Effects Of Extraction Procedures Research Articles

Antimicrobial activity of moringa peregrina seed oil: chemical composition and effect of extraction procedure

Background and objective: The importance of new sources of oils has recently emerged, one such source being Moringa. There is an urgent need to choose the most appropriate extraction method regarding its impact on the properties and stability of the extracted oil.The objective of this research work is to study the impact of two extraction methods on the chemical and thermal properties as well as the antimicrobial activity of Moringa peregrina seed oil.Methods: Moringa peregrina seeds were collected from their original growing locations in Sudan. Cold pressing (CP) and maceration inn-hexane (MH) was used to extract the oil, and their yields were found to be 9.12% and 21.87%, respectively. Chemical properties of the oil were studied and in each case triplicate analyses were completed. The mean and the standard deviation were then determined (mean±SD).Results: Besides the peroxide value, the chemical properties of the oil extracted by the two methods remained relatively unchanged. Additionally, the results revealed a higher activity of the cold pressed oil against all tested organisms (Bacillus subtilis, Staphylococcus aureus Escherichia coli, Pseudomonas aeruginosa, Candida albicans) compared to the one obtained by maceration method. Furthermore, the thermogravimetric analysis and derivative thermogravimetric analysis (TGA and DTGA) demonstrated significant variations in the onset of degradation between the oil samples extracted by the two methods: 200◦C (cold pressing) against 274◦C (maceration). The maximum mass loss for the oil extracted by the two methods does not differ significantly, and the final degradation temperature was similar. Conclusion: The differential scanning calorimeter (DSC) thermograms for the oil extracted by the two methods showed somewhat similar characteristics regarding the heating curves, while the cooling curves differed considerably. Keywords: Antimicrobial activity; Cold press; Maceration; Moringa peregrina; Thermal properties.

Effect of Extraction Procedures with Ultrasound and Cellulolytic Enzymes on the Structural and Functional Properties of Citrus grandis Osbeck Seed Mucilage.

The structural and functional properties of Citrus grandis Osbeck (CGO) seed mucilage by different extraction practices, including conventional citrate buffer, ultrasonic-assisted (UAE), enzymatic-assisted extraction (EAE) with cellulase or Celluclast® 1.5 L and various ultrasonic-assisted enzymatic extraction (UAEE) procedures were investigated. It was found that CGO seed from agricultural and processing byproducts is an excellent new source of high methoxyl pectin with quite high intrinsic viscosity (about 108.64 dL/g) and molecular weight (about 1.9 × 106) as compared with other pectin sources. UAEE with Celluclast® 1.5 L enhanced the extraction yield most pronouncedly (about 2.3 times). Moreover, the monosaccharide composition of CGO seed mucilage is least affected by EAE with Celluclast® 1.5 L. In contrast, EAE with cellulase dramatically reduces the galacturonic acid (GalA) content to less than 60 molar%, and increases the glucose (Glc) content pronouncedly (to about 40 molar%), which may be considered as an adverse effect in terms of pectin purity. Though extraction procedures involved with ultrasound and cellulolytic enzymes generally show a decrease in GalA contents, weight average molar mass and intrinsic viscosity, EAE with Celluclast® 1.5 L is least affected, followed by UAE and UAEE with Celluclast® 1.5 L. These features can be leveraged in favor of diversified applications.

Effect of extraction procedure on the yield and biological activities of hydroxychavicol from Piper betle L. leaves

Piper betle Linn is one of the most common ethnomedicinal plants with its extract being popularly used in the modern product to enhance functionality. However, extraction methods always lead to differences in biological activities. The objectives of this study were to evaluate the effects of the extraction methods on the yield and biological activities of hydroxychavicol from P. betle L. extracts and to determine the correlation between the hydroxychavicol content and biological activities of P. betle L. extracts such as antioxidant, antimicrobial, and anticancer properties. The purity of the hydroxychavicol and its concentration (quantitative) in the crude extracts were also evaluated using a reverse-phase HPLC while GC–MS was employed to determine other components (qualitative). The results showed that only certain extraction procedures gave high yields of hydroxychavicol as well as remarkable biological activities. The chloroform extract following boiling with water (M2) gave the highest percentage of hydroxychavicol content based on the HPLC analysis. M2 and pure hydroxychavicol actively inhibited all the five cancer cell lines studied except A549. M2 showed more effective inhibition activity against MCF 7 with an IC50 of 1.74 ug/mL. M2 extract also showed strong antibacterial activity against all the bacteria strains as well as a strong antifungal activity against Candida albicans. There was, however, a weak correlation between the hydroxychavicol content and the biological activities of P. betle L. extracts. In conclusion, extraction procedures greatly affect the yield and biological activities of hydroxychavicol from P. betle L. The designation of a single compound such as hydroxychavicol as a bioactive chemical marker compound in the P. betle L. extracts, however, is not enough to determine the biological activities of the extract.

Effect of extraction procedures on the chemical structure, antitumor and anticoagulant properties of ulvan from Ulva lactuca of Tunisia coast

The effect of extraction procedures on chemical composition, structural, antitumor and anticoagulant properties of the sulphated polysaccharide ‘ulvan’ from the green seaweed Ulva lactuca were investigated. The structural features of ulvans were carried out by FTIR and by one- and two- dimensional 1H and 13C NMR spectroscopic. The ulvans were mainly composed of rhamnose, xylose, and uronic acid. Chemical and spectroscopic analyses demonstrated that ulvans were constituted of (1→4)-β-glucuronic acid, (1→3,4)-α-L-rhamnose-3-sulphate and (1→4)-α-xylose.The extraction procedures effect were observed in chemical structure, Mw and biological activities. Cytotoxic activity of enzymatic-chemical extract on cervical cancer cells (HeLa) (IC50 = 1000 μg/mL) was higher than on normal peripheral blood lymphocytes cells (PBL). Acid extracts promoted to reduce HeLa cells and to grow PBL cells. At high concentrations, acid extracts showed the highest APTT and TT clotting time. Antitumoral and anticoagulant activities of ulvans from Ulva lactuca promote their use as effective therapeutic agent.

The Effect of Different Extraction Procedures on Antioxidant Activity of Garlic (Allium sativum L.) Essential Oil

This paper studies the effect of different extraction procedures such as soxhlet extraction using n-hexane, distillation method and supercritical extraction (SFE) on the physicochemical properties of garlic essential oil. The yield of garlic essential oil by soxhlet extraction, steam distillation and SFE-CO2 methods was approximately 0.441, 0.124 and 0.465 %, respectively. The results of the oil analysis by gas chromatography/mass spectrometry method show the presence of five major compounds, including diallyl sulfide, diallyl disulfide, 3-vinyl-1,2-dithiacyclohex-4-ene, 3-vinyl-1,2-dithiacyclohex-5-ene and diallyl trisulfide. The antioxidant activity of the essential oil obtained by the SFE-CO2 method was significantly higher than by the distillation method, but was lower than the acid ascorbic one.
 Keywords
 Garlic essential oil, SFE, GC-MS, antioxidant activity, extraction.
 References
 [1] R. Lawrencea, K. Lawrenceb, Antioxidant activity of garlic essential oil (Allium Sativum) grown in north Indian plains, Asian Pacific Journal of Tropical Biomedicine 1 (2011) 51-54. https://doi.org/10.1016/S2221-1691(11)60122-6.[2] Dziri, H. Casabianca, B. Hanchi, K. Hosni, Composition of garlic essential oil (Allium sativum L.) as influenced by drying method, Journal of Essential Oil Research 26 (2014) 91-96. https://doi.org/10.1080/10412905.2013.868329.R.[3] Li, W. Chen, W. Wang, W. Tian, X.Z. Rrui, Extraction of essential oils from garlic (Allium sativum) using ligarine as solvent and its immunity activity in gastric cancer rat, Medicinal Chemistry Research 19 (2010) 1092-1105. https://doi.org/10.1007/s00044-009-9255-z.[4] M.K. Gafar, A.U. Itodo, A. A. Warra, L. Abdullahi, Extraction and Physicochemical Determination of Garlic (Allium sativum L) Oil, International Journal of Food and Nutrition science 1 (2012) 4-7. [5] A.P. Sa´nchez-Camargo, J.A. Mendiola, E. Iba´n˜ez, M. Herrero, Supercritical Fluid Extraction, Reference Module in Chemistry, Molecular Sciences and Chemical Engineering (2014) 1-17. https://doi.org/10.1016/b978-0-12-409547-2.10753-x.[6] A. Rafe, M. S. Nadjafi, Physicochemical characteristics of garlic (Allium sativum L.) oil: Effect of extraction procedure, International Journal of Nutrition and Food Sciences 3 (2014) 1-5. https://doi.org/10.11648/j.ijnfs.s.2014030601.11.[7] J. M. del Valle, C. Mena, M. Budinich, Extraction of garlic with supercritical CO2 and conventional organic solvents, Brazilian Journal of Chemical Engineering, 25 (2008) 535-542. https://doi.org/10.1590/S0104-66322008000300011.[8] A.E. Andreatta, G. Foco, G. Mabe, S.B. Bottini, Extraction of garlic oil with quasi-critical solvents, 4th Mercosur Congress on Process Systems Engineering (2014) 1-9.[9] H. Kamali, N. Aminimoghadamfarouj, E. Golmakani, A. Nematollahi, The optimization of essential oils supercritical CO2 extraction from Lavandula hybrida through static-dynamic steps procedure and semi-continuous technique using response surface method, Pharmacognosy Res 7 (2015) 57-65. https://doi.org/10.4103/0974-8490.147209.[10] L.D. Lawson, Z.J. Wang, B.G. Hughes, Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic products, Planta Med, 57 (1991) 363-370. https://doi.org/10.1055/s-2006-960119.[11] E. A. O'Gara, D. J. Hill, D. J. Maslin, Activities of Garlic Oil, Garlic Powder, and Their Diallyl Constituents against Helicobacter pylori, Applied and Environmental Microbiology 66 (2000) 2269-2273. https://doi.org/10.1128/aem.66.5.2269-2273.2000.[12] X. Qiao, Molecular distillation separation and purification of essential oils of garlic, Food science Shandong 5 (2007) 60.[13] M. Iranshahi, A review of volatile sulfur-containing compounds from terrestrial plants: biosynthesis, distribution and analytical methods, The Journal of Essential Oil Research, 24 (2012) 393-434. https://doi.org/10.1080/10412905.2012.692918.[14] M. Corzo-Martı´nez, N. Corzo, M. Villamiel, Biological properties of onions and garlic, Trends in Food Science & Technology 18 (2007) 609-625. https://doi.org/10.1016/j.tifs.2007.07.011.[15] K. Khoshtinat, M. Barzegar, M. A. Sahari, Z. Hamidi, Comparison of Antioxidant and Antibacterial Activities of Free and Encapsulated Garlic Oil with Beta-cyclodextrin, Applied food biotechnology 3 (2016) 254-268. https://doi.org/10.22037/afb.v3i4.12631.

Effect of Extraction Procedure on Yield, Phytochemical Profile and Antibacterial Activity of Fenugreek Seed (Trigonella foenum-graecum) Crude Extracts

Background: Fenugreek (Trigonella foenum-graecum) is a medicinal plant known for its various pharmacological properties, including its antibacterial activity. The purpose of this study was to assess the extraction procedure effect on yield, phytochemical profile and antibacterial activity of fenugreek seed crude extracts. Methods: The extraction procedure of components from fenugreek seed possessing an antibacterial potential was first optimized. Extracts at the highest yield were analyzed for phytocomponents and their bacterial growth inhibitory effect was assessed by determining the diameter of the inhibition zone (IZ) and the minimum inhibition concentration (MIC). Results: Optimum conditions for highest yield of extract (270,78 mg/g) are as follows: solvent (water), substrate-solvent ratio (1:10), and extraction time (72 hours). Phytochemical screening revealed the presence of the major compounds known to have an antibacterial activity such as tannins and flavonoids in the aqueous and methanol extracts. The methanol extract was associated with an IZ diameter ranging from 8.46±2.25 mm up to 27.65±1.32 mm and displayed the lowest MIC (1.25 mg/ml). Our findings indicate that fenugreek seed extracted with methanol showed the best antibacterial effect against the targeted bacterial strain.

Effects of extraction procedures and plasticizer concentration on the optical, thermal, structural and antioxidant properties of novel ulvan films

Active films were produced with sulphated polysaccharides “ulvan”, extracted from the green seaweed Ulva lactuca with different extraction procedures, by varying the glycerol or sorbitol plasticizer concentration at 1% and 2% (w/v). The surface charge and glass transition temperature (Tg) of ulvans were carried out by zeta (ζ)-potential and DSC analysis, respectively. The investigation revealed that ulvans were anionic stable polymers and they had great Tg values. Regardless of the extraction procedure, ulvans can give successful films formulations. However, the optical, thermal, structural and antioxidant characteristics of ulvan films were strongly affected by extraction conditions and by the variation of the type and concentration of plasticizer. In general, as plasticizer concentration increased, ferrous chelating activity and compact structure increased as well, while, Tg, lightness and DPPH radical-scavenging activity decreased. Interestingly, the films plasticized with glycerol exhibited better compact structure, more negative temperature of transition, and greater free radical scavenging ability than with sorbitol. However, the films prepared with sorbitol had the highest L* values and chelating ability. The current study revealed a high correlation between zeta (ζ)-potential of ulvans and their Tg (R2 = 0.98), as well as with scavenging activity of ulvan films (R2 = 0.8–0.99).

Effect of extraction procedures on structural, thermal and antioxidant properties of ulvan from Ulva lactuca collected in Monastir coast

The present work aims to evaluate the effect of an acid extraction as well as a combined enzymatic-chemical extraction on structural, thermal and antioxidant properties of the sulphated polysaccharide ‘ulvan’ from the green seaweed Ulva lactuca. Structural characterization by FTIR and NMR spectroscopies showed the typical peaks of ulvan, namely, uronic acids, rhamnose and sulphate. FTIR analysis revealed that the extraction procedures were able to maintain ulvan structure. Despite differences in the extraction procedures, 13C NMR spectra were globally similar, proving a comparable chemical structure of ulvans. A major difference has been observed in signal intensity which reflected the resonance of glucose or xylose. Thermal characterization proved that ulvans were thermally stable until approximately 180°C. Antioxidant properties of ulvans were evaluated in vitro through different antioxidant assays. Ulvan, which is extracted at pH 1.5 and 90°C, exhibited the greatest scavenging activity (IC50=13.56μg/ml) towards DPPH radical. Result indicated that Mw has influenced inhibitory effect on DPPH radical of ulvan. The current study revealed also a high correlation between sulphate contents of ulvans and their reducing power (R2=−0.89) and their metal scavenging activity (R2=0.97). Overall, ulvans have peculiar structural, thermal and antioxidant properties which promote their use in food or pharmaceutical products as natural ingredient.

Effect of Extraction Procedures, Genotypes and Screening Methods to Measure the Antioxidant Potential and Phenolic Content of Orange-fleshed Sweetpotatoes (Ipomoea batatas L.)

Effect of Extraction Procedures, Genotypes and Screening Methods to Measure the Antioxidant Potential and Phenolic Content of Orange-fleshed Sweetpotatoes (Ipomoea batatas L.)

Effect of Extraction Procedures on Functional Properties of Eruca sativa Seed Mucilage

The effect of different extraction procedures on functional properties of mucilage extracted from Eruca sativa seed were investigated using response surface methodology. A Central Composite Face Design (CCFD) with three independent variables: temperature (25–85 °C), pH (4–10) and water to seed ratio (20:1–60:1) was used to study the response variables (yield, viscosity, emulsion stability, foam stability, solubility and water absorption capacity). For each response, a second-order polynomial model was developed using multiple linear regression analysis. The results indicated that extraction temperature and pH significantly (p < 0.05) affected all functional properties. Applying desirability function method, optimum operating conditions were found to be extraction temperature of 65.5 °C, pH: 4 and water to seed ratio of 60:1. At this optimum point, maximum extraction yield, viscosity, emulsion stability (ES), foam stability (FS), solubility and water absorption capacity (WAC) were found to be 10.3 (%), 357 (mPas), 87 (%), 87.5 (%), 28.5 (%) and 9.3 (g/g), respectively.

Harnessing of biohydrogen by acidogenic fermentation of Citrus limetta peelings: Effect of extraction procedure and pretreatment of biocatalyst

The extracts of Citrus limetta (sweet lime) peelings were evaluated as a fermentable substrate for hydrogen (H2) production by dark-fermentation (acidogenic) using both anaerobic mixed consortia and selectively enriched acidogenic mixed consortia. Extraction was carried by pretreating sweet lime peelings at 121 °C (1 bar pressure) at variable pH (6 and 7) and digestion time (20 and 40 min). Maximum organic matter extraction was observed at pH 7.0 (40 min). Fermentation was performed at different organic loading conditions [OL1, 1.17 kg COD/m3; OL2, 2.35 kg COD/m3; OL3, 4.69 kg COD/m3] under acidophilic microenvironment. H2 production was found to depend on the concentration of the substrate and composition. Increase in organic load showed consistent improvement in H2 production. Operation at OL3 employing selectively enriched inoculum documented higher cumulative H2 production (10.07 mmol) and H2 production rate (0.345 mmol/h) (pH 7; 40 min). Substrate degradation was also found to increase with increase in organic loading. Maximum substrate degradation (SD) was registered at pH 6 (40 min) with anaerobic culture (2.80 kg CODR/m3; ξCOD 31.82%) and at pH 7 (40 min) with selectively enriched acidogenic culture (3.20 kg CODR/m3; ξCOD 36.36%). Concentration of volatile fatty acids (VFAs) also improved with increase in organic load. Maximum VFA concentration (1098 mg/l) was observed with OL3 (pH 7; 40 min) by using selectively enriched culture.

Supercritical fluid extraction of oil from millet bran

AbstractProso millet bran [Panicum miliaceum (L.)], variety Dakota White, was extracted with supercritical carbon dioxide (SC‐CO2) to yield crude oil. The effects of operating parameters (pressure, temperature, and specific solvent flow) and of features of the raw material (moisture content and particle size) on oil extraction were investigated. Complete de‐oiling of ground millet bran pellets was achieved under 300 bar at 40°C with a specific solvent flow of 2–10 h−1 within 200 to 500 min. Solvent requirements were 20–30 kg CO2/kg raw material. Composition of crude SC‐CO2 oil extracted under optimal conditions, i.e., fatty acid profile, amount of unsaponifiables, tocopherols, free fatty acids, sterols, sterol esters, waxes, hydrocarbons, and phospholipids, was compared to that of crude oil obtained by petroleum ether extraction. These two oils were similar in terms of fatty acid profile and amount of free fatty acids, unsaponifiables, peroxides, and tocopherols. They differed in respect to phospholipids (present in petroleum etherextracted oil and absent in SC‐CO2 extracted oil), metals, and waxes (lower levels in SC‐CO2 extracted oil). The effects of extraction procedures on oxidative stability of crude SC‐CO2 oil were studied. Ensuring that all pieces of the extractor in contact with the oil were in stainless steel; cleaning the separator, i.e., washing with KOH, rinsing, purging with N2 and CO2, and heating; performing a couple of extractions before the main extraction; and achieving the extraction without interruption all positively influenced the oxidative stability of the oil. Conversely, increasing CO2 purity above 99.5% had no effect. Oxidative stability of the SC‐CO2 oil extracted under these conditions was only slightly lower than that of the oil extracted with petroleum ether.

Effect of extraction procedure on the molecular weight of wheat straw lignins

Wheat straw was treated with sodium hydroxide at various conditions, or ball-milled for 4, 8, 16, and 144 h in a porcelain rotary ball-mill and sequentially hydrolyzed by a cellulase for 3 days, and it was delignified by ethanol/water mixture (60:40, v v ) with 0.02 N H 2SO 4 as a catalyst at 75 °C for 1, 1.5, 2, 2.5, 3, 5 and 12 h, respectively. The alkali lignin fractions (LA) were isolated by two step precipitation. Milled lignins (LM) and enzyme lignins (LE) were extracted from the residues by 90% dioxane. Organosolv lignins (LO) were obtained by a traditional acidification method. The molecular weights of wheat straw lignins were determined by gel permeation chromatography (GPC). The effects of the extraction procedure on lignin molecular weight were examined in this study. The four lignin preparations showed low molecular-average weight (M w 1400–2020). Alkali lignins LA, which were relatively free of associated polysaccharides, appeared to offer the greatest potential for structural characterization of straw and grass lignins.

Effect of extraction methods on lipid yield and fatty acid composition of lipid classes containing γ‐linolenic acid extracted from fungi

AbstractThe effect of extraction procedures on the lipid yield and fatty acid composition of total lipid and main lipid structures (phospholipids, diacylglycerols, triacylglycerols, free fatty acids, and sterol esters) of fungal biomass (Mucor mucedo CCF‐1384) containing γ‐linolenic acid (GLA) was investigated. Seventeen extraction methods, divided into three groups, were tested: six with chloroform/methanol, five with hexane/alcohols, and six with common solvents or mixtures. The chloroform/methanol procedure (2∶1) was selected as standard, where lipid yield (TL/DCW, total lipid per dry cell weight) was 17.8%, considered to be 100% of lipids present. All chloroform/methanol extractions yielded more than 83% recorvey of lipids. Use of hexane/isopropanol solvent systems led to a maximum of 75% recovery. The best lipid yield was achieved by a two‐step extraction with ethanol and hexane (120%). Extraction efficiency of the other solvent systems reached a maximum of 73%. Triacylglycerols were the main structures of lipid isolated; only methanol‐extracted lipid contained 58.5% phospholipids. The fatty acid content of total recovered lipid was variable and depended on both the lipid class composition and the solvent system. GLA concentrations in total lipids isolated by hexane/alcohol procedures (7.3–10.7%) are comparable with classical chloroform/methanol systems (6.5–10.0%). The maximal GLA yield was obtained with chloroform/methanol/n‐butanol/water/0.1 M ethylenediaminetetraacetic acid (EDTA) (2∶1∶1∶1∶0.1, by vol) and after two‐step extraction with ethanol and hexane (14.3 and 13.7 g GLA/kg DCW, respectively). The highest GLA content was analyzed in the phospholipid fraction (16.1%) after using chloroform/methanol/n‐butanol/water/0.1 M EDTA (2∶1∶1∶1∶0.1, by vol). Remarkably low concentrations of polyunsaturated fatty acids were determined in the free fatty acid fraction.

Analysis of iron state in some Argentinian soils by dissolution methods and Mössbauer spectroscopy

Bahia Blanca (Argentina) soils, in particular entisols, are studied by Mossbauer spectroscopy. X-ray diffraction and scanning electron microscopy are used to characterize the samples. Samples were treated with different chemical iron extraction methods, in order to determine relative Feo and Fed fractions. The Feo/Fed ratios are obtained and the relative effect of iron extraction treatment on spectra components are determined. In addition, the effect of extraction procedures, dithionite-citrate-bicarbonate and oxalate, in the residual soil fraction are analyzed.

Determination of radon-222 and radium-226 in water samples by Cerenkov counting

Cerenkov radiation produced by the high-energy β-particles emitted from 214Bi, a daughter of 222Rn (and 226Ra), was utilized for the determination of 222Rn and 226Ra in water samples. For the determination of 222Rn the gas is extracted into an organic solvent and counted 2 h after extraction using a liquid scintillation counter. For the determination of 226Ra a sample storage time of 25 d is necessary to allow secular equilibrium to be established. The effects of extraction procedures, storage conditions and the nature of the organic solvent were evaluated using standard 226Ra solutions. Toluene was found to be the most suitable solvent, both as an extractant and as a transparent medium for Cerenkov radiation. Minimizing the volume of the air space above the liquid phase and centrifuging the organic solvent after extraction led to a good recovery of radon and a clean extraction, a detection limit of 35.1 mBq l–1 being achieved. Some results for water samples in the UK are presented.

Effects of extraction procedures on fulvic acid properties

Acid pyrophosphate (pH 2–4) is proposed as an extractant for soil fulvic acids. After XAD treatment of the extractant solution low-ash fulvic acids are obtained in high yield. The fulvic acids were subjected to the high pH and low pH conditions normally encountered in fulvic acid extraction. The observed changes induced in molecular weight distribution, equivalent weight, acid dissociation constants (pK i) and metal binding strength are reported.

Folacin content of alfalfa and mung bean sprouts: The effect of extraction procedures and maturity

AbstractThe folacin content of alfalfa (Medicago sativa) and mung bean (Vigna radiata) sprouts was determined by Lactobacillus casei. Several variations of extraction procedures were tested. The optimum conditions for extraction were autoclaving mung bean and alfalfa sprouts in phosphate buffer containing 0.3% and 0.4% ascorbate, respectively, before homogenisation in a blender. The optimum blending time for folacin extraction was 120s for mung bean and 15s for alfalfa sprouts. Folacin content on dry weight basis increased several times in both types of sprouts during germination. Mature alfalfa and mung bean sprouts were found to contain 186 and 178 μg folacin per 100 g fresh weight, respectively.

Effect of Extraction Procedures on Fluorescent Chromophores in Milk

ABSTRACTThe oxidation of membrane lipids of freeze‐dried Milk Fat Globule Membranes (MFGM) was studied using a fluorescence technique involving two different extraction procedures to obtain lipophilic fluorescent chromophores. MFGM underwent extensive lipid oxidation when stored under air, at controlled temperature and humidity and fluorescent compounds were formed with excitation maxima at 350 nm and emission maxima at 440 nm. Direct extraction of fluorescent compounds with an organic solvent mixture (Cl3CH:CH3OH 2:1 v/v) gave reproducible results reflecting well the progress of oxidation. Solvent extraction after previous reconstitution (to original water content) of the dry samples was less satisfactory.

PEP-Carboxylase Activities and the Regulation of CAM: Effects of Extraction Procedures and Leaf Age

The amplitude of the diurnal oscillation of malic acid accumulation in leaves of Kalanchoe daigremontiana and Kalanchoe blossfeldiana varies considerably with leaf position on the shoot (leaf age) and growth conditions. The total activity of phosphoenolpyruvate carboxylase (PEP-c capacity) measured in desalted crude extracts shows a different dependence on the leaf position and in the majority of experiments no significant diurnal change. In contrast PEP-c capacity shows a clear diurnal rhythm in extracts prepared from freezedried (lyophylised) fully expanded leaves of K. daigremontiana or phyllodia of K. tubiflora, the enzyme being 10 times more active at the end of the light period than at the end of darkness. This diurnal rhythm in PEP-c capacity is negatively linearly correlated to the malic acid content of the leaves during lyophylisation. When acidification is prevented by applying C02-free air during darkness, lyophylisation does not cause loss in PEP-c capacity overnight. In extracts prepared from lyophylised material having high malic acid and therefore low enzyme capacity, the enzyme activity can not be restored by desalting of the extracts or increasing the amount of polyethylenglycol in the extraction buffer. The extractability of protein is constant and not effected by lyophylisation. We conclude that during the freeze-drying procedure the PEP-c undergoes an irreversible inactivation, the degree of which is dependent on the malic acid content of the leaves.