Effects of high hydrostatic pressure on the structure and retrogradation inhibition of oat starch

As a non-thermal processing technology, high hydrostatic pressure (HHP) can be used for starch modification without affecting the quality and flavour constituents. The effect of HHP on starch is closely related to the treatment pressure of HHP. In this paper, we investigated the impacts of HHP treatment pressure (0, 100, 200, 300, 400, 500, 600 MPa) on the microstructure and retrogradation characteristics of oat starch, established the retrogradation kinetic model and elaborated the mechanism of HHP treatment inhibiting the retrogradation of oat starch. Results show that HHP treatment caused the microstructure of oat starch experienced crystallisation perfection (100–300 MPa), crystallisation destruction (400 MPa), crystallisation disintegration and gelatinisation (500–600 MPa). Results of oat starch retrogradation showed that, after treated at 500 MPa for 15 min, the recrystallisation rate of oat starch was reduced, the formation of nuclei at the early stage of oat starch retrogradation suppressed and its nucleation mode was changed from instantaneous to spontaneous, otherwise, the mobility of water in oat starch gel system reduced. Therefore, 500 MPa treated for 15 min can inhibits the retrogradation of oat starch. This study provides theoretical guidance for the application of HHP technology in starch modification and food processing.     

Lactobacillus plantarum ZLC-18 fermentation improve tyrosinase inhibition activity and antioxidant capacity in soybean hulls

Soybean hulls, the main byproduct in soybean processing, have many biological activities. However, the value of this byproduct is still far from being fully exploited. In this study, we investigated the anti-tyrosinase and antioxidant capacities in soybean hulls fermented by Lactobacillus plantarum ZLC-18 (L. plantarum ZLC-18). We found that L. plantarum ZLC-18 fermentation could markedly improve the anti-tyrosinase and antioxidant activities of soybean hulls. The anti-tyrosinase and antioxidant activities were positively correlated with the total phenolic and flavonoid contents. UPLC–MS analysis suggested that phenolic compounds (daidzin, genistin, vanillic acid and so on) were increased in soybean hulls after fermentation, and some of these compounds were shown to have anti-tyrosinase and antioxidant activities. Our study demonstrates that fermentation is an efficient strategy to enhance the bioactive function of soybean hulls. Moreover, this study provides evidence that soybean hulls can be used as a kind of functional food ingredient, thereby improving their economic benefits.     

西藏燕麦主要种植区灌溉定额空间分布及影响因素

燕麦为西藏自治区典型牧草之一,由于种植区地域辽阔,灌溉试验结果受限,西藏燕麦主要种植区的灌溉定额尚不明确。本文在西藏燕麦主要种植区内选取28个典型站点进行资料收集,遵循农业气候相似原则进行区域划分,基于水量平衡法揭示了西藏燕麦主要种植区灌溉定额的空间分布特征,并根据统计学原理分析了其影响因素。研究表明:燕麦主要种植区的灌溉定额呈由西藏中部至东部呈现先递增后递减的趋势,50%水文年下的燕麦灌溉定额在56~265 mm之间变化。降雨量是影响研究区内燕麦灌溉定额的主要因素(R²为0.515),ET₀次之(R²为0.152);其它气象因素中,日照时数对研究区燕麦灌溉定额影响较大(R²为0.462),且呈正相关关系;相对湿度对燕麦灌溉定额影响较小。西藏燕麦主要种植区的灌溉定额及其空间分布可为西藏自治区灌溉用水管理提供支撑。     

Ni2V2O7 dandelion microsphere for a high-performance electrocatalyst in water splitting

Water splitting is an effective way to produce hydrogen to solve the energy crisis problem, and inorganic metal compounds are widely used in electrocatalysis field due to efficient hydrogen evolution reaction (HER). Herein, we synthesize Ni₂V₂O₇ dandelion microsphere from nickel nitrate and vanadium pentoxide by “one-step hydrothermal” way, which exhibits large specific surface area of 102.74 m² g⁻¹. The as-prepared Ni₂V₂O₇ microsphere shows good electrocatalysis performances including OER overpotential of 358 mV and good stability, as well as HER overpotential of 195 mV. Furthermore, the Ni₂V₂O₇ microsphere electrode is assembled to Ni₂V₂O₇ microsphere//Ni₂V₂O₇ microsphere system, showing the water splitting voltage of 1.50 V at 10 mA cm⁻² by two-electrode method, which is much lower than those of commercial RuO₂//Pt/C system and most of spinel oxides electrocatalysts. Our work opens up a new and facile avenue for fabricating inorganic microsphere electrocatalyst in hydrogen production field.     

Development of a non-target metabolomics-based screening method for elucidating metabolic and probiotic potential of bifidobacteria

Traditional in vitro screening assays for identifying probiotics often fail to provide a metabolomic overview of candidate strains. Thus, this work aimed to develop a non-target metabolomics-based method for screening bifidobacteria from a broad perspective. First, methods for extracting intracellular metabolites of bifidobacteria were compared. Methanol extraction with bead mill and sonication was selected as it yielded the highest metabolome signal intensity and coverage. Multivariate analyses revealed obvious differences in the intracellular metabolome between species/strains. Fourteen differential metabolites that have previously been reported to possess probiotic function were identified. Bifidobacterium animalis subsp. lactis Probio-M8 (M8) had significantly more intracellular lactose than other species/strains but showed lower cell density and viable counts in stationary phase. Adding lactose in the culture medium significantly enhanced the growth of M8 strain but not other tested bifidobacteria. This work provided a new screening method and practical data for selecting potential candidates for further validation.     

锡盟地区小尾寒羊副产物营养成分分析与评价

以锡盟地区小尾寒羊的心、肝、脾、肺、肾、大肠、小肠、胃（瘤胃、网胃、瓣胃、皱胃）及血液等副产物为研究对象，对其常规营养成分、氨基酸、脂肪酸以及矿物质含量进行分析与评价。结果表明：锡盟地区小尾寒羊各副产物营养成分含量（鲜质量分数）为水分含量68.86%～83.62%、蛋白质含量11.10%～19.92%、脂肪含量0.19%～16.93%、灰分含量0.45%～3.82%；各副产物经酸水解处理后测定，含天冬氨酸、亮氨酸、赖氨酸等17 种氨基酸，其中包含人体必需的7 种氨基酸，必需氨基酸占氨基酸总量的34.44%～44.35%，且谷氨酸、天冬氨酸、亮氨酸等含量丰富；各副产物中不饱和脂肪酸含量（除羊血8.26%外）为35.56%～56.09%，其中以单不饱和脂肪酸为主，网胃、瓣胃、皱胃、大肠、小肠中油酸含量均在30%以上，且网胃、肝脏、肺脏中亚油酸含量较高；各副产物中含有多种微量元素，其中脾脏中K和Fe含量最高，4 个胃中Ca含量均较高。     

茶多酚对羊肉肌原纤维蛋白凝胶特性的影响

研究茶多酚对羊肉肌原纤维蛋白凝胶特性的影响，将不同添加量（0.00%、0.01%、0.05%、0.10%、0.50%、1.00%）的茶多酚加入到羊肉肌原纤维蛋白中，测定肌原纤维蛋白表面疏水性、乳化性能、保水性、质构特性，观察羊肉肌原纤维蛋白凝胶微观结构。结果表明，与对照组相比，茶多酚添加量为0.10%时，羊肉肌原纤维蛋白的表面疏水性最小，疏水基团暴露程度最轻，乳化活性指数达到最大（4.88 m2/g），乳化稳定性指数（86.54%）和保水性（95.22%）均达到最佳；随着茶多酚添加量的增加，羊肉肌原纤维蛋白凝胶的硬度、咀嚼度、胶着度均显著上升（P＜0.05），弹性、内聚性、回复性整体呈下降趋势（P＜0.05）。结论：添加适量茶多酚可以显著改善羊肉肌原纤维蛋白的凝胶特性，并且凝胶的微观结构更加致密、空隙更小、形状规则且分布均匀；茶多酚与肌原纤维蛋白的非共价结合和共价结合可能会影响蛋白质的功能特性，并且这种作用强度随着茶多酚添加量的变化而变化。     

双相区加速冷却处理对X80管线钢组织与性能的影响

采用双相区加速冷却法(加速冷却始冷温度为700 ℃)对X80管线钢进行热处理,获得了贝氏体和铁素体(B+F)双相组织。然后通过组织表征、力学性能测试以及在3.5wt%NaCl溶液中的耐蚀性进行研究。结果表明:热处理后获得的管线钢组织由板条状贝氏体、多边形铁素体及少量马氏体/奥氏体岛组成。与热处理前相比,(B+F)双相管线钢屈强比较低,为0.65,初始加工硬化指数为0.31,均匀伸长率达8.3%,塑性显著提升;双相组织中含有52.4%的铁素体,因而耐腐蚀性明显提高。通过双相区加速冷却法获得的(B+F)两相组织在塑变过程中发生协调变形,可以适应大变形的需求,同时耐蚀性优异,为大变形管线钢实际生产提供一定的借鉴。     

某省粮食储备库的仓储作业流程及优化方案

在现代粮食物流快速发展的大背景下,依据仓储管理的基本内涵,以某省级粮食储备库为研究对象,从入库作业、在库作业、出库作业等方面分析其仓储作业流程现状,指出其仓储作业流程存在的问题并分析原因。提出完善仓储作业流程、更新改造仓库设施设备、强化员工岗位技能培训等适用于该省粮食储备库仓储作业流程的优化方案,以期为粮食储备库仓储作业流程改进和优化提供理论支撑。     

苏尼特羊不同部位肌肉抗氧化系统的差异

以放牧条件下的苏尼特羊股二头肌、臂三头肌和背最长肌3个部位的肌肉为材料,测定其丙二醛(MDA)、氧合肌红蛋白(OMb)、高铁肌红蛋白(MMb)含量、抗氧化酶活性(超氧化物歧化酶SOD、过氧化氢酶CAT、谷胱甘肽过氧化物酶GSH-Px)、抗氧化能力(降铜离子还原能力CUPRAC、自由基清除率RSA)、色差和pH值等指标,比较不同部位之间的差异。结果表明:抗氧化酶和抗氧化性能中,臂三头肌的SOD与GSH-Px活性最高,而背最长肌中的CAT活性、CUPRAC和RSA最高。背最长肌的pH值最高,而MDA、L*值、a*值和b*值均显著低于股二头肌和臂三头肌(P<0.05)。股二头肌中OMb显著高于臂三头肌和背最长肌(P<0.05),而MMb显著低于其它部位(P<0.05)。苏尼特羊肌肉中的抗氧化酶之间具有协同作用,且抗氧化酶活力的增强能提高机体抗氧化性能,降低氧化程度。整体上,苏尼特羊背最长肌中抗氧化物质含量较高,脂质氧化程度低于其它两个部位,抗氧化能力较强。