Application of sourdough in gluten-free bakery products.

ABSTRACTSIn recent years, the demand for gluten-free (GF) bakery products has grown rapidly due to the remarkable rising number of celiac patients and the increasing health awareness of GF products. However, GF products generally suffer from defects such as poor sensorial level, low nutritional value, high prices and short shelf life. Sourdough is the important starter culture applied in bakery field, and it has been proven to be ideal for enhancing the overall quality of bakery products. This review aims to systematically reviewed the application of sourdough in GF bakery products and its improvement to GF bakery products in terms of texture, shelf life, nutrition and flavor. Its positive effects derive from the complex metabolic activities of sourdough microorganisms, such as acidification, proteolysis, production of exopolysaccharides (EPS), activation of endogenous enzymes, and production of antibacterial substances. Finally, researchers are encouraged to expand the use of sourdough in GF bakery products to increase the variety of GF products. And the technical and nutritional potential of sourdough should be developed more widely.

Effects of different cooking methods on proximate composition, digestion characteristics, and antioxidant activity of Lentinus edodes.

Lentinus edodes (SM) are highly appreciated by the food industry together with consumers for nutrition and flavour. It is hypothesized the results of our study can indicate to the suitable cooking method for maximal nutrient retention, this study investigated the effects of six cooking methods on the proximate composition, digestive properties, and antioxidant activities of SM in vitro simulated digestion. The results revealed that the ash and protein contents of cooked samples were reduced excluding steaming and roasting, and likewise minerals during deep-frying and boiling (e.g., Mg from 1080.07 to 629.03 mg/kg, deep-frying). A conspicuous rise in fat and energy was found in deep-frying and stir-frying. Steaming retained more reducing sugar (3.80 mg/mL). Roasting improved bioaccessibility of most amino acids (e.g., 82.61%, Asp). Using oil as a medium was associated with higher antioxidant activities using water. Steaming and roasting were better for preserving the nutrient composition of cooked Lentinus edodes.

Effect of in vitro simulated digestion and fecal fermentation on Boletus auripes polysaccharide characteristics and intestinal flora.

Boletus auripes is edible and medicinal boletus mushrooms rich in diverse nutrients and bioactive compounds, of which indigestible dietary polysaccharides are the most abundant compounds involved the regulation of gut microbes. However, the physicochemical, digestive, and fermentation characteristics of Boletus auripes polysaccharide (BAP) are not well studied. This study aimed to investigate the influence of different digestive stages on BAP's physicochemical characteristics and biological activities, and its effect on intestinal flora. We found that mannose (0.23 %), glucose (0.31 %), galactose (0.17 %), and fucose (0.19 %) were the main monosaccharides of BAP, with a high-molecular-weight (Mw) and a low-Mw fraction of 2084.83 and 62.93 kDa, respectively. During the course of digestion, there were slight alterations in the chemical composition, monosaccharide composition, and Mw of BAP. Despite these changes, the fundamental structural features of BAP remained largely unaffected. Moreover, the antioxidant and hypoglycemic activities of BAP were weakened under simulated saliva-gastrointestinal digestion. However, gut microbiota decomposed and utilized BAP to generate various short-chain fatty acids during fermentation, which decreased the pH of fecal cultures. Meanwhile, BAP modulated the gut microbiota composition and increased the relative abundance of Bacteroidetes. These findings suggest that BAP have potential for maintaining intestinal health and protecting against interrelated diseases.

Effect of hydroxypropyl-ß-cyclodextrin and lecithin co-stabilized nanoemulsions on the konjac glucomannan/pullulan film.

In this study, the various ratio of hydroxypropyl-ß-cyclodextrin (HPCD) to lecithin (LEC) was 0:1, 0.5:1, 1:1, 1.5:1 and 2:1 (w/w) co-stabilized cinnamon essential oil (CEO) nanoemulsions were prepared. These nanoemulsions were successfully incorporated in the konjac glucomannan/pullulan polysaccharides-based film matrix. The composition of nanoemulsions and the effect of various nanoemulsions on rheological, mechanical, Water vapor permeability, optical, color, morphology properties, and CEO retention rate of the composite films were characterized. The results demonstrated that HPCD and LEC nanoemulsions had small particle size under 120 nm and high stability during 21 days storage, the incorporation of nanoemulsions reduced the viscosity of film-solution, transmittance, Water vapor permeability and mechanical properties of films, but an appropriate HPCD content 1:1 w/w of nanoemulsions could restored the mechanical properties of the films. Otherwise, 1:1 w/w of nanoemulsion film also exhibited a more compact and uniform structure, Furthermore, 2:1 w/w of nanoemulsion films with high retention rate of CEO, and the antioxidant and better antibacterial activities against E. coli and S. aureus. The nanoemulsion films utilized in this study also prolonged the shelf life of Agaricus bisporus mushrooms and cherries while maintaining their commercial value.

In vitro simulated digestion of and microbial characteristics in colonic fermentation of polysaccharides from four varieties of Tibetan tea.

Polysaccharides as a functional prebiotic have numerous activities such as regulating intestinal microorganisms and polysaccharide is one of the functional active components in tea has been known. In this study, we aimed to investigate the physicochemical characteristics of polysaccharides from four kinds of Tibetan teas at simulated digestion stages and the effect on the microbiota of fecal fermentation stages in vitro. The results revealed that Tibetan tea polysaccharides were partially digested during digestion. Additionally, during in vitro fecal microbial fermentation, Tibetan tea polysaccharides can promote the growth of some beneficial bacteria such as Bifidobacterium, Prevotella and Phascolarctobacterium to change the composition of intestinal microorganisms and promote the production of short-chain fatty acids (SCFAs). Finally, a strong correlation was found between the production of SCFAs and microorganisms including Bacteroides, Bifidobacterium and Lachnoclostridium. These results suggest that Tibetan tea polysaccharides could be developed as a prebiotic to regulate human gut microbiota.

Effect of different cooking methods on the nutrient, and subsequent bioaccessibility and biological activities in Boletus auripes.

In this study, we investigated the effects of six different cooking methods on the nutrient composition, subsequent bioaccessibility, and biological activities of Boletus auripes using in vitro digestion. The cooking methods used included steaming, boiling, microwaving, stir-frying, frying, and roasting. The results indicated that the degree of protein hydrolysis and amino acid bioaccessibility were lowest during frying, while the opposite was true for microwaving. The fatty acid composition associated with cooking methods changed after digestion, especially linoleic acid, which significantly decreased (e.g., 53.34% to 21.32%, boiled). Mineral bioaccessibility varied by species and cooking method, with the lowest Fe (13.33%) and highest Mg (91.43%) in boiling. Cooking promoted carbohydrates release heavily, but not digestion, such as the superior bioaccessibility (17.21%) and inferior digestibility (6.23%) in roasting. Microwaving, with the lowest antioxidant activity, possessed notable hypoglycemic activity. The above study lays the foundation for choosing the appropriate cooking methods for B. auripes.

Effect of different cooking methods on the nutrients, antioxidant and hypoglycemic activities of Pleurotus cornucopiae in vitro simulated digestion.

To determine the chemical composition, nutritional value, and bioactivities of Pleurotus cornucopiae, the effects of six different cooking methods (boiling, steaming, microwaving, stir-frying, frying, and roasting) on nutrients, antioxidant and hypoglycemic activities were, for the first time, evaluated using in vitro simulated digestion. In contrast to frying, microwaving caused the lowest nutrients loss rate (protein: 11.81%, fat: 13.26%) and produced the highest α-amylase and α-glucosidase inhibitory activities. The fatty acid composition differed from that of undigested samples, frying and stir-frying released the most unsaturated fatty acids (especially oleic and linoleic acids), while steaming and microwaving released the most saturated fatty acids. Microwaving caused a lower mineral loss, whereas frying released the highest mineral content after digestion. Water-based cooking methods (boiling, steaming, and microwaving) had the lowest antioxidant activities but the highest hypoglycemic activities. The above data provides a valuable reference for the scientific cooking of P. cornucopiae.

Effect of fermentation time and addition amount of rice sourdoughs with different microbial compositions on the physicochemical properties of three gluten-free rice breads.

This study aimed to better understand the impact of microbial growth and metabolism on rice sourdough and their relationship with quality characteristics of rice breads. Therefore, this research determined the microbial compositions and biochemical characteristics of indica rice (IR), japonica rice (JR) and waxy rice (WR) sourdough within 72 h fermentation. And the effects of different fermentation time and dosage of rice sourdough on rheology of rice doughs, quality characteristics of rice breads were studied. The results showed that the dominant bacteria Leuconostoc changed the processing properties of rice doughs through producing organic acids and reducing sugars. Adding 30 % rice sourdough had the best effect on improving specific volume of rice breads. And IR and JR breads with sourdough fermented 48 h had the highest chewiness, cohesiveness, resilience and the lowest hardness, while WR breads had high viscosity and poor overall structure, which was not suitable for making gluten-free bread.

Preparation of pH-indicator films based on soy protein isolate/bromothymol blue and methyl red for monitoring fresh-cut apple freshness.

Intelligent pH-indicator films based on soy protein isolate (SPI) were prepared using pH-sensitive dyes (bromothymol blue and methyl red). The addition of mixed indicators imparts pH-indicator films with an appreciable microstructure, acceptable water resistance, and favorable optical properties. The incorporation of the mixed indicators did not lead to significant improvement in the mechanical properties of films due to weak ionic cross-linking by hydrogen bonding between the SPI macromolecules and low-molecular-weight indicators. Fourier-transform infrared spectroscopy indicated hydrogen bond-mediated intermolecular interactions, and scanning electron microscopy showed that BB/MR were well dispersed in the SPI film. The indicator addition hindered the sorption and passage of water molecules. The water vapor permeability, moisture sorption, moisture content, and total soluble matter were 4.32 to 6.12 ×10-12  g·cm/cm2 ·s·Pa, 36.70% to 73.33%, 25.28% to 44.11%, and 8.21% to 25.56%, respectively. Also, the addition of indicators reduced UV light transmittance with minimal effect on the transparency of the film. The presence of indicators enhanced the pH sensitivity, seen as a visible color reaction at different pHs (total color difference, ΔE > 5). When the pH-indicator film containing 8 ml/100 ml final film emulsions was used to monitor the fresh-cut apple freshness, a green color for fresh status was observed, which turned blue after 60 h. Collectively, our findings suggested that indicator-containing SPI films have the potential for monitoring the freshness of fruits. PRACTICAL APPLICATION: pH-indicator films can help consumers to identify the freshness of packaged food by a change in the color of the packaging material, which is easily visible to the unaided eye without the need for opening the packaging. This protects consumers' interests.

Calculations of spin-polarized Goos-Hänchen displacement in magnetically confined GaAs/Al x Ga1-x As nanostructure modulated by spin-orbit couplings.

We theoretically investigate Goos-Hänchen (GH) displacement by modelling the spin transport in an archetypal device structure-a magnetically confined GaAs/Al x Ga1-x As nanostructure modulated by spin-orbit coupling (SOC). Both Rashba and Dresselhaus SOCs are taken into account. The degree of spin-polarized GH displacement can be tuned by Rashba or Dresselhaus SOC, i.e. interfacial confining electric field or strain engineering. Based on such a semiconductor nanostructure, a controllable spatial spin splitter can be proposed for spintronics applications.

An Overview of Plant Phenolic Compounds and Their Importance in Human Nutrition and Management of Type 2 Diabetes.

In this paper, the biosynthesis process of phenolic compounds in plants is summarized, which include the shikimate, pentose phosphate and phenylpropanoid pathways. Plant phenolic compounds can act as antioxidants, structural polymers (lignin), attractants (flavonoids and carotenoids), UV screens (flavonoids), signal compounds (salicylic acid, flavonoids) and defense response chemicals (tannins, phytoalexins). From a human physiological standpoint, phenolic compounds are vital in defense responses, such as anti-aging, anti-inflammatory, antioxidant and anti-proliferative activities. Therefore, it is beneficial to eat such plant foods that have a high antioxidant compound content, which will cut down the incidence of certain chronic diseases, for instance diabetes, cancers and cardiovascular diseases, through the management of oxidative stress. Furthermore, berries and other fruits with low-amylase and high-glucosidase inhibitory activities could be thought of as candidate food items in the control of the early stages of hyperglycemia associated with type 2 diabetes.

Voltage-controllable spin beam splitter based on realistic magnetic-barrier nanostructure.

We report a theoretical investigation on the Goos-Hänchen (GH) effect of spin electron beams in realistic magnetic-barrier (MB) nanostructures under an applied voltage, which can be experimentally created by lithographic patterning of ferromagnetic (FM) or superconducting films. GH shifts of spin electron beams are calculated numerically for the InAs material system, with the help of the stationary phase method. It is shown that a significant spin polarization effect can be induced by such MB nanostructures with symmetric magnetic field profiles. It also is shown that both magnitude and sign of the spin polarization is closely relative to the electric barrier (EB) produced by a constant voltage applied to the metallic FM stripe of system. These interesting properties may provide an alternative way to spin injection into the semiconductor, and such nanostructures can serve as voltage-tunable spin beam splitters.