Alkaline Extraction Of Protein Research Articles

Co-production of plant- and microbial- proteins from waste tobacco leaves by optimizing alkaline extraction and strengthening pectin bioconversion

The production of alternative proteins is of great significance in the mitigation of food problems. This study proposes an integrated approach including protein extraction, enzymatic hydrolysis, and fermentation to produce both plant proteins and single-cell proteins as alternative proteins from tobacco leaves, a highly-abundant and protein-rich agricultural waste. Alkaline extraction of proteins before polysaccharide hydrolysis was found to be preferable for increasing the yields of plant proteins and mono-sugars. The combined use of pectinase-rich enzymes from Aspergillus brunneoviolaceus and hemicellulase-rich enzymes from Penicillium oxalicum achieved the release of 80.7 % of the sugars after 72 h. Cutaneotrichosporon cutaneum could simultaneously utilize multiple sugars, including galacturonic acid, in the enzymatic hydrolysate to produce single-cell proteins. Via this approach, 43.54 g crude proteins of high protein contents and rich in essential amino acids can be produced from 100.00 g waste tobacco leaves, providing a promising strategy for its valorization.

Mass spectrometric analysis of plant protein concentrates

The work is devoted to the study of the composition of protein concentrates from amaranth grains (Amaranthus hypochondriacus L.), Voronezh variety. Amaranth protein concentrates were obtained by the alkaline extraction of proteins, the neutralization of the solution, followed by ultrafiltration; by separating the starch fraction with amylolytic enzymes; alkaline extraction of proteins and their precipitation at pH 4.5. The conditions for protein extraction were selected, followed by gas chromatography-mass spectrometric analysis and their identification. It has been shown that proteins from amaranth grain were more efficiently extracted with a buffer containing urea at protein concentrations in solution of 1.7, 1.9, and 2.9 mg/cm3respectively, while the buffer with detergents was more effective for the extraction of low molecular weight proteins at protein concentrations in solution of 4.9, 2.9, and 9.0 mg/cm3 respectively. As a result of HPLC-MS/MS analysis followed by a search and identification in the UNIPROT database, it was established that the main protein of amaranth grain is 11S-globulin, which is a reserve protein of amaranth seeds. In amaranth concentrates, 14 unique proteins characteristic only for A.hipochondriacus L., as well as proteins that were not characteristic to this species, but were reliably identified. Based on the results of semi-quantitative analysis of the peptide profile of amaranth grain protein concentrates, a high frequency of occurrence of the main 11S-globulin proteins was established in all samples. The frequency of occurrence of other proteins in samples obtained by different methods differed significantly, which was associated with the peculiarities of protein isolation from amaranth grain. The obtained results can be used for the production of plant protein concentrates with a set protein composition.

Valorizacija ljušture invazivnih rakova iz reke Dunav (Faxonius limosus) - ekstrakcija i karakterizacija proteina

In order to deal with invasive crayfish (Faxonius limosus) impact on the native crayfish, as well as fish biodiversity in the Danube River, a possible solution would be to find and adopt mechanisms for its utilization for novel valuable product production. Apart from utilizing edible parts for novel food products, the shell waste can also be considered a source of valuable compounds. The complex structure of the shell mainly consists of three basic compounds: chitin, protein and minerals-mainly calcium carbonate. In this study, shell waste proteins were extracted using three extraction methods. The first method involved using naturally present enzymes (proteases and lipases) in crayfish wastes to recover proteins through an autolysis process. To accelerate the process, UV radiation was used. The remaining two extraction methods were alkaline extraction of proteins, wherein one method alkaline extraction was applied directly to the shell waste, and the other method, alkaline extraction followed an acidic demineralization step of the shell waste. The obtained protein concentrates were analysed for yield, crude protein content, DPPH radical scavenging ability, amino acid content, and structure. The results have shown that a similar percentage of protein content was obtained by all three methods: 67.20-68.03 %, but the extraction yield was considerably different. Alkaline deproteinization with or without the step of demineralization resulted in a 9.20-10.98 % yield, while UV radiation accelerated autolysis resulted in only a 3.41 % yield. Although protein extraction without using exogenous enzymes or chemicals is a very interesting approach, a drawback of this approach is the low process yield. FTIR spectroscopy revealed a secondary structure that was similar in all three concentrates, according to peak deconvolution, with the autolytic concentrate differing to a lesser extent, showing a slightly higher share of b-sheet structures. The DPPH assay revealed high antioxidant activity of the concentrates (72.00-88.06 %), probably originating from active peptides derived from proteins and residual carotenoids, mainly astaxanthin.

Alkaline Extraction of Protein from Sacha Inchi Oil Press-cake: Effect of pH, Temperature, and Extraction Time

Alkaline Extraction of Protein from Sacha Inchi Oil Press-cake: Effect of pH, Temperature, and Extraction Time

Effect of microwave treatment on the alkaline extraction of proteins and phenolics from perilla seed meal in varying pH conditions: An optimization study using multicomponent analysis

Perilla seed meal (PSM) is a by-product rich in proteins and bioactive compounds obtained by cold pressed oil extraction method. Microwave is an efficient nonconventional technology usually used to accelerate the recovery of the extracts. In this study, pH, microwave power and treatment time were optimized to maximize the recovery of targeted compounds using Box–Behnken design. The pH was found to be the most significant variable affecting the yield followed by microwave power and treatment time (based on F-value). Compared to conventional alkaline extraction, an increase in the yield of protein content by 10.58%, antioxidant activity by 7.48% and total phenolic content by 21.59% was recorded at the optimal values of pH (11.5) microwave power (160 W) and treatment time (30 s). Moreover, principle component analysis revealed opposite correlation between antioxidant activity and extraction of protein/phenolics suggesting the loss of bioactivity at the higher yield of extracts. Also, from the clustering analysis, the effect of microwave treatment found to be lower in more extreme alkaline conditions compared to lower pH values. Hence, lower alkaline conditions are suggested for the microwave treatment to develop better control system in the extraction industry.

Extraction of brewers’ spent grain in near subcritical conditions: A method to obtain high protein contents extracts

Accelerated solvent extractor (ASE) was used in extraction of proteins from brewers’ spent grain (BSG) using water as solvent in near subcritical conditions (<100 °C, ∼100 bar). Variables in the study were extraction time (20, 60 and 120 min) and NaOH concentration (0.01, 0.05 and 0.1 N) in the extraction solvent. Extractions were performed so that sample in aforementioned conditions was extracted in four different temperatures (21 (RT), 40, 60 and 80 °C). In between each extraction temperature extraction solvent was changed to fresh solvent. Ultrasonic and mild H 2 SO 4 pretreatments of BSG prior alkaline extraction (0.1 N NaOH, 60 min) were also experimented. Dissolved proteins were precipitated from the extracts by adjusting pH to 3, centrifuged and dried. Protein contents in dried precipitates, and in dried residual BSG after the extractions was determined using Kjeldahl method. The combined amount of precipitated proteins from four extractions varied from 21.3 to 65.3% (db) from the total amount of proteins in fresh BSG. Alkaline extraction of H 2 SO 4 pretreated BSG provided the highest, and 0.01 N NaOH as the extraction solvent the lowest proteins yields. Protein contents in the precipitated and dried extracts was more than three times the protein contents in BSG (18.6%) in 16 of the 41 analyzed extracts. Highest protein contents (69.7%) in dried extract was obtained when dried BSG was extracted with 0.05 N NaOH for 60 min at 40 °C. Water-extraction near subcritical conditions was shown to be a promising method to concentrate proteins from BSG with high protein contents and with low chemicals load. • Near subcritical conditions applied in alkaline extraction of proteins from BSG. • pH shift method affords high protein contents extracts from BSG. • Extractions of proteins from preserved six-month-old BSG samples. • Drying and grinding of BSG not required in extraction of proteins.

Value-Added Dietary Fiber Concentrate Obtained as Waste after Protein Isolation from Ethanol-Treated Sunflower Meal.

Deproteinized sunflower meal (DSM) was obtained as waste from ethanol-treated sunflower meal after alkaline extraction of proteins. The study aimed at biochemically and functionally characterizing the material concerning its potential practical application and valuability. The DSM consisted mainly of proteins (19.88%) and dietary fibers (61.06%) the majority of which were insoluble (53.09%). Cellulose (30.87%) and lignin (21.79%) were the most contributing compounds to the total amount of dietary fibers. The DSM contained Fe (133.29 mg/kg), Zn (201.56 mg/kg), and Cu (31.87 mg/kg). The analyses defined the DSM as a fiber concentrate with relatively high thermal stability. The distraction of the material began at 170°С with a maximum speed at 277°С. The highest water absorption capacity (WAC) of the DSM was observed at pH 6 and 7 (approximately 8 g H2O/g sample) under all studied conditions including pH from 3 to 10 and three levels of NaCl concentrations (0.00 M, 0.03 M, and 0.25 M). At pH 7, increasing temperature from 20°C to 60°C increased the WAC of the DSM from 8.13 g H2O/g sample to 9.80 g H2O/g sample, respectively. Further increase in the temperature diminished the WAC of the DSM. At pH 6, the increase in temperature did not influence positively the WAC of the DSM. The study demonstrated the potential of the DSM, a waste obtained from the protein isolation process, as a valuable ingredient/additive in the food industry.

Ultrasound‐assisted alkaline extraction of proteins in several algae and their nutritional characteristics

SummaryUltrasound‐assisted alkaline extraction (UAAE) and the nutritional quality of proteins from five algae (Arthrospira platensis, Cladophora glomerata, Porphyra tenera, Laminaria japonica and Undaria pinnatifida) were investigated. The UAAE of the A. platensis protein using a 60% amplitude level and 30 min extraction time provided the highest protein yield (81.86%) and altered the surface of A. platensis. Amino acid profiles revealed that lysine and branched‐chain amino acids (BCAAs) were dominant in most algal proteins. The C. glomerata protein had the highest digestibility (94.09%) and protein digestibility‐corrected amino acid scores for the BCAAs. The L. japonica protein demonstrated a rich source of aspartic and glutamic acids, giving an umami taste. The algal proteins contained low contents of carbohydrates (3.87–44.83 mg glucose equivalents g−1) and nucleic acids (0.60–8.57 mg g−1), while total phenolics were 6.13–70.13 mg gallic acid equivalents g−1. Algal proteins could be a good ingredient in developing vegan and vegetarian foods.

Deep eutectic solvents and alkaline extraction of protein from seabuckthorn seed meal: a comparison study

Seabuckthorn seed meal (SSM) is a waste of oil extraction industry that rich in protein. In order to seek suitable protein extraction method, three different deep eutectic solvents (DESs) (including choline chloride-glycerol, choline chloride-oxalic acid and choline chloride-urea) were developed for extracting protein from SSM and compared with alkaline. Result indicated that alkaline could effectively extract 56.9% protein from SSM and its protein content was 73.1%, higher than DES at 31.0%41.4% and 64.3%67.5%, respectively. However, compared to alkali, DES led to a product with less β-sheet, more β-turn, more essential amino acids, higher total amino acid content, especially choline chloride-urea which extracted protein showing an integrated and similar protein weight distribution compared to SSM. Also, this protein extracted chloride-urea showed a highest digestibility in vitro (by pepsin) (54.2%). These results indicated that choline chloride-urea extraction is better than alkaline extraction for SSM.

Study of a process of obtaining of protein preparation from sunflower seeds for application in food industry

The article deals with a study of processing methods of obtaining protein preparations from sunflower seeds. For obtaining of food-grade protein preparations from the defatted sunflower kernels phenolic compounds were additionally removed. Modern Russian and foreign literature sources devoted to the isolation of phenolic compounds from vegetable protein raw materials were analyzed. The objective of obtaining a light-colored food-grade protein preparation from sunflower seeds was solved through developing of a multi-stage extraction process with removal of various groups of non-protein compounds, including the stage of aqueous ethanol extraction and removal of phenolic compounds. Parameters of different stages of obtaining of protein substances from defatted sunflower seed kernels after removal of phenolic compounds were studied. These stages included alkaline extraction of protein and nitrogen-free extractives (NFE), separation of the insoluble residue, isoelectric precipitation of protein compounds from the clarified extract, neutralization of the protein suspension. Drying of the protein suspension was carried out on a laboratory spray installation Buchi Mini Spray Dryer with a temperature at the entrance of the dryer 180–190 ℃ and at the exit – up to 90 ℃. Protein preparations of light gray color were obtained with a crude protein content of 75,72% and 87,15% on dry matter basis, which corresponds to the crude protein content of commercial sunflower and soy protein concentrates. Solubility pattern of proteins and functional characteristics of finished protein preparations after spray drying have been analyzed. Based on the high fat-holding capacity and moderate fat-emulsifying properties of the obtained protein preparations it’s possible to recommend the obtained sunflower protein preparation for usage as a vegetable protein enricher and functional additive in food industry.

Integration of ultrasonic treatment in biorefinery of tea residue: protein structural characteristics and functionality, and the generation of by-products

The effect of integrating ultrasonic pretreatment with ethanol and Viscozyme in the alkaline extraction of protein from tea residue and the generation of possible by-products such as polyphenols and galacturonic acid was assessed. Four extraction pathways: ethanol, Viscozyme, ultrasound (EVU); water, Viscozyme, ultrasound (WVU); ethanol, water, ultrasound (EWU); and ethanol, Viscozyme, heat (EVH) were employed. EVU pretreatment together with alkaline extraction resulted in the highest protein recovery yield of 80.95% with a purification factor of 8.5. EVU enhanced the functionality of extracted proteins in terms of solubility, foam capacity and stability, and emulsion capacity and stability. Surface hydrophobicity of EVU extracted proteins increased compared to the other treatments. There was an increase in free sulfhydryl and a decrease in disulfide bond contents in all the treatments except EVH. Analysis of Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, non-protein nitrogen content and amino acid content revealed slight modification in the protein advance structure in terms of pretreatment, however, the main peptide chain and amino acid composition were not altered. Yield of 79.25 ± 0.75, 54.7 ± 0.98, and 116.50 ± 6.36 mg/g of polyphenols, galacturonic acid, and total sugars were respectively extracted along the extraction protocol as by-products.

Oxidative and physical stability of oil-in-water emulsions prepared with quinoa and amaranth proteins

Interactions of food proteins and lipids under oxidative conditions may lead to alterations in food texture as well as loss of nutritional and sensory quality. Oxidative and physical stability of oil-in-water emulsions stabilized with water-soluble proteins extracted from quinoa (Chenopodium quinoa) and amaranth (Amaranthus caudatus) was monitored in an oxidation study at 30 °C for 7 days. Alkaline extraction of proteins from the flours followed by acid precipitation and freeze-drying was conducted and purified rapeseed oil was used to prepare emulsions via high-pressure microfluidizer. Protein-stabilized emulsions showed lower physical and oxidative stability compared to Tween® 20-stabilized emulsions. Lipid oxidation volatile profiles of protein-stabilized emulsions indicated advanced oxidation. Comparison with the physically more stable emulsions stored at 6 °C pointed to the role of co-oxidation between proteins and lipids in coalescence of oil droplets and increase in droplet size. Emulsions stabilized with amaranth proteins showed higher resistance to oxidation compared to quinoa protein containing emulsions.

Evidence for the Formation of Benzacridine Derivatives in Alkaline-Treated Sunflower Meal and Model Solutions.

Sunflower extraction meal (SEM) is an economically interesting protein source. During alkaline extraction of proteins, the presence of chlorogenic acid (CQA) in the meal gives rise to the formation of o-quinones. Reactions with nucleophiles present in proteins can lead to green discoloration. Although such reactions have been known for a long time, there is a lack of information on the chemical nature of the reaction products. SEM and model systems consisting of amino acids and CQA were subjected to alkaline treatment and, for comparison, to oxidation of CQA by polyphenoloxidase (PPO). Several green trihydroxy benzacridine (TBA) derivatives were tentatively identified in all samples by UHPLC-DAD-MS/MS. Surprisingly, in alkaline-treated samples of particular amino acids as well as in SEM, the same six TBA isomers were detected. In contrast, the enzymatically oxidized samples resulted in only three TBA derivatives. Contrary to previous findings, neither peptide nor amino acid residues were attached to the resultant benzacridine core. The results indicate that the formation of TBA derivatives is caused by the reaction between CQA quinones and free NH2 groups. Further research is necessary to elucidate the structure of the addition products for a comprehensive evaluation of food and feed safety aspects.

Alkaline Extraction of Protein from Spent Honey Bees

ABSTRACTAdult honey bees killed after honey harvest were analyzed and evaluated as a raw material for protein extraction. Bees collected were 49.8% crude protein, 7.54% total lipid, and 27.1% reducing sugar (moisture‐free basis). Whole bees were homogenized, body proteins solubilized in alkali, chitin removed by filtration, and protein recovered by acid precipitation. Amount of protein solubilized by NaOH addition varied from negligible without alkali (pH 6.1) to 93% of body crude protein with severest treatment at pH 11.2. With alkali extraction at pH 10.5 and acid precipitation at pH 5.5, 59% of total solids were found in the precipitate and 41% remained in the supernatant. The precipitate was 66.3% crude protein, 9.4% total lipid and 7.9% ash. Heads, thoraces and abdomens were separated and each separately extracted (pH 10.5) and precipitated (pH 5.5). Amino acid analyses of heads (70.1% protein), thoraces (54.9% protein) and abdomens (36.6% protein) permitted evaluation of protein quality. Thorax protein was most homogeneous for amino acids analyzed, and all were nutritionally limited by sulfur containing amino acids.

Bacteriological Evaluation of Alkali-Extracted Protein from Poultry Residues

The effect of alkaline conditions (pH 10.5 for 30–60 min at 23°C) on the extraction of protein from mechanically deboned poultry residues (MDPR) was examined with respect to the general bacterial flora, coliforms and salmonellae. Standard plate counts decreased from 1.5 × 103 CFU/g in the MDPR to 2.0 × 102 CFU/g in the freshly extracted protein curd; coliform counts decreased from 4.9 × 101 MPN/g to 0. Coliforms survived only when the MDPR was mishandled for 5 h at 23°C before alkaline extraction whereas salmonellae appeared to be eliminated entirely, irrespective of preincubation abuse of the MDPR or introduction of increased levels of Salmonella infantis. Spoilage of the protein curds occurred in 14 days at 3°C but there was no increase in coliform numbers. Reappearance of salmonellae following storage was seen only in the protein extracted from MDPR inoculated with S. infantis. The destruction of salmonellae by pH 10 was confirmed in a tryptic soy broth model system, but only under ambient temperature exposure; neither growth nor destruction occurred at 3 or 10°C. It was concluded that alkaline extraction of protein from MDPR using the suggested operating conditions does not exaggerate any public health hazard involving salmonellae.

Alkaline Extraction of Protein from Spent Honey Bees

Alkaline Extraction of Protein from Spent Honey Bees

Alterations in the soluble protein patterns of tobacco and cowpea leaves following inoculation with tobacco necrosis virus

Changes in the soluble protein composition of both tobacco and cowpea leaves following inoculation with tobacco necrosis virus (TNV D R/1 : 1.5/19 : S/S : S/Fu [1]) have been investigated by the techniques of disc-electrophoresis. Both changes in relative amounts of proteins, and novel proteins have been observed. Changes in the protein constitution of soluble extracts were observed by densitometer tracings of polyacrylamide gels, and have been shown to be different for the two host plants, with other differences found by acid or alkaline extraction of protein. Acidic extraction of soluble protein appeared to be preferential for the new proteins found in infected leaves. In cowpea leaves the stimulation of new proteins seems to be related to symptom severity, with larger amounts found in necroticised tissue. The possible function of these proteins, and their rôle in induced resistance studies is discussed.