Determination of phenolic profile and antioxidant activity of pistachio hull using high-performance liquid chromatography–diode array detector–electro-spray ionization–mass spectrometry as affected by ultrasound and microwave

The phytochemicals content and radical scavenging activity of pistachio (Pistacia vera L.) hull extract obtained by different solvents (water, ethanol, and butanol) were measured and compared. Water was selected as superior solvent. Ultrasound-assisted aqueous extraction of the hull by power ultrasound (35 kHz) was more efficient in ascending the phytochemicals content than the sonochemical ultrasonication (130 kHz). High-performance liquid chromatography-mass spectrometry showed increased amounts of vanillic acid, p-coumaric acid, naringenin, and catechin in ultrasound-assisted extracts. Post-extraction sonication declined significantly the phenolics amount and antioxidant property of the aqueous extract. Microwave-assisted extraction increased the phenolics and flavonoids content at extract in a power-dependent trend.     

元江芦荟不同部位香气物质差异性分析

利用顶空-气相色谱-串联质谱(HS-GC-MS/MS)联用分析法在线分析云南元江库拉索芦荟根、叶表皮、凝胶3个部位的香气主要成分,采用峰面积归一化法计算各组分的相对含量。结果表明,元江芦荟不同部位香气物质差异性较大。     

Effect of High Pressure Pretreatments on Structural and Dehydration Characteristics of Aloe Vera (Aloe barbadensis Miller) Cubes

The effect of high-pressure (HP) pretreatments (300–500 MPa for 5–15 min) on dehydration characteristics of aloe vera cubes (AVC), dried at 50–70°C and air velocity of 1–2 m/s, was studied. Pretreatments resulted in higher drying rates, leading to a reduction in drying time compared to untreated ones. The drying rate and drying time were most significantly affected (p < 0.05) by the drying temperature, followed by air velocity, pressure level, and dwell time. HPP enhanced the firmness of AVC with a maximum of up to 21% for the sample treated at 500 MPa for 15 min. Microstructural analysis using scanning electron microscopy (SEM) indicated non-uniform structures in the pretreated and dried AVC samples. Semi-quantitative elemental detection (EDS) confirmed the presence of a considerable amount (14%) of calcium in aloe vera.     

Synthesis and magnetic properties of nano-sized Cu0.5Ni0.5Fe2O4 via citrate and aloe vera: A comparative study

In this report, Cu_0.5Ni_0.5Fe₂O₄ nanoparticles were synthesized by solgel using eco-friendly aloe vera extract and citric acid separately and their properties were discussed. Structural, Functional, morphological, magnetic properties of the samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Transmission electron microscopy (TEM), Vibrating sample magnetometer (VSM). XRD exhibited the samples have single phase cubic spinel with average size of 46.4?nm and 35.45?nm. Two characteristics bands of ferrite were confirmed by FTIR. TEM indicated different morphology of the samples with some regularity. VSM data showed that higher coercivity for the sample prepared by aloe vera extract.     

Essential oil yield and composition of Pistacia vera ‘Kerman’ fruits,peduncles and leaves grown in California

BACKGROUND: Pistacia vera ‘Kerman’ is the predominant pistachio nut cultivar in the United States (California), the world's second largest producer. Despite several reports on the essential oil (EO) content in the genus Pistacia, data on ‘Kerman’ are limited. The EO content and volatile organic compound (VOC) emissions of tree nut orchards are of current interest to researchers investigating insect pests and the potential role of EO and VOCs as semiochemicals. To establish a basis for the VOC output of pistachios, the EO content of fruits, peduncles, and leaves was analyzed. RESULTS: Evaluated plant parts contained limonene as the primary EO component, followed by α‐terpinolene. Peduncles were unique in containing relatively high levels of α‐thujene. The results were reproducible between two different geographical locations. In situ solid phase microextraction (SPME) studies demonstrated the volatile emission was representative of the EO composition. CONCLUSION: This is the first report detailing the content and distribution of EO and the unique limonene‐dominant profile for this Pistacia vera cultivar which may influence pistachio insect pest semiochemical research. Copyright © 2010 Society of Chemical Industry     

芦荟制品的酶促褐变及其控制措施

分析了芦荟制品酶促褐变机理，研究了加工过程，pH、温度、贮存时间等因素对芦荟制品酶促褐变的影响，总结了控制芦荟制品酶促褐变的主要方法，如热处理、酸处理、亚硫酸盐或其它化学试剂处理、隔绝或除去氧气等。     

芦荟汁抗菌作用研究

用一系列真菌和细菌试验了芦荟汁的抑菌作用。结果表明 :芦荟汁对G+和G- 氏细菌 ,以及部分霉菌的生长有较强的抑制作用 ;芦荟汁还具有热稳定性强 ,抑菌浓度低 ,抑菌pH范围广的特点。对酵母的抑制作用不明显。     

Effect of roasting on colour and volatile composition of pistachios (Pistacia vera L.)

Pistachios have been roasted following the Iranian traditional method (soaking in salty water, drying and roasting at 135 °C). Three Iranian pistachio cultivars (Ahmad Aghaei, Akbari and Kaleghouchi) were compared for their volatile compositions, colour and odour intensity. Lightness decreased in the course of roasting, which resulted from Maillard reaction. Raw pistachios had lower concentrations of most volatiles than roasted. A total of twenty‐six compounds were detected in roasted pistachios; these included aldehydes, terpenes, alcohols and only two pyrazines and one furan. These mixtures of volatiles implied that the Iranian roasting system is very soft, and samples retained most of the vegetable notes from fresh pistachios and some roasted notes were generated as well (from 2‐ethyl‐5‐methylpyrazine and 2,6‐dimethyl‐3‐ethylpyrazine). Sample from cultivar Akbari presented higher odour intensity than those by the other two cultivars, due mainly to higher concentrations of pyrazines developed during the roasting step.     

芦荟制品褐变原因的研究

根据芦荟在结构和成分上的特殊性 ,对芦荟制品褐变现象产生的原因进行了分析 ,并对运用物理和化学的方法控制芦荟制品褐变现象的效果进行了分析和探讨 ,结果认为合理运用物理和化学方法来控制芦荟制品褐变能获得较好的效果。