Bifidobacterium spp. as functional foods: A review of current status, challenges, and strategies.

Members of Bifidobacterium are among the first microbes to colonize the human intestine naturally, their abundance and diversity in the colon are closely related to host health. Recently, the gut microbiota has been gradually proven to be crucial mediators of various metabolic processes between the external environment and the host. Therefore, the health-promoting benefits of Bifidobacterium spp. and their applications in food have gradually been widely concerned. The main purpose of this review is to comprehensively introduce general features, colonization methods, and safety of Bifidobacterium spp. in the human gut, highlighting its health benefits and industrial applications. On this basis, the existing limitations and scope for future research are also discussed. Bifidobacteria have beneficial effects on the host's digestive system, immune system, and nervous system. However, the first prerequisite for functioning is to have enough live bacteria before consumption and successfully colonize the colon after ingestion. At present, strain breeding, optimization (e.g., selecting acid and bile resistant strains, adaptive evolution, high cell density culture), and external protection technology (e.g., microencapsulation and protectants) are the main strategies to address these challenges in food application.

Structural Analysis and Antioxidant Activity of Extracellular Polysaccharides Extracted from Culinary-Medicinal White Jelly Mushroom Tremella fuciformis (Tremellomycetes) Conidium Cells.

Using Tremella fuciformis conidium cells for submerged fermentation is a cost-effective way to harvest bioactive compounds. In this study, we emphasized the structural and functional analysis of extracellular polysaccharides (EPS) extracted from T. fuciformis conidium cells. An EPS high-yield strain tyc63 was selected and a 6-day optimum fermentation period was determined. Crude EPS was extracted and three high molecular weight (5189, 171.6, and 661 kDa) polysaccharides TFP-1, TFP-2, and TFP-3 were isolated and purified. TFP-1 is mainly composed of glucose, xylose, mannose, and fucose, while both TFP-2 and TFP-3 are mainly composed of rhamnose, arabinose, mannose, galactose, and glucose. FT-IR analysis revealed that TFP-1, TFP-2, and TFP-3 have typical polysaccharide structure. The antioxidant assay revealed that the crude EPS, TFP-1, TFP-2, and TFP-3 presented high free radical scavenging activities but low ferric reducing power, suggesting that the EPS produced by liquid fermentation could be used as a potent radical scavenger.

Structural characterization and immune-enhancing activity of a novel high-molecular-weight polysaccharide from Cordyceps militaris.

A novel homogeneous polysaccharide (CMP-III) was extracted and purified from C. militaris. Structural characterization revealed that CMP-III had an average molecular weight of 4.796 × 104 kDa and consisted of glucose, mannose and galactose with the molar ratio of 8.09:1.00:0.25. The main linkage types of CMP-III consisted of 1 â†’ 4)-α-D-Glc (70.08%), 1 â†’ 4,6)-α-D-Man (9.59%), 1→)-α-D-Man (10.79%) and 1 → 2,6)-α-D-Gal (3.93%) based on methylation and NMR analysis. The immunomodulatory assay indicated that CMP-III significantly promoted macrophage phagocytosis and secretion of NO, TNF-α and IL-6. Further study suggested that macrophage activated by CMP-III involved mitogen-activated protein kinases (MAPKs) and nuclear factor kappa-B (NF-κB) signaling pathways. Overall, these results suggested that CMP-III could be developed as a potent immunomodulatory agent for use in functional foods and dietary supplements.

Impacts of different soil fertility improvement practices with film mulched ridge-furrow til-lage on soil nutrient content, maize yield, and water use efficiency in Northwest China.

Improvement of soil quality is one of the most important ways to enhance fertility for efficient dryland crop production. However, the effects of different fertilization measurements with film mulched ridge-furrow tillage on soil fertility, crop yield, and water use efficiency (WUE) of maize largely remain unknown. A three-year field experiment was conducted at the Zhuanglang Experimental Station, Gansu Academy of Agricultural Sciences, located in the semiarid region of the Loess Plateau, Northwest China during 2014-2016. Maize breed Funong No.1 was used during the study. There were four treatments, including: 1) conventional planting (CP, served as control), 2) film mulched ridge-furrow with straw incorporation (FS), 3) film mulched ridge-furrow with optimizing fertilization (FF), and 4) film mulched ridge-furrow with controlled fertilization (FC). Seasonal and yearly changes of soil water content, topsoil organic matter (SOM), soil available nitrogen (AN), phosphorus (AP) and potassium (AK) concentration and crop yield were measured. Nitrogen and phosphorus fertilizer partial factor productivity (PFPN and PFPP), soil profile water storage (WC), crop seasonal water consumption (ET) and water use efficiency (WUE) were calculated. The results showed that FS, FF and FC effectively improved soil fertility via synergistic regulation of soil hydrothermal and nutritional condition. Water-fertilizer interaction effect greatly enhanced incorporated straw decomposition and crop growth, resulting in more returning of straw nutrients and crop biomass to soil, thus significantly increased soil water and fertilizer supply capacity. Compared to CP, the three treatments of FS, FF and FC efficiently increased the concentrations of SOM, AN, AP, and AK by 0.27 g·kg-1, 4.44 mg·kg-1, 0.20 mg·kg-1 and 4.53 mg·kg-1 with an order of FC＞FF＞FS, but had no significant difference among them. Meanwhile, in contrast to pre-sowing WC200, the three year's sum of FS,FF and FC increased WC200 at the end of growing season by 107.41, 38.99 and 28.35 mm, respectively. On average, FS, FC and FF significantly reduced maize ET by 60.50, 37.7 and 34.15 mm to CP, with a relative decrease of 12.6%, 7.9% and 7.1% respectively. By the synergistic effect of modified water and fertilizer environment, the three soil fertility improvement strategies greatly enhanced maize growth from tasseling to maturity stages in the relatively dry year. They affected maize growth in relatively more rain and warmer year, resulting in significantly increased maize yield by improving the yield traits (double ear rate, grain number per ear and 100-grain mass), PFPN, PFPP and WUE. Compared to CP, the PFPN,PFPP of FS, FF and FC increased by 1.82, 1.65, 1.62 and 2.41, 1.69, 1.63 times respectively. Yield and WUE were increased by 5986.1, 4972.31, 4585.63 kg·hm-2 and 13.27, 12.65, 14.01 kg·mm-1·hm-2 correspondingly raised by 81.5%, 67.7%, 62.5% and 86.5%, 82.5%, 91.3%. In conclusion, FS was more effective in water harvesting and drought resistance, while FC and FF were effective for high yield.

[Impacts of climate change on food production in Gansu: A review].

The climate of Gansu turned to be overall warming-drying and partly warming-wetting since 1986. In contrast to that of 1960, the average annual temperature had raised by 1.1°C with the average annual precipitation decreased by 28 mm correspondingly, which made the arid region expanded southward by 50 km in 2010. Climate warming increased the growth period effective accumulated temperature of main food grain crops and lengthened the crop growth period. It changed crop maturity, crop disposition, cropping system and generally increased the cultivatable area and planting altitude above the sea level of major crops and expanded northward the multiple cropping system, which further resulted in expansion of autumn grain crop sown area, shrink of summer grain crop sown area, and replacement of strong winter early maturing varieties by weak winter middle late maturing varieties. It benefited the crop yield by increasing the use efficiency of photo-thermal resources. Warming-wetting climate increased the climate productivity of oasis crop while warming-drying weather decreased the climate productivity of rainfed crops, which were mostly determined by the precipitation regimes and water conditions. Any advanced technique that can increase precipitation use ratio and water use efficiency as well as improve and promote soil quality and fertility should be regarded as an effective countermeasure to increase food grain production under climate change in Gsansu. So, selecting and breeding new crop varieties with the characteristics of strong resistance, weak winter, middle-late mature and high water use efficiency, establishing new planting structure and cropping system that suitable to the precipitation and temperature features of changed climate, are the development direction of food grain production in Gansu to cope with the climate change.