Effects of type of added salt and ionic strength on physicochemical and functional properties of casein isolates produced by electroacidification   总被引：1，自引：0，他引：1  

Bazinet L  Gendron C  Ippersiel D  René-Paradis J  Tétreault C  Beaudry J  Britten M  Mahdavi B  Amiot J  Lamarche F 《Journal of agricultural and food chemistry》2002,50(23):6875-6881

A procedure developed for soybean protein precipitation which was based on electrodialysis was tested for the production of acid casein from reconstituted skim milk. In a previous paper, the performance of bipolar membrane electroacidification (BMEA) was evaluated under different conditions of ionic strength (micro(added) = 0, 0.25, 0.5, or 1.0 M) and added salt (CaCl(2), NaCl, or KCl) (1). The aim of this study, which is the complement of the work on evaluation of BMEA performance, was to evaluate the functionality of the protein isolates produced by BMEA and to compare the BMEA isolates to commercial isolates and an isolate produced by chemical acidification. It was not possible to show differences between the functional properties of isolates produced by BMEA, except at 1 M CaCl(2) micro(added), due to the variability of the isolates. However, the results showed that it is possible to obtain isolates similar to commercial isolates and that the addition of salt during the process does not induce variations in functional properties. From results on mineral concentrations, it appeared that the addition of monovalent cations did not influence the retention of monovalent or divalent cations in the BMEA isolates, while addition of divalent cations (CaCl(2)) influenced the retention of magnesium. According to previous results on evaluation of BMEA performances under different conditions of ionic strength and added salt, the difference observed for the BMEA isolate produced at 1.0 M CaCl(2) was confirmed.  相似文献   

封丘地区土壤水分平衡研究 Ⅳ.雨养条件下三个不同湿度麦季的小麦耗水量与水分利用率          下载免费PDF全文

陈志雄  VauclinMichel 《土壤学报》1991,28(4):396-403

根据水量平衡方程式计算,雨养麦田三个试验麦季的耗水量分别为435.5、326和293.8mm,它们可代表该区过湿、一般和干旱年分的小麦耗水量.小麦地上部分生物量(茎杆+籽实)与其耗水量成正比,以第一麦季为100,第二、第三麦季分别为85和70;但籽实产量的反应与地上部生物量的反应并不一致,它们分别为100、102、70,以第二麦季最高.由于该麦季的耗水量相对较少,故有很高的水分利用率(1.73×10^-3kg/1)为华北地区所罕见.在耗水量中,土嚷储水的贡献约占50%.在降雨少而土壤储水丰足的年份,其贡献高达60%,是小麦水分的重要来源.在充分施肥条件下,小麦的水分利用率≥1.26×10^-3kg/1,它是建立预测小麦产量的经验模型的重要参数.  相似文献   

Book reviews     

K. C. Pillai  Arthur C. Stern  T. Viraraghavan  Michel Benarie  G. F. Humphrey  D. P. Ormrod  Jan S. M. Boleij  Michael Waldichuk  Jan Smeets 《Water, air, and soil pollution》1985,26(3):307-326

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Composition and some biological activities of the essential oils from an African pasture grass: Elionurus elegans Kunth     

Mevy JP  Bessiere JM  Dherbomez M  Viano J 《Journal of agricultural and food chemistry》2002,50(15):4240-4243

The volatile oils of the aerial parts and roots from a pasture plant, Elionurus elegans, were studied by GC-MS analyses. Both organs studied contained only terpenic constituents. The main components found in the extract essential oils of the aerial parts were campherenone (43.0%), caryophyllene oxide (4.9%), and bisabolone (4.9%), whereas those found in the root essential oils were campherenone (39.0%), epi-beta-santalene (12.0%), and caryophyllene oxide (4.6%). Furthermore, the oils were tested for antibacterial and antifungal activities. The results obtained led to a nonsignificant inhibitory effect, although an increase of the lag stage was shown for the kinetics growth of Candida albicans, Saccharomyces cerevisiae, Enterococcus hirae, and Staphylococcus aureus. When alpha-tocopherol is used as a control, the antioxidant activities of the oils obtained from the aerial parts and roots were 30 and 46% IC(50), respectively.  相似文献   

Assessment of strawberry aroma through solid-phase microextraction-gas chromatography and artificial neuron network methods. Variety classification versus growing years     

de Boishebert V  Urruty L  Giraudel JL  Montury M 《Journal of agricultural and food chemistry》2004,52(9):2472-2478

In a previous work, the SPME-GC-MS method (chemical analysis) coupled with KSOM-ANN treatment of the results (statistical algorithm) has proved to be efficient to classify 70 strawberry samples harvested in the same year, through the 17 varieties to which they belonged, in a two-dimensional map. As an extension, the present study confirms that these results were not dependent on the year of strawberry production and discusses what effects were observed between results obtained in different years. Samples of different strawberry varieties were harvested during the three campaigns of 2000, 2001, and 2002 and analyzed independently. The chemical data matrix obtained in each case allowed the verification of the proposal that the same discriminative effect could be obtained independently of the year of production by using maps of different sizes. Therefore, 30 measures obtained from samples of 9 varieties in 2000, 54 measures from 13 varieties in 2001, and 80 measures from 20 varieties in 2002 were correctly classified by using 20, 35, and 56 hexagon maps, respectively. In a second analysis based on the 2002 production, the chemical differences between variety aromatic features were noted through the increasing size of the map used. Finally, results relative to 7 varieties cultivated in 2001 and 2002 and stored under exactly the same conditions were computed together for elaborating a single map. An interesting effect of double classification according to the year and the varieties was observed.  相似文献   

Near‐infrared spectroscopy can predict the composition of organic matter in soil and litter     

Thomas Terhoeven‐Urselmans  Kerstin Michel  Mirjam Helfrich  Heiner Flessa  Bernard Ludwig 《植物养料与土壤学杂志》2006,169(2):168-174

The usefulness and limitations of near‐infrared reflectance spectroscopy (NIRS) for the assessment of several soil characteristics are still not sufficiently explored. The objective of this study was to evaluate the ability of visible and near‐infrared reflectance (VIS‐NIR) spectroscopy to predict the composition of organic matter in soils and litter. Reflectance spectra of the VIS‐NIR region (400–2500 nm) were recorded for 56 soil and litter samples from agricultural and forest sites. Spectra were used to predict general and biological characteristics of the samples as well as the C composition which was measured by ¹³C‐CPMAS‐NMR spectroscopy. A modified partial least‐square method and cross‐validation were used to develop equations for the different constituents over the whole spectrum (1st to 3rd derivation). Near‐infrared spectroscopy predicted well the C : N ratios, the percentages of O‐alkyl C and alkyl C, the ratio of alkyl C to O‐alkyl C, and the sum of phenolic oxidation products: the ratios of standard deviation of the laboratory results to standard error of cross‐validation (RSC) were greater than 2, the regression coefficients (a) of a linear regression (measured against predicted values) ranged from 0.9 to 1.1, and the correlation coefficients (r) were greater than 0.9. Satisfactorily (0.8 ≤ a ≤ 1.2, r ≥ 0.8, and 1.4 ≤ RSC ≤ 2.0) assessed were the contents of C, N, and production of DOC, the percentages of carbonyl C and aromatic C and the ratio of alkyl C to aromatic C. However, the N‐mineralization rate and the microbial biomass were predicted unsatisfactorily (RSC < 1.4). The good and satisfactory predictions reported above indicate a marked usefulness of NIRS in the assessment of biological and chemical characteristics of soils and litter.  相似文献   

Release of nucleotides and nucleosides during yeast autolysis: kinetics and potential impact on flavor     

Charpentier C  Aussenac J  Charpentier M  Prome JC  Duteurtre B  Feuillat M 《Journal of agricultural and food chemistry》2005,53(8):3000-3007

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Determination of monounsaturated alkyl side chain 2-alkylcyclobutanones in irradiated foods     

Horvatovich P  Miesch M  Hasselmann C  Delincée H  Marchioni E 《Journal of agricultural and food chemistry》2005,53(15):5836-5841

The 2-alkylcyclobutanones (2-ACBs) are formed from triglycerides by irradiation treatment and may be used as markers for this type of food processing. This paper describes a detection method for the analysis of monounsaturated alkyl side chain 2-ACBs, which is formed upon irradiation from monounsaturated fatty acids which frequently are the most abundant fatty acids in foods. The estimated radioproduction yields of the cis-2-(dodec-5'-enyl)-cyclobutanones (cis-2-dDeCB) and the cis-2-(tetradec-5'-enyl)-cyclobutanones (cis-2-tDeCB) were 1.0 +/- 0.5 and 0.9 +/- 0.2 nmol.mmol(-1) precursor fatty acid.kGy(-1), respectively, being similar to that of saturated 2-ACBs. The stability study of the s- and mu-2-ACBs in poultry meat samples irradiated at 10 kGy and stored for 3-4 weeks at 4 degrees C and 25 degrees C showed that these compounds undergo some transformation, their amounts being reduced by about 50%. These storage losses did not depend on the saturation state of the alkyl side chain. The EI-MS detection limit of 2-tDeCB is 3 times higher (0.6 pmol) than that of 2-dodecylcyclobutanone (0.2 pmol). Consequently, when the oleic acid content of the analyzed food exceeds the content of palmitic acid by a factor of 3, it would be of an advantage to apply 2-tDeCB as a marker for detection of the irradiation treatment.  相似文献   

Copper Accumulation in a Reservoir Ecosystem Following Copper Sulfate Treatment (St. Germain Les Belles, France)     

Eric van Hullebusch  Philippe Chatenet  Véronique Deluchat  Philippe M. Chazal  Didier Froissard  Michel Botineau  Axel Ghestem  Michel Baudu 《Water, air, and soil pollution》2003,150(1-4):3-22

Copper sulfate (CuSO₄) addition to freshwater for phytoplankton control has been practiced for decades, and remains the most effective algicidal treatment for numerous managed water bodies. A reservoir in the centre of France was the site for an investigation of copper distribution in aquatic systems after a copper sulfate treatment. Results of monitoring showed a rapid conversion of dissolved Cu to particulate forms, with significant accumulation in the sediments. Total sediment Cu content increased from approximately 37.7 to 45.4 μg g^-1 dry weight after the first treatment. Sequential extraction suggested that a significant portion of the sediment-borne Cu was associated with the organic fraction which may release Cu to the water column, although significant release would occur only under extreme changes in water chemistry. Based upon measured Cu concentrations, flows at the down-stream water, and known mass applied during treatment, mass balance calculations indicated that approximately 17% of the Cu was exported from the reservoir over a 70 day period following a 196 μg L^-1 Cu²⁺ (as CuSO₄·5H₂O) treatment.Copper bioaccumulation by a moss, Fontinalis antipyretica in the down-stream water showed that it was possible to distinguish between a treated and an untreated area. The impact of copper treatmentin the down-stream reservoir could be followed using mosses. There is a distance effect which could be exploited to determine potential copper impact for example. The largest amount of copper was probably adsorbed on downstream sediment or lost in running water. Thirty days after copper sulfate addition, Fontinalis still indicatedcopper exposure.  相似文献   

Diversity among landraces of Indian snapmelon (<Emphasis Type="Italic">Cucumis melo</Emphasis> var. <Emphasis Type="Italic">momordica</Emphasis>)     

N. P. S. Dhillon  R. Ranjana  Kuldeep Singh  I. Eduardo  A. J. Monforte  M. Pitrat  N. K. Dhillon  P. P. Singh 《Genetic Resources and Crop Evolution》2007,54(6):1267-1283

Diversity among 36 snapmelon landraces, collected from 2 agro-ecological regions of India (9 agro-climatic sub-regions), was assayed using RAPD primers, morphological traits of plant habit and fruit, 2 yield-associated traits, pest and disease resistance and biochemical composition (TSS, ascorbic acid, titrable acidity). Typical differences among accessions were observed in plant and fruit characteristics and snapmelon germplasm with high titrable acidity and possessing resistance to downy mildew, Cucumber mosaic virus, Zucchini yellow mosaic virus, Papaya ringspot virus, Aphis gossypii and Meloidogyne incognita was noticed in the collection. RAPD based grouping analysis revealed that Indian snapmelon was rich in genetic variation and region and sub-region approach should be followed across India for acquisition of additional melon landraces. Accessions of var. agrestis and var. momordica clustered together and there was a separate cluster of the accessions of var. reticulatus. Comparative analysis of the genetic variability among Indian snapmelons and an array of previously characterized reference accessions of melon from Spain, Israel, Korea, Japan, Maldives, Iraq, Pakistan and India using SSRs showed that Indian snapmelon germplasm contained a high degree of unique genetic variability which was needed to be preserved to broaden the genetic base of melon germplasm available with the scientific community. N. P. S. Dhillon and Ranjana contributed equally to this work and are considered the first authors.  相似文献