Removal Of Chlorophyll Research Articles

Singlet Oxygen Oxidation for 2‐Pentylfuran and 2‐Pentenyfuran Formation in Soybean Oil

ABSTRACT: 2‐Pentylfuran and isomers of 2‐pentenylfuran are known to be mainly responsible for the undesirable reversion flavor of soybean oil. Solid‐phase microextraction ‐ gas chromatography ‐ mass spectrometry was used to isolate, separate, and identify 2‐pentylfuran and isomers of 2‐pentenylfuran from soybean oil containing 5 ppm chlorophyll in a gas‐tight sample bottle during oxidation under light. Both 2‐pentylfuran and isomers of 2‐pentenylfuran increase as light exposure time and added chlorophyll increased. The compounds were neither formed in the oil containing 5 ppm chlorophyll under dark nor in the chlorophyll‐free soybean oil under light. The singlet oxygen oxidation mechanism for the formation of 2‐pentylfuran from linoleic acid and isomers of 2‐pentenylfuran from linolenic acid are proposed. Removal of chlorophyll will reduce reversion flavor formation.

In situ identification of symbiotic dinoflagellates, the genus Symbiodinium with fluorescence-labeled rRNA-targeted oligonucleotide probes

Fluorescence in situ hybridization has been used for the identification and analysis of populations of the dinoflagellate Symbiodinium that lives symbiotically in marine invertebrates. Conditions for in situ hybridization of Symbiodinium were optimized and used to identify the clade to which the isolate belongs using specific probes. The optimized in situ hybridization procedure used a combination of chlorophyll removal and permeabilization with hot ethanol. Incubation of the cells in 50% ethanol at 80 °C for 20 min rendered the cell wall permeable to Cy3-labeled probes. Symbiodinium clade-specific probes were designed based on 18S rRNA sequences. Symbiodinium A, B and C were distinguished by in situ hybridization with the specific probes SymA, SymB and SymC, respectively. The hybridization results using clade-specific probes corresponded with results obtained using restriction fragment length polymorphism (RFLP) analysis. Symbiodinium isolated from jellyfish Cassiopea sp. and sea anemone Aiptasia sp. were classified as belonging to clades A and B using the FISH procedure established in this study.

SEPARATION OF PROTEIN FRACTIONS IN ALFALFA JUICE: EFFECTS OF SOME PRE–TREATMENT METHODS

Particulates, insoluble proteins, and chlorophyll were removed from extracted alfalfa juice by heating to 55°C, followed by centrifugation. The decant absorbance was monitored at 435 and 675 nm in a spectrophotometer to compare relative chlorophyll removal. Laboratory-scale experiments with batch-type centrifugation at a relative centrifugation force (RCF) of 10,000g reduced juice absorbance by up to 98%. Continuous centrifugation in a decanter-type centrifuge was initially less successful in removing particulates. After modification of the inlet to gradually accelerate the particles to the peripheral speed, the separation was significantly improved and was comparable to batch-type centrifugation. Lower flow rates improved removal. Fermentation prior to centrifugation was also tested as a juice pre-treatment method for removal of particulates, insoluble proteins, and chlorophyll.

Carbon cycling in the northern Arabian Sea during the northeast monsoon: significance of salps

Winter cooling and mixing brings nutrients (nitrate and phosphate) to the surface waters over large parts of the northern Arabian Sea, but the rates of primary production as well as carbon export from the euphotic zone are not especially high during the northeast monsoon. A multi-disci- plinary time-series study conducted over a period of 13 d around 21° N, 64° E during the northeast monsoon of 1997 revealed substantial decreases in chlorophyll stocks in the mixed layer following the occurrence of a massive swarm of salps. A large increase in DOC was also observed during the same period. We propose that a deficiency of silicate relative to nitrate during this season may often limit the growth of diatoms, creating an ecological niche for filter feeders that can efficiently utilize abun- dant smaller plankton. This may lead to periodic removal of chlorophyll, thereby moderating primary production as well as episodic build-up of DOC in the upper layers. This DOC pool may be used as a nutrient source for the microbial loop in the surface layer during the following spring intermonsoon season and by the denitrifying bacteria in the oxygen-minimum zone.

FRUIT MATURITY, RIPENING, AND QUALITY RELATIONSHIPS

Maturity at harvest is the most important factor that determines storage-life and final fruit quality. Immature fruits are more subject to shrivelling and mechanical damage, and are of inferior flavour quality when ripe. Overripe fruits are likely to become soft and mealy with insipid flavour soon after harvest. Fruits picked either too early or too late in their season are more susceptible to postharvest physiological disorders than fruits picked at the proper maturity. All fruits, with a few exceptions (such as pears, avocados, and bananas), reach their best eating quality when allowed to ripen on the plant. However, some fruits are usually picked mature but unripe so that they can withstand the postharvest handling system when shipped long-distance. Most currently used maturity indices are based on a compromise between those indices that would ensure the best eating quality to the consumer and those that provide the needed flexibility in marketing. Fruits can be divided into two groups: 1) fruits that are not capable of continuing their ripening process once removed from the plant, and 2) fruits that can be harvested mature and ripened off the plant. Group I includes berries, cherry, citrus fruits, grape, lychee, pineapple, pomegranate, and tamarillo. Group 2 includes apple, apricot, avocado, banana, cherimoya, guava, kiwifruit, mango, nectarine, papaya, passion fruit, pear, peach, persimmon, plum, quince, sapodilla, sapote. Group I fruits produce very small quantities of ethylene and do not respond to ethylene treatment except in terms of degreening (removal of chlorophyll); these should be picked when fully-ripe to ensure good flavour quality. Fruits in Group 2 produce much larger quantities of ethylene in association with their ripening, and exposure to ethylene will result in faster and more uniform ripening.

Tentative identification of polyphenols in Sempervivum tectorum and assessment of the antimicrobial activity of Sempervivum L.

Polyphenols were isolated from sliced fresh leaves of Sempervivum tectorum. After 21 h of extraction by methanol and removal of chlorophyll, ethyl acetate was used to separate oligomeric and polymeric polyphenols: 0.07% of oligomeric and 0.13% of polymeric polyphenols were found. After acidic hydrolysis of the oligomeric polyphenols, it was established by TLC, HPLC, and FAB mass spectra that kaempferol was the unique aglycon of the three main oligomeric constituents of S. tectorum. Paper chromatography suggested delphinidol to be the only anthocyanidin detectable in the material obtained by acidic hydrolysis of the polymeric polyphenol fraction. After Haslam degradation of the same polymeric polyphenol fraction, only 4-thiobenzyl-(-)-epigallocatechin and 4-thiobenzyl-(-)-epigallocatechin-3-gallate were found and tentatively identified. We concluded that procyanidins of B2 type could be the major components of the polymeric polyphenol fraction of this plant. Antimicrobial activity of Sempervivum L. leaves against six of seven selected microorganisms was observed.

Adsorption of Chlorophyll and Pheophytin from Alkali-Refined Rapeseed and Soybean Oils with Attapulgite and Sepiolite.

Bleaching efficiency, amount adsorbed, k-value and equilibrium amount adsorbed were measured to determine maximum adsorption capacity of adsorbent for the removal of chlorophyll (Chl) derivatives. Cosmetic-grade attapulgite (A5) was equivalent to standard activated clay (SAC) in optimum clay dose for bleaching alkali-refined rapeseed and soybean oils. The dose was 2.0% wt/wt for rapeseed and 1.5% wt/wt for soybean. Adsorption capacity should be evaluated based on the equilibrium amount adsorbed from the adsorption isotherm but not on the bleaching efficiency, amount adsorbed or k-value. A5 was the same as SAC in equilibrium amounts of pheophytins (Phy) a/b adsorbed at low and high residual concentrations. A5 is thus useful for the adsorption removal of Chl and Phy as well as SAC.

EFFECTS OF CHEMICAL PRETREATMENT AND DRYING TEMPERATURES ON THE COMMERCIAL QUALITY OF CARDAMOM (Elettaria cardamomum)

ABSTRACTThe effects of processing conditions on quality of cardamom (Elettaria cardamomum), were tested using a predrying treatment of 2% sodium carbonate and drying temperatures of 35C, 45C and 55C, when drying was done continuously or in stages. Percent chlorophyll removal, total oil and essential oil content, % splits and % out‐turn were determined in chemically pre‐treated and non‐treated cardamom. The chlorophyll content was best retained in the chemically treated cardamom at 45C drying temperature. The loss in total oil content was minimum for the chemically pre‐treated cardamom at a drying temperature of 45C, while maximum terpenoids were retained at 45C in the untreated cardamom. The % splits was lowest for the untreated product continuously dried at 45C and the % out‐turn was highest for the chemically treated cardamom at 45C drying temperature. The recommended treatment conditions to meet trade quality standards were found to be a 45C drying temperature and chemically pretreated, continuously dried cardamom.

The reuse of spent bleaching earth: A feasibility study in waste minimisation for the edible oil industry

Spent bleaching earth, a solid waste from the edible oil industry can be converted to a clay-carbon adsorbent for potential reuse in the adsorptive cleansing of vegetable oils. Commercial and laboratory-prepared adsorbents were screened for their ability to remove coloured pigments, impurities and trace contaminants from rapeseed and crude coconut oils. Activated spent bleaching earth demonstrated efficient removal of benzol[a]pyrene from crude coconut oil reducing the concentration from 12·8 μg kg−1 in the crude oil to 1·3 μg kg−1 (89·8% w/w removal) in the treated product at a 2·0% w/w adsorbent dose. Soybean and rapeseed process wastes activated under identical conditions exhibited similar removal efficiencies of 89 and 86% w/w, respectively. This compared with a reduction in benzo[a]pyrene concentration to 10·8 μg kg−1 for virgin bleaching earth (15·6% w/w) and to less than 0·1 μg kg−1 for commercial powdered activated carbon (> 99·2% w/w). Activated spent bleaching earth exhibited limited removal of chlorophyll derivatives (27% w/w) and negligible uptake of the s-carotenoids and phosphorus from degummed rapeseed oil compared with the virgin bleaching earth which showed effective bleaching of chlorophyll derivatives (98% w/w), the s-carotenoids and removal of phosphorus (71% w/w). Adsorptive differences between these materials are interpreted with reference to interactions at the surfaces of acidulated montmorillonite and activated carbon. Processing incentives for the recovery and reuse of spent clay are discussed.

A microcolumn method for hexazinone and metabolite residues in soil and vegetation

A soil cleanup method using a disposable microcolumn and a modified capillary gas chromatographic method is described for the analysis of hexazinone (3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione) and two primary metabolites, 3-(4-hydroxycyclohexyl)-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione (metabolite A) and 3-cyclohexyl-6-(methylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione (metabolite B). The limits of detection (LOD) were 7, 18, and 36 ng g−1 for hexazinone, metabolite B, and metabolite A, respectively; limits of quantitation (LOQ) were 22, 52, and 99 ng g−1, respectively. The mean recoveries were 94 ± 3% and 94 ± 5% for hexazinone and the phytotoxic metabolite B fortified above LOQ and ranging from 0.03 to 6.25 and 0.06 to 12.5 μg g−1, respectively. The recoveries from the non-phytotoxic metabolite A above LOQ increased with concentrations from 0.125 to 25 μg g−1, but were consistent at each level. The final product of cleanup was stable for at least 6 months, and no derivatization was needed before gas chromatography. The use of toluene as the final solvent and the modification of the injection system of the gas chromatograph improved the stability of peak responses. The method is three times more efficient than conventional methods. The cleanup method for soils was modified for the analysis of vegetation samples. Efficient removal of chlorophyll enabled quantitation of hexazinone by gas chromatography. Recoveries of hexazinone ranged from 73 to 96% for forest litter and four different plant species.

Cytotoxic hydroxypolygodials. X-Ray molecular structure of (1R,3S,5aS,-9aS,9bR)-1,3,5,5a,6,7,8,9,9a,9b-decahydro-1,3-dimethoxy-6,6,9a-trimethylnaphtho[1,2-c]furan

Hydroxypolygodials, designed to have the simplified structure of the cytotoxic sesterterpene deacetylscalaradial isolated from the marine sponge Cacospongia scalaris, were synthesized starting from polygodial via fungal hydroxylation and chemical modification, and the expected biological activities were obtained. All the structures of the products were determined by mainly spectroscopic means. A simple method for removal of chlorophyll was devised, resulting in considerable improvement in the yield of polygodial.

Differential detergent‐solubilization of integral thylakoid membrane complexes in spinach chloroplasts

Progressive solubilization of spinach chloroplast thylakoids by Triton X-100 was employed to investigate the domain organization of the electron transport complexes in the thylakoid membrane. Triton/chlorophyll ratios of 1:1 were sufficient to disrupt fully the continuity of the thylakoid membrane network, but not sufficient to solubilize either photosystem I (PSI), photosystem II (PSII) or the cytochrome b6-f(Cyt b6-f) complex. Progressive with the Triton concentration increase (Triton/Chl greater than 1:1), a differential solubilization of the three electron transport complexes was observed. Solubilization of the Cyt b6-f complex from the thylakoid membrane preceded that of PSI and apparently occurred early in the solubilization of stroma-exposed segments of the chloroplast lamellae. The initial removal of chlorophyll (up to 40% of the total) occurred upon solubilization of PSI from the stroma-exposed lamella regions in which PSI is localized. The tightly appressed membrane of the grana partition regions was markedly resistant to solubilization by Triton X-100. Thus, solubilization of PSII from this membrane region was initiated only after all Cyt b6-f and PSI complexes were removed from the chloroplast lamellae. The results support the notion of extreme lateral heterogeneity in the organization of the electron transport complexes in higher plant chloroplasts and suggest a Cyt b6-f localization in the membrane of the narrow fret regions which serve as a continuum between the grana and stroma lamellae.

The effect of grazing by a gastropod, Nassarius obsoletus, on the benthic microbial community of a salt marsh mudflat

Removal of Nassarius obsoletus (Nassaridae: Gastropoda) from a salt marsh mudflat dominated by epibenthic microalgae resulted in highly significant increases in algal and total microbial standing stocks as measured by chlorophyll a and ATP respectively. This effect occurred within three days after the removal of the grazer and was maintained for the duration of each experiment (10 and 12 days). Concomitant with an increase in standing stock was an increase in the productivity (mg C fixed m −2 h −1). The assimilation number [mg C (mg Chl a) −1 h −1], however, was not affected by grazer removal. Energy charge ratios, which assessed the growth state of the microbial community, increased in ungrazed areas during the first few days after consumer removal. Disruption of the sediment surface to stimulate bioturbation by the N. obsoletus population had no effect on algal productivity or on the standing stocks of algae and microbes suggesting that the grazer's influence is not mediated through physical disturbance. Simulated grazing using a lens paper removal technique resulted in standing stocks and productivity which were higher than N. obsoletus grazed areas and comparable to ungrazed areas. N. obsoletus grazing rates must have exceeded the 5–10% removal of surface chlorophyll per day measured by the lens paper technique. Natural densities of N. obsoletus reduced both algal biomass and productivity. Although previous studies have documented mechanisms of positive feedback from consumers to producers, in this intertidal mudflat community, grazing appears to act strictly as a negative feedback regulator of benthic algal activity.

Determination of 2,4-dihydroxy-1,4(2 H)-benzoxazin-3-one glucosides in corn ( Zea mays L.)

A method has been developed for the determination of 2,4-dihydroxy-1,4(2 H)-benzoxazin-3-ones, which occur in corn ( Zea mays L.) plants as glucosides. The method involves freezing and thawing of corn tissue samples to allow enzyme-catalyzed cleavage of the glucosides, fragmentation, extraction of the released aglycons, removal of chlorophyll, conversion of the 2,4-dihydroxy-1,4(2 H)-benzoxazin-3-ones to the more stable 2(3)-benzoxazolinones, extraction of the 2(3)-benzoxazolinones, and quantitative ir measurement of the 2(3)-benzoxazolinones in methylene chloride solution. The amount of 2(3)-benzoxazolinone calculated as 6-methoxybenzoxazolinone (MBOA) obtained from B37 × B14 single-cross corn was found to be 1.56 mg 50 g fresh weight (10 samples; SD 0.16 mg). For synthetic samples, the precision of the method is that of the reproducibility of the spectrophotometer used. Depending upon the spectrophotometer used, a detection limit of 0.03–0.06 mg MBOA 50 g fresh tissue was observed.

Purification of chloroplast cytochrome b 559

Summary Cytochrome b 559 was purified from spinach chloroplast-grana membranes using polyacrylamide gel electrophoresis with non-ionic detergent as a final step. Other key steps included removal of chlorophyll from green particles with ethanol, extraction of cytochromes into solution at pH 8 with 2% Triton-urea (2 M or 4 M), stabilization of cytochromes b 559 and f, with dithiothreitol, and treatment with DEAE-cellulose to remove the major amount of impurities. Overall yield from ethanol-extracted particles was 30 to 50%. Proof of purity for b 559 as well as some properties are described.

FLUORESCENCE RESPONSES OF CHLOROPHYLL IN VIVO TO TREATMENT WITH ACETONE.

Fluorescence properties of isolated chloroplasts were studied in acetone-buffer mixtures of various concentration as well as during extraction. It was found that: When increasing the acetone concentration, the fluorescence band shifts to the short-wave side. Three concentration ranges are to be distinguished: the first one, 0–30%, causes only a slight shift, the second one, 30–50%, effects a considerable shift, whereas in the remaining range, the location of the band of dissolved chlorophyll is attained. The fluorescence yield depends on acetone concentration in a different way: in the 0–20% region it rises, then it drops around 30%, next it rises considerably until around 80% this yield reaches the value typical of dissolved chlorophyll. As evidenced by a shift of the fluorescence band to the long-wave side, reduction of an acetone concentration from 80% to 20% in the suspension medium of chloroplasts effects at least a partial recombination of chlorophyll and carrier. However, it is doubtful whether the produced complexes are identical with the naturally occurring ones. By means of a flow technique, the fluorescence time course was studied during chlorophyll removal from its carrier by 80% acetone. The results are in line with the earlier mentioned static data. Such a time course, however, differs markedly from that obtained with colloidal chlorophyll. Recombination experiments, performed with the flow technique, demonstrated that the fluorescence time course during formation of chlorophyll-carrier complexes follows a pattern different from the reverse of that of the just mentioned process. The results are discussed. They suggest that the structure of the naturally chlorophyll a types is rather specific.

Chlorophyll removal during earth bleaching of soybean oil

SummaryA spectrophotometric procedure for determining and calculating the chlorophyll content of unhardened as well as hardened soybean oil has been given. This procedure has proven satisfactory from a practical standpoint for controlling the greenness imparted to finished shortenings by chlorophyll. The influence of the refining, hydrogenation and deodorization operations on the chlorophyll content has also been reviewed.Isotherms have also been presented which illustrate the complexity encountered in bleaching soybean oil with respect to chlorophyll.