Extraction Of Free Amino Acids Research Articles

Functional food ingredient - chromium complex with protein fermentolysate of bivalve Mactra chinensis for the prevention of hyperlipidemia and obesity

The creation of specialized food systems capable of correcting body weight and influencing lipid metabolism is an urgent task at the present stage. The main way to create such food systems is to modify product profiles (lipid, protein, carbohydrate, mineral, vitamin, etc.). The aim of the study was to obtain and characterize a new food source of an organic form of chromium for the prevention of hyperlipidemia and obesity in the form of a complex with peptide fractions of fermentolysate proteins of the Mactra chinensis bivalve mollusk from the Far Eastern region. Material and methods. Soft food parts of the Mactra chinensis bivalve mollusk from the Far Eastern region (the motor muscle and mantle) were used as objects of research. Mollusk specimens were collected in the Amur Bay in June - September 2022. Biotechnological modification of soft tissue proteins was carried out using alkaline protease protozyme B with the following parameters: the duration of the process - 12 and 24 hours, pH - 7.0-7.2, temperature 55 °C. The fractional composition of proteins and peptides was determined by medium pressure gel permeation chromatography, the molecular weight (MW) of proteins and peptides was calculated using MW markers by comparing retention volumes. Extraction of free amino acids was carried out with 70% ethanol for 24 hours at a temperature of 20 °C, the composition and quantitative content of amino acids were determined by HPLC. The complexation reaction was carried out by adding to the fermentolysate with stirring a 10% aqueous solution of CrCl3×6H2O in a mass ratio of 6.25 × nitrogen in the liquid fraction : chromium (III) chloride = 20:1. Process conditions: temperature 20-25 °C, time 60 min, pH 7.0-7.1. The chromium content was determined by the atomic absorption method using spectrophotometer. Results. The content of low-molecular fractions increased more significantly over time in the mantle fermentolysate. The content of the high-molecular fraction of peptides weighing more than 160 kDa was minimal for both the muscle and the mantle and didn't exceed 1.1%. Low-molecular fractions weighing no more than 18 kDa in the 24-hour fermentolysate accounted for 79.6% for the muscle and 86.9% for the mantle. The obtained fermentolysates were characterized by a high content of the biologically active amino acid taurine - 25.9% (muscle) and 30.05% (mantle) of the total amino acid content. The high content of such essential amino acids as glycine, alanine, leucine, lysine, and the conditionally essential amino acid arginine was also determined. The obtained fermentolysates of soft tissue proteins of the Mactra chinensis were characterized by a fairly balanced amino acid composition. It has been experimentally established that more than 84% of the total chromium content in muscle fermentolysate and 80.9% in mantle fermentolysate was associated with peptide fractions with molecular weights from 24 to 1.4 kDa, and the highest specific chromium content - 1.67 mg/g protein (muscle) and 1.58 mg/g protein (mantle) was determined in the interval fractions with molecular weights of 18.0-12.5 kDa. The minimum specific content of the trace element was established for high-molecular fractions of 160-67 kDa and low-molecular fraction weighing less than 1.4 kDa. Conclusion. Biotechnological modification of soft tissue proteins of the Mactra chinensis bivalve mollusk from the Far Eastern region made it possible to obtain a balanced amino acid composition fermentolysate with a high content of the free biologically active amino acid taurine. Fortification of the obtained fermentolysate with chromium demonstrated high efficiency of its binding to the amino acid and peptide matrices of the protein hydrolysate. The chromium complex with fermentolysate of proteins of the Mactra chinensis bivalve mollusk can be used as a food source of chromium and taurine, including as a functional ingredient in special food systems for the prevention of hyperlipidemia and obesity.

Effect of Solvent Type and Germination Time on The Level of Free Amino Acid and Peptides of Germinated Pigeon Pea (Cajanus cajan (L.) Millsp) Extract

Germination can activate the degradation of storage protein in legumes releasing peptides and free amino acids for seed growth. These compounds have many benefits in many fields, especially in food and health. This study aimed to determine the effect of solvent type and germination time on the level of free amino acids (FAA) and the level of peptides (MW < 10 kDa) of germinated pigeon pea extract. The extraction of free amino acids and the dissolved protein from germinated pigeon pea flour was carried out using two kinds of solvents, namely water, and 0.1 N HCl. The variation of germination times of pigeon pea seeds was carried out at 12, 24, 36, 48, 60, 72, 84, and 96 hours. The level of FAA was determined spectrophotometrically using the ninhydrin method after the deproteination step, while the level of peptides was determined spectrophotometrically using the biuret method. The results showed that using 0.1 N HCl as a solvent produced a higher level of FAA and peptides in the extract than using water. The increase of germination time can increase the level of FAA with the peak achieved in 36 hours. The increase of germination time can increase the level of peptides with the peak of peptides level achieved on 84 hours of germination. These results showed that seed germination is a potential method for producing free amino acids and peptides which accumulate at a specific time

Simultaneous Detection and Analysis of Free Amino Acids and Glutathione in Different Shrimp.

An amino acid analyzer method for the simultaneous determination of 20 free amino acids (FAAs) and glutathione (GSH) in Penaeus vannamei (PV), Penaeus vannamei, Penaeus hidulis (PH) and Penaeus japonicus (PJ) were developed. The effects of different concentrations of trichloroacetic acid (TCA) and ethanol on the extraction of free amino acids were investigated, and 120 g·L−1 TCA was found to be ideal. The target analytes were eluted in sodium citrate buffer B1 (pH = 3.3) containing 135 mL·L−1 ethanol and 1 mol·L−1 sodium hydroxide (7 mL) and at the optimizing conversion time of sodium citrate buffer B2 (pH = 3.2) and sodium citrate buffer B3 (pH = 4.0) of 5.6 min, and the effective separation was achieved within 29.5 min. The developed method showed good linearity (R2 ≥ 0.9991) in the range of 1–250 µg·mL−1 with good intra-day and inter-day precision (relative standard deviations ≤ 2.38%) and spike recovery (86.42–103.64%). GSH and cysteine were used to identify marine prawn and freshwater shrimp. Hydroxyproline and serine were used to distinguish PV and Macrobrachium nipponense (MN) from others, respectively. The highest content of the total FAAs was found in PV, and principal component analysis revealed that PV had the highest comprehensive score for FAAs and GSH. Arginine was found to have the greatest influence on shrimp flavor.

Supercritical fluid extraction of free amino acids from sugar beet and sugar cane molasses

In this work supercritical fluid extraction (SFE) was used to extract free amino acids (AAs) from sugar beet (SGB) and sugar cane (SGC) molasses. The effect of different variables such as, pressure (150–350 bar), temperature (40–60 °C) and extraction time (10–90 min) was evaluated to optimize the extraction using response surface methodology (RSM).The results of SGB and SGC molasses extraction showed that the optimal condition were 184 and 316 bar; 43 and 50 °C and 76 and 76 min, respectively. Under the optimum condition, the extraction recoveries of AAs for SGB and SGC molasses were 42% and 31% for aspartic acid, 63% and 37%, for glutamic acid, 46% and 48% for alanine and 31% and 20% for lysine sequentially. This study indicated that SFE might be employed to extract of AAs from SGB and SGC molasses with acceptable selectivity and extraction efficiency.

HISTAMINE DETERMINATION IN FISHERY PRODUCTS: ALTERNATIVE METHODS FOR EXTRACTION AND QUANTIFICATION

HISTAMINE DETERMINATION IN FISHERY PRODUCTS: ALTERNATIVE METHODS FOR EXTRACTION AND QUANTIFICATION

STUDY OF AMINO ACID COMPOSITION IN A THALICTRUM FOETIDUM L. HERB

Submitted article is concerned with the study of amino acid composition in a Thalictrum foetidum L. herb. Investigations have been performed by the high performance liquid chromatography method based on the extraction of free amino acids from the herbal raw material and on the acid hydrolysis of the herbal medicinal products followed by analysis of hydrolizates using the HPLC with precolumn derivatization with 9-fluorenylmethoxycarbonyl chloride (FMOC) and o-phthaldialdehyde (OPA) attended by the detection with fluorescence detector. Amino acid identification has been performed by the comparison of retention times with the mixture of standard amino acids (Agilent 5061-3334). The content of bound amino acids has been determined by the subtraction of free amino acids composition from their total composition. As a result of study 15 essential and non-essential amino acids have been found. It is important to note that L-Serine, L-Histidine, Glycine and L-Phenylalanine are not in a free state in Thalictrum foetidum L. herb. The quantity of L-Glutamic and L-Aspartic acids is 17.47 and 13.41 µg/mg, respectively (common amino acids). The content of abovementioned acids in a bound state is 15.66 and 9.84 µg/mg, respectively. As for content of other amino acids which were found in Thalictrum foetidum L. herb, it has to be said about their practically the same composition which is in the range from 4 to 5 µg/mg. Content of L-Histidine (1.80 µg/mg in general and bound state) and L-Tyrosine (1.76 µg/mg in general state and 0.08 µg/mg in bound state) is minimum in this herb. It has been established that amino acids are in a free and bound state in the investigated herbal raw material. Content of bound amino acids is higher than general content. Among the amino acids, which are in the overwhelming majority in the studied herb, it stands to mention L-Glutamic and L-Aspartic. These amino acids play an important role in supporting the physiological processes of the body, especially nervous system. In consideration of experimental data to be noticed is that Thalictrum foetidum L. is a promising plant for creation of phytotherapeutic medications with neurally mediated action.

Effects of sonication on the extraction of free-amino acids from moromi and application to the laboratory scale rapid fermentation of soy sauce

Soy sauce fermentation was simulated in a laboratory and subjected to 10min of sonication. A full factorial design, including different cycles, probe size, and amplitude was used. The composition of 17 free-amino acids (FAAs) was determined by the AccQ-Tag method with fluorescent detection. Main effect plots showed total FAAs extraction was favoured under continuous sonication at 100% amplitude using a 14mm diameter transducer probe, reaching 1214.2±64.3mg/100ml of total FAAs. Moreover, after 7days of fermentation, sonication treatment caused significantly higher levels (p<0.05) of glutamic acids (343.0±22.09mg/100g), total FAAs (1720.0±70.6mg/100g), and essential FAAs (776.3±7.0mg/100g) 3days sooner than the control. Meanwhile, enzymatic and microbial behaviours remained undisturbed. Collectively, the sonication to moromi resulted in maturation 57% faster than the untreated control.

A Rapid and Accurate Extraction Procedure for Analysing Free Amino Acids in Meat Samples by GC-MS.

This study evaluated the use of a mixer mill as the homogenization tool for the extraction of free amino acids in meat samples, with the main goal of analyzing a large number of samples in the shortest time and minimizing sample amount and solvent volume. Ground samples (0.2 g) were mixed with 1.5 mL HCl 0.1 M and homogenized in the mixer mill. The final biphasic system was separated by centrifugation. The supernatant was deproteinized, derivatized and analyzed by gas chromatography. This procedure showed a high extracting ability, especially in samples with high free amino acid content (recovery = 88.73–104.94%). It also showed a low limit of detection and quantification (3.8 · 10−4–6.6 · 10−4 μg μL−1 and 1.3 · 10−3–2.2 · 10−2 μg μL−1, resp.) for most amino acids, an adequate precision (2.15–20.15% for run-to-run), and a linear response for all amino acids (R 2 = 0.741–0.998) in the range of 1–100 µg mL−1. Moreover, it takes less time and requires lower amount of sample and solvent than conventional techniques. Thus, this is a cost and time efficient tool for homogenizing in the extraction procedure of free amino acids from meat samples, being an adequate option for routine analysis.

Extraction and sample preparation.

As everyone knows, the role played by extraction and sample preparation in the analytical sciences cannot be overemphasized. Despite tremendous advances in chromatography, detection, and other aspects of analysis, extraction and sample preparation remain a preanalysis ritual of critical importance. It has been estimated that around 50% to 70% possibly even more of the time and effort that goes into an analytical process comprises extraction and sample preparation. Sample preparation procedure can vary in the degree of selectivity, speed, and convenience, depending on the approach and conditions used, as well as on the geometric configurations of the extraction phase and conditions. Proper design of the extraction devices and procedures facilitates rapid and convenient on-site implementation, coupled with separation/quantification and/or automation. This special issue addresses the research studies on the sample preparation, analytical extraction, and sample clean-up techniques. For example, M. Jablonska-Czapla reported a review on chemical speciation and provided numerous examples of the hyphenated technique usage (e.g., the LC-ICP-MS application in the speciation analysis of chromium, antimony, arsenic, or thallium in water and bottom sediment samples). T. Perez-Palacios et al. investigated the use of a mixer mill as the homogenization tool for the extraction of free amino acids in meat samples, with the main goal of analyzing a large number of samples in the shortest time and minimizing sample amount and solvent volume. It takes less time and requires lower amount of sample and solvent than conventional techniques. N. Sher et al. studied colorimetric visible spectrophotometric quantification methods for amino acids, namely, tranexamic acid and pregabalin. Both drugs contain the amino group, and when reacted with 2,4-dinitrophenol and 2,4,6-trinitrophenol they give rise to yellow colored complexes showing absorption maximum at 418 nm and 425 nm, respectively, based on the Lewis acid base reaction. J. A. Rodriguez et al. reported magnetic solid phase extraction of tartrazine from nonalcoholic beverages. The method involves the extraction and clean-up by activated carbon covered with magnetite dispersed in the sample, followed by the magnetic isolation and desorption of the analyte by basified methanol. The proposed methodology saves time and is less expensive than the reference method. M. Khorshid et al. reported QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for extraction followed by solid phase extraction for sample purification and gas chromatography mass spectrometer, GCMS, for determination of 16 PAHs in fish at low LOQ level. E. A. Pfannkoch et al. reported combination QuEChERS and SBSE methods for extraction and concentration PAHs from fish and shellfish. I. Amin et al. reported a semiautomated extraction protocol of HCV-RNA using Favorgen RNA extraction kit. The kit provided protocol was modified by replacing manual spin steps with vacuum filtration. The assay performance was evaluated by real time qPCR based on Taqman technology. W. Wang et al. reported a high throughput sample preparation method utilizing mixed-mode solid phase extraction (SPE) in 96-well plate format for the determination of free arachidonic acid in plasma by LC-MS/MS. J. Knutsson et al. reported an uncertainty budget for the determination of fully labile Cu in water using a DGT passive sampler. H.-R. Lee et al. reported two different ionization techniques including electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the analysis of cholesteryl esters (CEs). The ESI technique proved to be effective in ionizing more kinds of CEs than the APCI technique. J. Wang et al. evaluated various existing protein extraction buffers with zebrafish liver tumor samples and found that sodium deoxycholate (DOC) based extraction buffer with heat denaturation was the most effective approach for highly efficient extraction of proteins from complex tissues such as the zebrafish liver tumor. B. B. Burckhardt and S. Laeer developed sample preparation exemplified by solid phase extraction for the bioanalytical method development of low-volume assays for pediatric studies according to international agency guidelines. A. Rehman et al. suggested that Oxalis corniculata has good antibacterial, antifungal, and insecticidal properties and can be used for the treatment of infections and control of insects. The plant extracts could be a new source for antibiotics and pesticides with minimum noxious effects on the environment. Further studies may also lead to isolating and characterizing the active compounds of the plant extracts and elucidating their biological mechanisms of action.

Analyses of Arabidopsis ecotypes reveal metabolic diversity to convert D-amino acids

For a long time D-enantiomers of proteinogenic L-amino acids were assumed to be physiologically irrelevant for plants. But there is growing evidence that D-amino acids (D-AAs) also fulfil important physiological functions in these organisms. However, the knowledge about the metabolic fate of D-AAs in plants is still scarce and more information about it is needed. To close this gap we established an optimized protocol for the processing and analysis of D- and L-AAs from large numbers of Arabidopsis lines. This included the application of 18 different D-AAs to seedlings, the extraction of free amino acids from the samples and the determination of 16 L-AAs and their corresponding D-enantiomers. To validate our approach we searched for genetic accessions with aberrant amino acid metabolism. Therefore we applied D-AAs on 17 ecotypes of Arabidopsis thaliana and analysed their free amino acid contents. These analyses confirmed the suitability of the system for the analysis of large sets of plant samples with enhanced velocity and improved accuracy. Furthermore, the resulting data led to the definition of standard amino acid profiles in response to D-AAs of Arabidopsis seedlings. Within these analyses the ecotype Landsberg erecta was found with aberrant metabolic patterns like drastically reduced capabilities to convert different D-AAs to D-alanine and D-glutamate. The presented experimental setup and results of this study offer starting points to dissect the metabolic pathway of D-AAs in plants.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-559) contains supplementary material, which is available to authorized users.

Supercritical fluid extraction of free amino acids from broccoli leaves

The extraction of free amino acids (AAs) from broccoli leaves using supercritical fluid extraction (SFE) with CO2 modified with methanol, is presented in this work. The effect of the different variables was studied, showing the percentage of methanol a strong influence on the extraction. The best results in terms of extraction yield were obtained at 250bar, 70°C, 35% methanol as organic modifier, a flow rate of 2mL/min, and 5min and 30min as static and dynamic extraction times, respectively. The extraction yield obtained with the SFE method was comparable to that obtained employing conventional solvent extraction with methanol–water (70:30) and minor than using water, but the relative proportion of the AAs in the extracts was very different. For example, the use of SFE allowed the enrichment in proline and glutamine of the extracts. The selected conditions were applied to obtain SFE extracts of broccoli leaves from different varieties (Naxos, Nubia, Marathon, Parthenon and Viola). The highest levels of AAs were found in the SFE extracts from the Nubia variety.

Determination of free amino acids and ammonium ion in saffron ( Crocus sativus L.) from different geographical origins

Amino acids are important in human nutrition and also influence the sensory traits of products. Up to now, no report has been available on the free amino acid content of saffron spice. This study developed a rapid method for the extraction of free amino acids and ammonium ion from saffron, thus permitting the differentiation of saffron samples by origin. The first step tested the extraction time (15, 30, 60, 120 and 240 min) and extractive solvent (water, 0.1 N HCl, 0.5 N HCl and 1 N HCl). The best results for the free amino acids and ammonium ion extraction were obtained using 0.1 N HCl during 60 min. Subsequently, these compounds were derivatised using diethyl ethoxymethylenemalonate (DEEMM) and analysed by HPLC. Using this method, 20 saffron samples from different countries (Spain, Italy, Greece and Iran) were analysed. Alanine, proline and aspartic acid were the major amino acids in all the samples. Alanine presented the maximum value in Iranian samples with 0.17 ± 0.02 mg/100 mg of saffron. The highest concentration of proline (0.087 ± 0.01 mg/100 mg) appeared in Greek samples and the maximum value of aspartic acid was 0.04 ± 0.01 mg/100 mg in Spanish samples. Greek and Iranian saffron presented the highest total free amino acid content, 0.50 ± 0.08 mg/100 mg and 0.55 ± 0.07 mg/100 mg, respectively. Furthermore, the free amino acid profile enabled us to differentiate the Iranian samples from the European samples ( p < 0.05).

Identification of S-methylmethionine in Petit Manseng grapes as dimethyl sulphide precursor in wine

A procedure for the extraction of free amino acids was applied to isolate S-methylmethionine (SMM) from late harvest Petit Manseng grapes. Grapes were destemmed and crushed, and the obtained clarified must was percolated through cation-exchange resins (Dowex 50 WX4-100). The retained compounds were eluted with ammonia solution and the extract was finally concentrated. Taking into account the potential DMS (PDMS using heat-alkaline treatment assay) of the initial grape juice used (51.5 nmol mL −1) and the concentration factor of the extract (17.9-fold), the PDMS of the final extract (678 nmol mL −1) gave an overall recovery of 73.5% for juice SMM. This compound was identified and quantified (484.5 nmol mL −1 relatively to [ 2H 3]-SMM used as internal standard) by its selective detection in this extract without derivatization by MALDI-TOF-MS using instrumentation and procedures previously reported to analyze SMM in complex natural extracts. SMM and 22 other amino acids in the initial must and in the final SMM extract were also determined using a Biochrom 30 amino acid analyser with post-column ninhydrin derivatization. SMM peak identification and quantification (401.2 nmol mL −1 relatively to norleucine used as internal standard) were carried out by comparison with commercial SMM.

Effective Ways of Decreasing Acrylamide Content in Potato Crisps during Processing

The aim of this work was to examine the effect of blanching or soaking in different acid solutions on the acrylamide content in potato crisps. Furthermore, the effects of a shorter frying time and a lower frying temperature combined with a postdrying were investigated. Soaking or blanching of potato slices in acidic solutions decreased the pH of potato juice and increased the extraction of amino acids and sugars. Potato crisps obtained after such pretreatments were characterized by lower acrylamide content. The most effective extraction of free amino acids and sugars as well as the largest decrease of acrylamide content (90%) in crisps was obtained when potato slices were soaked in acetic acid solution for 60 min at 20 degrees C. Shorter frying time followed by postdrying resulted in low-moisture potato crisps. Furthermore, the postdrying treatment gave a decreases in acrylamide content of approximately 70% when potato slices were fried at 185 degrees C and approximately 80% when potato slices were fried at 160 degrees C. Effective ways of decreasing acrylamide content in crisps production have been found. Crisps with low acrylamide content and good sensory quality can be obtained either by blanching in acetic acid as pretreatment or by a short frying followed by postdrying.

Free amino acids of leaves and berries of Cabernet Sauvignon grapevines

&lt;p style="text-align: justify;"&gt;The composition of free amino acids was studied from leaves, pericarps, skins, musts and seeds of &lt;em&gt;Vitis vinifera&lt;/em&gt; L. cv. Cabernet Sauvignon. Vineyards were in the Bordeaux region and the grapevines were conducted in espalier and lyre systems. Grapes were collected at maturity and lyophilized after sampling. Extraction of free amino acids was done with a hydroalcoholic solution and their analysis was performed with an autoanalyzer. A standard of 34 amino acids was utilized for the qualitative analysis. The results showed that, for both espalier and lyre training systems, respectively, the free amino acids were predominant in the pericarps (12.85 and 11.21 mg/g dw) - 16.88 and 15.12 mg/g dw in skins and 3.29 and 2.88 g/l in musts -, followed by the seeds (2.37 and 2.32 mg/g dw) and leaves (1.87 and 1.98 mg/g dw). The most abundant free amino acids in leaves were glutamic acid (23.8 and 28.8 p. cent), aspartic acid (8.8 and 11.1 p. cent), and glutamine (10.1 and 9.4 p. cent). Proline (41.8 and 41.5 p. cent) and arginine (22.8 and 22.4 p. cent) predominated in the pericarps. In seeds, the main amino acids were proline (14.5 and 15.8 p. cent), arginine (11.0 and 11.8 p. cent), histidine (11.2 and 8.7 p. cent), and glutamic acid (11.3 and 8.2 p. cent). Grapevine training system showed some differences in the total amount and in the percentages of each free amino acid, but the pattern of these compounds for each tissue was similar for both training systems.&lt;/p&gt;

Microwave-assisted extraction of free amino acids from foods

A microwave-assisted solvent extraction technique was developed for the extraction of free amino acids from foods. Four different samples were subjected to microwave extraction with varying amounts of extractant at several temperature values, for varying times to determine optimum extraction conditions. The extractions were performed with or without shaking the vessels in order to investigate the effects of mixing on the extraction efficiency and reproducibility. A comparison was made between this method and the traditional 1 h shaking extraction. The experiments indicated that the microwave-assisted extraction is an effective technique for the extraction of free amino acids from samples of plant or animal origin. The extraction yields obtained by the microwave method were about 10% better than by the conventional shaking technique. The times needed for the complete sample preparations were reduced by 66% with the application of microwaves.

Extraction of free amino acids from tomato leaves

Conditions for extraction of free amino acids from tomato leaves were examined. Two methods of sample preservation were also tested. Best results were obtained when samples were preserved by lyophilization and extracted by Soxhlet for 6 h at 40°C at a ratio of 1 g plant material/80 mL 80% (v/v) ethanol.

Extraction of free amino acids

A solvent is percolated through the sample of freeze-dried potatoes in a column until no more free amino acids are extracted. The simple method can operate unattended and with other materials. NH3 and ARG are the last to be removed. Maillard intermediates survive.

Extraktion freier Aminosäuren aus Pilzsporen (Phycomyces blakesleeanus)

Extraction of free amino acids from fungal spores (Phycornyces blakesleeanus)Because extraction conditions are crucial for the reliability of biochemical analysis of fungal spore materia1, comparative investigations on methods were conducted, using the amount of free amino acids as a parameter of exhaustive extraction. It was found that optimal conditions are: Extraction in a Soxhlet apparatus with methanol as extracting medium (for 8 hours under reduced pressure and 40°C boiling temperature) or treatment with ice‐cold perchloric acid (10 % for 30 minutes) or trichloroacetic acid (10 % for 30 minutes). A pretreatment of the material by desintegration was not necessary. Extraction with hot water (70 or l00T) or with ethanol, propanol, butanol, 3,3 %perchloric or trichloroacetic acid proved to be inappropriate.All of the common amino acids were detected in the extracts except proline and phenylalanine. A few amino acids make up the majority of the pool (glutamic acid, glutamine, aspartic acid, asparagine, alanine and y‐butyric acid). These amino acids comprised about 80% of the total intracellular pool (ca. 12000 moles/l00mg spores) and account for nearly 2% of the spore dry weight. Sacrosine, probably being present in considerable amounts, could not be determined quantitatively.

Effect of harvest date and maturity upon free amino acid levels in three varieties of peanuts.

AbstractAn improved method for the extraction of free amino acids and a peptide of unknown composition with a methanol:chloroform:water mixture (60:25:15; v:v:v) was described. The largest variations were related to maturity. If the amino acids were ranked in descending order, glutamic acid, followed by asparagine (including asparagine, glutamine, threonine, and serine), topped the list in the mature and low intermediate groups, except in Valencia at 141 days. The peptide and phenylalanine were usually in the top six, while aspartic acid occurred there fairly often. Arginine was the highest in immature peanuts. Proline was found in higher concentrations in immature peanuts than previously reported. The presence of two nonprotein amino acids (γ‐methyleneglutamine and γ‐methyleneglutamic acid) in mature kernels was confirmed.