The Current State of Knowledge on Salvia hispanica and Salviae hispanicae semen (Chia Seeds)

Chia seeds (Salviae hispanicae semen) are obtained from Salvia hispanica L. This raw material is distinguished by its rich chemical composition and valuable nutritional properties. It is currently referred to as “health food”. The purpose of the present work was to perform a literature review on S. hispanica and chia seeds, focusing on their chemical composition, biological properties, dietary importance, and medicinal uses. The valuable biological properties of chia seeds are related to their rich chemical composition, with particularly high content of polyunsaturated fatty acids, essential amino acids, polyphenols, as well as vitamins and bioelements. The available scientific literature indicates the cardioprotective, hypotensive, antidiabetic, and antiatherosclerotic effects of this raw material. In addition, studies based on in vitro assays and animal and human models have proven that chia seeds are characterized by neuroprotective, hepatoprotective, anti-inflammatory, and antioxidant properties. These properties indicate a valuable role of chia in the prevention of civilization diseases. Chia seeds are increasingly popular in functional food and cosmetic and pharmaceutical industries. That is attributed not only to their desirable chemical composition and biological activity but also to their high availability. Nevertheless, S. hispanica is also the object of specific biotechnological studies aimed at elaboration of micropropagation protocols of this plant species.     

基于UMAP辅助的模糊C聚类方法进行太赫兹光谱识别

太赫兹(THz)具有低能性、瞬态性、波谱分析能力强的优点,在物质鉴别方面具有广阔的应用前景。现有的基于THz的物质鉴别方法,虽然取得了一定的效果,但是存在容易陷入局部最优的问题,从而导致识别精度不高。均匀流形逼近与投影(UMAP)作为一种非线性降维方法,其假设数据均匀分布在黎曼流形上,可以对具有模糊拓扑结构的流形进行建模。UMAP降维的过程是通过最小化两个拓扑表示之间的交叉熵,从而实现低维空间中数据表示的布局优化。传统的模糊C聚类方法(FCM)在聚类时,初始聚类中心往往随机给定,当初始聚类中心选择不恰当时,容易导致错误的聚类。为此,提出一种基于UMAP辅助的模糊C聚类算法,首先运用UMAP对输入的THz样本矩阵进行降维;再根据类与类之间距离最大化的原则,选择合适的初始聚类中心;最后利用模糊C均值聚类的方法进行聚类。所提出的方法不仅能够解决聚类过程中类与类之间过度拥挤的现象,而且能够反映出类别间的距离信息以便于给样本选择合适的初始聚类中心。为了验证提出的聚类方法的可靠性,运用太赫兹时域光谱技术对鲁棉研28、鲁棉研29、鲁棉研36、中棉28四种不同类型的转基因棉花种子进行了探测,利用基于U...     

Antimicrobial Activities of Plant Extracts against Solanum tuberosum L. Phytopathogens

The purpose of the study was to select an environmentally friendly plant biopesticide to protect seed potatoes against phytopathogens. The scope included the evaluation of the antimicrobial activities of 22 plant water extracts, 22 water-glycol extracts, and 3 subcritical carbon dioxide extracts using the agar diffusion method against 10 potato phytopathogens. For the most effective extracts, minimal inhibitory concentration (MIC), chemical composition analysis by gas chromatography–mass spectrometry and in situ assays on seed potatoes were performed. Garlic water extract was finally selected as the most effective in phytopathogen growth inhibition, both in vitro and in situ, with MIC values ranging between 6.3–25 mg/mL. 5-Hydroxymethylfurfural was determined to be the main component of this extract (33.24%). Garlic water extract was proposed as a potential biopesticide against potato phytopathogens.     

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Studies on the workability of precise seeders by means of labelling methods has been possible due to the solution of the following problems: labelling of seeds, radiation collimation of labelled seeds being sown, elaboration of measuring and registering systems as well as processing systems of a measuring signal. The developed method allows for precise, quick and fully objective evaluation of the studied seeders to be done under natural conditions.     

Microwave-assisted alkaline digestion combined with microwave-assisted distillation for the determination of iodide and total iodine in edible seaweed by catalytic spectrophotometry

Microwave energy has been novelty applied to speed up a tetramethylammonium hydroxide (TMAH) alkaline digestion of seaweed samples and to assist distillation of iodine from seaweed alkaline digests. Iodide in the alkaline digests from seaweed and distilled iodine, reduced back to iodine in a hydroxylamine hydrochloride solution, was determined by a catalytic spectrophotometric method based on the catalytic effect of iodide on the oxidation of As(III) by Ce(IV) in H₂SO₄/HCl medium (Sandell-Kolthoff reaction). The determination of iodide was directly performed in the alkaline digests, while total iodine was assessed by analyzing the hydroxylamine hydrochloride solution after the distillation process. Microwave-assisted alkaline digestion was performed using 7.5 mL of TMAH and irradiating samples at 670 W for two 5.5 min steps. Microwave-assisted distillation was carried out using 4.0 mL of the alkaline digest and 3 mL of a 2.2 M hydrochloric acid and 0.05% (m/v) sodium nitrite solution, with a microwave power at 670 W for two 90 s steps. The distillate (iodine vapor) was bubbled in 10 mL of a 500 μg mL⁻¹ hydroxylamine hydrochloride solution (accepting solution). The linear calibration ranges were 0.30-20.0 and 0.40-20.0 μg L⁻¹ for iodide determination and total iodine determination, respectively. The limit of detection was 9.2 μg g⁻¹ for iodide and 28.5 μg g⁻¹ for total iodine. Repeatability of the overall procedures, expressed as R.S.D. for 11 determinations, was 2.6% for 196.3 μg g⁻¹ of iodide measured after microwave-assisted alkaline digestion, and 5.8% for 954.3 μg g⁻¹ of total iodine by microwave-assisted alkaline digestion followed by microwave-assisted distillation. Finally, accuracy of the methods was assessed by analyzing the NIST-09 (Sargasso) certified reference material and the methods were applied to the determination of iodide and total iodine in different Atlantic edible seaweed samples with satisfactory results.     

蔬菜中叶酸的催化氧化荧光法测定

建立了催化氧化荧光法间接测定叶酸的新方法。在pH5.0的HAc-NaAc缓冲溶液中,Co2+催化KIO4氧化叶酸产生强荧光,以262 nm为激发波长,在445 nm处测定叶酸的氧化产物蝶呤-6-羧酸的荧光强度,研究了反应的适宜条件及动力学参数,并探讨了反应机理。在优化实验条件下,叶酸浓度在1.0×10-8~1.0×10-5mol/L范围内与荧光强度呈良好线性关系,回归方程为ΔIF=10.82c(μmol/L)+2.867,相关系数r=0.998 5,方法的检出限为5×10-9mol/L。对5×10-7mol/L叶酸标准溶液进行11次平行测定,相对标准偏差(RSD)为0.1%。该法使用Co2+为催化剂,大大提高了方法的灵敏度。方法用于蔬菜中叶酸的测定,加标回收率为93%~104%,6次测定的相对标准偏差为0.98%~2.1%,结果令人满意。     

气相色谱质谱法测定植物油中脂肪酸

建立了气相色谱质谱法测定食用植物性油中脂肪酸检测的方法。植物油中的脂肪酸甘油酯在碱性条件下被水解为游离脂肪酸,随后采用三氟化硼将其转化为脂肪酸甲酯。采用同位素标记脂肪酸进行加标回收试验,回收率在94%以上。通过质谱的选择离子检测模式对硬脂酸、油酸、亚油酸等10种目标脂肪酸进行了检测,结果显示,该方法可用于油品的质量检测和日常分析。     

Dynamic covalent hydrazine chemistry as a selective extraction and cleanup technique for the quantification of the Fusarium mycotoxin zearalenone in edible oils

A novel, cost-efficient method for the analytical extraction of the Fusarium mycotoxin zearalenone (ZON) from edible oils by dynamic covalent hydrazine chemistry (DCHC) was developed and validated for its application with high performance liquid chromatography-fluorescence detection (HPLC-FLD). ZON is extracted from the edible oil by hydrazone formation on a polymer resin functionalised with hydrazine groups and subsequently released by hydrolysis. Specifity and precision of this approach are superior to liquid partitioning or gel permeation chromatography (GPC). DCHC also extracts zearalanone (ZAN) but not α-/β-zearalenol or -zearalanol. The hydrodynamic properties of ZON, which were estimated using molecular simulation data, indicate that the compound is unaffected by nanofiltration through the resin pores and thus selectively extracted. The method's levels of detection and quantification are 10 and 30 μg/kg, using 0.2 g of sample. Linearity is given in the range of 10–20,000 μg/kg, the average recovery being 89%. Bias and relative standard deviations do not exceed 7%. In a sample survey of 44 commercial edible oils based on various agricultural commodities (maize, olives, nuts, seeds, etc.) ZON was detected in four maize oil samples, the average content in the positive samples being 99 μg/kg. The HPLC-FLD results were confirmed by HPLC–tandem mass spectrometry and compared to those obtained by a liquid partitioning based sample preparation procedure.     

Ultrasound-assisted extraction and determination of tartaric and malic acids from grapes and winemaking by-products

The optimization of an ultrasound-assisted extraction (UAE) method for tartaric and malic acids from grape derived samples is shown. A fractional factorial experimental design allowed for the determination of the effects of seven extraction variables. Relationships between all the variables were examined. By applying graphical analysis, the best extractions conditions were obtained. The most important variables were the extracting liquid and the extraction temperature. Later, a central composite design was applied for optimizing the temperature and the composition of the extracting liquid. The optimized method was applied to grapes and to winemaking by-products. The repeatability of the method was studied and the recovery of tartaric and malic acids was established. Organic acids quantification was done by liquid chromatography (LC) using a post-column buffer and a conductivity detector.     

12种蔬菜作物对铅,铜,镉抗性的研究

通过对12种常见蔬菜作物幼苗在Hoagland营养液中进行水培处理,对其在3种重金属(Pb2 ,Cu2 ,Cd2 )胁迫下的抗性进行了比较研究.结果表明:在12.00 mg/L Pb2 胁迫下,抗性最强的为苋菜,抗性最弱的为大白菜或小白菜;在0.50 mg/L Cu2 胁迫下,抗性最强的为空心菜,抗性最弱的为小白菜;在1.00 mg/L Cd2 胁迫下,抗性最强的为空心菜,抗性最弱的为大白菜.