Effect of UV-C irradiation on inactivation of Aspergillus flavus and Aspergillus parasiticus and quality parameters of roasted coffee bean (Coffea arabica L.)

ABSTRACT

This study investigated the antifungal effect of ultraviolet-C (UV-C) against Aspergillus flavus and Aspergillus parasiticus on roasted coffee beans. Also, any changes in the quality of the roasted coffee beans were measured after UV-C irradiation. As UV-C irradiation time increased (0–2 h), the number of surviving A. flavus and A. parasiticus spores significantly (P < .05) decreased. The reduction values of A. flavus in round part, crack part, and whole roasted coffee beans were 2.16, 0.71, and 1.58 log₁₀ CFU g^?1, respectively, and the reduction values of A. parasiticus in round part, crack part, and whole roasted coffee beans were 1.03, 0.37, and 0.72 log₁₀ CFU g^?1, respectively, after 2 h of UV-C irradiation. Field emission scanning electron microscopy showed that the morphology of A. flavus and A. parasiticus spores included expanded wrinkles that were deformed by UV-C irradiation. The Hunter colours were significantly reduced (P < .05). There was no significant change (P > .05) in moisture content, but the pH was significantly decreased (P < .05). Most of the sensory parameters did not change, but there was a significant difference (P < .05) in flavour. Based on this study, 2 h of UV-C irradiation was effective in reducing 90% of A. flavus, but it was not effective against A. parasiticus present on roasted coffee beans. Also, Hunter colour, pH, and sensory parameters (flavour) were changed by UV-C irradiation.     

Volatile constituents of roasted tigernut oil (Cyperus esculentus L.)

BACKGROUND: Volatile compounds play a key role in determining the sensory appreciation of vegetable oils. In this study a systematic evaluation of odorants responsible for the characteristic flavour of roasted tigernut oil was carried out. RESULTS: A total of 75 odour‐active volatiles were identified. From these, 13 aroma compounds showing high flavour dilution factors in the range of 16 to 128 were quantified by their odour activity values (OAVs). On the basis of high OAVs in oil, the following aroma compounds [vanillin (chocolate, sweet vanilla), 5‐ethylfurfural (caramel, spicy), 2,3‐dihydro‐3,5‐dihydroxy‐6‐methyl‐4H‐pyran‐4‐one (caramel), phenyl acetaldehyde (honey‐like), ethanone, 1‐(4‐hydroxy‐3‐methoxyphenyl) (faint vanilla)] were elucidated as important contributors to the overall chocolate, sweet vanilla, butterscotch aroma of the oil. CONCLUSION: Odorants with high concentrations in the roasted tigernut oil such as 5‐hydroxymethylfurfural, ethyl hexadecanoate, n‐propyl‐9,12‐octadecadienoate gave relatively low OAVs, so their contributions to the overall orthonasal aroma impression of roasted tigernut oil can be assumed to be low. © 2012 Society of Chemical Industry     

焙烧钼精矿块新生产线压制工艺参数优化与研究

焙烧钼精矿块的生产较钼铁具有辅料消耗少、节能、环保以及生产成本低的独特优势，随着焙烧钼精矿块炼钢技术的日趋完善和进步，国内使用钼铁炼钢将随之减少，利用焙烧钼精矿块用于炼钢其前景广阔。本文通过焙烧钼精矿块新生产线对添加剂浓度／用量、干燥时间、物料粒度选择等不同参数试验，从而确定了焙烧钼精矿块新生产线压制最佳工艺参数，同时提高了焙烧钼精矿块成球率和产品质量，深受国内外用户青睐，经济效益明显。     

出口鳗鱼中溴氰菊酯残留量的气相色谱分析

建立了出口鳗鱼中溴氰菊酯残留量的气相色谱检测方法.样品经乙腈提取、弗罗里硅土柱净化后,经气相色谱分离,ECD检测器检测.样品在0.002～0.010mg/kg范围内添加,平均回收率在79.2%～85.9%之间,变异系数在4.2%～5.8%之间.以S/N=3计算,方法检出限为2.0 μg/kg.结果表明,该法简便、灵敏、准确,适用于出口鳗鱼中溴氰菊酯残留量的分析.     

复方海鳗鱼皮明胶改善缺铁性贫血活性的研究

本文研究了复方海鳗鱼皮明胶(Fufang Pike Eel Skin Gelatin,FEG)对大鼠缺铁性贫血的改善作用,旨在找到一种新型的复方补血品。本文采用热提法制备海鳗鱼皮明胶,配合当归、白芍、川芎、黄芪、炒山楂、制首乌和熟地黄七种中药材熬制得到FEG。采用传统的低铁饮食辅助尾静脉放血的方法建立缺铁性贫血(Iron Deficiency Anemia,IDA)模型,将IDA大鼠随机分成模型组、FEG和复方阿胶高低剂量组。灌胃30 d,通过测定大鼠的血红蛋白(Hb)、红细胞数(RBC)、血清中的铁(SI)、铁蛋白(SF)和可溶性转铁蛋白受体(Soluble Transferrin Receptor,s Tf R)浓度等指标以及肝脏HE染色和骨髓涂片评价其补血效果。结果表明,FEG高剂量组能够显著提高IDA大鼠的RBC(p0.01),降低网织红细胞数(p0.05)、肝脏(p0.01)、脾脏(p0.05)和肾脏系数(p0.01),缓解骨髓异常增生和肝组织紊乱;使Hb浓度由77.21 g/L提高到175.86 g/L;使SI和SF浓度分别升高了2.9和0.6倍,s Tf R浓度降低了19.42%。复方海鳗鱼皮明胶能够有效地改善缺铁性贫血。     

新疆烤羊肉串中杂环胺的生成规律研究进展

烤羊肉串, 作为新疆特色美食, 以其引人入胜的外观和独特的风味深受广大消费者追捧。然而, 这类经过高温加工的食品容易产生多种致癌物质, 其中之一就是杂环胺。杂环胺主要源自富含蛋白质的动物性食品, 具有强烈的致癌和致突变特性。过量摄入将会提高人体患癌风险, 对人体健康构成严重威胁。杂环胺的生成与反应底物、加工方式以及加工条件等密切相关。本文总结了杂环胺在热加工肉类中的分布状况及其生成的主要因素, 重点综述了新疆特色美食烤羊肉串中杂环胺的生成规律以及抑制策略, 旨在为今后新疆烤羊肉串的绿色加工以及杂环胺的减控方法提供科学理论依据。对消费者的健康饮食具有重要的指导意义。     

Non-isothermal reduction characteristics of roasted high alumina iron ore pellets

Non-isothermal reduction of roasted Guangxi high alumina iron ore pellets with CO and H₂ was conducted with high temperature synchronisation thermal analyser (NETZSCH STA 409C/CD) to understand the reduction characteristic of the ore. Chemical analysis, X-ray diffraction examination and scanning electron microscope analysis were adopted to analyse the roasted and reduced pellets. The results show that there are three main phases of Fe₂O₃, Al₂O₃ and Al₃Fe₅O₁₂ in the roasted pellets. During reduction process, the iron bonded in hercynite and fayalite is difficult to be reduced by CO so that the final reduction degree is only 35.62% at the setting temperature of 1573?K. But with H₂ atmosphere, the reduction degree can reach 100% at about 1520?K. It suggests that the ferric ion can completely be reduced to metallic iron by H₂.     

解冻条件对鳗鱼寿司品质的影响

目的分析烤鳗原料解冻条件对鳗鱼寿司品质影响。方法比较分析烤鳗原料在25、5、-5℃3种温度条件下自然解冻时间、鳗鱼寿司成品率、解冻损失率、持水率以及pH的不同,并进行微生物检测比较,探究烤鳗解冻对鳗鱼寿司品质影响,确定适宜的解冻条件。结果鳗鱼寿司采用低温(-5℃)长时间自然解冻,可使所加工鳗鱼寿司成品率高、解冻损失率低、鳗鱼肌肉持水率较高,肌肉组织的损伤和肌原纤维蛋白质变性均较小。结论烤鳗原料采用低温解冻虽然解冻时间较长,但是鳗鱼寿司品质保持最好,适合企业生产实际需求。     

米茶焙炒挥发性气味的形成与特征研究

以籼米为原料,经浸润、焙炒等工序制得米茶。采用电子鼻、顶空固相微萃取(HS-SPME)和气相色谱-质谱联用技术(GC-MS),研究焙炒过程中米茶挥发性成分的形成,为揭示谷物饮料的香气形成提供理论参考。大米的挥发性气味物质主要是己醛、壬醛等醛类,右旋萜二烯、酯类及烷烃类,随着焙炒时间的延长,挥发性物质种类和浓度逐渐丰富,米茶挥发性物质组成以醛、烷烃和杂环类为主,兼有较大比例醇、酯和酮类。焙炒米茶的香气成分主要是2-戊基呋喃、2-戊基吡啶和3-乙基-2,5-二甲基吡嗪等杂环物质。建立的基于电子鼻传感器的米茶香气成分预测模型具有很高的拟合精度。