Phenylalanine ammonia‐lyase and phenolic compounds in leaves and fruits of Olea europaea L. cv. Picual during ripening

BACKGROUND: The kinetic and molecular properties of phenylalanine ammonia‐lyase (PAL) in leaves and fruit of the olive tree (Picual variety) have been studied during the seasonal process of fruit maturation. The concentrations of total phenolic compounds, oleuropein, hydroxytyrosol and tyrosol, have also been determined. This study has been made in rainfed 30‐year‐old olive trees in Jaén, Spain, cultivated by the traditional method. RESULTS: PAL specific activity was assayed and hyperbolic kinetics were observed in both organs. The K_m value for L ‐Phe was 0.22 mmol L^?1 in leaf and 0.26 mmol L^?1 in fruit. In leaf, the highest PAL specific activity was found in the stage prior to veraison. By immunoblot, a PAL‐immunoreactive 75 kDa polypeptide was detected in leaf and fruit. In leaf, the level of this protein progressively rose until the last stages of ripening at the same time that total phenols increased. In fruit, PAL activity and protein change as in two series coinciding with different fruit‐maturation period. By immunohistochemistry under light microscopy, PAL was located in the epidermis and parenchyma cells of leaf and fruit. CONCLUSION: These results demonstrate the involvement and regulation of PAL during fruit ripening of olive, cv. Picual. Copyright © 2008 Society of Chemical Industry     

Characteristics of the leaf parts of some traditional Korean salad plants used for food

BACKGROUND: Total phenolics content, antioxidant activity and cytotoxicity of the methanol extracts from leaf parts of 13 Korean traditional salad plants were investigated in order to determine their properties. RESULTS: The highest phenolics content (mg ferulic acid equivalents kg^?1 dry weight (d.w.), omit one) was found in methanol extracts from Polygonum aviculare, at 293.7 ± 6.0, followed by Euonymus alatus, at 250.7 ± 3.3, Saxifraga stolonifera, at 125.0 ± 8.1 and Ligularia fischeri, at 122.5 ± 5.9. The methanol plant extracts dose‐dependently increased free radical scavenging activity. Methanol extracts of Polygonum aviculare, Euonymus alatus and Saxifraga stolonifera, at 31 mg kg^?1, exhibited the highest 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity (%) by 90.8 ± 4.2, 85.7 ± 3.9 and 64.1 ± 3.2, respectively. According to 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay, the methanol extracts from Portulaca oleracea (IC₅₀ < 25.0 µg mL^?1) showed the highest cytotoxicity against Calu‐6, followed by Plantago asiatica (49.2 µg mL^?1) and Osmunda japonica (89.6 µg mL^?1). CONCLUSION: Total phenolics content of the tested plant extracts was correlated with the DPPH radical scavenging activity, suggesting the phenolics compounds are contributing to the antioxidant properties of Korean salad plants. The leaf parts of the 13 Korean traditional salad plants described here that are currently used as foods may also provide some benefit to human health, and research into their potential benefits as preventative and/or therapeutic agents is warranted. Copyright © 2008 Society of Chemical Industry     

Identification of angiotensin converting enzyme inhibitory and antioxidant peptides in a whey protein concentrate hydrolysate produced at semi‐pilot scale

Antioxidant and angiotensin converting enzyme (ACE) inhibitory peptides were identified in a 5 kDa ultrafiltration permeate of a whey protein hydrolysate generated at semi‐pilot scale. Further laboratory scale ultrafiltration of this 5 kDa permeate resulted in a 0.65 kDa permeate with antioxidant, (1.11 ± 0.074 μmol TE per mg dry weight, oxygen radical absorbance capacity, ORAC) and ACE inhibitory (ACE IC₅₀ 0.215 ± 0.043 mg mL^?1) activities. Semi‐preparative (SP) reverse phase high‐performance liquid chromatography (RP‐HPLC) of the 0.65 kDa permeate resulted in a fraction (SP_F3) with a 4.4‐fold increase in ORAC activity (4.83 ± 0.45 μmol TE mg dry weight) and a 1.3‐fold increase in ACE inhibitory activity (84.35 ± 1.36% inhibition when assayed at 0.28 mg mL^?1). Peptides within SP_F3 were identified using UPLC‐ESI‐MS/MS. Met‐Pro‐Ile had the highest ORAC activity (205.75 ± 12.08 μmol TE per mmol peptide) while Met‐Ala‐Ala and Val‐Ala‐Gly‐Thr had the highest ACE inhibitory activities (IC₅₀:515.50 ± 1.11 and 610.30 ± 2.41 μm , respectively).     

烤烟组培苗与常规苗大田防御酶活性的比较

为比较烤烟组培苗与常规苗烟苗素质及大田期的抗性差异,以烤烟品种(系)K326、粤烟97、华烟06的组培苗与常规苗为试验材料,测定了苗期农艺性状及根系活力和大田期多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)、抗坏血酸过氧化物酶(APX)、β-1,3-葡聚糖酶等防御性酶活性,并调查了田间发病率。结果表明:组培苗在株高、叶数、茎围、根系体积、根系活力、干鲜重等方面均优于常规苗。在整个大田生育期内,不同处理烤烟的防御酶活性基本呈现出上升—下降—上升的变化趋势。旺长期前,组培苗与常规苗之间防御酶活性差异不大,旺长期受到病虫害侵染后,各处理的防御酶活性均先下降然后上升,并在较长一段时间内处于较高水平,且组培苗防御酶活性增加的幅度高于常规苗,其中K326组培苗的PPO、PAL、β-1,3-葡聚糖酶活性分别比常规苗高出29.58%、15.30%、73.03%,华烟06组培苗APX活性高于常规苗58.43%,差异显著。组培苗的花叶病、气候斑病及虫害发生率等均低于常规苗,表现出较强的抗性。      

Fuzzy and Conventional Modeling of Open Sun Drying Kinetics for Roasted Green Wheat

Roasted green wheat is a high-value product made by roasting green (under-mature) wheat. Due to its high initial moisture content, drying is needed to avoid fast deterioration. Open sun drying of this product is by far the most common practice due to its simplicity, effectiveness, and low cost. The assumption of open sun drying adequacy to prevent deterioration was tested in this study. The drying data were fitted into eight common thin-layer drying models. Goodness of fit for each model was evaluated using coefficient of determination (R²) and root mean square error. The two-term exponential model was found to best describe open sun drying of roasted green wheat with R², and root mean square error values of 0.988 and 0.038, respectively. A fuzzy model of open sun drying for roasted green wheat was also developed and compared with conventional modeling. The results showed a much better performance of fuzzy model compared to conventional models with a much lower value of root mean square error (1.2?×?10^?6). The effective diffusivity was also evaluated for roasted green wheat kernels and found to be 1.7?×?10^?11 m²/s, which was in agreement with published data. The results showed that open sun drying for 5.5 h was effective and adequate to reduce moisture content to a safe level and to prevent deterioration of this product. These findings will provide valuable information for the design of a commercial roasted green wheat solar drying system.     

Thermo‐physical properties of composite bread dough with maize and cassava flours

Composite wheat–cassava and wheat–maize flours were produced in ratio 100:0. 60:40, 50:50, 40:60 and 0:100 respectively. Thermo‐physical properties of bread dough were determined. For wheat –cassava composite bread dough, moisture content ranged between 44.02 ± 2.04 to 51.31 ± 2.99% dry basis (db), density (1035.2 ± 20.4 to 975.6 ± 12.6 kg m^?3), specific heat capacity (2.51 ± 0.61 to 3.01 ± 0.42 kJ kg^?1 K) and thermal conductivity (0.362 ± 0.13 to 0.473 ± 0.12 W mK^?1). While wheat–maize mixture gave 44.14 ± 1.94 to 45.09 ± 1.26%(db) of moisture content, 981.4 ± 16.3–960.4 ± 22.5 kg m^?3 density, 1.77 ± 0.17–2.61 ± 0.63 kJ kg^?1 K specific heat capacity and 0.36 ± 0.07–0.39 ± 0.02 W mK^?1 thermal conductivity. Effects of substitutions was significant on moisture content and thermal conductivity of dough while non significant influence was recorded on density and specific heat capacity at P < 0.05.     

Image analysis and quality attributes of malting barley grain dried with infrared radiation and in a spouted bed

The impact of drying two spring barley cultivars (Mauritia and Prestige) in a spouted‐bed and in infrared radiation (IR) dryers on grain dimensions, colour, pigment content, vitality and malt quality was investigated. The results indicate that the investigated drying methods led to kernel dimension changes. Kernel shrinkage was typical of spouted bed drying, while kernel expansion was observed after IR drying at the intensity of 900 W m^?2. An increase in the intensity of yellowness (b*) on the surface of dried grain and a decrease in the yellowness intensity of kernel cross‐section were also observed. The aforementioned changes were associated with the decomposition of carotenoids (endosperm colour) and reduction of soluble proanthocyanidin and total phenolic compounds (surface colour). The drying processes also lowered germination energy and capacity, in addition to susceptibility to moisture diffusion into the endosperm. These adverse results were cultivar dependent and affected the quality of malt and wort only to a limited extent. The main changes were an increase in the Kolbach index in malt from Mauritia cv., and a fluctuation of the diastatic power of malt that did not exceed ±3%. Generally, drying of barley grain in spouted bed should be conducted at an inlet air temperature of 40 °C and using an IR drier at a radiation intensity of 600 W m^?2.     

Energy and nutrient digestibilities in wheat dried distillers' grains with solubles fed to growing pigs

The aim of this study was to characterize the nutritional profile and to determine the digestibilities of nutrients in wheat‐based dried distillers' grains with solubles (DDGS) fed to growing pigs. Six ileal cannulated barrows individually housed in metabolism crates were fed experimental diets which consisted of a basal wheat‐based diet or the basal diet with wheat replaced by 400 g kg^?1 mixed wheat or winter wheat DDGS in a replicated 3 × 3 Latin square design. Ileal digesta and fecal samples were collected for determining apparent ileal (AID) and apparent total tract digestibilities (ATTD), respectively. The contents of proximate components and amino acids in DDGS were about three times higher than in wheat. The AID and ATTD of dry matter, nitrogen and energy were lower (P < 0.05) in DDGS compared with wheat. The DDGS samples had lower (P < 0.05) AID of amino acids compared with wheat; average values for lysine, threonine and isoleucine in DDGS were 43.8, 62.9 and 68.0%, respectively. The ileal and fecal digestible energy content in DDGS averaged 9.7 ± 1.18 and 13.5 ± 0.61 MJ kg^?1, respectively. Respective values for wheat were 13.3 ± 0.52 and 14.6 ± 0.22 MJ kg^?1 and both were higher (P < 0.05) than in DDGS. Copyright © 2005 Society of Chemical Industry     

Alleviation of salt stress in wheat seedlings by mammalian sex hormones

BACKGROUND: Salinity is one of the most serious constraints facing agriculture today. Some mechanical, chemical and biological approaches are being pursued to cope with soil salinity. Although exogenously treated mammalian sex hormones (MSHs), progesterone, β‐estradiol and androsterone, activate significant effects in various biological aspects in plants growing under normal conditions, there is no report investigating their effects on plants growing under salt stress. The present study aimed to investigate whether MSHs could alleviate the destructive effect of salt stress on wheat seedlings and thereby increase their salt tolerance. Wheat leaves were sprayed with 10^?6, 10^?8 and 10^?10 mol L^?1 concentrations of MSH on the ninth day after sowing. MSH‐treated seedlings (10‐day‐old seedlings) were subjected to salt stress for 5 days (between days 10 and 15). RESULTS: At all the concentrations tested, MSH treatment provided a significant protection against to detrimental effects of salt stress in wheat seedlings. It improved dry weight, sugar, proline, protein, chlorophyll and glutathione contents in comparison to salinity alone. Similarly, superoxide dismutase, peroxidase, catalase, ascorbate peroxidase and nitrate reductase activities also were augmented by MSH treatment. On the other hand, increases in lipid peroxidation level, superoxide production and hydrogen peroxide content arising from salt treatment were reduced by MSH treatment. The highest salt tolerance was obtained at the concentrations of 10^?6 mol L^?1 for progesterone and 10^?8 mol L^?1 for β‐estradiol and for androsterone. CONCLUSION: MSHs could be used effectively to protect wheat seedlings from the destructive effects of salt stress by stimulating both enzymatic and non‐enzymatic antioxidant mechanism and by promoting levels of osmotic protectants such as proline and sugars resulting in osmotic adjustment, carbon storage and radical scavenging in plants. Copyright © 2011 Society of Chemical Industry     

Production of a root‐specific flavour compound, 2‐hydroxy‐4‐methoxy benzaldehyde by normal root cultures of Decalepis hamiltonii Wight and Arn (Asclepiadaceae)

The flavour compound 2‐hydroxy‐4‐methoxy benzaldehyde from normal roots of swallow root (Decalepis hamiltonii) raised in vitro was extracted with dichloromethane, evaporated to dryness and dissolved in ethanol for qualitative (TLC) and quantitative (GC‐MS) analysis. Maximum root biomass and the maximum content of flavour compound (40 ± 2.1 µg g^?1 dry weight) were recorded after 45 days of growth on Murashige and Skoog medium containing 1.0 mg l^?1 α‐naphthaleneacetic acid. Copyright © 2004 Society of Chemical Industry     

Azospirillum improves lettuce growth and transplant under saline conditions

BACKGROUND: Recent studies have shown that as a plant‐growth‐promoting rhizobacteria (PGPR), Azospirillum inoculation could contribute to the mitigation of the negative effects caused by salt on lettuce growth. Moreover, the use of PGPR to alleviate the effects of transplant in vegetables has also been recognized. However, the scarce data available on the use of Azospirillum to improve lettuce growth before and after transplant under saline conditions prompted us to focus our research on this topic. RESULTS: Early germination and seedling settlement of seeds exposed to 0 and 40 mol m^?3 NaCl were clearly improved by Azospirillum inoculation. At 0 mol m^?3 NaCl, plant establishment, leaf mass and root mass parameters before transplant were significantly higher in inoculated plants than in non‐inoculated controls. At harvest, leaf fresh weight, ascorbic acid content and plant survival to transplant were also significantly higher in Azospirillum‐inoculated plants grown at 0 mol m^?3 NaCl. In addition to these effects, leaf dry weight, area and chlorophyll content were also increased by Azospirillum inoculation when plants were grown at 40 mol m^?3 NaCl. CONCLUSION: Azospirillum‐inoculated lettuce seeds yield a higher number of transplanted plants with superior quality than non‐inoculated controls grown at 0 or at 40 mol m^?3 NaCl. Copyright © 2012 Society of Chemical Industry     

Response surface optimisation of spray dryer operational parameters for low‐phenylalanine skim milk powder

The aim of this study was to optimise the spray‐drying process for low‐phenylalanine (low‐Phe) milk. Influence of inlet air temperature (100, 150 and 200 °C), feed flow rate (5, 10 and 15 mL min^?1) and air flow rate (400, 600 and 800 L h^?1) on the solubility, yield, water activity and moisture content (MC) of the milk powder were assessed using response surface methodology. The following optimum process parameters were determined: inlet air temperature of 160 °C, feed flow rate of 8 mL min^?1 and air flow rate of 400 L h^?1. The predicted values for the solubility, yield, water activity and MC were 98.77%, 88.08%, 0.263% and 5.48%, respectively. With the optimum parameters, the experimental values for the solubility, yield, water activity and MC were 97.56 ± 0.03%, 87.00 ± 0.10%, 0.26 ± 0.01% and 5.53 ± 0.08%, respectively. The similarity of the experimental results to the predicted values verified the models.     

Effect of drying kinetics on main bioactive compounds and antioxidant activity of acerola (Malpighia emarginata D.C.) residue

This study investigates the drying kinetics of residue of acerola, in a fixed‐bed dryer, analysing the effect of the process variables on the antioxidant properties of the residue. A complete factorial design 3² has been performed, where the independent variables studied were as follows: air velocity (0.5, 1.0 and 1.5 m s^?1) and air‐drying temperature (40, 50 and 60 °C). The bioactive compounds studied were L‐ascorbic acid, total phenolic, total flavonoids and antioxidant activity (expressed as IC₅₀) was determined using free radical DPPH^?. Both independent variables studied have shown to be statistically significant. The content of ascorbic acid was the highest at 60 °C and 1.0 m s^?1 (126.2 ± 0.004 mg 100 g^?1) while for the fresh residue 16.12 ± 0.003 mg 100 g^?1, whereas the total phenolic showed the highest content at 50 °C and 1.5 m s^?1 (46.2 ± 0.003 mg gallic acid.100 g^?1) while for the fresh residue 12.59 ± 0.001 mg gallic acid.100 g^?1. The drying conditions play an important role in determining the final quality of the product mainly in terms of antioxidant activity.     

Retention of Ginsenosides in Dried Ginseng Root: Comparison of Drying Methods

North American ginseng (Panax quinquefolius) has a long history of use and is currently a commercially reliable natural health commodity. Ginsenosides or triterpene saponins are generally regarded as bioactive constituents for several observed health effects associated with ginseng. North American ginseng was dried using 3 different drying techniques to assess the ginsenoside content of prepared extracts. Drying methods included freeze‐drying (FD), air‐drying (AD), and vacuum microwave‐drying (VMD) of ginseng root. High‐performance liquid chromatography (HPLC) analysis showed that FD ginseng processing gave greater (P≥ 0.05) amounts of the fingerprint ginsenosides Rg1 (28 ± 0.9 mg/g, dry weight) and Re (45 ± 0.1) compared with AD (Rg1 19 ± 0.7, Re 29 ± 0.1) and VMD (Rg1 22 ± 0.8, Re 24 ± 0.1); whereas, VMD produced greater amounts of Rb1 (83 ± 0.1) and Rd (13 ± 0.0) than FD (Rb1 62 ± 0.1, Rd 9 ± 0.1) and AD (Rb1 69 ± 0.1, Rd 5 ± 0.0), respectively. Total ginsenoside content was similar for FD and VMD and was the lowest (P≥ 0.05) for AD. Electrospray mass spectrometry (ESI‐MS) analysis showed a total of 12 compounds detected in FD ginseng compared with 10 compounds in ginseng dried by both VMD and AD. Our results support the fact that FD and VMD drying methods of North American ginseng can improve both extraction efficiency and actual retention of individual ginsenoside in root material.     

Salt-induced modulation in inorganic nutrients, antioxidant enzymes, proline content and seed oil composition in safflower (Carthamus tinctorius L.)

BACKGROUND: Safflower (Carthamus tinctorius L.) has gained considerable ground as a potential oil‐seed crop. However, its yield and oil production are adversely affected under saline conditions. The present study was conducted to appraise the influence of salt (NaCl) stress on yield, accumulation of different inorganic elements, free proline and activities of some key antioxidant enzymes in plant tissues as well as seed oil components in safflower. Two safflower accessions differing in salt tolerance (Safflower‐33 (salt sensitive) and Safflower‐39 (salt tolerant)) were grown under saline (150 mmol L^?1) conditions and salt‐induced changes in the earlier‐mentioned physiological attributes were determined. RESULTS: Salt stress enhanced leaf and root Na⁺, Cl^? and proline accumulation and activities of leaf superoxide dismutase, catalase and peroxidase, while it decreased K⁺, Ca²⁺ and K⁺/Ca²⁺ and Ca²⁺/Na⁺ ratios and seed yield, 100‐seed weight, number of seeds, as well as capitula, seed oil contents and oil palmitic acid. No significant effect of salt stress was observed on seed oil α‐tocopherols, stearic acid, oleic acid or linoleic acid contents. Of the two safflower lines, salt‐sensitive Safflower‐33 was higher in leaf and root Na⁺ and Cl^?, while Safflower‐39 was higher in leaf and root K⁺, K⁺/Ca²⁺ and Ca²⁺/Na⁺ and seed yield, 100‐seed weight, catalase activity, seed oil contents, seed oil α‐tocopherol and palmitic acid. Other attributes remained almost unaffected in both accessions. CONCLUSION: Overall, high salt tolerance of Safflower‐39 could be attributed to Na⁺ and Cl^? exclusion, high accumulation of K⁺ and free proline, enhanced CAT activity, seed oil α‐tocopherols and palmitic acid contents. Copyright © 2011 Society of Chemical Industry     

Application of ultrafiltration in the study of phenolic isolates and melanoidins from pale and black brewers' spent grain

Two types of brewers' spent grain (BSG), pale and black, were studied employing ultrafiltration (UF cut‐off, 10 kDa) to obtain high‐molecular‐weight (HMW) and low‐molecular‐weight (LMW) phenolic fractions from one pale (P2) and one black (B2) BSG extracts. Of the four UF fractions obtained, the HMW B2 fraction had highest level of polyphenols (5.73 ± 0.25 mg GAE g^?1 BSG dw) and protein (18.82 ± 0.41 mg protein g^?1 BSG dw). Metal‐chelating ability and antioxidative properties were also identified. Antioxidant activity evaluated using the DPPH and FRAP assays, indicated that activity in B2 extracts was associated mainly with the HMW fraction (3.10 ± 0.10 and 2.49 ± 0.09 TE g^?1 BSG dw, respectively), whereas in P2 samples, antioxidant activity was highest in LMW fractions (0.58 ± 0.01 and 0.92 ± 0.03 TE g^?1 BSG dw, respectively). The high antioxidant activity and metal‐chelating ability observed for black BSG extracts may be attributed to the presence of coloured melanoidinic structures.     

Thin-layer drying characteristics of kurut, a Turkish dried dairy by-product

Kurut, which is made in villages of Eastern part of Turkey, is a sun‐dried dairy product. Thin‐layer drying behaviour of kurut at a temperature range of 35–60 °C, with 5 °C increments, and constant thickness of 0.5 cm and drying air velocity of 1.5 m s^?1 was determined in a convective type dryer. The data of sample weight, dry and wet‐bulb temperatures were recorded continuously during each experiment and drying curves obtained. The drying process took place in the falling rate period. Drying curves were then fitted to eleven mathematical models available in the literature to estimate a suitable model for drying of kurut. Two‐term model gave better predictions than other models and satisfactorily described the thin‐layer characteristics of kurut. The effective diffusivity varied from 2.444 × 10^?9 to 3.597 × 10^?9 m² s^?1 over the temperature range. The temperature dependence of diffusivity coefficient was described by the Arrhenius‐type relationship. The activation energy for moisture diffusivity was found to be 19.88 kJ mol^?1.     

Chemical composition and antioxidant and radical‐scavenging activities of Periploca laevigata root bark extracts

BACKGROUND: The root powder of Periploca laevigata is used for preparing soft drinks and as an aromatic in Tunisia. The infusion or decoction of its root bark has widespread use in folk medicine. The plant is used to treat digestive disorders and hypertensive effects as well as other health problems. RESULTS: The antioxidant activities of extracts of P. laevigata root bark obtained with solvents of different polarity were investigated using assays of 1,1‐diphenyl‐2‐picrylhydrazyl radical‐scavenging activity, ferric‐reducing capacity, β‐carotene‐bleaching ability, hydroxyl radical‐scavenging activity and lipid peroxidation inhibition. The methanol extract, with the highest amount of total phenolics and flavonoids, showed the highest antioxidant activities in all assays, followed by the water extract. Gas chromatography/mass spectrometry was used to determine the composition of the water and methanol extracts. Thirty‐four compounds were identified in the methanol extract, with proflavine (516.2 g kg^?1 dry matter (DM)) and 4‐methoxysalicylaldehyde (198.3 g kg^?1 DM) being the most abundant. Sixteen compounds were identified in the water extract, of which 4‐hydroxy‐3‐methoxyphenethylene glycol (351.2 g kg^?1 DM) was the main component. CONCLUSION: As far as is known, this is the first report on the chemical composition and biological activities of phenolic extracts from P. laevigata. The results of the study indicate that the root bark of this plant might be a good candidate for further investigation in developing new antioxidants. Copyright © 2009 Society of Chemical Industry     

The influence of organ,season and drying method on chemical composition and antioxidant and antimicrobial activities of Juniperus phoenicea L. essential oils

BACKGROUND: Juniperus phoenicea is an important medicinal plant. In the present study, essential oils (18 samples) from leaves and berries of Juniperus phoenicea L. (Cupressaceae), obtained by various drying methods and in different collection months, were analysed by gas chromatography–mass spectrometry and also evaluated for in vitro antimicrobial and antioxidant activities. Correlations were studied between antimicrobial activity and the chemical composition of essential oils. RESULTS: Sixty‐seven compounds were identified in essential oils, representing 97.7–100%. Essential oils were dominated by monoterpenes and sesquiterpenes, which presented 35.0–93.3% and 6.7–62.0%, respectively, depending of organ, season and drying method. Antimicrobial tests showed that essential oils strongly inhibited the growth of Gram‐positive microorganisms and Mucor ramamnianus, but was inactive against Gram‐negative strains. Antioxidant activity was tested using the ABTS radical‐scavenging assay. Most samples showed good activity (the best IC₅₀ = 41.7 ± 1.5 mg L^?1). CONCLUSIONS: It could be concluded that drying of leaves of J. phoenicea in the sun and berries in oven‐drying was more suitable and was recommended for obtaining higher essential oil yield, but for a higher percentage of some special components such as α‐pinene and δ‐3‐carene shade‐drying was more suitable. Copyright © 2009 Society of Chemical Industry     

Effect of chitosan solution on the inhibition of Acidovorax citrulli causing bacterial fruit blotch of watermelon

BACKGROUND: The production of watermelon in China has been seriously hampered by fruit blotch disease and limited control measures are now applied. Chitosan has been employed to control a variety of plant diseases and is considered to be the most promising biochemical to control this disease. RESULTS: The in vitro antibacterial effect of chitosan and its ability in protection of watermelon seedlings from bacterial fruit blotch were evaluated. Results showed that three types of chitosan, in particular, chitosan A at 0.40 mg mL^?1 significantly inhibited the growth of Acidovorax citrulli. The antibacterial activity of chitosan A was affected by chitosan concentration and incubation time. The direct antibacterial activity of chitosan may be attributed to membrane lysis evidenced by transmission electron microscopic observation. The disease index of watermelon seedlings planted in soil and the death rate of seedlings planted in perlite were significantly reduced by chitosan A at 0.40 mg mL^?1 compared to the pathogen control. Fresh and dry weight of watermelon seedlings planted in soil was increased by chitosan seed treatment, but not by chitosan leaf spraying. CONCLUSION: The results indicated that chitosan solution may have a potential in controlling bacterial fruit blotch of watermelon. © 2013 Society of Chemical Industry