Analytical Methods Applied to the Chemical Characterization and Antioxidant Properties of Three Wild Edible Mushroom Species from Northeastern Portugal

The chemical composition and the antioxidant potential of three species of wild mushrooms from Northeastern Portugal, namely Agaricus albertii, Agaricus urinascens var. excellens, and Pleurotus eryngii, were compared. Standard procedures were followed in the nutritional value evaluation, while chromatographic procedures were used to analyze free sugars, fatty acids, tocopherols, phenolic compounds, and organic acids. To assess the antioxidant potential, reducing power, radical-scavenging activity, and lipid peroxidation inhibition were evaluated. P. eryngii revealed the highest levels of macronutrients, except proteins, as also the highest sugars, tocopherols, and monounsaturated fatty acids contents. A. albertii and A. urinascens var. excellens showed similar macronutrients composition. However, A. albertii revealed the highest content in PUFA and phenolic compounds. P. eryngii revealed the highest reducing power and radical-scavenging activity and A. albertii the highest lipid peroxidation inhibition. This study provides a detailed chemical characterization and antioxidant potential evaluation of three species of wild mushrooms from Portugal not yet previously reported. Thus, this work intended to contribute to the increase of information concerning species of edible mushrooms (directed to the scientific community and general population) as well as contribute to the conservation of these resources as sources of compounds of interest.     

Effects of Gamma Irradiation on the Chemical Composition and Antioxidant Activity of Lactarius deliciosus L. Wild Edible Mushroom

The short shelf-life of mushrooms is an obstacle to the distribution and marketing of the fresh product. There has been extensive research on finding the most appropriate technology for mushrooms preservation and a particular interest arises for wild species. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. Herein, the effects of gamma irradiation on Lactarius deliciosus (L. ex Fr.) S. F. Gray chemical composition and antioxidant activity were evaluated in samples submitted to different storage periods (0, 4 and 8 days) at 4 °C. The irradiation treatments were performed in a Co-60 experimental equipment. Nutritional value was accessed by macronutrients analysis and determination of energetic value; fatty acid, sugar and tocopherol profiles were determined by gas chromatography–flame ionization detector, high-performance liquid chromatography (HPLC) refractive index and HPLC fluorescence, respectively. The antioxidant activity was evaluated through radical scavenging activity, reducing power, lipid peroxidation inhibition and phenolics content. The obtained data show that, until 1 kGy, gamma irradiation might provide a useful alternative to ensure the quality and extend the life of mushrooms, since its effects on macronutrients, energetic value, tocopherols and antioxidant activity EC₅₀ values were less significant than the changes caused by storage time. Moreover, the chemical and nutritional composition was similar in irradiated and non-irradiated L. deliciosus samples.     

食用菌馒头粉的配方设计及其品质改良

本文研究营养均衡的高品质食用菌馒头粉的配方,参照FAO/WHO规定氨基酸组成标准模式,采用氨基酸评分法计算食用菌粉和小麦粉的氨基酸组成,利用Excel线性规划求解出食用菌馒头粉的最优配方,并探讨改良剂对食用菌馒头质构特性、感官特性和面团微观结构的影响,设计响应面试验优化复合改良剂的配方。研究表明:小麦粉的氨基酸评分为33.45,食用菌馒头粉的最优配方为:小麦粉60.59%,袖珍菇粉23.07%,海鲜菇粉5.28%,双孢菇粉11.06%。在此基础上对食用菌馒头改良,设计Box-Behnken响应面试验优化改良剂的最佳配方为:谷朊粉添加量10.18%,单甘酯添加量0.50%,真菌α-淀粉酶添加量35.85 mg/kg,木聚糖酶添加量51.43 mg/kg,在此条件下,食用菌馒头感官评分的最大值为86.37,以此配方蒸制出的食用菌馒头品质较好,营养价值较高。     

食用油脂中芥酸的测定方法进展

目前已有许多关于食用油脂中芥酸测定的各种方法的报道,这些方法包括:气相色谱法、薄层色谱法、纸层析法、高效液相色谱法、质谱法、滴定法、分光光度法、浊度法和这些方法联用。给出了这些方法的重要操作条件和特点,并叙述了脂肪酸甲酯的快速制备方法。引用参考文献32篇。     

几种竹子原料的化学组成与纤维形态及其CMP制浆性能的研究

比较了粉单竹、撑篙竹、撑绿竹三种竹子原料的化学组成、纤维形态、制浆性能。从原料组份看,粉单竹的化学组成优于撑篙竹和撑绿竹,含有较高的纤维素和半纤维素,较低的木素和抽出物含量。通过纤维特性分析,粉单竹具有优质造纸材料所要求的纤维形态,粉单竹的纤维长度和纤维长宽比属优以上。扫描电子显微镜观测显示:粉单竹以呈多层结构、壁薄、胞腔大的纤维细胞为主,且含有较多的薄壁细胞。粉单竹的CMP制浆性能在几种竹子中也是最好的。因此,筛选粉单竹作为竹子化机浆和生物化机浆的研究对象。     

Comparison between Supercritical CO2 Extraction and Hydrodistillation for Two Species of Eucalyptus: Yield,Chemical Composition,and Antioxidant Activity

In this work, 2 Eucalyptus species extracts (Eucalyptus cinerea and Eucalyptus camaldulensis) were prepared by hydrodistillation (HD) and supercritical carbon dioxide extraction (SCE) techniques. The best yields of E. cinerea and E. camaldulensis (27.5 and 8.8 g/kg, respectively) were obtained using SCE at 90 bar, 40 °C compared to HD (23 and 6.2 g/kg, respectively). Extracts were quantified by gas chromatography‐flame ionization detection and identified by gas chromatography‐mass spectrometry. 1,8‐cineole and p‐menth‐1‐en‐8‐ol were the major compounds of E. cinerea essential oil obtained by HD (64.89% and 8.15%, respectively) or by SCE (16.1% and 31.87%, respectively). Whereas, in case of E. camaldulensis, 1,8‐cineole (45.71%) and p‐cymene (17.14%) were the major compounds obtained by HD, and 8,14‐cedranoxide (43.79%) and elemol (6.3%) by SCE. Their antioxidant activity was assessed using 2 methods: 2,2‐azino‐di‐3‐ethylbenzothialozine‐sulphonic acid radical cation (ABTS^?+) and 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH^?). In the SCE extracts from both E. cinerea and E. camaldulensis, a promising radical scavenging activity was observed with ABTS^?+, (65 and 128 mg/L, respectively). The total phenolics composition of the extracts was measured and the range was 2 to 60 mg of gallic acid equivalent/g dry plant material. The SCE method was superior to HD, regarding shorter extraction times (30 min for SCE compared with 4 h for HD), a low environmental impact, allows production of nondegraded compounds and being part of green chemistry.     

银杏叶提取物的化学成分、生物活性及应用研究进展

银杏叶提取物有多种化学成分和药理功能,在药品、食品行业有巨大的开发潜能。查阅大量文献,对现有的关于不同条件下银杏叶提取物的化学成分、生物活性及其具体应用的资料进行分析、研究和综合,以期为今后银杏资源的开发利用和更深层次的研究做参考。     

Simultaneous Spectrophotometric Determination of 2-Thiouracil and 2-Mercaptobenzimidazole in Animal Tissue Using Multivariate Calibration Methods: Concerns and Rapid Methods for Detection

ABSTRACT: Two multivariate calibration methods, partial least squares (PLS) and principal component regression (PCR), were applied to the spectrophotometric simultaneous determination of 2-mercaptobenzimidazole (MB) and 2-thiouracil (TU). A genetic algorithm (GA) using partial least squares was successfully utilized as a variable selection method. The concentration model was based on the absorption spectra in the range of 200 to 350 nm for 25 different mixtures of MB and TU. The calibration curve was linear across the concentration range of 1 to 10 μg mL⁻¹ and 1.5 to 15 μg mL⁻¹ for MB and TU, respectively. The values of the root mean squares error of prediction (RMSEP) were 0.3984, 0.1066, and 0.0713 for MB and 0.2010, 0.1667, and 0.1115 for TU, which were obtained using PCR, PLS, and GA-PLS, respectively. Finally, the practical applicability of the GA-PLS method was effectively evaluated by the concurrent detection of both analytes in animal tissues. It should also be mentioned that the proposed method is a simple and rapid way that requires no preliminary separation steps and can be used easily for the analysis of these compounds, especially in quality control laboratories.     

Functional Properties of the Great Northern Bean (Phaseolus Vulgaris L.) Proteins. Amino Acid Composition, In Vitro Digestibility, and Application to Cookies

The Great Northern bean flour proteins, albumins, and protein isolates were characterized by high acidic ammo acid content while globulins and protein concentrates had high proportion of hydrophobic amino acids. Sulfur containing ammo acids and leucine were first and second limiting ammo acids in these proteins, respectively. The bean proteins were resistant to in vitro enzymatic attack. Heating improved in vitro susceptibility of these bean proteins to enzymatic hydrolysis. Moist heat was more effective than dry heat in improving in vitro digestibility of the bean proteins. Cookie diameter was negatively correlated to alkaline water retention capacity of the blends of wheat flour with bean flour (r =–0.90) and protein concentrates (r =–0.93).     

Standardization of Nanoparticle Characterization: Methods for Testing Properties,Stability, and Functionality of Edible Nanoparticles

There has been a rapid increase in the fabrication of various kinds of edible nanoparticles for oral delivery of bioactive agents, such as those constructed from proteins, carbohydrates, lipids, and/or minerals. It is currently difficult to compare the relative advantages and disadvantages of different kinds of nanoparticle-based delivery systems because researchers use different analytical instruments and protocols to characterize them. In this paper, we briefly review the various analytical methods available for characterizing the properties of edible nanoparticles, such as composition, morphology, size, charge, physical state, and stability. This information is then used to propose a number of standardized protocols for characterizing nanoparticle properties, for evaluating their stability to environmental stresses, and for predicting their biological fate. Implementation of these protocols would facilitate comparison of the performance of nanoparticles under standardized conditions, which would facilitate the rational selection of nanoparticle-based delivery systems for different applications in the food, health care, and pharmaceutical industries.     

大豆蛋白功能特性的测定方法及其在肉制品中的使用

介绍了大豆蛋白的功能特性测定方法及其在肉制品中的具体应用和作用.     

The Association between Chromaticity,Phenolics, Carotenoids,and In Vitro Antioxidant Activity of Frozen Fruit Pulp in Brazil: An Application of Chemometrics

A total of 19 Brazilian frozen pulps from the following fruits: açai (Euterpe oleracea), blackberry (Rubus sp.), cajá (Spondias mombin), cashew (Anacardium occidentale), cocoa (Theobroma cacao), coconut (Cocos nucifera), grape (Vitis sp.), graviola (Annona muricata), guava (Psidium guajava), papaya (Carica papaya), peach (Prunus persica), pineapple (Ananas comosus), pineapple and mint (A. comosus and Mentha spicata), red fruits (Rubus sp. and Fragaria sp.), seriguela (Spondias purpurea), strawberry (Fragaria sp.), tamarind (Tamarindus indica), umbu (Spondias tuberosa), and yellow passion fruit (Passiflora edulis) were analyzed in terms of chromaticity, phenolic compounds, carotenoids, and in vitro antioxidant activity using ferric reducing antioxidant power (FRAP) and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assays. Data were processed using principal component analysis (PCA) and hierarchical cluster analysis (HCA). Antioxidant capacity was measured by DPPH and FRAP assays, which showed significant (P < 0.01) correlation with total phenolic compounds (r = 0.88 and 0.70, respectively), total flavonoids (r = 0.63 and 0.81, respectively), and total monomeric anthocyanins (r = 0.59 and 0.73, respectively). PCA explained 74.82% of total variance of data, and the separation into 3 groups in a scatter plot was verified. Three clusters also suggested by HCA, corroborated with PCA, in which cluster 3 was formed by strawberry, red fruits, blackberry, açaí, and grape pulps. This cluster showed the highest contents of total phenolic compounds, total flavonoids, and antioxidant activity.     

气相色谱法测定不同产地花椒挥发油中芳樟醇和柠檬烯含量的研究

采用气相色谱法测定了不同产地32批次花椒挥发油中柠檬烯和芳樟醇的含量.结果发现:青花椒挥发油中柠檬烯的含量均值为12.888 mg/g,红花椒挥发油中柠檬烯的含量均值为14.040 mg/g,青花椒挥发油中柠檬烯的含量与红花椒之间无显著性差异(P＞0.05);青花椒挥发油中芳樟醇的含量均值为红花椒的9.13倍,分别为72.523 mg/g和7.941 mg/g,且青花椒挥发油中芳樟醇的含量与红花椒之间存在极显著性差异(P≤0.01).该试验结果可作为青花椒和红花椒品种间鉴别指标的依据之一.     

电感耦合等离子体质谱法测定高钙片中铅、砷、铬和镉含量的不确定度评定

对采用电感耦合等离子体质谱(inductively couple plasma mass spectrometer,ICP-MS)法测定高钙片中铅、砷、铬和镉含量的测量不确定度进行评定。依据有关规定,建立测定高钙片中4种元素含量的不确定度数学模型,分析测量不确定度的来源,计算各不确定度分量并进行合成。结果表明,铅、砷、铬和镉的扩展不确定度分别为0.056、0.026、0.015、0.024 mg/kg;不确定度主要来源于标准溶液的配制、测量重复性和标准曲线拟合。     

ICP-MS法同时测试卷烟纸中锌、硒、锂、镁

将电感耦合等离子体质谱技术应用于卷烟纸中锌、硒、锂、镁测定,根据卷烟纸的特殊性,样品利用微波消解的方法,分析时采用电感耦合等离子体质谱检测。该方法具有良好的线性(r=0.999977~0.999998)和精密度(RSD在5.0%以下),回收率在95.8%~102.3%之间,检出限在0.054μg/L~0.121μg/L之间。该方法操作简单、快速,灵敏度高,结果准确、可靠。     

Species Authentication Methods in Foods and Feeds: the Present,Past, and Future of Halal Forensics

We extensively reviewed the existing as well as the potentials of the molecular biology and nanotechnology methods for the identification of animal-derived materials in foods and feeds. The verification of animal-derived materials in foods and feeds is mandatory by several religious as well as regional and state laws. It is also essential to limit the transmission of food-borne pathogens and allergens. Verification of declared components further helps prevent unfair trades and protect consumers' trusts, religious faiths, and hard-earned fortunes. In this review, special emphasis is given to the molecular markers and their tracing tools in biology and nanotechnology. Among the four types of biomolecules, known as proteins, lipids, carbohydrates, and nucleic acids, DNA has been reported as the most appropriate biomarker to identify the source of animal-derived materials. While PCR has got enormous attention as the most effective molecular identification tool, PCR-based methods are not suitable for the unambiguous identification of very short DNA targets (15–30 bp) which can survive even in the harsh conditions of food and feed processing. Nanotechnology-based approaches using nanogap electrodes, quantum dots (QDs), and SERS-active nanoparticle shells are highly sensitive and can detect very short oligo targets almost at single-molecule sensitivity. However, nanogap fabrication has remained a challenging task and also involves complicated surface modification and immobilization chemistries. QD and SERS-based techniques also demand surface modifications and immobilization chemistries. On the other hand, gold nanoparticle (GNP)-based hybridization detection is label-free, sensitive, and does not involve any modification chemistry and expensive instrumentations. GNP-based biosensors offer a low-cost platform to detect and quantify short-length DNA markers in mixed biological and processed commercial foods.     

GC/MS Method for the Determination of Adipate Plasticizers in Ham Sausage and Its Application to Kinetic and Penetration Studies

ABSTRACT:  A GC/MS method was developed and successfully validated for the determination of adipate plasticizers in ham sausage migrated from polyvinylidene chloride (PVDC) packaging film. The sample pretreatment includes liquid extraction, solvent evaporation, and reconstitution before and after solid phase extraction (SPE). For the 5 adipate plasticizers studied, the SPE process with Oasis MAX cartridge showed an extraction efficiency from 85.7% to 106%, and the calibration curves are all linear in the range of 5 to 1000 ng/g with correlation coefficients greater than 0.998. The method proved to be accurate and precise; the average intraday recovery ranges from 85.4% to 114.6% with a %CV value from 2.5 to 11.3, and the average interday recovery from 83.6% to 118.5% with a %CV value from 2.8 to 15.6, respectively, for the adipate plasticizers. The method is sensitive and was effectively applied in the kinetic and penetration studies of the adipate plasticizers migrating from food-grade PVDC packaging film into ham sausage. The experimental data showed that approximately 6.8% of dibutyl adipate (DBA) in the packaging film migrated into the ham sausage in 4 mo and the migration reached the innermost portion of the sausage in 6 mo.