modify the properties of pea starches.

Physicochemical properties, structural properties, and in vitro digestibility of pea starch treated with high hydrostatic pressure

The invention discloses a processing method for miscellaneous grain bean noodles. In specific to the problems that the miscellaneous grain beans contain no mucedin, and are difficult to form and have high broken rate when applied to noodle production, the method is used for developing nutritional and healthy noodles made from miscellaneous grain beans by means of the high and new food technologies such as a miscellaneous grain bean extrusion and pregelatinization processing technology, a multi-layer overlapping rolling technology of miscellaneous grain bean breads and wheat breads, an auxiliary preparation technology and the like. In the method disclosed by the invention, the protein molecules of the miscellaneous grain bean powder and the wheat powder are mutually combined to form a macro-molecular gluten network structure, thereby strengthening the toughness and a three-dimension space network structure of a dough are enhanced so that the strength and the extensibility of the dough are increased, and the whole dough has firmer network and better elasticity and toughness. In addition, on the basis of the technologies, the application of an ultra-micro powder physical modification technology can be used for effectively improving the quality indexes such as appearance, glossiness and the like of the noodles. By adoption of the invention, the adding amount of the miscellaneous grain beans in the noodles can be 10-90%.

Processing method for miscellaneous grain bean noodles

Processing method of whole grain vermicelli

The invention discloses a method for preparing stabilized whole wheat flour, which comprises the following steps of: (1) in the process of processing flour, respectively collecting albumen, embryo and bran; (2) performing stabilization treatment on the bran and the embryo by adopting an extrusion method to obtain an extruded material; (3) drying the stabilized material, crushing (sieving by using an 80-mesh sieve) or performing super micron milling (to make the grain size less than or equal to 74 mu m); and (4) uniformly mixing the albumen obtained in the step (1) with the embryo powder and bran powder obtained in the step (3) in a ratio of the albumen to the embryo to the bran collected in the step (1), and packaging to obtain the stabilized whole wheat flour. By the method, lipase activity and fatty acid content in the bran and the embryo can be effectively reduced, the whole wheat flour product keeps the nutrient components of the natural whole wheat, the storage stability is improved, the flour property and processing and edible quality are improved, and the utilization rate and value-added benefit of wheat are improved.

Wang Liping

Papers

Free and bound phenolic profiles of the bran from different rice varieties and their antioxidant activity and inhibitory effects on ɑ-amylose and ɑ-glucosidase

Physicochemical properties, structural properties, and in vitro digestibility of pea starch treated with high hydrostatic pressure

Processing method for miscellaneous grain bean noodles

Processing method of whole grain vermicelli

Method for preparing stabilized whole wheat flour