摘要:

Conditions were developed whereby onion tissue cultures could produce alk(en)yl‐L‐cysteine sulfoxides (ACSOs) at levels exceeding those in mature onion bulbs. Callus cultures grown in Gamborg's B5 basal medium with minimal organics supplemented with 2,4‐dichlorophenoxyacetic acid (at 2.5 μM) and 6‐benzyl‐aminopurine (at 1 μM) exhibited greening and partially differentiated roots within 6 months culture, and could be maintained for over 1 year. Within 10–12 months, callus cultures produced up to twice as much 1‐propenyl‐L‐cysteine sulfoxide (1‐PeCSO) and up to 6 times as much methyl‐L‐cysteine sulfoxide (MCSO) as found in mature onion bulbs. These callus cultures also had greater levels of glutamic acid, glycine and valine than mature onion bulbs. The supplementation of growth media with the elicitors, salicylic acid (SA), onion cell wall fragments (CWF) and acid‐cleaved chitosans (ACC) had differential effects of ACSO yields in 10–12 month old callus cultures. CWF suppressed tissue levels of both 1‐PeCSO and MCSO, SA suppressed tissue levels of MCSO more so than 1‐PeCSO, and ACC suppressed tissue levels of 1‐PeCSO with little effect on MCSO levels.

ISSN:0890-5436    

DOI:10.1080/08905439609549912

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Phenolic metabolites from oregano and related species in the family Lamiaceae are important sources of antimicrobials and antioxidants. The content of phenolic metabolites in oregano and related species are highly variable due to genetic heterogeneity. This genetic heterogeneity is due to the breeding character being influenced by natural cross‐pollination. In order to develop gene pools to improve ingredient quality and quantity genetically uniform shoot‐based clonal lines were isolated using plant tissue culture techniques. Clonal lines were generated from multiple shoots induced by 1 mg/1 benzylaminopurine in standard Murashige and Skoog medium with 3 % sucrose. Under these optimum conditions 7–10 shoots per explant were generated for further clonal propagation or regeneration of plants. Shoot‐inducing hormones like thidiazuron and adenine sulfate did not improve multiple shoot‐forming ability. Individual shoots of several individual clonal lines with each originating from a single heterozygous seed were then inoculated with a novelPseudomonassp. Following 30 days of growth on hormone‐free Murashige and Skoog medium, morphology, tolerance toPseudomonas, phenolics and rosmarinic acid content were measured and compared to uninoculated controls in 7 clonal lines of oregano. Results indicate thatPseudomonassp.‐mediated stimulation of phenolics and rosmarinic acid in various oregano clonal lines were directly correlated to tolerance toPseudomonassp.. Among these clonal lines, OM‐1 had the highest increase in phenolics and rosmarinic acid with corresponding enhanced tolerance toPseudomonassp.. This provides an unique strategy to isolate high phenolics‐producing, genetically uniform clonal lines usingPseudomonassp.. From a basic research perspective such clonal lines are essential for characterization of biochemical pathways of specific phenolic metabolites. From an applied research perspective, selection of elite clonal lines serve to provide extracts with uniform phenolic ingredients for use as antioxidants and antimicrobials in food systems.

ISSN:0890-5436    

DOI:10.1080/08905439609549913

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The formation of acetaldehyde, ethyl acetate, propanol‐1, isobutanol, amyl alcohols and methanol in repeated batch fermentations and continuous fermentations of wort, performed by a cryotolerant and alcohol resistant strain ofSaccharomyces cerevisiaespecies, immobilized on delignified cellulosic (D.C.) material and gluten pellets was studied mainly at low temperatures. It was found that the fine and fruity aroma of beers obtained at lower temperatures may be attributed mainly to increase of % ethyl acetate on total volatiles determined and to decrease of amyl alcohols. D.C. material resulted to lower contents of higher alcohols in batch and continuous brewing as compared with gluten and free cells principally at low temperatures. Amyl alcohols and other higher alcohols were reduced in all cases (immobilized and free cells) as the temperature was decreased. Same change of amyl alcohols and other higher alcohols is reported in the case of gluten pellets as the temperature was reduced. However, their contents are higher than those of free cells. In general, comparing the contents of ethyl acetate from continuous and batch process, continuous resulted to higher values. In all cases, the flavor was remained stable for the long period of ten months storage.

ISSN:0890-5436    

DOI:10.1080/08905439609549914

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The methanol content of alcohol from potatoes is produced primarily by alkali ester hydrolysis and not by enzymatic ester hydrolysis of the pectins as shown by, the results of experiments with citrus petin solution, mash identical potato pectin solution and potato mashes. In the case of citrus pectin, the activation energy of the ester hydrolysis was determined between 148 and 65 KJ / mol, depending on the pH‐value. With the isolated potato pectin, practice‐oriented methanol release which was independant of the activities of pectin esterases could be shown. The results were verified in mash experiments. A potential technological way of reducing the methanol release in the production of alcohols from potatoes is using lower pH‐values at preprocessing heat treatment. For this liquefaction enzymes have to be found.

ISSN:0890-5436    

DOI:10.1080/08905439609549915

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The continuous production of lactic acid from deproteinized whey by immobilized single and mixed culture ofL. caseiandL. lactisin Ca‐alginate beads has been investigated. A coimmobilized culture system gave better results than immobilized single cultures regarding lactic acid concentration, productivity, yield, and lactose utilization. Maximum lactic acid productivity of 7 g/lh was obtained at D=0.4 h−1with a yield of 70% lactic acid and 50% lactose utilization. At a dilution rate of 0.1 h−1, a lactic acid productivity of 2.5 g/lh was obtained with a 55.5% lactic acid yield and 90% lactose utilization. The bioreactor system was operated at a constant dilution rate of 0.1 h−1for 20 days without loss of original activity. In this case, the average lactic acid productivity, lactic acid yield and lactose utilization were 24 g/lh, 55% and 90%, respectively.

ISSN:0890-5436    

DOI:10.1080/08905439609549916

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Enzymatic browning and its prevention Chang Y. Lee and John R. Whitaker American Chemical Society, Washington, DC., 1995 No. 600, 338 pages

ISSN:0890-5436    

DOI:10.1080/08905439609549917

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0890-5436    

DOI:10.1080/08905439609549911

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor