Headspace Evaluation of Methanethiol and Dimethyl Trisulfide in Aqueous Solutions of Soy-protein Isolates

Volatile compounds from 2 samples of aqueous soy‐protein isolates (SPI) (7%) were analyzed using both static and dynamic headspace methods. Based on dynamic headspace analyses, the most powerful odorants were (1) dimethyl trisulfide, (2) methanethiol, (3) hexanal, (4) an unidentified charred, sweaty feet‐like odor, (5) 2‐pentyl furan, (6) 2,3‐butadione, and (7) an unknown burnt‐like odor. The most powerful odorants by static headspace analyses were (1) dimethyl trisulfide, (2) hexanal, (3) methanethiol, and (4) 2‐pentyl furan. Using deuterium labeled DMTS as an internal standard, DMTS was quantified at 60.1 and 45.5 ppb in the SPIs. This corresponds to odor values of 6014 and 4554, respectively. Using a cool, on‐column technique, direct injection of concentrated‐headspace volatiles and solvent‐recovered volatiles with an internal standard of d₆‐DMTS detected both methanethiol and DMTS at similar levels as with the traditional injection methods.     

Volatile Flavor Components of Nira (Allium tuberosum Rottl.)

The flavor components of Nira (Allium tuberosum Rottl.) have been studied by a combination of gas chromatography and mass-spectrometry. Twenty-nine compounds were identified in the oil obtained from extraction of the steam distillate of Nira. The identified compounds include 7 sulfides, 2 ketones, 18 alcohols and 2 esters. The main volatile components were dimethyl disulfide and dimethyl trisulfide.     

Characteristic Flavor of Traditional Soup Made by Stewing Chinese Yellow‐Feather Chickens

The traditional recipe for Chinese chicken soup creates a popular taste of particular umami and aroma. The present study investigated the effects of stewing time (1, 2, and 3 h) on the principal taste‐active and volatile compounds and the overall flavor profile of traditional Chinese chicken soup by measuring the contents of free amino acids (FAAs), 5′‐nucleotides, minerals and volatile compounds and by evaluating the taste and aroma profiles using an electronic nose, an electronic tongue and a human panel. Results showed that the major umami‐related compounds in the chicken soup were inosine 5′‐monophosphate (IMP) and chloride, both of which increased significantly (P < 0.05) during stewing. The taste active values (TAVs) of the equivalent umami concentration (EUC) increased from 4.08 to 9.93 (P < 0.05) after stewing for 3 h. Although the FAA and mineral contents increased significantly (P < 0.05), their TAVs were less than 1. The volatile compounds were mainly hexanal, heptanal, octanal, nonanal, (E)‐2‐nonanal, (E)‐2‐decenal, (E,E)‐2,4‐decadienal, 1‐hexanol, and 2‐pentyl furan. With the prolonged stewing time, the aldehydes first increased and then decreased significantly (P < 0.05), while 1‐hexanol and 2‐pentyl furan increased steadily (P < 0.05). The aroma scores of the chicken soup reached the maximum after stewing for 3 h. The discrepancy in overall flavor characteristics tended to stabilize after 2 h of stewing. In general, stewing time has a positive effect on improving the flavor profiles of chicken soup, especially within the first 2 h.     

Contribution to the characterization of acetylated protein fractions of vicia faba in view of their functional properties

Whilst the emulsifying properties of the protein fraction of vicia faba are almost independent on the acetylation degree, the shear modulus of the gels produced by heat denaturation increases at first with increasing acetylation degree, decreases with further increase of the acetylation, and comes finally to zero for very high acetylation degrees. By changes of pH and by influence of added NaCl, CaCl₂, AlCl₃, and starch, the shear modulus of gels of acetylated protein fractions of vicia faba can be increased, by addition of sunflower oil it can be decreased. On the base of studies on the fraction profile and on the changes of the content of sulfhydryl and disulfide groups of the protein fractions of vicia faba and the corresponding gels in dependence on the acetylation degree, an interpretation of the results is given.     

Studies on the effects of microwave drying and cabinet tray drying on the chemical composition of volatile oils of garlic powders

Garlic cloves in the form of bits were dried in a cabinet tray dryer and a microwave dryer, and pulverized to obtain free flowing powder. The volatile oil was obtained by hydro-steam distillation method. Fresh cloves and the powders resulting from the two drying methods were used for obtaining the volatile oil, which was analyzed by GC-MS. The studies were mainly restricted to comparing the effect of drying methods on the volatile oil composition of the powders. Although the drying time was reduced considerably from 8 h in a cabinet dryer to 0.25 h in a microwave dryer, essential oil yield and color values were lower, and flavor quality varied considerably. The relative concentrations of major peaks such as diallyl disulfide, diallyl tetrasulfide increased in both the drying methods, and it was more so in microwave-dried samples. However, the concentrations of the other two major peaks, diallyl trisulfide and allyl methyl trisulfide, decreased in both drying methods, and they were lower in microwave-dried samples. Hunter values of L and b were lower for samples obtained by microwave drying as compared to those of cabinet-dried samples.     

Chemical composition,antioxidant and antimicrobial activities of essential oil obtained from Ferula assa-foetida oleo-gum-resin: Effect of collection time

The properties of essential oils obtained from Ferula assa-foetida oleo-gum-resins (OGRs) collectioned in three collections times in 15 June (OGR1), 30 June (OGR2) and 15 July (OGR3) 2011 was investigated. Essential oil from OGR1 was constituted high levels of (E)-1-propenyl sec-butyl disulfide (23.9%) and 10-epi-γ-eudesmol (15.1%). Essential oil from OGR2 was constituted high levels of (Z)-1-propenyl sec-butyl disulfide (27.7%) and (E)-1-propenyl sec-butyl disulfide (20.3%). Essential oil from OGR3 was constituted high levels of β-pinene (47.1%) and α-pinene (21.3%). Inhibitory concentration (IC50) for radical scavenging were 0.012–0.035, 0.025–0.047 and 0.035–0.066 mg/ml of essential oil obtained from OGR1, OGR2 and OGR3, respectively. Minimal inhibitory concentration (MIC) for Gram-positive and Gram-negative bacteria and fungi grpwth were 0.028–0.111, 0.027–0.107 and 0.018–0.058 mg/ml of essential oil obtained from OGR1, OGR2 and OGR3, respectively. Essential oils obtained from different OGRs have different composition and biological activity thus have different applications in food and health industry.     

Oxygen Radical Absorbance Capacity of Volatile Oils from Japanese Edible Wild Plants (Diplazium Squamigerum,Laportea Macrostachya,and Vitis Coignetiae)

The volatile oils from the Japanese wild edible plants of Diplazium squamigerum, Laportea macrostachya, and Vitis coignetiae were investigated by capillary gas chromatography and gas chromatography-mass spectrometry. The major components of D. squamigerum oil were linalool (28.7%), palmitic acid (13.9%), and α-terpineol (5.5%); of L. macrostachya oil were palmitic acid (14.1%), nonanal (9.2%), and linoleic acid (8.9%); and of V. coignetiae oil were nonanal (13.2%), geraniol (11.6%), and phenylacetaldehyde (8.5%). These oils were assayed to determine their antioxidant activity by the oxygen radical absorbance capacity assay using fluorescein as the fluorescent probe. The oxygen radical absorbance capacity values varied from 1255 ± 393 trolox equivalents (μmol TE/g) for D. squamigerum oil, from 514 ± 65 μmol TE/g for L. macrostachya oil, and from 911 ± 118 μmol TE/g for V. coignetiae oil. The difference in the antioxidant activities among D. squamigerum oil, L. macrostachya oil, and V. coignetiae oil were attributed to their different monoterpene alcohol contents and composition in the samples. These data provided evidence that the volatile oil from Japanese edible plants is a good dietary source of antioxidants.     

Relative Oxidative Stability of Diacylglycerol and Triacylglycerol Oils

To compare the oxidative stability between diacylglycerol (DAG) oil and conventional triacylglycerol (TAG) oil (that is, soybean oil), the prepared stripped diacylglycerol oil (SDO) and soybean oil (SSBO) were stored at 60 °C in the dark for 144 h. During storage peroxide values (POVs), contents of aldehydes, unsaturated fatty acids were measured to evaluate the oxidative stabilities of the 2 oils. The results showed the content of C18:2, C18:3, and total unsaturated fatty acid decreased faster in DAG oil than in soybean oil, whereas the decreased rate of C18:1 was similar in 2 oils. Also, both rate constants (K₁ and K₂) obtained from POV (K₁) and total aldehydes (K₂) indicated that DAG oil (K₁ = 3.22 mmol/mol FA h^?1, K₂ = 0.023 h^?1) was oxidized more rapidly than soybean oil (K₁ = 2.56 mmol/mol FA h^?1, K₂ = 0.021 h^?1), which was mainly due to the difference of acylglycerol composition of the 2 oils along with higher C18:3 (9.6%) in SDO than SSBO (5.7%). It is concluded that DAG was more easily oxidized than soybean oil at 60 °C in the dark for 144 h.     

Benzo[a]pyrene and total polycyclic aromatic hydrocarbons (PAHs) levels in vegetable oils and fats do not reflect the occurrence of the eight genotoxic PAHs

Concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in 115 samples of olive oil (extra virgin olive oil, virgin olive oil, olive oil, pomace olive oil and blended olive oil), cooking oil (corn oil, sunflower oil, sesame oil, palm olein oil, soya oil, canola oil, mustard oil, peanut oil and mixed vegetable oil) and fat (butter and table margarine) collected from retail stores in Kuwait. Carcinogenic benzo[a]pyrene (BaP) was detected in 43% of the samples analyzed. Benz[a]anthracene and chrysene were detected in 37 and 45% of the samples, respectively, that did not contain BaP. Of the individual non-carcinogenic PAHs, naphthalene showed the highest mean concentration (14 µg kg^?1), while for the carcinogenic PAHs, BaP (0.92 µg kg^?1) and chrysene (0.87 µg kg^?1) showed the highest mean values. Approximately 20% of the samples within the olive oil and cooking oil sub-categories exceeded the EU maximum tolerable limit for BaP, with the highest level of 6.77 and 11.1 µg kg^?1, respectively. For the fat sub-category, 9% of the samples exceeded the tolerance limit, with the highest level of 3.67 µg kg^?1. The Kuwaiti general population's dietary exposure to the genotoxic PAHs (PAH8: benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene and benzo[ghi]perylene) was estimated to be 196 ng day^?1 (3.3 ng kg^?1 bw day^?1, assuming an average adult body weight of 60 kg). Results indicated that PAH8 and BaP_eq (total sum benzo[a]pyrene equivalents) are more reliable measures of the concentrations of other carcinogenic PAHs in oil and fat samples, while BaP and PAHs alone are not good indicators of the occurrence or degree of contamination by carcinogenic PAHs in these food products.     

Influence of the different oils used in dough formulation on the lipid fraction of taralli

Abstract: An experimental investigation was carried out to evaluate the quality of taralli as a function of the type of oil used in their dough formulation. To this end, 4 types of oil (extra virgin olive oil, olive oil, olive‐pomace oil, and refined palm oil) were utilized to prepare taralli to investigate on the lipid fraction degradation and evaluate the taralli acceptability by consumers. The data obtained pointed out that taralli manufactured with extra virgin olive oil were significantly more appreciated than those made with refined oils due to their visual appearance and odor. Moreover, with respect to the other kinds of oil, the use of extra virgin olive oil led to significantly lower values (P < 0.05) of specific absorption at 232 and 270 nm (K₂₃₂ and K₂₇₀, respectively) and of triacylglycerol oligopolymers. It also proved to present a much lower content in oxidized triacylglycerols and diacylglycerols than olive‐pomace oil and refined palm oil, respectively. Furthermore, trans fatty acid isomers were absent in taralli made with extra virgin olive oil but were constantly present in those produced with refined oils.     

Comparison of encapsulation properties of major garlic oil components by hydroxypropyl β-cyclodextrin

The major garlic oil (GO) components were encapsulated by hydroxypropyl β-cyclodextrin (HP-β-CD), and their encapsulation properties were compared in this study. Our results showed that the optimal conditions for the GO encapsulation were as follows: weigh ratio at 12:88 (GO: HP-β-CD), pH at 5.0, and inclusion time at 4 h. Furthermore, results from the phase solubility curves indicated that two components of diallyl disulfide (DADS) and diallyl trisulfide (DATS) had higher water solubility caused by HP-β-CD and that DATS-HP-β-CD complex had higher stability constant (K _1:1 = 6.702 × 10⁵) and more significant change in free energy ( \Updelta G_\textCOMP^* \Updelta G_{\text{COMP}}^{*}  = −3.496 × 10⁴) than DADS-HP-β-CD. These findings indicated that DATS was better suited to be encapsulated by HP-β-CD compared to DADS. The result finally obtained from gas chromatography–flame ionization detector (GC–FID) confirmed the easier inclusion properties of DATS by HP-β-CD.     

Modifications in Disulfide Reactivity of Milk Induced by Different Pasteurization Conditions

The effect of pasteurization and repasteurization on disulfide chemical reactivity of milk proteins was tested after proteolytic digestion. Pasteurization at 75°C, but not at 80°C or repasteurization, resulted in a decrease in disulfide reactivity compared with raw milk. No differences among heated milks were observed in in vitro protein digestibility, electrophoretic behavior or surface hydrophobicity. Whey proteins extracted from milk pasteurized at 75 and 80° had lower solubility, protein digestibility, disulfide reactivity and surface hydrophobicity than those extracted from raw milks. SDS-PAGE and surface hydrophobicity parameters (K_d, F_max) of whey proteins suggested that differences in disulfide reactivity were a consequence of disulfide-mediated selective aggregation of the whey proteins.     

In Vitro Determination of the Antifungal Activity of Artemisia campestris Essential Oil from Algeria

The chemical composition of the essential oil isolated from the aerial parts of Artemisia campestris from Algeria and its antifungal activity against 10 filamentous fungal strains were investigated. The A. campestris essential oil was obtained in a yield of 0.71% (v/w). The major constituents of the oil were α-pinene (18.65%), β-pinene (16.78%), β-myrcene (17.34%), and germacrene D (10.34%). Our study showed that A. campestris essential oil was a potent antifungal agent against some pathogenic fungal species. Fusarium graminearum was the most sensitive strain to A. campestris essential oil with minimal inhibitory concentration and minimal fungicidal concentration values of 1.25 µL/mL (v/v). The essential oil also exhibited a strong fungicidal activity against the tested fungi, except for Penicillium citrinum, P. viridicatum, and Aspergillus niger (MFC >20 µL/mL). Our findings suggested the application of A. campestris essential oil as a biofungicide in order to reduce the dependence on synthetic fungicides and ensure food safety and quality.     

Physicochemical properties,total phenol and tocopherol of some Acacia seed oils

BACKGROUND: Recently, there has been an increase in the number of investigations into the possible use of vegetable oils as a source of oleochemicals to supplement petrochemicals. We have therefore determined the physicochemical properties of Acacia oils and compared them with groundnut oil as a first step toward their possible industrial utilization. RESULTS: The chemical properties of Acacia oils compared well and surpassed those of groundnut oil in iodine value (1549.3, 1783.3 and 1093.1 g iodine kg^?1 oil for A. colei, A. tumida and groundnut oils, respectively), saponification value (201.74, 202.15 and 198.01 g KOH kg^?1 oil for A. colei, A. tumida and groundnut oils, respectively). Total phenol and tocopherol content of Acacia oils were also higher compared with groundnut oil. Refractive index, specific gravity and viscosity were higher in Acacia seed oils than in groundnut oil but the smoke point of Acacia oil was lower than that of groundnut oil. Acacia oils were higher in some essential elements (Mg, Ca, Fe, Zn and Cu) when compare with groundnut oil. CONCLUSION: The properties of Acacia oils revealed that they could be useful as drying oils, in soap making and as lubricants at low temperatures. They could also be dietary sources of natural antioxidants and essential elements. Copyright © 2007 Society of Chemical Industry     

Antimicrobial activity of eucalyptus essential oil against Pseudomonas in vitro and potential application in refrigerated storage of pork meat

The objective of this study was to investigate the influence of eucalyptus essential oil (EO) on the Pseudomonas in vitro and application in the pork meat. Eucalyptus oil showed the greatest antimicrobial activity to Pseudomonas among five EOs (tea tree oil, eucalyptus oil, clove oil, mentha oil and garlic oil) in vitro. Eucalyptus oil treatment caused the increasing of membrane permeability and the modifications of ultrastructure and morphology of Pseudomonas spp. and P. aeruginosa. Treatment of refrigerated pork with eucalyptus oil led to a significant decrease P. spp. count, pH, total volatile basic nitrogen and 2‐thiobarbituric acid values, as well as higher sensory scores of custom acceptance than those in control at the end of cold storage. It was conclude that eucalyptus EO is a potential alternative to chemical treatment to control the spoilage and extend the shelf life of refrigerated pork meat.     

Identification and Detection of Adulterated Camellia Oleifera Abel. Oils by Near Infrared Transmittance Spectroscopy

Under the serious circumstances of Camellia oleifera adulteration, the accurate examination for quality trait of C. oleifera oil is extremely urgent. The use of near infrared transmittance spectroscopy as a rapid and cost-efficient classification technique for the authentication of Camellia oil was investigated. At the same time, the feasibility of near infrared transmittance spectroscopy for the rapid determination of soybean oil and maize oil adulterated in binary and ternary system Camellia oils was explored. The results showed that identifications was made based on the slight difference in raw near infrared transmittance spectra in Camellia oils, soybean oils, maize oils, and those adulterated with soybean and maize oil with discriminant equations techniques. Furthermore, the performance of near infrared transmittance spectroscopy models for binary and ternary system adulterated Camellia oils was satisfactory. Moreover, the near infrared transmittance spectroscopy calibration model of soybean oil (0–50%) in binary system adulterated Camellia oils was the best, and correlation coefficients of the cross-validation (R_cv) was 0.99999. For the near infrared transmittance spectroscopy calibration model of maize oil in binary system (0–50%) and ternary system (0–40%) adulterated Camellia oils, the R_cv were 0.99996 and 0.99961, respectively. In addition, the coefficients of external validation for three models were obtained (0.9998, 0.9999, and 0.9967, respectively). In all, near infrared transmittance spectroscopy could be conducted to identify Camellia oils and detect soybean oil and maize oil adulterated in binary and ternay system Camellia oils from the methodology.     

Effect of distillation waste water and plant hormones on spearmint growth and composition

BACKGROUND: Distillation waste water (DWW) is a by‐product from steam distillation of essential‐oil crops; and currently, it is discharged into streams and rivers. The effects of DWW from 13 essential‐oil crops, extracts from two alkaloid‐containing species, and three plant hormones (methyl jasmonate, MJ; gibberellic acid, GA3; and salicylic acid, SA) were evaluated on productivity, essential‐oil content and composition of spearmint (Mentha spicata L.) cv. ‘Native’. RESULTS: Spearmint plant height was increased by the application of GA3 and Melissa officinalis DWW but suppressed by the application of Rosmarinus officinalis and Tagetes lucida DWW. Generally, MJ, GA3 and M. officinalis and Mentha arvensis DWW increased dry yields. The concentration of L ‐carvone in the oil ranged from 550 g kg^?1 (with Monarda citriodora DWW) to 670 g kg^?1 (with T. lucida DWW). M. citriodora DWW reduced the concentration of L ‐carvone in the oil by 23% relative to the control. CONCLUSION: Results suggest that DWW from essential‐oil crops may affect monoterpene synthesis in M. spicata and, hence, may have a direct effect on the essential oil composition. DWW from essential‐oil crops may be used as a growth promoter and modifier of the essential oil composition of spearmint. Copyright © 2011 Society of Chemical Industry     

Chemical composition and in vitro antimicrobial activity of the essential oil of Origanum minutiflorum O Schwarz & PH Davis

The essential oil obtained by hydrodistillation from the aerial parts of Origanum minutiflorum O Schwarz & PH Davis, an endemic species in Turkey, was analysed for its antimicrobial activity in vitro. Gas chromatography/mass spectrometry analysis of the essential oil resulted in the identification of 34 constituents accounting for 961.5 mL L^?1 of the oil, the major compounds present being carvacrol (793.4 mL L^?1), p‐cymene (32.6 mL L^?1) and γ‐terpinene (21.4 mL L^?1). The in vitro antimicrobial activity of the essential oil was investigated in order to evaluate its efficacy against 16 bacteria and two yeasts, using disc diffusion and minimum inhibitory concentration methods. The essential oil showed strong antimicrobial activity against all test micro‐organisms except Pseudomonas aeruginosa. Its main components carvacrol and p‐cymene were also assayed for their antimicrobial activities. Carvacrol exhibited comparable activity to the crude oil, proving it to be the main component responsible for the biological activity observed. This study demonstrates the in vitro antimicrobial activity of the essential oil of this endemic remedy against a wide spectrum of clinically important micro‐organisms, including pathogenic yeasts, being the first report on the anticandidal properties of the essential oil of O. minutiflorum. Copyright © 2006 Society of Chemical Industry     

Variation in oil content and fatty acid composition of the seed oil of Acacia species collected from the northwest zone of India

BACKGROUND: The oil content and fatty acid composition of the mature seeds of Acacia species collected from natural habitat of the northwest zone of the Indian subcontinent (Rajasthan) were analyzed in order to determine their potential for human or animal consumption. RESULTS: Oil content varied between 40 and 102 g kg^?1. The highest oil content was obtained in Acacia bivenosa DC. (102 g kg^?1) among the nine Acacia species. The fatty acid composition showed higher levels of unsaturated fatty acids, especially linoleic acid (～757.7 g kg^?1 in A. bivenosa), oleic acid (～525.0 g kg^?1 in A. nubica) and dominant saturated fatty acids were found to be 192.5 g kg^?1 palmitic acid and 275.6 g kg^?1 stearic acid in A. leucophloea and A. nubica respectively. Seed oils of Acacia species can thus be classified in the linoleic–oleic acid group. Significant variations were observed in oil content and fatty acid composition of Acacia species. CONCLUSION: The present study revealed that the seed oil of Acacia species could be a new source of high linoleic–oleic acid‐rich edible oil and its full potential should be exploited. The use of oil from Acacia seed is of potential economic benefit to the poor native population of the areas where it is cultivated. The fatty acid composition of Acacia seed oils is very similar to that reported for commercially available edible vegetable oils like soybean, mustard, sunflower, groundnut and olive. Hence the seed oil of Acacia species could be a new source of edible vegetable oil after toxicological studies. Copyright © 2012 Society of Chemical Industry     

Original article: Antifungal activities of cinnamon oil against Rhizopus nigricans,Aspergillus flavus and Penicillium expansum in vitro and in vivo fruit test

The postharvest pathogens such as R. nigricans, A. flavas and P. expansum are the causal agents of jujube or orange fruit, therefore, in vitro and in vivo antifungal activities of cinnamon oil to inactivate these fungi were investigated. Cinnamaldehyde is the main constituent of cinnamon oil. The minimum inhibitory concentrations of cinnamon oil against Rhizopus nigricans, Aspergillus flavus and Penicillium expansum were 0.64% (v/v), 0.16% (v/v) and 0.16% (v/v), respectively. The antifungal activity of cinnamon oil against A. flavus and P. expansum was stronger than that against R. nigricans and the activity was improved with increasing its concentration. In an in vivo study, cinnamon oil with concentrations of 2.0% (v/v) and 3.0% (v/v) showed complete control the growth of fungi in wound‐inoculated Lingwu Long Jujube and Sand Sugar Orange fruits. These results revealed that cinnamon oil has a good potential to be as a natural antifungal agent for fruit applications.