Salmonella enterica serovar Choleraesuis on fresh-cut cucumber slices after reduction treatments

Cucumber is a popular fruit around the world and has been implicated in Salmonella food poisonings. S. Choleraesuis is a serovar that can cause pig and human infections but was rarely examined in food safety context. To investigate S. Choleraesuis behavior on cucumber slices, it was inoculated, at 10⁴ colony forming units (CFU)/mL, onto fresh-cut cucumber slices and subjected to reduction with either high hydrostatic pressurization (HHP), hydrogen peroxide (H₂O₂), or Peredibacter sp. BD2GS treatment, its reduction and survival during 48 h storage at 4 °C and 25 °C were compared.Reduction tests revealed that 5% H₂O₂ was most effective in killing S. Choleraesuis, with 97.5% reduction after 15 min action, compared to 90.7%, 87.7%, 29.2% and 60.2% reduction rates with HHP, 2.5% H₂O₂, high- and low-dose BD2GS treatments, respectively.At the end of storage, contrast to no changes at 4 °C, S. Choleraesuis counts rose significantly (p < 0.05) at 25 °C. Compared to control that reached 7.1 ± 0.1 log CFU/g, HHP, 5% and 2.5% H₂O₂ attained 6.3 ± 0.1, 6.7 ± 0.1 and 6.4 ± 0.2 log CFU/g correspondingly, whereas high- and low-dose BD2GS attained 4.9 ± 0.1 and 5.9 ± 0.1 log CFU/g respectively. A shared growth peak of between 9 h and 12 h was noted in all treatments except high-dose BD2GS where it occurred in the first 3 h. Results of this study revealed the effectiveness of 5% H₂O₂ in the reduction of S. Choleraesuis, and demonstrated that if not stored properly, contaminated cucumber slices, though treated, can still have potentials to cause S. Choleraesuis outbreaks.     

鸡骨火腿肠的研制

以鸡骨粉为强化剂,研究鸡骨粉颗粒大小、鸡骨粉的添加量、猪肉的肥瘦比以及玉米淀粉的添加量对火腿肠品质的影响。通过单因素试验和L9(34)正交试验,确定出鸡骨粉火腿的最佳工艺配方为猪肉重量100g,m(肥肉)∶m(瘦肉)=1︰4(即肥肉20 g,瘦肉80 g),淀粉25.0 g,水60.0 g,120目的鸡骨粉1.30 g,食盐5.5 g,香辛料适量,制得的肠体表面光滑,富有弹性,组织致密,切片较光滑平整,切面呈粉红色,口感较细腻无粗糙感,咸淡适中,具有浓郁的鸡骨的香味。     

超高压与超声波对蓝靛果多酚提取及抗氧化活性的影响

采用响应面法对蓝靛果多酚超高压提取条件进行优化,并从提取量、提取条件和提取多酚抗氧化活性等因素综合比较超高压和超声波提取蓝靛果多酚的差异。结果表明:响应面优化超高压提取条件为料液比1∶19(g/m L)、提取温度30℃、提取压力406 MPa、超高压时间11.5 min、乙醇体积分数50%,此条件下多酚提取量最高,为(778.23±3.45)mg/100 g果浆;超声波辅助提取条件为料液比1∶25(g/m L)、提取温度40℃、乙醇体积分数50%、超声功率500 W、提取时间90 min,此条件下多酚提取量为(785.74±3.89)mg/100 g果浆,略高于超高压提取。抗氧化实验结果表明,经过超高压提取的蓝靛果多酚对1,1-二苯基-2-三硝基苯肼自由基清除能力、2,2’-联氨-双-(3-乙基苯并噻唑啉-6-磺酸)二胺盐自由基清除能力、Fe3+还原能力显著高于同质量浓度条件下超声波提取的蓝靛果多酚和VC对照组。综上,虽然超高压提取缩短了蓝靛果多酚提取时间,且提取的多酚活性高,但受到容器大小的限制,在大批量提取蓝靛果多酚的情况下,超高压提取的效率和提取量仍然不及超声波提取,因此,从多酚提取量和提取效率的角度考虑,超声波提取蓝靛果多酚优于超高压提取。     

实时荧光PCR法快速鉴别狐狸貉子肉源性成分研究

根据狐狸线粒体基因组中的保守序列和貉子线粒体D-loop基因保守序列设计狐狸、貉子特异性引物和Taq Man探针,建立一种基于实时荧光聚合酶链式反应的肉及肉制品狐狸、貉子源性成分测定方法,通过特异性、灵敏性、线性检测对该方法体系进行检验和评价。本研究建立的狐狸、貉子源性成分实时荧光聚合酶链式测定方法体系具有良好的特异性及灵敏性,最低可检测0.5 pg/μL纯狐狸DNA和5 pg/μL纯貉子DNA。本研究建立的狐狸貉子源性成分荧光PCR检测方法,可以用来检测实际样品中是否含有狐狸貉子源性。     

山楂多酚微胶囊制备及理化性质分析

为改善山楂多酚稳定性,提高生物利用率,以β-环糊精、乳清分离蛋白和阿拉伯胶为复合壁材,山楂多酚为芯材,通过喷雾干燥法制备了山楂多酚微胶囊,分析了微胶囊的粒径、表观形貌、稳定性、缓释性及抗氧化性。结果表明,最佳制备工艺为芯壁比1:3(v/v),进风温度165℃,乳化时间11.4 min,在此优化条件下山楂多酚微胶囊的包埋率为94.45%±1.03%,载药量为17.99%±0.20%。微胶囊平均粒径为6.77μm,颗粒完整,近似球形,在胃液中具有良好的稳定性,肠液中有良好的释放性能,模拟胃液消化2 h后山楂多酚与山楂多酚微胶囊释放率分别为13.38%和9.75%,肠液消化6 h后释放率分别为95.99%和72.53%。包埋后抗氧化性和稳定性均有明显提升,山楂多酚对DPPH、OH、O₂^-自由基清除率IC₅₀值分别为12.669μg/mL,1.131、0.581 mg/mL;山楂多酚微胶囊分别为0.939μg/mL,0.129、0.546 mg/mL。光照10 d,山楂多酚与山楂多酚微胶囊的保留率分别为64.99%和86.74%...     

Effect of microbial transglutaminase on NMR relaxometry and microstructure of pork myofibrillar protein gel

The effect of microbial transglutaminase (MTG) on nuclear magnetic resonance relaxation (NMR) behaviour, water holding capacity (WHC) and microstructure of pork myofibrillar protein (PMP) gel was studied. The enzymatic protein preparation had significantly lower values of spin–spin relaxation time (T ₂), higher WHC and more porous microstructure in comparison with the control system. T ₂ was reduced from 226 ms (peak value) of the PMP gel containing no MTG to 188 ms of the PMP gel containing 2 U/g protein. However, no further decrease was shown when the concentration of MTG increased. The reduction was attributed to reduced mobility of water protons in the system. Scanning electron micrographs (SEM) showed the mobility of water in the proteins gel network was related to gel microstructure.     

花色苷分子结构修饰及其生理活性研究进展

花青素是植物界分布最广、种类众多的一类天然色素,是植物的主要呈色物质,在自然界中多以糖苷（花色苷）的形式存在,具有多种重要的生理功能和生物活性。花色苷具有酚羟基,结构稳定性较差,易受外界条件如pH值、温度、光、O2、金属离子和酶等因素的影响,在食品加工中易分解失去原有的鲜艳颜色,限制了花色苷的贮藏和在食品加工领域中的应用。花色苷分子结构修饰可增加其对外界环境和食品添加剂及食品加工中的稳定性,使其在较大pH值范围内呈现良好色泽。本文系统介绍了不同类型（花色苷酰基化、花色苷酯基化及形成吡喃类衍生物）花色苷结构修饰的原料来源、结构特征及其生理活性,为进一步开展花色苷的结构稳定性与生理活性研究及其在食品加工领域中的护色与应用提供参考。     

Controlled growth of hierarchical FeCo2O4 ultrathin nanosheets and Co3O4 nanowires on nickle foam for supercapacitors

In recent years, the tenable design and synthesis of the core/shell heterostructure as electrode for the supercapacitor, have attained a huge attention and concerns. In this article, the three-dimensional heterostructure consisting of FeCo₂O₄ ultrathin nanosheets grown on the space of vertical Co₃O₄ nanowires has been designed and synthesized onto nickel foam (NF) for pseudocapacitive electrode applications. According to previous research, the NF@ FeCo₂O₄ electrodes can only exhibit specific capacity of 1172 F g⁻¹ at a current density of 1 A g⁻¹. In addition, although the capacity of the NF@Co₃O₄ electrodes can reach to 1482 F g⁻¹ and it has the disadvantage of agglomeration, which restricts the diffusion of ions and has a negative effect on the progress of electrochemical reactions. Therefore, a core-shell nanostructure is fabricated by an improved two-step hydrothermal process, which improves the probability of ion reaction with more efficient charge transfer. Furthermore, in as-prepared unique core/shell heterostructure, the resultant electrode possesses the merits of large capacitance of 1680 F g⁻¹ at a current density of 1 A g⁻¹, an excellent rate capability of 70.1% at 20 A g⁻¹ and only 9.8% loss of initial capacitance at a high charge/discharge current density after 2000 cycles. These results demonstrate that this kind of distinct electrode has potential utilization for supercapacitor.     

HACCP质量管理体系在干白葡萄酒生产中的应用

运用HACCP管理体系的基本原理分析干白葡萄酒生产中潜在的危害及其控制措施,确定了关键控制点,建立了HACCP质量管理体系。通过HACCP体系的应用提高了干白葡萄酒的质量和安全性。     

黄粉虫高蛋白火腿肠的研制

以黄粉虫脱脂粉为主要辅料,通过单因素试验、正交试验,确定黄粉虫高蛋白火腿肠的最佳配方为:黄粉虫脱脂粉粗细度为100目,猪肉与黄粉虫脱脂粉的质量比为73∶27,猪肉的肥瘦质量比为1∶5,红薯淀粉添加量为猪肉和黄粉虫脱脂粉总量的45%,食盐3%,味精0.6%,红薯淀粉与水的质量比为1∶2.5,亚硝酸钠为瘦肉的0.015%,香辛料适量。黄粉虫高蛋白火腿肠的蛋白质含量为13.90%,而未加黄粉虫的对照组火腿肠的蛋白质的含量仅为8.63%。在火腿肠中添加黄粉虫脱脂粉可大大提高火腿肠中蛋白质含量。