麦卢卡蜂蜜快速鉴别技术的开发与应用

建立了一种简单、快速的麦卢卡蜂蜜鉴别方法。该方法通过简单液液萃取,并结合LC-MS/MS高灵敏度检测技术,可实现对麦卢卡蜂蜜标志物-丁香酸甲酯的定量检测,以及对麦卢卡蜂蜜样品的特征峰(535.0-323.0,535.0-211.0)的识别。通过比较各类蜂蜜中丁香酸甲酯的含量差异性,并结合麦卢卡蜜的特征峰分析,可实现对麦卢卡蜂蜜和我国6种常见蜂蜜(油菜蜜、洋槐蜜、椴树蜜、荔枝蜜、荆条蜜和枣花蜜)的品种鉴别。     

蜂蜜流变特性及其质量鉴定

对紫云英蜂蜜和白砂糖溶液以及二者的混和液进行流变试验,建立了流变体模型(New-ton)。并就温度和浓度对粘度的影响进行分析,提出采用测粘度的方法鉴别紫云蜜是否掺水和掺糖。     

云南3种特色蜂蜜糖组分的稳定碳同位素比值测定与分析

为了研究云南3种特色蜂蜜的碳同位素分布规律,本试验采用元素分析-同位素比质谱法(EA-IRMS)和液相色谱-同位素比质谱法(LC-IRMS)对60份云南特色蜂蜜(苕子蜜、澳洲坚果蜜和橡胶蜜)的六项碳同位素比值,即果糖、葡萄糖、二糖、三糖、蜂蜜和蜂蜜蛋白的δ¹³C值进行了测定。对云南3种特色蜂蜜的六项碳同位素比值的分布区间、果糖与葡萄糖的差值(Δδ¹³C_{果糖-葡萄糖})、蛋白与蜂蜜的差值(Δδ¹³C_{蛋白-蜂蜜})、最大差值(Δδ¹³C_max)、果葡比(F/G)等参数进行了统计和偏最小二乘判别分析,并与现有蜂蜜掺假鉴别的指标进行了比对。结果表明,部分蜂蜜样品(占比20%)不满足现有评价标准(Δδ¹³C_max ≤±2.1‰)。通过构建偏最小二乘法判别分析(PLS-DA)模型可以实现3个蜜种的有效分类鉴别,主要差异性指标为三糖的δ¹³C值、三糖含量和二糖含量。本研究结果为特色蜂蜜的鉴别和品质评价提供了技术支撑,有利于促进云南乃至我国蜂蜜品质和质量的提升。     

国产蜂蜜流变特性研究(英)

采用流变学方法对国产蜂蜜流变特性进行了研究。流变试验数据分析表明国产蜂蜜流变模型为Ｎｅｗｔｏｎ体，而非过去所认为的Ｂｉｎｇｈａｍ体。影响国产蜂蜜粘度的诸因素中，水分的影响最为显著。建立了国产蜂蜜ｗ－ｔ－η图，以充分描述其水分、温度与粘度之间的各种关系     

南京市售蜂蜜的流变特性(第1报)——蜂蜜的流变模型

作者用NXS—11型旋转粘度计对八种南京市售蜂蜜进行测定,并对试验数据进行回归分析,建立了这八种蜂蜜的通用流变模型——Bingham模型。     

蜂蜜中转基因成分的PCR检测

我国是蜂蜜生产大国,棉花是主要蜜源植物之一。近些年来,我国种植的棉花大多为转基因抗虫棉,棉花蜜中是否含有转基因成分,引起国内外广大消费者的密切关注。本文以抗虫棉种植地采取的棉花蜜为原料,采用改良CTAB法,在DNA提取过程中,用PBS缓冲液除去其中大部分的可溶性多糖,并提高CTAB提取缓冲液中NaCl浓度以去除残余多糖,从蜂蜜中成功提取出片段完整、纯度较高的DNA,DNA得率为486ng/mL,OD260/OD280为2.01,能够满足后续PCR定性检测的需求。从以转基因棉花为蜜源的蜂蜜中检测出外源DNA片段,建立了蜂蜜中转基因成分的PCR检测技术。本研究对转基因食品标识制度的完善、转基因食品监管、减少贸易摩擦以及保证消费者权益等具有重要意义。     

近红外光谱结合化学计量学方法检测蜂蜜产地

为了实现蜂蜜产地的快速判别,应用近红外光谱结合化学计量学方法对蜂蜜产地进行了判别分析。kennard-Stone法划分训练集和预测集。光谱用一阶导数加自归一化预处理后,再用小波变换（WT）进行压缩和滤噪。结合滤波后光谱信息,分别用径向基神经网络（RBFNN）和偏最小二乘-线性判别分析（PLS-LDA）建立了苹果蜜产地和油菜蜜产地的判别模型。对不同小波基和分解尺度进行了讨论。对苹果蜜,WT-RBFNN模型和WT-PLS-LDA模型都是小波基为db1、分解尺度为2时的预测精度较好,都为96.2%。对油菜蜜：WT-RBFNN模型在小波基为db4和分解尺度为1时,预测精度较好,为85.7%;WT-PLS-LDA模型在小波基为db9、分解尺度也为1时,预测精度较好,为90.5%。研究表明：WT结合线性的PLS-LDA建模比WT结合非线性的RBFNN建模更适于蜂蜜产地判别;近红外光谱技术具有快速判别蜂蜜产地的潜力。     

加热处理对蜂蜜酒香气物质的影响

为研究适合蜂蜜酒发酵的优良工艺条件,以2批荆条蜜(白色和浅琥珀色)为原料,在酒精发酵前对发酵醪液进行加热处理,以不加热处理的样品为对照,采用酿酒酵母FX10进行发酵,发酵结束后测定蜂蜜酒的各项理化指标及挥发性化合物的含量。结果表明,供试酒样中共检测出77种挥发性物质,其中酯类39种、醇类20种、酸类8种、萜烯类4种、羰基化合物6种。加热处理可以显著增加蜂蜜酒中香气物质的种类和含量,含量较高的香气物质有乙酸乙酯、乙酸苯乙酯、乙酸异戊酯、己酸乙酯、辛酸乙酯、癸酸乙酯、月桂酸乙酯、9-十六碳烯酸乙酯、异戊醇、β-苯乙醇、辛酸和癸酸。对蜂蜜酒中香气物质进行主成分分析,发现加热处理的酒样中酯类物质对酒香贡献较大;对照酒样中酯类物质对酒香贡献较小,而醇类物质是其主要挥发性成分。本研究结果为蜂蜜酒的生产提供了一定的理论依据。     

3个金柑品种叶绿素荧光特性的比较研究

以融安金柑、滑皮金柑和脆蜜金柑3个金柑品种为研究对象,测定其叶绿素含量和叶绿素荧光参数,并进行数据比较分析,探究3个品种间的光合生理特性,旨在为金柑品种的光合作用机理和栽培技术研究提供科学参考。研究结果表明融安金柑的叶绿素a (Chla)、叶绿素b(Chlb)、总叶绿素(Chl)及类胡萝卜(Car)含量显著高于滑皮金柑和脆蜜金柑,但叶绿素a与叶绿素b比值(Chla/Chlb)显著低于滑皮金柑和脆蜜金柑。此外,3个金柑品种的叶片叶绿素荧光参数比较分析结果显示,融安金柑的Fo和NPQ值显著高于滑皮金柑和脆蜜金柑,Fv/Fm、ΦPSII和ETR值显著低于滑皮金柑和脆蜜金柑,滑皮金柑和脆蜜金柑之间的叶绿素荧光参数差异不显著。综合比较,滑皮金柑和脆蜜金柑的叶片光合效率高于融安金柑,但融安金柑对抵御光抑制的能力强于前两者,具有较强的耐光性。     

近红外光谱结合小波变换预处理在蜂蜜产地快速检测中的应用

应用近红外光谱结合化学计量学方法对蜂蜜产地进行了判别分析。kennard-Stone法划分训练集和预测集。光谱用一阶导数加自归一化预处理后,再用小波变换（WT）进行压缩和滤噪。结合滤波后光谱信息,分别用径向基神经网络（RBFNN）和偏最小二乘-线性判别分析（PLS-LDA）建立了苹果蜜产地和油菜蜜产地判别模型。对不同小波基和分解尺度进行了详细讨论。对苹果蜜,WT-RBFNN模型和WT-PLS-LDA模型都是小波基为db1、分解尺度为2时的预测精度最好,都为96.2%。对油菜蜜：WT-RBFNN模型在小波基为db4和分解尺度为1时,预测精度最好;WT-PLS-LDA模型在小波基为db9、分解尺度也为1时,预测精度最好,为90.5%;预测精度WT-PLS-LDA模型优于WT-RBFNN模型。研究表明：WT结合线性的PLS-LDA建模比WT结合非线性的RBFNN建模更适于蜂蜜产地鉴别;近红外光谱结合WT-PLS-LDA可实现对蜂蜜产地的快速无损检测,为蜂蜜产地鉴别提供了一种新方法。     

Effects of Sewage Sludge and Acacia dealbata Composts on Soil Biochemical and Chemical Properties

We studied the effects of different composts made of different mixtures of sewage sludge and Acacia plants on the soil biochemical and chemical properties. The proportions of mixed acacia plant and sewage sludge were: AL1/1 (50% acacia/50% sewage sludge), AL1/2 (33.3% acacia/66.6% sewage sludge), and AL1/3 (25% acacia/75% sewage sludge). Composts were added to the soil at a rate of 2%. Soil samples were collected during 150 days and analyzed for soil enzyme activities and chemical properties. An unamended soil was used as the control. Compared to the AL1/1 treatment, soil dehydrogenase, urease, phosphatase and β-glucosidase activities decreased respectively by 14.6%, 15.4%, 12.5%, and 19.3% for AL1/2 treatment and by 20.7%, 25.6%, 23.7%, and 28.4% for AL1/3 treatment. Soil water-soluble carbohydrates and polyphenols were the greatest in AL1/1. The lowest contents of heavy metals in the AL1/1 compost may be responsible for the increase of soil biochemical and chemical properties.     

Acacia, cattle and migratory birds in southeastern Mexico

Acacia pennatula groves in mid-elevation valleys of southern Mexico supported both the highest density and diversity of migratory birds compared to other habitats in the region. In addition, we found the highest numbers for over half of the common migratory species. Despite the high degree of leaf loss during the late winter, acacia groves do not experience greater declines in insectivorous migratory bird populations than other local habitats. Color-marked individuals of canopy species had a strong tendency to remain resident within a single acacia grove throughout the winter. Management of native acacias on subtropical rangelands for wood products, fodder, and soil improvement would probably directly and indirectly benefit migratory song bird populations. Neotropical acacia woodland is primarily associated with grazing land for livestock which might discourage some from considering acacia management a viable option for migratory bird conservation. However, acacias were probably widespread in recent geologic time under drier conditions with heavy browsing and seed dispersal by a now extinct megafauna. Two observations suggest a foraging advantage for acacia use: the higher density of migratory birds in acacia is a result of higher numbers of canopy insectivores; and acacias are selected by migrants when they occur in mixed habitat. We hypothesize that plant investment in mechanical defenses (thorns) reduces energy available for chemical defenses effective against insect herbivores.     

Kinetics of formation and functional properties of conjugates prepared by dry-state incubation of beta-lactoglobulin/acacia gum electrostatic complexes

The formation of conjugates between beta-lactoglobulin and acacia gum based on electrostatic complexes formed at pH 4.2 was investigated upon dry-state incubation for up to 14 days at 60 degrees C and 79% relative humidity (RH). By means of SEC-HPLC and RP-HPLC, it was shown that the beta-lactoglobulin incubated alone was able to form polymers with molecular masses higher than 200 kDa until 50% of the initial monomeric protein disappeared after 14 days. In the presence of acacia gum at initial protein to polysaccharide weight mixing ratios of 2:1 and 1:2, only 35% of the initial beta-lactoglobulin monomers disappeared after 14 days. Using RP-HPLC, an apparent reaction order of 2 was found for the disappearance of monomeric beta-lactoglobulin both in the presence or absence of acacia gum. However, the reaction rate was faster in the absence of acacia gum. SDS-PAGE electrophoresis with silver staining confirmed the formation of beta-lactoglobulin/acacia gum conjugates. The solubility curves of the incubated beta-lactoglobulin showed a minimum around pH 4-5. By contrast, the minimum of solubility of the beta-lactoglobulin/acacia gum incubated mixtures shifted to lower pH values compared to initial mixtures. The conjugates exhibited higher foam capacity than the incubated protein as well as lower equilibrium air/water surface tension. Conjugation at ratio 1:2 led to increased interfacial viscosity (300 mN s m(-1) at 0.01 Hz) compared to beta-lactoglobulin alone (100 mN s m(-1) at 0.01 Hz), but similar interfacial elasticity (30-40 mN m(-1)). The foam capacity of the conjugates was significantly higher than that of the incubated beta-lactoglobulin as well as foam expansion and drainage time, especially at pH 5.3, i.e., higher than the pH of formation of the conjugates.     

甘薯粉团的触变性研究

针对传统的粉丝加工过程中粉团所表现出的流变性质,作者用NXS—11型旋转粘度计对粉团的触变性进行了初步的测定和研究。通过回归分析,建立起粉团在触变条件下的流变模型方程并探讨了粉团含水量、含芡量对粉团触变性的影响以及粉团的表观粘度随剪切时间变化的一般性规律。     

Geographical characterization of polyfloral and acacia honeys by nuclear magnetic resonance and chemometrics

The importance of geographical origin determination is an increasing and pressing requirement for all foods. Honey is one of the largest studied foods due to its nutritional and medicinal properties in a correct diet. In this paper, a total of 41 honey samples (polyfloral and acacia) from different countries have been analyzed in terms of (1)H NMR spectroscopy coupled with multivariate statistical methods. Unsupervised principal component analysis resulted as an efficient tool in distinguishing (1)H NMR spectra of polyfloral and acacia honey samples and for geographical characterization of the latter ones. Hierarchical projection to latent structures discriminant analysis was successfully applied for the discrimination among polyfloral honey samples of different geographical origins. (13)C NMR spectroscopy was applied to honey samples with the aim to investigate possible sugar isoforms differentiation. Our preliminary data indicated a different isoforms ratio between betaFP and betaFF only for polyfloral Argentinean samples, while Hungarian samples showed resonance shifts for some carbons of alphaFF, betaFP, betaFF, and alphaGP isoforms for both varieties. These data confirmed the potentiality of (13)C spectroscopy in food characterization, especially in sugar-based foods.     

Effect of toasting intensity at cooperage on phenolic compounds in acacia (Robinia pseudoacacia) heartwood

The phenolic composition of heartwood from Robinia pseudoacacia, commonly known as false acacia, before and after toasting in cooperage was studied by HPLC-DAD and HPLC-DAD/ESI-MS/MS. A total of 41 flavonoid and nonflavonoid compounds were identified, some tentatively, and quantified. Seasoned acacia wood showed high concentrations of flavonoid and low levels of nonflavonoid compounds, the main compounds being the dihydroflavonols dihydrorobinetin, fustin, tetrahydroxy, and trihydroxymethoxy dihydroflavonol, the flavonol robinetin, the flavanones robtin and butin, and a leucorobinetinidin, none of which are found in oak wood. The low molecular weight (LMW) phenolic compounds present also differed from those found in oak, since compounds with a β-resorcylic structure, gallic related compounds, protocatechuic aldehyde, and some hydroxycinnamic compounds are included, but only a little gallic and ellagic acid. Toasting changed the chromatographic profiles of extracts spectacularly. Thus, the toasted acacia wood contributed flavonoids and condensed tannins (prorobinetin type) in inverse proportion to toasting intensity, while LMW phenolic compounds were directly proportional to toasting intensity, except for gallic and ellagic acid and related compounds. Even though toasting reduced differences between oak and acacia, particular characteristics of this wood must be taken into account when considering its use in cooperage: the presence of flavonoids and compounds with β-resorcylic structure and the absence of hydrolyzable tannins.     

Importance of Protein‐Rich Components in Emulsifying Properties of Corn Fiber Gum

Purified corn fiber gum (CFG‐F) isolated from fine (kernel endosperm‐derived) corn fiber that contained ≈2% residual protein was extracted with 70% aqueous ethanol. The aqueous ethanol extract (AEE), which contained 19.5% of the total CFG, contained a high percentage of the proteinaceous material present in the original gum sample. The AEE gum contained 6.81% protein by weight. The residue (R), which constituted 66% of the total CFG‐F, contained only 0.55% of protein. The emulsifying properties of R and AEE in a model oil‐in‐water emulsification system were studied by measuring turbidity after 1, 2, and 3 weeks, particle size after 4 weeks, and by confocal laser scanning microscopy after three months of storage at room temperature. These gums were compared with the standard well‐known emulsifiers native acacia gum (NAG) and modified acacia gum (MAG). The results indicate that although AEE contains protein‐rich components, it is not as good an emulsifier as the residue which contains only 0.55% of protein. However, emulsions prepared with the whole (unfractionated) CFG‐F under similar conditions were more stable showing higher turbidity and smaller particles size than those prepared with either R or AEE.     

Use of Acacia Waste Compost as an Alternative Component for Horticultural Substrates

The rising cost of peat and pine bark has boosted the demand for alternative organic materials for container growing media. Here, composts of invasive acacia (Acacia longifolia and Acacia melanoxylon) residues were evaluated as alternative organic materials for horticultural substrates. Compost bulk density was less than 0.4 g cm^?3 and total pore space was more than 85 percent of the total volume, as established for an ideal substrate. The matured acacia compost air capacity, easily available water, buffering capacity, and total water-holding capacity were also within acceptable recommended values. With increased composting time the physical characteristics of the composts were improved, but the same was not true for chemical characteristics such as pH and electrical conductivity. The replacement of pine bark compost by acacia compost in a commercial substrate did not negatively affect either lettuce emergence or lettuce growth, suggesting that acacia compost can be successfully used as an alternative component for horticultural substrates.     

Honey as a protective agent against lipid oxidation in ground turkey.

Lipid oxidation is a major deteriorative factor in meats. Sources of natural antioxidants that are as effective as commercially available antioxidants are desired. The objective of this research was to investigate honey as an inhibitor of lipid oxidation in ground poultry. The antioxidant content of different varieties of honey was investigated spectrophotometrically and honey's effectiveness in reducing oxidation of ground poultry determined by monitoring thiobarbituric acid reactive substances (TBARS). Buckwheat honey had the highest antioxidant content and acacia honey the lowest. Honeys of different floral sources differed in their protection against lipid oxidation. Buckwheat honey (5%, w/w) reduced TBARS approximately 70%, whereas acacia honey reduced TBARS approximately 34% at 3 days of storage at 4 degrees C. In comparison to butylated hydroxytoluene and tocopherol (0.02% of total fat), honey (at 5% of the weight of the meat) was much more effective at preventing oxidation. Honey has great potential as an antioxidant source and may result in greater acceptability of meat products and prevent negative health implications of oxidized meats.     

Nectar Flavonol rhamnosides are floral markers of acacia (Robinia pseudacacia) honey

With the objective of finding floral markers for the determination of the botanical origin of acacia (robinia) honey, the phytochemicals present in nectar collected from Robinia pseudacacia flowers were analyzed by high-performance liquid chromatography-tandem mass spectrometry. Eight flavonoid glycosides were detected and characterized as kaempferol combinations with rhamnose and hexose. Acacia honey produced in the same location where the nectar was collected contained nectar-derived kaempferol rhamnosides. This is the first time that flavonoid glycosides have been found as honey constituents. Differences in the stability of nectar flavonoids during honey elaboration and ripening in the hive were shown to be due to hydrolytic enzymatic activity and to oxidation probably related to hydrogen peroxide (glucose-oxidase) activity. Acacia honeys contained propolis-derived flavonoid aglycones (468-4348 microg/100 g) and hydroxycinnamic acid derivatives (281-3249 microg/100 g). In addition, nectar-derived kaempferol glycosides were detected in all of the acacia honey samples analyzed (100-800 microg/100 g). These flavonoids were not detected in any of the different honey samples analyzed previously from different floral origins other than acacia. Finding flavonoid glycosides in honey related to floral origin is particularly relevant as it considerably enlarges the number of possible suitable markers to be used for the determination of the floral origin of honeys.