Anthocyanin-fortified konjac glucomannan/sodium alginate composite edible boba: characteristics of texture,microstructure, in vitro release behaviour and antioxidant capacity

Konjac glucomannan/sodium alginate composite edible boba (KGM/SA-boba) with good taste is very popular in China, and it is an outstanding carrier for health potential ingredients. In this work, KGM/SA-boba were fortified with 0.25, 0.50, 0.75 and 1.00% purple sweet potato anthocyanin (PSPA), then characterised by the water distribution, texture, microstructure, in vitro release property of PSPA and antioxidant capacity. LF-NMR analysis demonstrated that the free water of KGM/SA-boba could transfer to tightly bound water with the addition of PSPA that made it with better water-binding ability, higher springiness and lower hardness. And the results of SEM and rheology showed that PSPA could stabilise the microstructure of KGM/SA-boba by forming more amorphous regions and hydrogen bonds proved by the results of DSC and FT-IR. Furthermore, 50% of PSPA in PSPA-fortified KGM/SA-boba can be released at the first hour in a simulated gastrointestinal environment. And the scavenging capacity of DPPH and ABTS of the PSPA-fortified KGM/SA-boba after digestion was higher than that of PSPA alone. Generally, PSPA could improve the texture while KGM/SA-boba in turn would make PSPA more stable in the gastrointestinal digestive system.     

Synthesis and performance evaluation of a new drag reducer based on acrylamide/12-allyloxydodecyl acid sodium

Hydraulic fracturing with slickwater is a field-proven stimulation technology used in tight reservoirs. Because of the high pumping rate associated with slickwater fracturing, drag reduction (DR) is critical in minimizing pressure drop and the success of oilfield operations. In this paper, a new type of drag reducer (SPR) was synthesized with acrylamide and 12-allyloxydodecyl acid sodium, and its drag reduction performance was evaluated. The results showed that the new drag reducer features low molecular weight, fast-dissolving rate and low interfacial tension. The algorithm of estimating the drag reduction rate of non-Newtonian fluid SPR was proposed and validated. Empirical or semianalytical models for estimating the friction ratio (σ) or friction factor (λ or f) were used to simulate the turbulence behavior of the SPR drag reducer under different Reynolds numbers (Re). The modified Virk's correlation could accurately model the turbulent behavior of the SPR drag reducer. A unified calculation formula was established in this study for different pipe diameters.     

Preparation and characterization of calcium phosphate cement with enhanced tissue adhesion for bone defect repair

Anti-washout and tissue adhesion properties are essential for the clinical application of injectable bone materials. In this study, we prepared calcium phosphate cement (CPC) with anti-washout and tissue adhesion properties and attempted to build covalent bonds between CPC and the amino groups in bone tissue under a self-regulating pH system in the CPC (acidic to basic). The results of push-out tests demonstrated that a significant enhancement (from 6.42 ± 0.76 N to 61.5 ± 4.09 N) in tissue adhesion was obtained with the addition of 6% (w/w) oxidized sodium alginate (OSA) in CPC. The FTIR, XRD, anti-washout test, XPS, pH test, and SEM results suggested that the synergistic effect of OSA-citric acid (CA) led to the formation of a three-dimensional gel network structure in the CPC, and the Schiff base reaction between aldehyde and amino groups induced adhesion between CPC and the bone tissue. Further, the addition of less OSA had no significant negative effect on the hydration properties of CPC. Our work aims to promote the development of injectable bone material in clinical applications.     

Enhanced dielectric and piezoelectric properties in potassium sodium niobate/polyvinylidene fluoride composites using nano-silicon carbide as an additive

Piezoelectric materials are an indispensable part of modern life. Yet the existing environmental issues with conventional lead-based piezoelectrics has motivated scientist to develop novel substitutes including lead-free piezoelectric polymer composites. Following this path, the present research has focused on the fabrication of ternary composites of Polyvinylidene fluoride (PVDF)/Potassium Sodium Niobate (KNN)/nano-Silicon carbide (SiC) via hot compression molding and studying the effect of additives on the PVDF structure and the electrical properties of the composite. The obtained scanning electron micrographs and density measurements showed that the fabrication method provided dense samples. The activated polarization phenomena in the prepared samples enhanced dielectric permittivity and dielectric loss at a constant frequency with increasing KNN and SiC contents. Besides the expected dipole polarization, the presence of interfaces in the composites gave rise to the Maxwell–Wagner–Sillars effect and its corresponding polarization phenomenon. The semiconductive nature of SiC also promoted space charge polarization. However, these properties were frequency-dependent because the first two polarization mechanisms are deactivated at high frequencies. XRD patterns showed that SiC addition can alter the primary crystalline structure of PVDF and promote β-phase formation in the poled samples. Piezoelectric measurements confirmed the significant role of SiC addition to PVDF-KNN composites. The most significant increase in the piezoelectric properties was observed in PVDF-60KNN-1SiC, with a 183% increase in d₃₃ value. The PVDF-80KNN-1SiC had the highest d₃₃ value of 30.5 pC/N. It also had the best piezoelectric voltage coefficient and hence the highest figure of merit. Higher SiC contents restrict the efficiency of poling by forming a conductive path across the sample which would deteriorate the piezoelectric performance of the material. The present findings show that PVDF-KNN-SiC composites can be considered as a potential flexible piezoelectric material for future applications.     

碳酸钠碱性介质氧脱木素促进火炬松酶解糖化的研究

分别采用硫酸盐法（KP）和绿液法（GL）蒸煮火炬松，并以碳酸钠为碱性介质进行氧脱木素，所得浆料分别标记为KP-OC浆和GL-OC浆，分析了这两种浆料的化学组分，并对这两种浆料进行酶解以提取可发酵单糖。结果显示，在120℃氧脱木素4 h所得的KP-OC浆和GL-OC浆的木素脱出率均明显优于相近条件下以氢氧化钠为碱性介质且脱木素1 h的浆料。对于GL-OC浆和KP-OC浆，当酶用量为10 FPU/g时，酶解单糖得率、总单糖提取率最高分别可达73.2%和95.8%、72.4%和75.7%，均优于相近条件下以氢氧化钠为碱性介质氧脱木素的浆料。     

2018年湖北省食品中苯甲酸、山梨酸、糖精钠的抽检结果分析

目的 了解湖北省食品中苯甲酸、山梨酸、糖精钠的使用安全状况, 为省食品安全监管工作提供科学依据。方法 对2018年各类食品按照相关标准进行检验和评价, 对检测结果进行分析。结果 2018年共检测食品887批次, 总合格率为94.25%。苯甲酸、山梨酸超标使用的情况分布在水果制品、豆制品和餐饮食品中。结论 2018年湖北省食品安全状况总体良好, 但也存在一些问题。相关部门应加大对小作坊的监督力度, 规范生产, 保障消费者的身体健康。     

富硒低钠盐中碘含量的测定

目的探讨富硒低钠加碘盐中碘含量的测定方法。方法通过不同的实验条件,优化国标GB/T13025.7-2012《制盐工业通用试验方法碘的测定》中氧化还原滴定法中的试剂用量,检测出富硒低钠加碘盐中的碘含量。结果改变碘化钾溶液量、淀粉溶液量、磷酸-草酸溶液量均无法测定富硒低钠盐中的碘含量;只有当次氯酸钠溶液用量≥5mL时,加入碘化钾溶液,才可以使富硒低钠加碘盐溶液显色,然后通过实验确定次氯酸钠的最佳用量,再滴定测定碘含量。结论富硒低钠加碘盐中含有还原性物质,测定其碘含量需加大次氯酸钠溶液的用量。     

几种防霉剂对单个腌制咸鸭蛋的腌制效果比较

目的 研究苯甲酸钠、百部、丙酸钙、双乙酸钠、丁香提取物及肉桂提取物6种防霉剂对咸蛋裹料防霉特性和咸蛋腌制效果的影响。方法 分别添加0.1%双乙酸钠、丙酸钙、苯甲酸钠、肉桂提取物、丁香提取物、百部到咸蛋裹料中，以蒸馏水为空白对照组，接种鲜鸭蛋表面菌液有菌液均匀涂布于培养基上，37 ℃恒温培养30 d测定各组菌落总数，初筛出3种防霉剂与咸蛋裹料复配，分别以黄泥腌制、不添加防霉剂的空白裹料作为对照，设置5个试验组腌制咸蛋，每7 d抽测一次霉变率、蛋内菌落总数、蛋白含盐率、蛋黄含盐率、感官评价等指标。结果 各组抑菌效果有显著性差异（p＜0.05）：丁香提取物＞肉桂提取物＞苯甲酸钠＞双乙酸钠＞丙酸钙＞百部＞空白对照，优选出的丁香提取物、肉桂醛和苯甲酸钠添加到改性淀粉为主要成分的咸蛋单个腌制裹料中腌制咸蛋，丁香提取物组的蛋内菌落总数显著高于其他组（p＜0.05），蛋内微生物控制在×102数量级内，霉变率为0；腌制35 d蛋白含盐率低于4.5 %、蛋黄含盐率高于1%，整体感观评分最优。结论 防霉剂能显著降低改性淀粉单个腌制咸蛋的霉变率和蛋内菌落总数。按0.1 %比例添加丁香提取物可制得与黄泥腌制效果相近的咸蛋，咸蛋整体更呈现一种宜人的丁香醇香风味。