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1.
Crit Rev Food Sci Nutr ; : 1-9, 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39175221

RESUMO

Research on new food sources is a worldwide challenge due to the constant increase in the global population. In this scenario, insects and bug based products have been investigated as feasible food alternatives. They are nutritionally healthy and environmentally sustainable. Eating insects (entomophagy) or utilizing their macronutrients in food formulations can efficiently solve the demand for nutritious food. The benefits of insect-based foods are reported in the literature, mainly because they are viable sources of fat (∼38%) and proteins (∼68%). Fats and oils are recognized as essential nutrients in human nutrition, as they provide a concentrated source of energy and act as structural components of cell membranes and signaling pathways. The high levels of fats/oils of edible insects open the perspective in the food industry to be used as ingredients in the enrichment of several products, such as cookies, biscuits, butter, and margarine, among others, thus contributing to consumer acceptance. Insect fat/oil can be obtained using extraction techniques, such as solvent and supercritical CO2 methods. The method depends on the insect species, fat/oil yield, and process costs. Thus, this review aims to provide current information on the consumption, application, and extraction of edible insect oils.

2.
J Food Sci Technol ; 60(2): 797-808, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36712212

RESUMO

The present work used water-soluble protein concentrates from the microalga Tetradesmus obliquus to stabilize sunflower oil emulsions. Microalgal cells were disrupted by sonication, and proteins were separated from the biomass using two methods, isoelectric and solvent precipitations. The protein extracts were concentrated by lyophilization, and the concentrates were used to produce emulsions with three amounts of Tetradesmus obliquus protein concentrate (TobPC) (0.1, 0.5, and 1.0% w/v). Emulsions were homogenized through sonication and characterized for creaming index, optical microscopy, size distribution, ζ-potential, and rheology. Isoelectric precipitation resulted in TobPC with a high protein content (51.46 ± 2.37%) and a better dispersibility profile. Emulsion stability was higher for both the isoelectric TobPC and control systems than for the TobPC solvent. Solvent TobPC does not efficiently stabilize emulsions at low protein concentrations that showed microscopically larger oil droplets and flocculation spots. A high phase separation velocity was observed for solvent TobPC, probably due to the higher hydrodynamic droplet diameters. The increase in TobPC content in the emulsions resulted in more stable emulsions for all samples. Therefore, Tetradesmus obliquus protein concentrates are a potential emulsifying agent.

3.
Crit Rev Food Sci Nutr ; 61(12): 1976-2002, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32462889

RESUMO

Many countries have been experienced an increase in protein consumption due to the population growth and adoption of protein-rich dietaries. Unfortunately, conventional-based protein agroindustry is associated with environmental impacts that might aggravate as the humankind increase. Thus, it is important to screen for novel protein sources that are environmentally friendly. Microalgae farming is a promising alternative to couple the anthropic emissions with the production of food and feed. Some microalgae show protein contents two times higher than conventional protein sources. The use of whole microalgae biomass as a protein source in food and feed is simple and well-established. Conversely, the production of microalgae protein supplements and isolates requires the development of feasible and robust processes able to fractionate the microalgae biomass in different value-added products. Since most of the proteins are inside the microalgae cells, several techniques of disruption have been proposed to increase the efficiency to extract them. After the disruption of the microalgae cells, the proteins can be extracted, concentrated, isolated or purified allowing the development of different products. This critical review addresses the current state of the production of microalgae proteins for multifarious applications, and possibilities to concatenate the production of proteins and advanced biofuels.


Assuntos
Microalgas , Biocombustíveis , Biomassa , Alimentos , Proteínas
4.
Bioprocess Biosyst Eng ; 44(8): 1639-1647, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33689015

RESUMO

Taking into account that the industrial processing of passion fruit generates significant amounts of waste (only the peels represent 51% of the total mass of the fruit), in the present study an economic analysis was conducted to evaluate industrial line viability for pectin extraction from passion fruit peels. Knowing that absolute ethanol (99.50% purity), used in the precipitation and washing steps, has a higher cost, a simulation of extractive distillation was performed using solvents ethylene glycol and glycerol, in the software Aspen Plus v.11, being possible to recover 99.63% of ethanol for both solvents. The results of the economic evaluation showed that the process using ethylene glycol has an advantage, mainly due to its higher profitability (1.13 times higher), lower production cost (94.86% of the price using glycerol), and a lower breakeven point (around 3% smaller). The financial indicators showed profitability and attractiveness for the implementation of this processing line.


Assuntos
Biotecnologia/métodos , Etanol/química , Pectinas/biossíntese , Biotecnologia/economia , Brasil , Simulação por Computador , Etilenoglicol/química , Tecnologia de Alimentos , Glicerol/química , Passiflora , Pectinas/economia , Reprodutibilidade dos Testes , Risco , Sensibilidade e Especificidade , Software , Solventes/química
5.
J Food Sci Technol ; 58(5): 1797-1807, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33897016

RESUMO

Chitosan (CH) is a biopolymer derived from chitin, which is the second most abundant polysaccharide in nature, after cellulose. Their functional groups -NH2 and -OH can form intermolecular interactions with water and other molecules, enabling a variety of applications for CH. -NH2 groups become protonated in acidic solutions, causing an increase in electrostatic repulsion between CH chains, which facilitates their dispersion in aqueous media. Aqueous solutions of acetic acid and/or acetates buffers have been used to disperse CH, but may not be adequate for technological applications, espeacially because of the strong flavor this acid confers to formulations. In this study, 0.125; 0.250; 0.500; 0.750 and 1.000 g (100 g)-1 CH dispersions were prepared in acidic aqueous media (50 mmol L-1), not only with acetic (AA), but also with glycolic (GA), propionic (PA), or lactic (LA), acid aiming to evaluate the effects of biopolymer concentration and type of organic acid on: electrical conductivity, pH, density and rheological characteristics of dispersions. Moreover, ζ potential values of CH chains dispersed in these acidic aqueous media were assessed. pH, density and consistency index were influenced by the biopolymer concentration, but not by the acid type. At a given biopolymer concentration, ζ potential signs (+) and values suggested that electrostatic interactions between CH chains and counter-anions occurred, regardless of the type of the organic acid. Thus, at least from a physicochemical point of view, GA, PA or LA showed to be suitable to replace AA when preparing dispersions containing from 0.125 to 1.000 g (100 g)-1 CH for technological purposes, such as thickening or stabilizer in formulated food products.

6.
Crit Rev Food Sci Nutr ; 57(8): 1618-1630, 2017 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-26114306

RESUMO

We have prepared a review of the physical-chemical composition and the functional and anti-nutritional properties of quinoa (Chenopodium quinoa Willd.). It is a plant of the Chenopodiaceae family, originally from the Andean regions, adaptable to different types of soils and climatic conditions. Its composition has attracted the attention of scientific community for its high nutritional value, being rich in proteins, lipids, fibers, vitamins, and minerals, with an extraordinary balance of essential amino acids. It is also gluten-free, a characteristic that enables its use by celiac patients. In spite of all these attributes, quinoa is not widely used by consumers due to the high cost of imported grain and little knowledge of its benefits. More studies are required to increase knowledge about this "pseudo-cereal" to demonstrate its functional and nutritional benefits and to study its anti-nutritional effects, since it presents high commercial value and excellent nutritional quality.


Assuntos
Chenopodium quinoa/química , Valor Nutritivo , Aminoácidos Essenciais/análise , Antioxidantes/análise , Carboidratos da Dieta/análise , Gorduras na Dieta/análise , Fibras na Dieta/análise , Proteínas Alimentares/análise , Flavonoides/análise , Humanos , Micronutrientes/análise , Nitratos/análise , Oxalatos/análise , Ácido Fítico/análise , Polifenóis/análise , Saponinas/análise , Taninos/análise , Inibidores da Tripsina/análise , Grãos Integrais/química
7.
Crit Rev Food Sci Nutr ; 56(7): 1108-25, 2016 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-24824044

RESUMO

The products formed by glycosylation of food proteins with carbohydrates via the Maillard reaction, also known as conjugates, are agents capable of changing and improving techno-functional characteristics of proteins. The Maillard reaction uses the covalent bond between a group of a reducing carbohydrates and an amino group of a protein. This reaction does not require additional chemicals as it occurs naturally under controlled conditions of temperature, time, pH, and moisture. Moreover, there is growing interest in modifying proteins for industrial food applications. This review analyses the current state of art of the Maillard reaction on food protein functionalities. It also discusses the influence of the Maillard reaction on the conditions and formulation of reagents that improve desirable techno-functional characteristics of food protein.


Assuntos
Proteínas Alimentares/química , Alimentos , Reação de Maillard , Polissacarídeos/química , Fenômenos Químicos , Carboidratos da Dieta , Glicosilação , Temperatura Alta
8.
Foods ; 13(17)2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39272579

RESUMO

Palm oil, derived from Elaeis guineensis, is a critical component of the global edible oil and industrial fat market. This review provides a comprehensive overview of the sustainability of the palm oil chain, focusing on industrial applications, environmental implications, and economic sustainability. The processing of palm oil, from fruit pulp to refined oil, is detailed, highlighting the importance of refining in maintaining quality and extending application ranges. While palm oil offers health benefits because of its rich fatty acid composition and antioxidant properties, its production poses significant environmental challenges. This review underscores ongoing efforts to balance technological and culinary demands with environmental stewardship and sustainable economic growth. Emerging trends, including interspecific hybrids such as E. guineensis and E. oleifera, are discussed for their potential to increase sustainability and productivity.

9.
Carbohydr Polym ; 315: 120977, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37230616

RESUMO

Granular macroscopic chitosan/carboxymethylcellulose polyelectrolytic complexes (CHS/CMC macro-PECs) were produced and tested as adsorbents for six pollutants often present in wastewaters: sunset yellow (YS), methylene blue (MB), Congo red (CR) and safranin (S), cadmium (Cd2+) and lead (Pb2+). The optimum adsorption pH values at 25 °C were 3.0, 11.0, 2.0, 9.0, 10.0, and 9.0 for YS, MB, CR, S, Cd2+, and Pb2+, respectively. Kinetic studies indicated that the pseudos-econd order model best represented the adsorption kinetics of YS, MB, CR, and Cd2+, whereas the pseudo-first order model was the most suitable for S and Pb2+ adsorption. The Langmuir, Freundlich, and Redlich-Peterson isotherms were fitted to experimental adsorption data, with the Langmuir model providing the best fit. The maximum adsorption capacity (qmáx) of CHS/CMC macro-PECs for the removal of YS, MB, CR, S, Cd2+, and Pb2+ was 37.81, 36.44, 70.86, 72.50, 75.43, and 74.42 mg/g, respectively (corresponding to 98.91 %, 94.71 %, 85.73 %, 94.66 %, 98.46 %, and 97.14 %). Desorption assays showed that CHS/CMC macro-PECs can be regenerated after adsorbing any of the six pollutants studied, with possibility of reuse. These results provide an accurate quantitative characterization of the adsorption of organic and inorganic pollutants on CHS/CMC macro-PECs, indicating a novel technological applicability of these two inexpensive, easy-to-obtain polysaccharides for water decontamination.

10.
Foods ; 12(9)2023 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-37174442

RESUMO

Pequi is a natural source of bioactive compounds with wide versatility for fresh or processed fruit consumption, but it is still little explored economically. Functional foods are the subject of diverse scientific research since, in addition to being nourishing, they contain bioactive compounds capable of promoting several benefits to the human body. Pequi is a fruit species native to the Brazilian Cerrado, which is rich in oil and has components with a high nutritional value, such as unsaturated fatty acids (omega-3, omega-6, EPA, and DHA), antioxidants (carotenoids and phenolic compounds), and vitamins. Therefore, the present narrative review aims to compile and critically evaluate the methods used to extract oil from the pulp and almonds of pequi and describes the carotenoid separation from the oil because carotenoids are natural pigments of great interest in the pharmaceutical and food industries. It is emphasized that the main challenges linked to bioactive compound extraction are their susceptibility to degradation in the processing and storage stages of pequi and its derived products.

11.
Mol Nutr Food Res ; 67(12): e2200308, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36938670

RESUMO

SCOPE: Human milk (HM) has a wide range of proteins with biological and nutritional functions, essential for newborns. The roles of proteins and their proteoforms in HM are not fully understood. This study aims to assess, by 2-DE proteomics, the differential proteoforms in HM, present in colostrum (COL), transition (TRA), and mature milk (MAT), aiming to contribute to understanding neonates' protein needs. METHODS AND RESULTS: HM samples are collected from 39 healthy lactating women. COL presents the higher concentration of essential amino acids. After MALDI-MS/MS and bioinformatics analysis, proteoforms are differentially detected. Abundances of ß-casein (CSN2), α-s1 casein, and α-lactalbumin (LALBA) are higher in MAT; CSN2s are found in 11 spots and the isoforms increase in size as the pI becomes more acidic; regarding LALBA, two variant forms are found with different abundances in TRA and MAT; CSN2, LALBA, lactotransferrin (LTF), and serum albumin forms are present in all lactation phases. CONCLUSION: This study reveals differential proteoforms in COL involved in tissue growth and body development, besides essential amino acids, and, in MAT, involved in muscle mass gain, strengthening of the immune system, and energy production. The results provide new insight about proteoforms involved in maturation of the newborn's organs and systems.


Assuntos
Caseínas , Leite Humano , Recém-Nascido , Feminino , Humanos , Animais , Leite Humano/química , Caseínas/análise , Lactação , Lactalbumina , Lactoferrina , Albumina Sérica/análise , Proteômica , Espectrometria de Massas em Tandem , Leite/química , Fatores de Transcrição , Aminoácidos Essenciais , Proteínas do Leite/química
12.
J Food Sci ; 88(7): 3049-3062, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37248720

RESUMO

Protein nanostructures can be used in food applications to improve the techno-functional properties of a food formulation. This study aims to find the best conditions for the production and conformational change of α-lactalbumin nanostructured aggregates. The criteria to determine the best operating conditions to produce α-lactalbumin nanostructured aggregates were intensification of foaming and emulsification, techno-functional proprieties, cytotoxic, and antibacterial activity of nanostructures compared with native α-lactalbumin. Conformational alterations occurred in the α-helix and sheet-ß protein structures. The size obtained by dynamic light scattering was 163.84 nm with a polydispersity index of 0.29. The nano protein improved the techno-functional property compared to the native protein. Additionally, nanostructures had no cytotoxic effect and were innocuous to bacterial activity. Thus, this study presents the best conditions to produce α-lactalbumin nanostructured aggregates with improved properties that allow new food industry applications.


Assuntos
Lactalbumina , Nanoestruturas , Lactalbumina/química
13.
Food Chem ; 367: 130733, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34375890

RESUMO

We used computational molecular dynamics (MD) to assess molecular conformations of apo- and holo-forms (respectively without and with Ca2+) of bovine α-lactalbumin (α-La) at different temperatures, and to correlate them with the protein's foaming properties. At 4 °C and 25 °C no major protein conformation changes occurred. At 75 °C, lots of changes were evidenced: the Ca2+ depletion triggered the complete loss of h2b, h3c helices and S1, S2 and S3 ß-sheets, and partial losses of H1, H2 and H3 α-helices. The absence of Ca2+ in apo-α-La and its leaving from holo-α-La triggered electrostatic repulsion among Asp82, Asp84 and Asp87, leading to the formation of a hydrophobic cluster involving Phe9, Phe31, Ile1, Va42, Ile55, Phe80 and Leu81. These conformational changes were related to an interfacial tension decrease and to a foaming capacity increase, for both apo-α-La and holo-α-La. This study exemplifies how powerful MD is as a tool to provide a better understanding of the molecular origins of food proteins' techno-functionalities.


Assuntos
Lactalbumina , Simulação de Dinâmica Molecular , Animais , Cátions , Bovinos , Estrutura Secundária de Proteína , Temperatura
14.
J Hum Lact ; 38(2): 309-322, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34308701

RESUMO

BACKGROUND: The retention of human milk nutrients in gastric tubes used to feed premature infants is a challenge to be overcome. RESEARCH AIMS: To evaluate (1) the performance of six homogenizers (mixing processor, piston valve, ultrasonic bath, ultraturrax, stirring mixer, and ultrasound probe) for the fat retention reduction in gastric tubes; (2) the influence of the best homogenization conditions on the fatty acid and protein profiles of human milk; and (3) the cost/benefit ratio for the inclusion of homogenization as a new step in human milk processing. METHODS: The influence of different levels and times of homogenization on reducing fat retention of human milk in probes was evaluated in this comparative prospective cross-sectional study. After homogenization, human milk flowed through a gavage and infusion pump apparatus used for feeding. Fat content was quantified before and after feeding. The techniques that reduced fat globule sizes and/or promoted a lower percentage of fat holding were evaluated for efficiency, variations in the fatty acid and protein profiles, and energy density and operating costs. RESULTS: Homogenization led to a reduction in fat retention in feeding probes. The mixer processor and the ultrasound probe reduced fat retention by 99.23% (SD = 0.07) and 99.95% (SD = 0.02), respectively, and did not negatively influence fatty acid and protein profiles. The mixer processor demonstrated low energy density and low cost for human milk processing. CONCLUSION: Homogenization promoted reduced fat retention in the feed probe and could help maintain fat nutrients of human milk during enteral feeding.


Assuntos
Aleitamento Materno , Leite Humano , Estudos Transversais , Ácidos Graxos/análise , Feminino , Humanos , Lactente , Leite Humano/química , Estudos Prospectivos
15.
Carbohydr Polym ; 255: 117526, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33436258

RESUMO

Biopolymers mixtures appear as a strategy to improve sensorial/technological characteristics of gel-like products. Thus, self-sustaining starch (S100/C0) hydrogels were prepared with a partial replacement of the gelling agent by 5.0 % (S95/C5), 7.5 % (S92.5/C7.5), or 10.0 % chitosan (S90/C10), and containing yellow sunset (INS 110). Major visual changes or significant differences on L*a*b* parameters were not observed for starch/chitosan hydrogels. Creep-recovery data was modeled using the simulated annealing algorithm, and relative recovery results showed an increase for S95/C5 (82.6 %), when compared to S100/C0 (72.9 %). After 312 h, chitosan strongly reduced the INS 110 release from hydrogels to an ethanolic solution (3.1∙10-4 and 4.1∙10-3 g/100 mL for S95/C5 and S100/C0, respectively) or to a sucrose solution (1.1∙10-3 and 6.5∙10-3 g/100 mL for S95/C5 and S100/C0, respectively). Such results highlighted that chitosan not only presented a techno-functionality on starch hydrogels by improving their elasticity but also by hindering the release of yellow sunset.

16.
J Biomol Struct Dyn ; 39(4): 1386-1403, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32066337

RESUMO

The angiotensin-converting enzyme (ACE) plays a key role in blood pressure regulation process, and its inhibition is one of the main drug targets for the treatment of hypertension. Though various peptides from milk proteins are well-known for their ACE-inhibitory capacity, research devoted to understand the molecular bases of such property remain scarce, specifically for such peptides. Therefore, in this work, computational molecular docking and molecular dynamics calculations were performed to enlighten the intermolecular interactions involved in ACE inhibition by six different casein-derived peptides (FFVAPFPEVFGK, FALPQYLK, ALNEINQFYQK, YLGYLEQLLR, HQGLPQEVLNENLLR and NAVPITPTLNR). Two top ranked docking poses for each peptide (one with N- and the other C-terminal peptide extremity oriented towards the ACE active site) were selected for dynamic simulations (50 ns; GROMOS53A6 force field), and the results were correlated to in vitro ACE inhibition capacity. Two molecular features appeared to be essential for peptides to present high ACE inhibition capacity in vitro: i) to interact with the S1 active site residues (Ala354, Glu384, and Tyr523) by hydrogen bonds; ii) to interact with Zn2+ coordinated residues (His383, His387, and Glu411) by short-lenght hydrogen bonds, as observed in the cases of ALNEINQFYQK (IACE = 80.7%), NAVPITPTLNR (IACE = 80.7%), and FALPQYLK (IACE = 79.0%). Regardless of the temporal stability of these strong interactions, they promoted some disruption of Zn2+ tetrahedral coordination during the molecular dynamics trajectories, and were pointed as the main reason for the greatest ACE inhibition by these peptides. On the other hand, peptides with intermediate inhibition capacity (50% < IACE < 45%) interacted mainly by weaker interactions (e.g.: electrostatic and hydrophobic) with the Zn2+ coordinated residues, and were not able to change significantly its tetrahedral coordination structure. These findings may: i) assist the discrimination in silico of "good" and "bad" ACE-inhibitory peptides from other food sources, and/or ii) aid in designing de novo new molecules with ACE-inhibitory capacity. Communicated by Ramaswamy Sarma.


Assuntos
Inibidores da Enzima Conversora de Angiotensina , Caseínas , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Angiotensinas , Animais , Bovinos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Peptídeos , Peptidil Dipeptidase A/metabolismo
17.
Int J Biol Macromol ; 153: 995-1004, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31751721

RESUMO

Nanostructures from conjugates of tara gum and α-lactalbumin were obtained via the heat-gelation process with pH adjustment. The conjugates were produced by Maillard reaction using the dry-heating method in lyophilized or spray-dried mixtures of TG and α-la and were characterized by browning index (BI) and percentage of free amino groups (% FAG). Nanostructured systems were characterized by dynamic light scattering, ζ-potential, circular dichroism, and intrinsic fluorescence to evaluate the structures. The most appropriate time of conjugation was 2 days. The spray-dried and lyophilized mixtures presented different values of BI and % FAG (p < 0.05), indicating that the glycosylation was more intense in lyophilized mixtures. Nanostructures with average sizes lower than 300 nm were formed under different conditions of temperature, pH, and heating time. Analyses of circular dichroism and intrinsic fluorescence showed conformational changes in the nanostructures, mainly a decrease in the α-helix content in spray-dried systems. The characteristics presented by the studied systems showed that it is possible to obtain nanostructures from conjugates of tara gum and α-lactalbumin.


Assuntos
Lactalbumina/química , Nanoestruturas/química , Gomas Vegetais/química , Liofilização , Modelos Moleculares , Conformação Proteica
18.
Int J Biol Macromol ; 128: 140-148, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30682485

RESUMO

Chitosan is a polysaccharide well-known for its applicability as a biocompatible, biodegradable, and non-toxic material to produce drugs excipients and food coatings. Acidic media are required to disperse chitosan, and aqueous solutions of acetic acid have been typically used for this purpose. However, this acid has several sensory drawbacks. In this study, chitosan was dispersed [0.1 g·(100 mL)-1] in aqueous media containing acetic (AA), glycolic (GA), propionic (PA), or lactic (LA) acid, at 10, 20, 30, 40, or 50 mmol·L-1. The increase of acid concentration reduced pH and viscosity of the dispersions, and |ζ potential| of dispersed particles. Conversely, it increased electrical conductivity and density of the dispersions, and hydrodynamic diameter of dispersed particles. At a given concentration, these effects were slightly more pronounced for dispersions formed with GA or LA, compared to AA or PA. FT-IR data suggested more intense attractive interactions of chitosan chains with glycolate and lactate anions, than with acetate and propionate. Chitosan chains interacted more strongly with hydroxylated acids counter-anions than with their non-hydroxylated counterparts, leading to slight quantitative changes of physicochemical properties of these systems. Then, in physicochemical terms, GA, LA or PA are suitable to replace AA when preparing aqueous chitosan dispersions for technological applications.


Assuntos
Ácido Acético/química , Fenômenos Químicos , Quitosana/química , Glicolatos/química , Ácido Láctico/química , Acetilação , Condutividade Elétrica , Concentração de Íons de Hidrogênio , Peso Molecular , Reologia , Soluções , Viscosidade
19.
Ultrason Sonochem ; 59: 104754, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31479885

RESUMO

Chitosan is a natural polycationic polysaccharide with several known biotechnological functionalities, but its application in food products as ingredient or additive remains nowadays unusual. Additionally, ultrasonic production of food-grade emulsions is still an open research field, so ultrasound applicability for such purpose must be evaluated case by case. In this study, chitosan was dispersed in acid aqueous media containing acetic, glycolic, propionic or lactic acid (50 mmol·L-1), then added of the emulsifier Tween 20, and finally mixed to sunflower oil, through ultrasonic homogenization (20 kHz, 500 W, 4 min), in order to prepare O/W emulsions (oil fraction = 0.25). In all studied systems, oil droplets with average hydrodynamic diameter < 600 nm were obtained. The increase of chitosan concentration promoted the augment in consistency and the elastic character of the emulsions. Emulsions containing more than 0.500 g·(100 g)-1 of chitosan presented a minor increase of both oil droplets average hydrodynamic diameter and PDI, during storage for 28 days. Furthermore, such systems showed no phase separation when exposed to centrifugation, freeze-thawing, and freeze-thaw-heating cycles. Two main findings may be highlighted from this study: i) ultrasound processing is a promising approach to produce food-grade emulsified systems containing chitosan, and ii) chitosan is a suitable alternative as thickener/stabilizer for acidic emulsions, being its performance influenced by the biopolymer concentration and not by the organic acid present in the medium.

20.
Artigo em Inglês | MEDLINE | ID: mdl-18434262

RESUMO

This work aimed to study the partition of cheese whey proteins alpha-lactoalbumin and beta-lactoglobulin using aqueous two-phase system by applying the cloud point extraction technique. The cloud point temperatures were determined under different concentrations of copolymer and salt. The system providing the best protein separation conditions was 20 mass% of copolymer PE61 and potassium phosphate salt solution of 100 mM, at pH 7. The protein alpha-lactoalbumin remained preferentially in the aqueous phase and the beta-lactoglobulin was transferred to the copolymer phase.


Assuntos
Lactalbumina/isolamento & purificação , Lactoglobulinas/isolamento & purificação , Temperatura
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