Multielement analysis of Chinese tea (Camellia sinensis) by total-reflection X-ray fluorescence

 Total-reflection X–ray fluorescence (TXRF) was used for the simultaneous determination of 15 elements in tea samples which were produced either by acid digestion or acidified infusion of tea leaves (Camellia sinensis). The accuracy and precision of the method were checked by its application to a certified reference material (GBW 08505 : tea). A variety of 39 tea samples of different kinds and/or qualities produced in different regions of China were analysed. The range and mean of the concentrations of elements in the tea leaves (0.1–30.000 μg g^–1) and their solubility in infusions (0.5–85%) were determined and the influence of the origin, type and quality of the tea samples was studied. In some tea leaves produced in a Se-rich region, the content of Se was found to be very high (up to 7.5 μg g^–1), in contrast to a concentration of only about 0.1 μg g^–1 Se in most of the tea leaves examined. Received: 27 January 1998     

Availability of essential elements in Indian and US tea brands

Fifteen different brands of Indian tea leaves and seven US brands of flavoured tea were analysed for Na, K, Mn, Cu and Br by thermal neutron activation analysis (TNAA). Mn was also analysed by spectrophotometric and atomic absorption spectrometry (AAS) methods. In Indian tea, Mn concentration was found to be in the range 371–758 μg/g with a mean concentration of 575 ± 96 μg/g whereas in US tea it was in the range 79–768 μg/g with a mean concentration of 329 ± 231 μg/g. Na and Cu contents were also widely different in tea leaves from India and the USA but K contents were similar in the two tea leaves. Bromine was absent in tea leaves from the USA. Several standard or certified reference materials (SRMs/CRMs), including two tea leaves standards, were also analysed for data validation.     

Content of various elements in different parts of the tea plant and in infusions of black tea from Southern India

Contents of various elements in dyferent parts of the tea plant (shoot, mature leaf, small stem, thick wood and root), black tea manufactured by the crush-tear-curl and orthodox processes, and tea brew after 1 and 5 min of infusion were determined by inductively coupled plasma atomic emission spectrometry. From these, the amount of each element assimilated in the production of 1000 kg of marketable tea, as well as the quantity of each element brought into infusion and thus possib f y taken up through drinking tea, were calculated and discussed. Among the various elements assimilated by the tea plant, the shoot jraction (economically important for manufacturing commercial tea) contained high concentrations of N, P, K and Mg while the mature leaf accumulated Al, Bu, Ca, Cd, Mn, Pb and Sr. Of the dgerent elements brought into infusion while brewing black tea, the amount of K was found to be the largest (> 10000 μg g⁻¹ tea) followed by P (700–1200 μg g⁻¹), Mg (300–700 μg g⁻¹), Ca and A1 (each 150–300 μg⁻¹), Mn (60–150 μg g⁻¹), Cu, Na, Si and Z n (each 6–50 μg g⁻¹), B, Ba, Cr, Fe, Ni and Pb (each Id μg g⁻¹), and Sr, Co and Gd (each <1μg g⁻¹). The proportion of the totalamount of an element brought into infusion showed that the elements Ba, Ca, Fe and Sr were less soluble (<10 % of total amount), Al, B, Cd, Co, Cr, Cu, Mg, Mn, P, Pb, Si and Zn were moderately soluble (10–50 %), and K, Nu and Ni were highly soluble (>50%). The overall mean of the extent of solubility of all elements in 1 and 5 min showed that, out of the amount soluble in 5 min, about 68% was dissolved within 1 min.     

HPLC determination of stevioside in plant material and food samples

 An HPLC method for the determination of sweet-tasting stevioside (STS) in the leaves of the plant Stevia rebaudiana and in some beverages (e.g. tea, orange juice) was developed. The pre-separation procedure consisted of extraction of STS from the plant material using boiling water and a solid-phase extraction (SPE). Recovery rates of the SPE for the analysed matrices ranged from 92.8% to 97.8% (for concentrations of STS of 105, 210 and 300 μg/ml; Relative Standard Deviation (RSD)≤3.3%). The chromatographic separations were realized using a C₁₈ column, the mobile phase consisting of methanol and water, and with UV detection at 210 nm. The limits of determination of STS were 5 μg/ml for the leaf extracts and the tea sample and 8 μg/ml for the juice sample. Received: 7 April 1998     

HPLC determination of stevioside in plant material and food samples

 An HPLC method for the determination of sweet-tasting stevioside (STS) in the leaves of the plant Stevia rebaudiana and in some beverages (e.g. tea, orange juice) was developed. The pre-separation procedure consisted of extraction of STS from the plant material using boiling water and a solid-phase extraction (SPE). Recovery rates of the SPE for the analysed matrices ranged from 92.8% to 97.8% (for concentrations of STS of 105, 210 and 300 μg/ml; Relative Standard Deviation (RSD)≤3.3%). The chromatographic separations were realized using a C₁₈ column, the mobile phase consisting of methanol and water, and with UV detection at 210 nm. The limits of determination of STS were 5 μg/ml for the leaf extracts and the tea sample and 8 μg/ml for the juice sample. Received: 7 April 1998     

Evaluation and Improvement of Extraction Methods for the Analysis of Aflatoxins B1, B2, G1 and G2 from Naturally Contaminated Maize

The extraction procedure for aflatoxin determination in maize is based on a methanol–water (8 + 2 v/v) or an acetone–water (85 + 15 v/v) mixture. Initially, the extraction efficiency of two solvents was evaluated for each aflatoxin. Different results were obtained for highly contaminated maize: significantly higher levels of aflatoxin B₁ were obtained by acetone–water, on the contrary higher levels of aflatoxin G₂ were achieved by methanol–water. Then, acetone–water mixtures in different proportions (7 + 3, 6 + 4 and 5 + 5 v/v) were tested to improve the extraction of aflatoxin G₂. Applying these extraction mixtures, the values both of aflatoxin B₁ and of other aflatoxins were generally higher compared to those obtained by acetone–water 85 + 15; moreover, acetone–water (6 + 4) and (7 + 3) showed the best extraction efficiency for all aflatoxins.     

Effect of extraction techniques on the chemical composition and antioxidant activity of Eucalyptus camaldulensis var. brevirostris leaf oils

 The volatile oil compositions of Eucalyptus camaldulensis var. brevirostris leaves obtained by hydrodistillation (HD) and supercritical fluid extraction methods (SFE) were analysed qualitatively and quantitatively by GLC-MS. Ninety different components were separated and most of them identified. In both extracts the main constituents were found to be β-phellandrene (8.94 and 4.09%), p–cymene (24.01 and 10.61%), cryptone (12.71 and 9.82%) and spathulenol (14.43 and 13.14%). The yield of the monoterpene hydrocarbons in HD oil (0.288 g/100 g fresh leaves) was slightly higher compared with that in the SFE extract (0.242 g/100 g fresh leaves). The SFE extract possessed higher concentrations of the sesquiterpenes, light oxygenated compounds and heavy oxygenated compounds than the HD oil. The relationship between the antioxidant activity and chemical composition of the extracted oils was investigated. The significant amounts of p–cymen-7-ol and thymol are responsible for the antioxidative activity of both extracts. The concentration of both compounds, but especially that of p–cymen-7-ol (2.25%), is higher in the SFE extract. This corresponds with the higher antioxidative activity of the SFE compared with the HD extract. p–Cymen-7-ol, a compound newly identified in leaves of Eucalyptus species, exhibited superior antioxidant activity in comparison with that of butylated hydroxyanisole.     

Effect of extraction techniques on the chemical composition and antioxidant activity of Eucalyptus camaldulensis var. brevirostris leaf oils

 The volatile oil compositions of Eucalyptus camaldulensis var. brevirostris leaves obtained by hydrodistillation (HD) and supercritical fluid extraction methods (SFE) were analysed qualitatively and quantitatively by GLC-MS. Ninety different components were separated and most of them identified. In both extracts the main constituents were found to be β-phellandrene (8.94 and 4.09%), p–cymene (24.01 and 10.61%), cryptone (12.71 and 9.82%) and spathulenol (14.43 and 13.14%). The yield of the monoterpene hydrocarbons in HD oil (0.288 g/100 g fresh leaves) was slightly higher compared with that in the SFE extract (0.242 g/100 g fresh leaves). The SFE extract possessed higher concentrations of the sesquiterpenes, light oxygenated compounds and heavy oxygenated compounds than the HD oil. The relationship between the antioxidant activity and chemical composition of the extracted oils was investigated. The significant amounts of p–cymen-7-ol and thymol are responsible for the antioxidative activity of both extracts. The concentration of both compounds, but especially that of p–cymen-7-ol (2.25%), is higher in the SFE extract. This corresponds with the higher antioxidative activity of the SFE compared with the HD extract. p–Cymen-7-ol, a compound newly identified in leaves of Eucalyptus species, exhibited superior antioxidant activity in comparison with that of butylated hydroxyanisole. Received: 30 April 1998     

Micronutrients (B,Co, Cu,Fe, Mn,Mo, and Zn) content in made tea (Camellia sinensis L.) and tea infusion with health prospect: A critical review

Tea (Camellia sinensis L.) is a perennial acidophilic crop, and known to be a nonalcoholic stimulating beverage that is most widely consumed after water. The aim of this review paper is to provide a detailed documentation of selected micronutrient contents, viz. boron (B), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn) in made tea and tea infusion. Available data from the literature were used to calculate human health aspect associated with the consumption of tea infusion. A wide range of micronutrients reported in both made tea and tea infusion could be the major sources of micronutrients for human. The content of B, Co, Cu, Fe, Mn, Mo, and Zn in made tea are ranged from 3.04 to 58.44 μg g^?1, below detectable limit (BDL) to 122.4 μg g^?1, BDL to 602 μg g^?1, 0.275 to 13,040 μg g^?1, 0.004 to 15,866 μg g^?1, 0.04 to 570.80 μg g^?1 and 0.01 to 1120 μg g^?1, respectively. Only 3.2 μg L^?1 to 7.25 mg L^?1, 0.01 μg L^?1 to 7 mg L^?1, 3.80 μg L^?1 to 6.13 mg L^?1, 135.59 μg L^?1 ?11.05 mg L^?1, 0.05 μg L^?1 to 1980.34 mg L^?1, 0.012 to 3.78 μg L^?1, and 1.12 μg L^?1 to 2.32 μg L^?1 of B, Co, Cu, Fe, Mn, Mo, and Zn, respectively, are found in tea infusion which are lower than the prescribed limit of micronutrients in drinking water by World Health Organization. Furthermore, micronutrient contents in tea infusion depend on infusion procedure as well as on the instrument used for analysis. The proportion of micronutrients found in different tea types are 1.0–88.9% for B, 10–60% for Co, 2.0–97.8% for Cu, 67.8–89.9% for Fe, 71.0–87.4% for Mn, 13.3–34% for Mo, and 34.9–83% for Zn. From the results, it can also be concluded that consumption of three cups of tea infusion per day does not have any adverse effect on human health with respect to the referred micronutrients rather got beneficial effects to human.     

Differentiation of eight tea (Camellia sinensis) cultivars in China by elemental fingerprint of their leaves

BACKGROUND: Tea is an infusion made from dried leaves of tea (Camellia sinensis) and can be a good dietary source of essential trace metals for humans. Therefore, it is necessary to consider variations in element content of tea leaves among tea cultivars. Thus, elemental fingerprint techniques, based on elemental contents (Al, B, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, and Zn) determined by inductively coupled plasma atomic emission spectrometry (ICP‐AES) and multivariate statistical analysis, have been used to differentiate eight tea cultivars. RESULTS: The ranges of element concentrations in leaves of the eight cultivars were in good agreement with those obtained in previous studies and the level of most elements in tea leaves was significantly different among cultivars. The classifications of eight tea cultivars were 100% accurate in total by principal component analysis (PCA), hierarchical cluster analysis (HCA), linear discriminant analysis (LDA), and back‐propagation neural network (BPNN) analysis. CONCLUSION: Each cultivar presented a distinctive element fingerprint and the elements in tea leaves can be significant predictors in differentiating tea cultivars. Copyright © 2009 Society of Chemical Industry     

Levels of essential and non-essential metals in leaves of the tea plant (Camellia sinensis L.) and soil of Wushwush farms,Ethiopia

Five tea clones of the Camellia assamica variety grown in Wushwush tea plantation farms, Ethiopia, were analyzed for their contents of essential, non-essential and toxic metals (K, Ca, Mg, Fe, Mn, Cu, Zn, Na, Cd and Pb) by atomic absorption flame emission spectroscopy. Both the tea leaves and the soils of the study farms showed similar accumulation patterns in their contents of the studied macronutrients. Among the macronutrient metals, K was the most abundant element in the tea leaves (17.7–24.8 mg/g) and the soils (7.14–9.73 mg/g). Mn was the predominant micronutrient heavy metal in the tea leaf tissues ranging between 501 and 1281 mg/kg. Level of Fe (29.6–100 mg/kg) in the leaf tissue was found to be the second most abundant micronutrient next to Mn whereas concentrations of Cu and Co were relatively lower both in the soil and tea samples. The toxic heavy metals Pb and Cd in the leaf tissues were present at levels too low to be detected by the analytical technique used in this study. The soils were found to be acidic (pH 5.04–5.49) with high organic matter (5.48–6.02%). Fe was the most abundant metal followed by Mn, Na and Zn in the soils. Unlike the tea leaves, the soils were found to contain traces of the toxic metal, Cd (0.02–1.10 mg/kg). The levels of most of the metals determined in this study compared well with those reported for tea leaves from some other parts of the world.     

Optimization of supercritical CO2 extraction of phytosterol-enriched oil from Kalahari melon seeds

Supercritical carbon dioxide (SC-CO₂) extraction of oil from Kalahari melon seeds was investigated in this study. Response surface methodology was applied to model and optimize the extraction, namely pressure (200–400 bar), temperature (40–80 °C), and supercritical fluid flow rate (10–20 mL/min). Well-fitting models were successfully established for oil recovery (R ² = 0.9672) and phytosterol concentration (milligrams per 100 g; R ² = 0.8150) through multiple linear regressions with backward elimination. The effect of supercritical fluid flow rate was the most significant (P < 0.05) factor that affected oil recovery but this factor had no significant (P > 0.05) effect on phytosterol concentration. The optimal processing conditions for oil recovery and phytosterol concentration were pressure of 300 bar, temperature at 40 °C, and supercritical fluid flow rate of 12 mL/min. These optimal conditions yielded a 76.3% oil recovery and 836.5 mg/100 g of phytosterol concentration. The oil content in the Kalahari melon seeds as estimated by Soxhlet extraction was around 30.5/100 g. The phytosterol concentration in the oil extracted with SC-CO₂ extraction was 94% higher than that obtained with solvent extraction.     

Elemental Content and Total Antioxidant Activity of <Emphasis Type="Italic">Salvia fruticosa</Emphasis>

The determination of 18 elements (V, Cr, Cu, Co, Se, Sr, Sn, Sb, Ba, Bi, Pb, Cd, As, Ni, Mn, Fe, Mg and Zn) in leaves, flowers and the infusion from Salvia fruticosa, a sage grown in Greece, is described. For this purpose, flame atomic absorption spectrometry has been used for the determination of Fe, Mg, Zn and inductively coupled plasma-mass spectrometry has been used for the determination of V, Cr, Cu, Co, Se, Sr, Sn, Sb, Ba, Bi, Pb, Cd, As, Ni, Mn using ⁴⁵Sc ⁷²Ge, ¹¹⁵In and ²³²Th as internal standards. The elemental content was found to be in the range of 0.01 (Bi)-30.8 (Mn) mg/Kg (leaves), 0.30 (Bi)-39.1 (Mn) mg/Kg (flowers), 0.003 (Sb)-20.4 (Mn) mg/Kg (infusion) for V, Cr, Cu, Co, Se, Sr, Sn, Sb, Ba, Bi, Pb, Cd, As, Ni, Mn and in the range of 0.07 (Zn)-3.21 (Mg) g/kg (leaves) for Fe, Mg and Zn. The majority of the samples were collected from six sites in the island Crete and transplanted and grown in a model farm. Chemometric techniques were used to investigate the original site classification according to their elemental content, and it was proved that the initial cultivation sites were characterized by only five elements (Sb, V, Zn, Cd and Cr). The application of factor analysis revealed significant correlation between certain elements, denoting their common sources. In addition, the total antioxidant activity of the herbal preparation was determined by measuring the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. Microwave-assisted extraction (MAE) was used to extract total antioxidants and the effect of temperature, time and solvent in the extraction efficiency was investigated. The determination of the antioxidant activity was based on the % inhibition of the absorbance signal of the radical DPPH at 515 nm, after the addition of herbal’s extract. The IC₅₀ values were found to be in the range of 10.6–40.1 mg/L.     

Optimal extraction conditions for simultaneous determination of catechins and caffeine in green tea leaves

The amount of catechins and caffeine in green tea are considered a standard of quality evaluation for green tea. The objectives of this study were to investigate the optimal conditions for simultaneous extraction of catechins and caffeine and to compare their quantity and composition within the exotic tea varieties. Moreover, 8 tea varieties of exotic origin were tested with the optimal extraction conditions found in this study. Regarding the caffeine and catechins contents, a 2 h room temperature extraction using a 2% phosphoric acid-40% EtOH solution was the most suitable simultaneous extraction method. The total catechins and caffeine contents of the tea leaves ranged 44.25–64.80 and 9.26–13.11 mg/g, respectively. The optimal extraction method of catechins and caffeine in tea leaves may be used for further studies and breeding of high quality tea plants.     

Structural Relaxation of Salmon Gelatin Films in the Glassy State

Mechanical relaxation of glassy carbohydrates has been reported extensively in the literature; however, little work is available on protein-based systems. This study deals with the structural relaxation of salmon (Salmo salar) gelatin in the glassy state. Skin gelatin was obtained by an acid–alkaline extraction method. Molecular weight (M _w) was determined by capillary viscometry. Films prepared by casting (7% w/v) were equilibrated to a moisture content of ~18.4% (db). The glass transition temperature (T _g) and enthalpic relaxation were determined by differential scanning calorimetry (DSC). Mechanical properties were assessed using a texture analyzer at constant temperature and moisture content. DSC showed a T _g ~34°C, and the selected storage temperature (T _a ) was 29°C (T _g − T _a = 5°C). The films were aged for 0, 4, 8, 16, and 40 h. Viscometry produced values of M _w ~90.2 kDa. The stress relaxation was modeled by the Kohlrausch–Wlliams–Watts (KWW) equation, reporting an increase in relaxation time (τ ₀) as the ageing time increased (τ ₀ ~6.41E + 03 s for 0 h; τ ₀ ~9.01E + 05 s for 40 h). β parameter was smaller for the aged films, indicating a spread of relaxation times. The derivative of KWW equation (dφ/dt) indicated a more rapid relaxation in a fresh sample compared with aged films. DSC showed an excess in enthalpy (ΔH) on the aged samples due to the non-equilibrium state of the matrix. ΔH increased with ageing time with values of ΔH ~2.42 J/g for the films aged for 40 h. This work demonstrated molecular relaxation process of gelatin in the glassy state, which must be taken into account if this material is used as a structure forming matrix.     

Variation in essential,trace and toxic elemental contents in Murraya koenigii – A spice and medicinal herb from different Indian states

Curry leaves (Murraya koenigii), collected from 19 different Indian states, were analyzed for six minor (Ca, Cl, K, Mg, Na and P) and 20 trace (As, Ba, Br, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mn, Rb, Sb, Sc, Se, Sr, Th, V and Zn) elements by instrumental neutron activation analysis (INAA). In addition, Ni, Cd and Pb were determined by atomic absorption spectrophotometry (AAS). Most elements vary over a wide range, depending on geo-environmental factors and local soil characteristics. Fe, Mn, Na, K, Rb, Se and P vary by a factor of 3–5 whereas Br, Cs, Sc, Th and Zn vary by an order of magnitude. Leaves collected from the southern zone were enriched in K, Mg, Mn, Cl and P but depleted in Se. However, leaves from the northern zone were particularly enriched in Ca whereas those from the western zone were enriched in Zn. Concentrations of most elements from the eastern zone were on par with the mean values. Cr, Fe, Cu, V and Zn are known to play an important role in the maintenance of normoglycemia by activating β-cells of pancreas. Percent contributions of diabetically important elements from curry leaves were 1–2% of daily dietary intake (DDI) but are likely to be in bioavailable form thus making them effective for treatment of diabetes. Rb and Cs are linearly correlated (r = 0.93) as their salts enhance the absorption of insulin in the lower respiratory tract by breakdown of glucose. Inorganic elements may remain complexed with organic ligands.     

Sorption Isotherms of Barnyard Millet Grain and Kernel

The moisture sorption isotherms of grain and kernel of barnyard millet (Echinochloa frumentacea) were determined at 20, 30, 40, and 50 °C. A gravimetric static method was used under 0.112–0.964 water activity (a _w) range for the determination of sorption isotherms. The models were compared using the coefficient of determination (r ²), reduced chi-square (χ ²) values, and on the basis of residual plots. In grain, modified Chung–Pfost (r ² > 0.99; χ ² < 0.7) and modified Oswin (r ² > 0.99; χ ² < 0.55) models were found suitable for predicting the M _e –a _w relationship for adsorption and desorption, respectively. Modified Henderson model was found to give the best fit (r ² > 0.99 and χ ² < 0.55) for describing the adsorption and desorption of the kernel. The isosteric heat, calculated using Clausius–Clapeyron equation, was varied between 46.76 and 61.71 kJ g⁻¹ mol⁻¹ at moisture levels 7–21% (d.b.) for grain and 47.11–63.52 kJ g⁻¹ mol⁻¹ at moisture level between 4% and 20% (d.b.) for kernel. The monolayer moisture content values ranged from 4.3% to 6% d.b. in the case of adsorption of barnyard millet grain and 5.2–6.6% d.b. in the case of desorption at the temperature ranges of 50–20 °C. The monolayer moisture values of barnyard millet kernel ranged from 4.4% to 6.67% d.b. in adsorption and 4.6% to 7.3% d.b. in desorption in the temperature ranges of 50–20 °C.     

Multivariate Optimization for the Development of a Fast and Simple Ultrasound-Assisted Extraction Procedure for Multielemental Determination in Tea Leaves by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES)

The current study describes a fast and efficient procedure of ultrasound-assisted extraction for determination of Ca, Mg, K, Na, Cu, Zn, Mn, and Al in tea leaves by inductively coupled plasma optical emission spectrometry (ICP OES). The variables of procedure were optimized using the Box–Behnken design and the conditions selected were nitric acid concentration (1.0 mol L^?1), sonication time (7 min), and sonication temperature (75 °C). The extraction efficiency was calculated using the analyte concentration obtained by a total digestion procedure as reference. Accuracy was confirmed by analysis of certified reference material of apple leaves (NIST 1515) and spinach leaves (NIST 1570a) using the procedure proposed. A statistical evaluation using Student’s t test showed that there is no significant difference between the value obtained with the proposed procedure and the certified value, at 95% confidence level. The proposed procedure was successfully applied and is a good alternative to conventional acid digestion procedure and can be applied to routine analysis for determination of Ca, Mg, K, Na, Zn, Mn, Cu, and Al in tea leaves used for the preparation of infusions.     

Effect of Acetic Acid and Commercial Protease Pretreatment on Salting and Characteristics of Salted Duck Egg

Salting of duck egg pretreated with 5% acetic acid and different commercial proteases (flavourzyme, protamex, alcalase, and neutrase) was studied. After 2 weeks of salting, duck eggs soaked in 5% acetic acid for 30 min, followed by soaking in 5% (w/v) flavourzyme and neutrase had the highest hardening ratio (90.14 ± 2.43%, 90.25 ± 1.23%) with the coincidental increase in salt content in egg white and decrease in moisture content of yolk, compared with those from other treatments (p < 0.05). However, similar hardening ratio of the sample treated with alcalase was obtained to that of sample treated with either flavourzyme or neutrase (P > 0.05). After 1 week of salting, protamex showed the similar effect on hardening ratio to other proteases (p > 0.05). When eggs were pretreated with neutrase at different concentrations (0.25%, 0.5%, and 0.75%, w/v) for different times (30, 60, and 90 min), those pretreated with 0.25% (w/v) neutrase for 90 min had the shorter salting time, while soaking time did not have the impact on hardening ratio for egg treated with 0.5% and 0.75% neutrase (P > 0.05). The oil exudation of egg treated with 0.25% neutrase had the higher oil exudates than the control at week 2 and 3 of salting (P < 0.05). Treatment of neutrase had no impact on viscosity of egg white, regardless of salting time (P > 0.05). Microstructure study revealed that shell of salted egg pretreated with acetic acid had rough and porous surfaces when compared with control, whereas no changes in microstructure and FTIR spectra of shell membrane were found. Therefore, pretreatment of egg with 5% acetic acid for 30 min, followed by 0.25% neutrase for 90 min prior to salting could expedite the salting process and yielded egg yolk with hardening ratio and oil exudates, comparable to the traditionally salted egg.     

Ultrasonically Assisted Extraction of Rutin from <Emphasis Type="Italic">Artemisia selengensis</Emphasis> Turcz: Comparison with Conventional Extraction Techniques

Ultrasonically assisted extraction (UAE) followed by high performance liquid chromatography (HPLC) analysis method for the fast extraction and determination of rutin in Artemisia selengensis Turcz has been developed. Artemisia selengensis Turcz has been used as food and herbal medicine for thousands of years in China. Rutin is one of the main active ingredients of this plant. The extraction of rutin from Artemisia selengensis Turcz was investigated by UAE. Special emphasis has been given to optimize the extraction conditions which were those with 90:10 (v/v) methanol–ethanol as solvent, 30:1 liquid–solid ratio, and 40 min extraction time. In order to show the superiority of UAE, other extractions were investigated, including microwave-assisted extraction, reflux extraction, and marinated extraction. The results showed that UAE was most suitable for the extraction of rutin in Artemisia selengensis Turcz because of its high extraction efficiency. Reversed phase-HPLC with ultraviolet detection was employed for the analysis of rutin in Artemisia selengensis Turcz. Under the optimum conditions, the calibration curve for the analyte was linear in the range of 0.34–20.7 μg mL⁻¹. The mean recovery of rutin was 100.77%, and its relative standard deviation was 0.37% (n = 5). Three kinds of Artemisia selengensis Turcz from different habitats were investigated. The total content of rutin was 9.90, 6.23, 5.56 mg g⁻¹, respectively.