Alkaline Extraction Research Articles

How ultrasonication treatment drives the interplay between lysinoalanine inhibition and conformational performances: A case study on alkali-extracted rice residue protein isolate.

Lysinoalanine (LAL) formed during alkaline extraction of rice residue protein (RRPI), which limited its application in the food industry. In this study, the influence of ultrasonication parameters (acoustic power density, ultrasound duration, and ultrasound temperature) on the inhibition of LAL formation and conformational attributes of RRPI during alkaline extraction was elucidated. The results suggested that the acoustic power density substantially modified the chemical interaction forces between RRPI molecules. At a power density of 60W/L, the ionic bonds (14.37%) and hydrophobic interactions (49.28%) reached the maximum, while hydrogen bonds (15.29%) and disulfide bonds (21.06%) reached the minimum. Moreover, acoustic power density at 60W/L caused a decrease of 18.02% and 12.2% in α-helix, and β-turn, respectively, shifting toward β-sheet, random coil, with an increase of 7.31% and 36.16%. Following ultrasonication, the protein particle size distribution curve shifted in the direction of smaller particle size, forming a relatively concentrated and uniform protein distribution. Sonication power, temperature, and time decreased the absolute value of Zeta potential. Furthermore, significant destruction in microstructure was elicited by sonication, which made the structure looser and more microparticles. Pearson correlation analysis suggested that the inhibition in the levels of LAL was most influenced by the increase of sulfhydryl groups and Zeta potential, as well as the reduction of α-helix content, in which the alteration of the total sulfhydryl group content had a great impact on the Zeta potential and the free sulfhydryl group. The principal component analysis demonstrated a notable correlation between the total sulfhydryl group and both the Zeta potential and free sulfhydryl group of RRPI.

Structure and functionality of Pleurotus geesteranus protein isolate as a function of pH.

Edible mushroom proteins hold great potential for food applications, but those extracted using the alkaline extraction-acid precipitation method typically exhibit poor solubility in neutral water, with the structural changes during acid precipitation remaining unclear. In this study, Pleurotus geesteranus protein isolate (PGPI) with high water solubility was prepared with alkaline extraction, followed by dialysis and freeze-drying, and the effects of pH on the structural and functional properties of PGPI were systematically investigated. PGPI was enriched in essential and aromatic amino acids, and the molecular weight of bands in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile was mainly distributed below 45kDa. The zeta potential of PGPI changed from +16.84 to 17.58mV when the pH increased from 2 to 9, with a pI of 4.3. At pH 7, PGPI showed a size of 232.7nm. Away from pH 7, the particle size of PGPI increased. When the pH decreased from 7 to 2, PGPI exhibited a lower α-helix structure content and a higher β-sheet content and a gradual decrease in fluorescence intensity. In addition, as the pH approached 4, H0 and the content of SS group increased to a peak. These results indicated that lowering the pH induced the development of more ordered protein structure, which could be the primary reason for the poor water solubility of P. geesteranus protein obtained through alkaline extraction and acid precipitation. Additionally, these structural changes result in alterations to its functional properties, including water-holding capacity, oil-holding capacity, foaming capacity, foaming stability, emulsion activity index, and emulsion stability index.

High-intensity ultrasound-assisted alkaline extraction of soy protein: Optimization, modeling, physicochemical and functional properties

This study examined the effect of high-intensity ultrasound-assisted alkaline extraction (HUAE) on the extraction yield and the physicochemical and functional properties of soy protein (SP) using the two-pot multivariate method for the first time. Plackett-Burman Design (PBD) coupled with Response Surface Methodology (RSM) was systematically utilized to select and subsequently optimize the HUAE parameters. Based on PBD results, the significant extraction factors were liquid to solid ratio (LSR), temperature, ultrasonic amplitude, and extraction time. The optimum conditions for the maximal extraction yield and minimal energy consumption were 50:1 mL/g LSR, 50 °C, 48 % ultrasonic amplitude, and 10 min extraction time. At optimum conditions, the extraction yield (35.28 %) was significantly improved compared to traditional extraction (26.39 %). Besides, HUAE resulted in modification of the protein secondary and tertiary structures due to the unfolding of protein molecules and the exposure of hydrophobic groups or regions as shown by FTIR spectroscopy, free sulfhydryl analysis, and scanning electron microscopy. These structural changes led to decreased solubility and emulsifying activity but improved emulsion stabilization and antioxidant properties. With future development, HUAE could potentially produce soy protein for targeted applications, broadening its utilization and meeting the need for more sustainable alternative processing.

Preparation of salt-free Pleurotus eryngii protein with enhanced colloidal stability and emulsifying properties by ceramic membrane filtration

Fungi proteins represent a potential alternative to animal proteins, which are regarded as a prospective source of edible proteins due to more sustainable and efficient cultivation of fungi. Nevertheless, the extraction of fungi proteins typically involves alkali extraction combined with acid precipitation (AEAP), yielding considerable amounts of salt that causes aggregation and inferior functional properties of proteins. In this study, we put forward a novel extraction method by direct filtration of Na+ and OH− from the alkaline extraction solutions using ceramic membranes. This method enabled the continuous, efficient and cost-effective production of Pleurotus eryngii protein (PEP). The PEP prepared by this technology featured a uniform distribution of nanoparticles (∼129.5 nm) with higher water dispersity, colloidal stability and surface active properties as compared to that prepared by the AEAP method. Moreover, the microstructures of PEP can be tailored with various nanoparticle sizes and size distribution profiles, allowing for the adjustment of long-term stabilities and surface activities. Our study renovated the production technology of fungi proteins to enhance their functionalities as well as the application prospects in the future food industry.

Effects of alkaline extraction on behavior of rare earth elements in coal ashes.

The effects of alkaline extraction on the behavior of rare earth elements in coal ashes were investigated in the present study. Independent variables are the concentration of extractant and particle size of coal ashes. Sodium hydroxide was used as an extractant, and the molarity of the solvents varied from 1.0 to 7.0M. The coal ashes used here were fly and bottom ashes. Fly and bottom ashes were classified into four samples by particle size, with each categorized at both 45 and 300µm. The particle size distribution and crystalline characteristics of coal ashes, leaching, and the contents of rare earth elements in coal ashes after alkaline extraction were investigated, and the effects of independent variables on the content of rare earth elements in coal ashes were discussed. The test results showed that the dissolution of amorphous phase in coal ashes mainly occurred when the molarity was not more than 3M, while dissolution and precipitation such as geopolymerization and the formation of zeolite occurred simultaneously when the molarity was more than 5M. The dissolution and formation of precipitates such as geopolymer in the present study affected the variation of the rare earth element contents in the ashes. Besides, the ashes being smaller in size was more favorable for an increase in the rare earth elements in coal ashes.

Optimization of Polysaccharide Extraction from Polygonatum cyrtonema Hua by Freeze–Thaw Method Using Response Surface Methodology

Polygonatum cyrtonema polysaccharides have a variety of pharmacological effects. The commonly used extraction methods include traditional hot water extraction, alkaline extraction, enzymatic hydrolysis method, ultrasonic-assisted extraction, etc., but there are problems such as low yield, high temperature, high cost, strict extraction conditions, and insufficient environmental protection. In this study, crude polysaccharide extraction from the Polygonatum cyrtonema Hua was performed using the freeze–thaw method. Response surface methodology (RSM), based on a three-level, three-variable Box–Behnken design (BBD), was employed to obtain the best possible combination of water-to-raw material ratio (A: 30–50), freezing time (B: 2–10 h), and thawing temperature (C: 40–60 °C) for maximum polysaccharide extraction. Using the multiple regression analysis and analysis of variance (ANOVA), the experimental data were fitted to a second-order polynomial equation and were used to generate the mathematical model of optimization experiments. The optimum extraction conditions were as follows: a water-to-raw material ratio of 36.95:1, a freezing time of 4.8 h, and a thawing temperature of 55.99 °C. Under the optimal extraction conditions, the extraction rate of Polygonatum cyrtonema Hua polysaccharide (PCP) was 65.76 ± 0.32%, which is well in close agreement with the value predicted by the model, 65.92%. In addition, PCP has significant antioxidant activity. This result shows that the freeze–thaw method can improve the extraction efficiency, maintain the structural integrity of polysaccharides, simplify the extraction process, promote the dispersion of polysaccharides, and is suitable for large-scale industrial production.

Effects of acid, alkaline and enzymatic extraction methods on functional, structural and antioxidant properties of dietary fiber fractions from quince (Cydonia oblonga Miller)

In this study, quince soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) were obtained by acid extraction, enzyme extraction and alkaline extraction methods. The acid extracted DF displayed higher results compared to enzyme and alkaline extraction methods in terms of water holding capacity (15.97 g/g SDF), oil holding capacity (1.05 g/g SDF) and nitrite ion adsorption capacity (92.83 mg/g SDF). The antioxidant activity and phenolic content of acid extracted IDF were significantly higher than the other quince DFs. In addition, quince DFs exhibited in vitro hypoglycaemic activity, exhibiting high glucose adsorption capacity (237 mg/g) and α-amylase inhibition activity (82 %). Similarly, acid extracted SDF of quince showed in vitro hypolipidemic activity, with cholesterol adsorption capacity of 155 mg/g and lipase inhibition activity of 36 %. The structures and thermal properties of quince DFs were characterized by FT-IR and TGA. Quince DFs with high functional properties might be suitable agents for functional food formulations, such as meat products, low-calorie fruit bars, flour mixtures, etc.

Plastid LPAT1 is an integral inner envelope membrane protein with the acyltransferase domain located in the stroma.

The N-terminal transmembrane domain of LPAT1 crosses the inner membrane placing the N terminus in the intermembrane space and the C-terminal enzymatic domain in the stroma. Galactolipids mono- and di-galactosyl diacylglycerol are the major and vital lipids of photosynthetic membranes. They are synthesized by five enzymes hosted at different sub-chloroplast locations. However, localization and topology of the second-acting enzyme, lysophosphatidic acid acyltransferase 1 (LPAT1), which acylates thesn-2 position of glycerol-3-phosphate (G3P) to produce phosphatidic acid (PA), remain unclear. It is not known whether LPAT1 is located at the outer or the inner envelope membrane and whether its enzymatic domain faces the cytosol, the intermembrane space, or the stroma. Even the size of mature LPAT1 in chloroplasts is not known. More information is essential for understanding the pathways of metabolite flow and for future engineering endeavors to modify glycerolipid biosynthesis. We used LPAT1 preproteins translatedin vitrofor import assays to determine the precise size of the mature protein and found that the LPAT1 transit peptide is at least 85 residues in length, substantially longer than previously predicted. A construct comprising LPAT1 fused to the Venus fluorescent protein and driven by theLPAT1promoter was used to complement an Arabidopsislpat1 knockout mutant. To determine the sub-chloroplast location and topology of LPAT1, we performed protease treatment and alkaline extraction using chloroplasts containingin vitro-imported LPAT1 and chloroplasts isolated from LPAT1-Venus-complemented transgenic plants. We show that LPAT1 traverses the inner membrane via an N-terminal transmembrane domain, with its N terminus protruding into the intermembrane space and the C-terminal enzymatic domain residing in the stroma, hence displaying a different membrane topology from its bacterial homolog, PlsC.

Improving yield, functional properties, and aroma profile of rice bran protein through innovative extraction and precipitation methods

Rice bran is a milling byproduct and rice bran protein (RBP) is a promising source of plant-based protein. This study investigated the impact of alkaline and acid extractions followed by isoelectric point (IEP) and heat coagulation precipitations on the quality and functionalities of RBP. Alkaline extraction, followed by IEP and heat coagulation, showed the highest protein recovery of 48.77%, which is double that of conventional alkaline extraction and IEP. The FTIR data showed that β-sheet and α-helix content reduced; however, random coil and β-turn increased by acid and heat addition. Addition of heat coagulation to IEP after alkaline extraction increased solubility from 62.94% to 94.74%. However, the emulsification and surface hydrophobicity were decreased during heat and acid-assisted extraction. The in-vitro digestibility was the highest at 83.57% in alkaline-acid extraction, followed by heat and IEP. The aroma profile of RBP shows a complex mixture of ethanol-2-butoxy, 2-methyl-4-vinyl-phenol, 2,4—heptagonal, (E,E)-, Undecane, and 5-methyl to form a typical flavor with waxy and rancid undernotes. The total amount of volatile compounds in conventional extraction was 1.97 μg/g, while alkaline-acid extraction with IEP had only 0.87 μg/g. The RBP from alkaline-acid extraction with IEP showed the least volatile compounds and most neutral proteins.

Spray dried protein concentrates from white button and oyster mushrooms produced by ultrasound-assisted alkaline extraction and isoelectric precipitation.

In the present study, the optimization of ultrasound-assisted alkaline extraction (UAAE) and isoelectric precipitation (IEP) was applied to white button (WBM) and oyster (OYM) mushroom flours to produce functional spray dried mushroom protein concentrates. Solid-to-liquid ratio (5-15% w/v), ultrasound power (0-900 W) and type of acid [HCl or acetic acid (AcOH)] were evaluated for their effect on the extraction and protein yields from mushroom flours submitted to UAAE-IEP protein extraction. Prioritized conditions with maximized protein yield (5% w/v, 900 W, AcOH, for WBM; 5% w/v, 900 W, HCl for OYM) were used to produce spray dried protein concentrates from white button (WBM-PC) and oyster (OYM-PC) mushrooms with high solids recovery (62.3-65.8%). WBM-PC and OYM-PC had high protein content (5.19-5.81 g kg-1), in addition to remarkable foaming capacity (82.5-235.0%) and foam stability (7.0-162.5%), as well as antioxidant phenolics. Highly pH-dependent behavior was observed for solubility (> 90%, at pH 10) and emulsifying properties (emulsification activity index: > 50 m2 g-1, emulsion stability index: > 65%, at pH 10). UAAE-IEP followed by spray drying increased surface hydrophobicity and free sulfhydryl groups by up to 196.5% and 117.5%, respectively, which improved oil holding capacity (359.9-421.0%) and least gelation concentration (6.0-8.0%) of spray dried mushroom protein concentrates. Overall, the present study showed that optimized UAAE-IEP coupled with spray drying is an efficient strategy to produce novel mushroom protein concentrates with enhanced functional attributes for multiple food applications. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Ultrasonic-microwave assisted extraction of selenium-rich rice bran protein: a study on its structural and physicochemical properties

This study explores the effects of different extraction methods on the physicochemical properties and functional performance of selenium-rich rice bran protein (Se-RBP). Four extraction techniques—alkaline extraction (AAE), microwave extraction (MAE), ultrasonic extraction (UAE), and ultrasonic-assisted microwave extraction (UMAE)—were assessed for their efficiency and impact on protein structure, solubility, and functional properties, including emulsifying and foaming capacities. The results demonstrate that UMAE significantly enhances the functional properties of Se-RBP, achieving an emulsion stability index of 86.76% and a foaming capacity of 188.63%, both of which outperform the other methods. Furthermore, UMAE-treated Se-RBP exhibited a 35.43% increase in selenium bioavailability following gastrointestinal digestion. UMAE also delivered the highest antioxidant activity, reducing the IC50 for DPPH radical scavenging to 0.85 mg/mL. These improvements are attributed to UMAE’s ability to achieve a finer, more uniform particle distribution and increased exposure of bioactive compounds. This study reveals the potential of UMAE in optimizing the extraction and functional utilization of Se-RBP.

Sustainable fungi-based protein extraction from agro-waste mushroom stem using deep eutectic solvents

This study evaluated the nutritional and functional qualities of the mushroom stem (MS) powder and its protein concentrates, which were extracted using alkaline and deep eutectic solvent (DES)-based methods. MS powder is rich in protein (23.02 %) and carbohydrates (63.01 %). Alkaline extraction yielded the highest protein content (45.90 %) but lower recovery rates (15.39 %) compared to DES extractions using a 1:2 M ratio of choline chloride: glycerol (DES-CG) and choline chloride: lactic acid (DES-CL), which had recovery rates of 22.04 % and 21.47 %, respectively. DES solvents provided strong hydrogen bonding, as indicated by FTIR analysis, and produced uniform, smooth particles according to SEM imaging. Both DES and alkaline methods achieved similar protein solubility values (72–75 %). However, DES methods better preserved emulsion capabilities and balanced foaming properties, enhancing foam capacity and maintaining stability. The findings suggest that DES methods are more sustainable and efficient for extracting proteins from MS powder, optimizing both functional properties and environmental sustainability in food applications.

Canola meal extract as a low-cost substrate in Mortierella alpina culture for the production of arachidonic acid

The demand for high-quality and cost-effective raw materials is growing across various industries. Canola meal (CM), a low-cost by-product of canola processing facilities, boasts an impressive nutritional profile comprising protein, carbohydrates, vitamins, and minerals, making it a potential candidate for microbial culture media. Saskatchewan leads globally in canola production and plans to expand its canola processing facilities. Commercial valorization of CM could not only optimize the management of this by-product but also offer additional incentives and financial returns to regional canola stakeholders. Efficient utilization of canola meal extract (CME) in producing polyunsaturated fatty acids (PUFAs), such as arachidonic acid (ARA), holds promise as valuable ingredients or base chemicals for the food, feed, and nutraceutical industries. This study focused on incorporating pH 10.5 treated alkaline extract (AE) and temperature 160°C treated subcritical extract (SE) of CM into the culture medium of Mortierella alpina, an oleaginous fungus, by replacing conventional yeast extract (YE). Trials investigated the effect of aeration levels ranging from 0.5 to 2.0 vvm and revealed that increasing oxygen supply significantly boosted fungal growth rate and ARA content in biomass up to 0.39 day⁻¹ and 21.86 %, respectively. ARA production correlated positively with biomass accumulation and lipid content. Replacing YE with CME resulted in less significant differences (P < 0.05) in biomass and lipid accumulation. Additionally, AE- and SE-supplemented media exhibited higher ARA accumulation of 144.91 mg/L and 165.8 mg/L, respectively, compared to standard media (124.87 mg/L). Therefore, this study introduces canola meal extract (CME) as a novel nitrogen source in microbial media, with comparative demonstrations showing its efficiency to be similar to that of conventional extracts.

Extraction Condition Optimization, Quantitative Analysis, and Anti-AD Bioactivity Evaluation of Acorn Polyphenols from Quercus variabilis, Quercus aliena, and Quercus dentata

In the present study, Quercus variabilis (Q. variabilis), Quercus aliena (Q. aliena), and Quercus dentata (Q. dentata) acorn kernels were taken as the research objects, and the free polyphenols and bound polyphenols in acorn kernels were extracted using improved ultrasound-assisted ethanolic and alkaline extraction methods, after which the contents of gallic acid, quercetin, azelaic acid, ellagic acid, and ferulic acid were quantified by LC-MC/MS. The results demonstrated that Q. variabilis and Q. aliena acorns were suitable as raw materials to extract ellagic acid, the contents of ferulic acid and bound gallic acid in them were different, and Q. aliena acorns were more suitable for the research of gallic acid, but not for azelaic acid. Results on APP/PS1 transgenic mice verified that five polyphenols significantly suppressed the progression of AD. This study provides a theoretical basis for the drug development of acorn polyphenols.

HUMIC ACIDS: PROPERTIES, STRUCTURE, AND APPLICATION

Humic substances (HSs) are a diverse class of natural compounds with no fixed chemical composition, formed from plant and microbial residues through the action of environmental factors and living organisms over many years. Despite extensive research spanning two centuries, the complex and variable nature of HSs' structure remains a subject of scientific inquiry. These substances, notably humic acids, fulvic acids, and humin, play crucial roles in ecological and environmental processes due to their abundant functional groups and resilience to biodegradation. This review explores the intricate structure and properties of HSs, their classification, and their occurrence in nature. It highlights the different models proposed to describe the structural fragments of humic acids, emphasizing their aromatic cores and diverse functional groups. The variability in the molecular weight distribution of HSs, attributed to their polydisperse nature, is also discussed, along with methods used for their determination, such as exclusion chromatography. Furthermore, the elemental and functional compositions of humic acids are examined, detailing their acid-base properties and capacity for heavy metal complexation. The synthesis of HSs from natural sources, such as soil, peat, coal, and artificial processes, is covered, showcasing methods like alkaline extraction and hydrothermal treatment. Recent advancements in artificial humification, including oxidative ammonolysis and Fenton reagent-based oxidation, are reviewed for their potential in producing environmentally friendly humic materials from lignin and waste biomass. The study concludes by underscoring the environmental significance and practical applications of HSs, particularly in agriculture, soil conditioning, and environmental remediation. The diverse properties and synthesis methods of HSs make them promising candidates for sustainable material production and environmental management. Humic acids are versatile compounds beneficial for human health due to their potent antioxidant properties, immune-modulating effects, and support for gastrointestinal health and detoxification. Structurally diverse, they feature groups like carboxyl, phenolic hydroxyl, quinones, ketonic carbonyls, amino, and sulfhydryl, contributing to their stability and amphiphilic nature. In pharmaceutical applications, they show promise for drug delivery, antioxidant therapies, wound healing, antimicrobial actions, and biofilm disruption, underlining their biocompatibility and safety. Key words:

Extraction and characterization of cellulose from agricultural waste of hemp (&lt;i&gt;Cannabis sativa)&lt;/i&gt; and parthenium (&lt;i&gt;Parthenium hysterophorus)&lt;/i&gt;

The current study focused on the extraction of cellulose from two selected plants, hemp (Cannabis sativa) and parthenium (Parthenium hysterophorus). The research successfully isolated high-purity cellulose from both plants using a chlorination and alkaline extraction process. A higher yield (%) (38.4 ± 0.18) was obtained from hemp compared to parthenium (22 ± 0.82). Characterization techniques were used to probe the structure and properties of the extracted cellulose. Fourier transform infrared spectroscopy analysis revealed functional groups characteristic of cellulose, while X-ray diffraction confirmed its highly crystalline structure in both samples. Scanning electron microscopy provided valuable insights into the cellulose morphology, indicating a smoother surface and reduced fiber diameter after treatment due to the removal of noncellulosic components. The research paved the way for the development of eco-friendly bioproducts utilizing cellulose from hemp and parthenium, promoting a more sustainable future.

Utilization of Forest Residues for Cellulose Extraction from Timber Species in the High Montane Forest of Chimborazo, Ecuador

The present study explored the extraction of cellulose from forest residues of four timber species, namely Cedrela montana Moritz ex Turcz, Buddleja incana Ruiz &amp; Pav, Vallea stipularis L. f. and Myrsine andina (Mez) Pipoly, in the high montane forest of Chimborazo province, Ecuador, for the sustainable utilization of leaves, branches, and flowers. An alkaline extraction method was used on the residues without the need for prior degreasing. An ANOVA analysis was applied to evaluate significant differences in cellulose extraction yields among the species’ residues. The characterization techniques used were Fourier transform infrared spectroscopy (FTIR) and polarized light optical microscopy, which confirmed the successful extraction of cellulose with characteristics comparable to standard cotton cellulose and other traditional species. The results showed significant variations in cellulose yield among the species, with Vallea stipularis L. f achieving the highest yield of 80.83%. The crystallinity of the samples was clearly evidenced by the polarity of the light in the samples during microscopy, demonstrating that the residues can be a viable and sustainable source of cellulose, contributing to a circular economy and reducing the environmental impact of forest waste.

Optimized ceramic membrane-based method for efficient and acid-free rice protein preparation from alkaline extracts

Rice protein, stands out as a high-quality plant-based protein, suitable for dietary supplementation and food processing. Traditional methods, involving alkaline extraction and acid precipitation, are challenged by the extensive use of chemicals and the difficulty in desalination. This study proposed a novel separation method that utilizes ceramic membranes for direct alkali filtration, eliminating the formation of salts by acid neutralization. The membrane pore size and the operating parameters such as transmembrane pressure, cross-flow velocity, and pH were optimized to enable a high flux (>80 L m−2·h−1) and favorable protein rejection (>95 %) while permitting the removal of excess alkali. Additionally, the effects of non-protein substances, e.g., starch, present in the alkaline extract on the separation performance were explored. Subsequently, an optimized strategy for starch removal was proposed, involving the concentration of the alkali extract using an ultrafiltration membrane, followed by enzymatic hydrolysis of starch and diafiltration to eliminate the residuals of starch hydrolysates and alkali. Under stabilization of protein particles by carboxymethyl cellulose, rice protein with a uniform particle size of 25 nm and a purity of over 80 % was produced. The direct removal of alkali from alkali extracts of rice by ceramic membranes presents a promising strategy for producing rice protein with high purity and reduced aggregation degree, enabling better functionalities such as solubility than the conventional alkali-extraction and acid-precipitation method.

Production and characterisation of protein isolates from Chilean granado beans (Phaseolus vulgaris L.)

SummaryGranado beans, widely cultivated in Chile, offer plant‐based proteins with functional benefits for healthier food formulations. These legumes have a 28% protein content (dry basis) with peptides called lectins that have the potential of reducing type‐II diabetes. Our lab has developed a membrane‐based method to produce protein isolates from oilseeds. This method was adapted for granado beans. The process involves alkaline extraction at pH 10, followed by ultrafiltration, diafiltration, acid precipitation at pH 4 and freeze‐drying. The resulting precipitated protein isolate contains 81% protein, comparable to other legumes. However, the acid‐soluble protein isolate (SPI) has a protein content of only 53% due to co‐recovery of high molecular weight carbohydrates. The total phenolic compound contents of the protein products were low resulting in both products having an attractive light colour with no astringent taste. The characterisation of the SPI by High‐Performance Liquid Chromatography found that it contained about 40% starch and other carbohydrates. To increase the protein content of SPI to ~90%, further purification steps to remove the carbohydrates are necessary.

Characterization of mango seed kernel starch: Extraction and Analysis

During mango (Mangifera indica) processing, significant by-products like peel and kernel are generated. Mango seed kernels are cost-effective and readily available materials for starch extraction. This study explores low-cost methods to extract mango kernel starch (MKS) from Surjapuri (X) and Amrapali (Y) varieties using distilled water and alkaline solution. Proximate analysis revealed starch yield variations from 44.49 % to 62.11 %, with moisture content between 4.32 % and 5.89 %, protein content from 0.067 % to 0.069 %, fat content from 0.22 % to 0.24 %, and ash content from 0.12 % to 0.14 %. X-variety starch extracted using distilled water had a higher yield (62.11 %), foaming capacity (5.94 %), and emulsion capacity (6.36 %), while alkaline extraction showed higher water absorption (0.16 %) and oil absorption (0.15 %). Y-variety starch showed higher amylose content (23.50 %) with distilled water extraction and higher pH (7.94) with alkaline extraction. X-variety starch had higher swelling power (11.35 g g-1) with distilled water extraction and higher solubility (0.27 %) with alkaline extraction at 90 °C. Principal component analysis (PCA), Heat map, and Pearson correlation analyses highlighted significant relationships between proximate and physicochemical properties. These results suggest that distilled water extraction is an effective, low-cost method for isolating high-quality MKS, with potential applications in various industries.