Effectiveness of the Natural Antioxidant 2,4,4′-Trihydroxychalcone on the Oxidation of Sunflower Oil during Storage

This study aimed to investigate the effectiveness of 2,4,4′-trihydroxychalcone as a natural antioxidant on the oxidation of sunflower oil during an 88-day storage period and to compare its strength with the synthetic antioxidant butylated hydroxytoluene (BHT). Seven groups of the sunflower oil samples were prepared: pure oil (control), oil treated with different concentrations (100, 500, and 1000 ppm) of 2,4,4′-trihydroxychalcone, and oil treated with different concentrations (100, 500, and 1000 ppm) of BHT. Specific parameters, namely, the peroxide value (PV), acid value (AV), p-anisidine value (p-AnV), thiobarbituric acid reactive substance (TBARS) value and total oxidation (TOTOX) value were used to assess the extent of the deterioration of the oil by estimating the primary and secondary oxidation products. The results showed that 2,4,4′-trihydroxychalcone effectively decreased the production of the primary and secondary oxidation products of sunflower oil during storage, as indicated by reductions in the PVs, AVs, p-AnVs, TBARS values and TOTOX values of the sunflower oil. When compared to BHT, 2,4,4′-trihydroxychalcone showed either a similar or stronger effect in inhibiting the primary and secondary oxidation products. These findings suggest that, 2,4,4′-trihydroxychalcone is a suitable natural alternative to synthetic antioxidants to improve the oxidative stability of sunflower oil.     

Phytochemical Profile and Antioxidant Activities of Coleus amboinicus Lour. Cultivated in Indonesia and Poland

Coleus amboinicus Lour., Lamiaceae, is a perennial herb that is native to Indonesia and also cultivated in Africa, Asia and Australia. The major phytochemicals responsible for its bioactivity are rosmarinic acid (RA) and its analogues, flavonoids and abietane diterpenoids. The possibility of cultivation in a colder climate would extend the use of this herb and provide new opportunities to herb growers and livestock farmers. Our study to compare feed value and phytochemical composition of C. amboinicus plants cultivated in its original region, Indonesia, and in Poland. The crude protein content was significantly higher in plants cultivated in Indonesia compared to those cultivated in Poland—21% and 13% of dry matter, respectively. The higher ADF contents were detected in C. amboinicus cultivated in Indonesia, 38–41%, in comparison to 34% in plants cultivated in Poland. The phytochemical composition was also significantly influenced by the cultivation location. Polish samples were higher in polyphenols (RA and its analogues), and also had 1.5–2-fold higher antioxidant potential, as measured by DPPH scavenging, phosphomolybdenum reduction and Fenton reaction driven lipid peroxidation. The Indonesian samples contained more diterpenoid compounds, such as dihydroxyroyleanone, and the sum of terpenoids was ca. 10 times higher than in samples from Poland (15.59–23.64 vs. 1.87 µg/g of extracts). In conclusion, C. amboinicus is suitable for cultivation in non-optimal climatic conditions but some nutritional properties and bioactivity are significantly affected.     

火山岩坡残积土地区暴雨滑坡泥石流的形成机理

暴雨条件诱发的浅层坡残积土质斜坡破坏的机理受控于土体在低有效围压条件下的应力应变特性。1993年11月4～5日,香港大屿山地区特大局部性暴雨导致在120km²范围内产生自然滑坡泥石流800余处,且绝大多数发生于火山岩风化坡残积土地区。本文对火山岩风化坡残积土开展了室内偏压固结不排水剪和偏压固结常剪应力排水剪试验,揭示了该类土的应力应变特性;在此基础上,分析了暴雨滑坡泥石流的形成机理和过程。     

高效液相色谱法同时测定塑料和纸质包装材料中6种荧光增白剂

建立了同时测定塑料和纸质食品包装材料中6种脂溶性荧光增白剂(FWA 135、FWA 184、FWA 185、FWA199、FWA 378和FWA 393)的高效液相色谱方法。用三氯甲烷-乙腈(3∶7,v/v)混合溶液提取,经HLB小柱净化后用高效液相色谱-荧光检测法进行定性定量分析。采用Phenomenex C18色谱柱分离,以5 mmol/L的乙酸铵水溶液和乙腈为流动相,进行梯度洗脱。结果显示:FWA 393在15~1500μg/L范围内的线性关系良好,其余5种荧光增白剂在5~500μg/L范围内线性关系良好,相关系数均大于0.999;加标回收率为80.4%~125.0%;相对标准偏差(RSD,n=6)为1%~13%。应用该方法分析了市场销售的12个样品以验证方法的实用性。该方法前处理简单,回收率高,精密度好,适用于食品包装材料中6种荧光增白剂的检测。     

食品中霉菌毒素样品前处理及分析方法研究进展

霉菌毒素广泛存在于食物和动物饲料中,可经食物链传递危及动物与人体健康,带来严重的食品安全问题。食品基体复杂,霉菌毒素结构多样、含量极低,其分离分析需要高效的前处理技术及快速灵敏的分析方法。该文综述了基于分子印迹聚合物、量子点材料、石墨烯类碳材料、生物材料等新型分离介质的固相(微)萃取、液相(微)萃取、免疫亲和层析、磁分离等样品前处理技术及液相色谱-质谱、免疫分析法、生物传感器等分析方法在食品霉菌毒素分析中的应用,并展望了其发展趋势。     

电感耦合等离子体发射光谱法测定膨化食品中铝

目的探讨微波消解-电感耦合等离子体发射光谱法(ICP-OES)测定膨化食品中铝的可行性。方法样品经微波消解后,采用ICP-OES对膨化食品中铝进行测定。结果 ICP-OES法相对标准偏差(RSD)4.0%,线性相关系数0.999 9,回收率88.46%。结论 ICP-OES测定膨化食品中铝具有RSD小、线性相关系数好、准确度高、测定快速等优点,是测定膨化食品中铝的理想方法。     

高效液相色谱法同时测定功能饮料中烟酰胺、咖啡因、维生素B_6、柠檬黄、胭脂红和苯甲酸的含量

建立了一种同时快速检测功能饮料中烟酰胺、咖啡因、维生素B_6、柠檬黄、胭脂红和苯甲酸6种食品添加剂的高效液相色谱方法。6种食品添加剂的检出限分别为烟酰胺0.1 mg/L,咖啡因0.1 mg/L,维生素B6 0.2 mg/L,柠檬黄0.2 mg/L,胭脂红0.1 mg/L,苯甲酸0.1 mg/L,测定结果的相对标准偏差不大于4.57%(n=6),加标回收率在95.80%~113.68%之间。该方法满足GB/T 5009.197–2003,GB/T 23495–2009和SN/T 2105–2008对于上述6种食品添加剂检出限的要求。     

高效液相色谱法同时测定食品中的8种添加剂

建立高效液相色谱法同时测定食品中的安赛蜜、苯甲酸、山梨酸、苋菜红、脱氢乙酸、胭脂红、日落黄、诱惑红8种添加剂。样品采用Agilent zorbax sb–C_(18)色谱柱梯度洗脱,紫外检测器检测,外标法定量分析。结果表明,8种添加剂的质量浓度在0.5~20μg/m L范围内与其色谱峰面积线性关系良好,相关系数均大于0.999,方法检出限为0.06~0.18 mg/kg。样品的加标回收率为91.3%~101.1%,测定结果的相对偏差为0.47%~1.35%(n=6)。该方法操作简单,灵敏度高,结果准确可靠,适用于食品添加剂的常规分析。     

国内标准物质概况及重点领域发展现状

介绍标准物质的层级分类及重点领域内标准物质的研发现状。标准物质有两种分类方法:术语层级分类和计量学层级分类,国内标准物质按照等级划分为一级、二级标准物质、标准样品和行业标准样品。介绍了标准物质生产资质和标准物质证书的要求,以及重点领域医药、金属、油品、食品、环境标准物质的发展现状。