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1.
Food Res Int ; 170: 112961, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37316008

RESUMO

The oil extracted from baru (Dipteryx alata Vog.) seeds is in bioactive compounds and it presents potential to be used in food and cosmetic industries. Therefore, this study aims to provide insights into the stability of baru oil-in-water (O/W) nanoemulsions. For this purpose, the effects of the ionic strength (0, 100 and 200 mM), pH (6, 7 and 8), and storage time (28 days) on the kinetic stability of these colloidal dispersions were evaluated. The nanoemulsions were characterized in terms of interfacial properties, rheology, zeta potential (ζ), average droplet diameter, polydispersity index (PDI), microstructure, and creaming index. In general, for samples, the equilibrium interfacial tension ranged from 1.21 to 3.4 mN.m-1, and the interfacial layer presented an elastic behavior with low dilatational viscoelasticity. Results show that the nanoemulsions present a Newtonian flow behavior, with a viscosity ranging from 1.99 to 2.39 mPa.s. The nanoemulsions presented an average diameter of 237-315 nm with a low polydispersity index (<0.39), and a ζ-potential ranging from 39.4 to 50.3 mV after 28 days of storage at 25 °C. The results obtained for the ζ-potential suggest strong electrostatic repulsions between the droplets, which is an indicative of relative kinetic stability. In fact, macroscopically, all the nanoemulsions were relatively stable after 28 days of storage, except the nanoemulsions added with NaCl. Nanoemulsions produced with baru oil present a great potential to be used in the food, cosmetic, and pharmaceutical industries.


Assuntos
Dipteryx , Asco , Cinética , Reologia , Sementes
2.
Prep Biochem Biotechnol ; 53(3): 297-307, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35671239

RESUMO

Enzyme immobilization has been reported as a promising approach to improving parameters such as thermal stability, pH and reusability. In this study, a polyacrylamide cryogel functionalized with L-phenylalanine was prepared to be used in the adsorption of ß-glucosidase from Thermoascus aurantiacus, aiming at its separation and also its immobilization on the cryogel matrix. The enzyme was produced by solid state fermentation. First, the adsorption was studied as a function of the pH and the resulting yield (Y, %) and purification factor (PF, dimensionless) were determined (1.57-5.13 and 64.19-91.20, respectively). The PF and yield from eluate samples obtained at pH 3.0 were the highest (5.13 and 91.20, respectively). Then, ß-glucosidase was immobilized on the hydrophobic cryogel and the recovery activities (%) were determined as a function of temperature and in the presence of different saline solutions. The values ranged from 14.45 to 45.97. As expected, salt type and ionic strength affected the activity remained in the immobilized ß-glucosidase. The average bioreactor activity was 39.9 U/g of dry cryogel and its operational stability was measured, with no decrease in activity being observed during seven cycles. Kinetic parameters of free and immobilized enzyme were determined according to different models.


Assuntos
Criogéis , Thermoascus , Criogéis/química , Adsorção , beta-Glucosidase/química , Enzimas Imobilizadas/química , Interações Hidrofóbicas e Hidrofílicas , Concentração de Íons de Hidrogênio
3.
J Sep Sci ; 46(3): e2200639, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36459687

RESUMO

This study proposed the development of a monolithic supermacroporous affinity column for direct capture of lactoperoxidase, a glycoprotein present in milk, whey, and colostrum, with several applications due to its wide antimicrobial activity. A poly(acrylamide)-based cryogel was produced by radical co-polymerization of monomers in frozen aqueous solution and activated with p-aminobenzenesulfonamide as a ligand for specific interaction with the lactoperoxidase. The axial liquid dispersion coefficients at different liquid flow rates were determined by measuring residence time distributions using the tracer pulse-response method. The axial dispersion coefficient was low and the height equivalent to theoretical plate was not dependent on the flow velocity. The adsorptive capacity of affinity cryogel was studied as a function of flow velocity and the best condition was 0.9 cm/min. The response surface methodology was applied to optimize the capture of the enzyme, as a function of pH and salt concentration. Higher purification factor value was found at a salt concentration of 80 mmol/L and pH of 8.0 (p < 0.05). There was no influence of the variables under study on the yield (p > 0.05). The results indicated that affinity cryogel is a promising chromatography support for the use in high-throughput one-step purification of lactoperoxidase from whey.


Assuntos
Criogéis , Lactoperoxidase , Criogéis/química , Soro do Leite , Ligantes , Adsorção , Cromatografia de Afinidade/métodos
4.
Food Res Int ; 159: 111583, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35940758

RESUMO

Red beetroot (Beta vulgaris L.) is a great source of betalains. The main betalains are the betacyanins, responsible for the purple color, and betaxanthins, which present a brownish color. These pigments can present antioxidant activity and are very unstable under certain conditions, such as temperature, extreme ranges of pH, and exposure to light. The aim of this work was to obtain beetroot extract (BE) via ultrasound and transform it into nanoparticles by using polyethylene glycol (PBE) and polyethylene glycol with low molecular weight chitosan (PCBE) as dispersants. The stability of the main betalains in the nanodispersions and the effects of the nanodispersions on the color and rheological properties of commercial Greek yogurt were evaluated. Compared to pristine BE, PCBE nanoparticles presented increased stability for the main betalains in acidic conditions (pH 3.0 and 5.0) of 56% and 22%, respectively. Both PBE and PCBE showed enhanced relative thermal stability compared to pristine BE. Furthermore, PCBE improved commercial Greek yogurt's rheological properties and color parameters. PCBE nanodispersions can be successfully applied as a color additive to commercial Greek yogurt.


Assuntos
Betalaínas , Iogurte , Betacianinas/análise , Betalaínas/análise , Betaxantinas/análise , Polietilenoglicóis , Verduras/química
5.
J Sep Sci ; 45(2): 401-410, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34687586

RESUMO

This study focused on the extraction, purification, and physicochemical characterization of γ-conglutin, a protein present in lupin seeds with properties of reducing blood glucose levels. Total protein was extracted with an alkaline-saline solvent, followed by isoelectric precipitation. Chromatographic purification of the precipitated fraction was performed using a cation exchange supermacroporous cryogel column. Electrophoresis of the eluted fraction from chromatography presented a single band of ∼48 kDa under non-reducing conditions (two bands of ∼30 and ∼17 kDa, under reducing conditions) confirming the success of the purification protocol. Liquid chromatography-tandem mass spectrometry analysis confirmed the identity of the protein as γ-conglutin. The purified γ-conglutin had an isoelectric point of 7.51, ß-sheets prevailing as a secondary structure, and denaturation temperature close to 68°C. The outcome of this work showed that γ-conglutin was obtained with a high degree of purity. The proposed purification protocol is simple and can be easily scaled up.


Assuntos
Lupinus , Cátions/análise , Criogéis , Lupinus/química , Lupinus/metabolismo , Proteínas de Plantas/análise , Sementes/química
6.
J Food Sci Technol ; 58(7): 2815-2824, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34194115

RESUMO

The line scale is widely used in different lengths to quantify the intensity of descriptors in sensory evaluation. Since studies related to its size are still limited the objective was to determine what variables of descriptive sensory evaluation can be influenced when different scale length is considered in two different methods: Optimized Descriptive Profile (ODP) (low degree of training) and Conventional Profile (CP) (high degree of training). Five chocolate samples were evaluated by two panels, one using the 9 cm and the other using the 15 cm line scale. The panels performed the sensory analysis using the ODP and after the CP method. The following criteria were investigated: interaction between sample and evaluator, discriminative capacity, repeatability of results, and frequency of score use on the unstructured scale. The influence of scale length on sensory responses was similar in the two methods (ODP and CP). When comparing the two scales in both methods, it was observed that the 15 cm scale resulted in an improvement in discriminative capacity, reduction of interaction and the evaluators tended to distribute their ratings more evenly across this scale length. The repeatability of results showed a slight tendency to be better on the 9 cm scale.

7.
Food Chem ; 357: 129693, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33882436

RESUMO

This article presents a study of the interfacial properties of oil-in-water emulsions containing sugar esters and polysaccharides. Sucrose fatty acid esters were synthesized using immobilized Candida antarctica lipase B. A yield of 53.4% was obtained using 2-methyl-2-butanol and 1:3 M ratio of sucrose:stearic acid. Equilibrium surface tension was 45 mN/m and low critical micellar concentration (CMC) value was obtained (ca. 10 mg/mL), characteristic of non-ionic surfactant. The interfacial properties of mixtures of sucrose esters and polysaccharides, at the oil-water interface were determined using a pendant drop tensiometer. Addition of polysaccharides increased the interfacial tension. Studies of interfacial viscoelasticity showed that the films were predominantly elastic. The presence of polysaccharides in emulsions resulted in flocculated droplets. All the emulsions presented great stability along 28 days with no creaming formation.

8.
Food Res Int ; 137: 109474, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33233140

RESUMO

Babassu oil is a raw material widely used in the pharmaceutical and biofuels industry. However, its physical-chemical and thermal characteristics are not widely described in the literature. This article describes these characteristics and, thus, seeks to increase the application of this raw material in the food industry. In this work, two different types of babassu oils, extra-virgin and virgin, were studied. The physicochemical characteristics, lipid profile, composition of the triacylglycerol and thermal properties of both oils were determined. Moreover, the crystallization and melting behavior was determined and the FTIR-ATR spectra of the oils acquired. The results show that the main fatty acids present are medium-chain and the type of extraction modifies the amounts of fatty acids present in each type of oil. Despite this, its physical-chemical characteristics and thermal properties are the same, except color and thermal stability, where extra-virgin oil is lighter and more stable than virgin babassu oil.


Assuntos
Arecaceae , Ácidos Graxos , Alimentos , Extratos Vegetais , Óleos de Plantas
9.
J Texture Stud ; 50(6): 547-555, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31276201

RESUMO

The objective of this study was to assess the microstructural characteristics of goat's milk chocolates formulated with different concentrations of cocoa mass by rheological measurements and microscopy. For rheological characterization, rotational and oscillatory tests were performed, while crystal morphology was observed by means of atomic force microscopy (AFM) and 3D optical profilometer. It was verified that the chocolates presented pseudoplastic and thixotropic behavior. The Herschel-Bulkley model adequately described the flow behavior of the formulations. In the oscillatory tests, it was found that the tangent δ (loss) decreased from 0.33 to 0.17 as a function of the increase in cocoa mass concentration. The creep recovery tests were consistent with the other rheological tests. The analysis of AFM and profilometer indicated that there are different microscopic pores on the surface of the chocolates, and that with the increase in the concentration of cocoa mass, it has a structure with greater interactions.


Assuntos
Chocolate/análise , Leite/química , Animais , Cacau/química , Fenômenos Químicos , Manipulação de Alimentos , Cabras , Reologia , Viscosidade
10.
Int J Biol Macromol ; 135: 226-232, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31128179

RESUMO

The surface properties and foaming of ovalbumin and guar gum aqueous solutions was investigated in the presence of sucrose or sorbitol. All solutions had a broad particle size distribution (395.60 at 1137.50 nm). Higher ovalbumin concentrations had lower equilibrium surface tension and higher absolute values of the zeta potential, regardless the presence of sucrose or sorbitol. Mixtures containing ovalbumin and guar gum resulted in a predominantly elastic character of the air-water interface probably due to the formation of a complex (hydrogen bonding and/or hydrophobic interactions) between ovalbumin and guar gum. Besides, the increase in guar gum concentration enhanced the elasticity of the surface film. Higher concentrations of both polymers were required to provide higher kinetic stability to the system, although the increase in guar gum concentration reduced foam capacity due to the increase in the apparent viscosity. Foams formed in the presence of sucrose or sorbitol showed similar half-lives.


Assuntos
Galactanos/química , Mananas/química , Ovalbumina/química , Gomas Vegetais/química , Sorbitol/química , Sacarose/química , Substâncias Viscoelásticas/química , Tamanho da Partícula , Reologia , Propriedades de Superfície , Tensão Superficial , Substâncias Viscoelásticas/análise
11.
Ultrason Sonochem ; 50: 339-353, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30287179

RESUMO

For the preparation of nanoemulsions, the correct choice of emulsifiers, together with the emulsification methods, directly influences the final product quality. The present study reports the ultrasound-assisted preparation of oil-in-water nanoemulsions produced with mucilage extracted from leaves of Pereskia aculeata Miller (ora-pro-nobis; OPN). The OPN mucilage (%) and soybean oil (%) concentration range, and the process operating parameters, ultrasonic power amplitude (%) and sonication time (min), were optimized based on the mean droplet diameter (d32). The effect of the mucilage and oil concentrations was also investigated by the response variables such as polydispersity, density, turbidity, viscosity, zeta-potential, and interfacial tension. The higher OPN mucilage concentrations (%) with lower amounts of soybean oil (%) favored nanoemulsion formations (116 ≤ d32 ≤ 171 nm) and increased polydispersity, density, and zeta-potential. On increasing OPN mucilage and soybean oil the turbidity of the dispersions increased. All colloidal systems showed Newtonian behavior, and the viscosity in the systems increased due to the greater OPN mucilage concentration in the aqueous phase at a certain oil concentration. In addition, lower values of equilibrium interfacial tension were found with increasing OPN mucilage concentrations. Finally, from the stability test, it can be pointed out that the OPN mucilage concentration should be between 1.0 and 1.5% and the oil concentration should be less than 5%, so that lower d32 values are maintained over time. Therefore, mucilage extracted from OPN and the ultrasound technique can be used in the preparation of nanoemulsions.


Assuntos
Cactaceae/química , Emulsões , Nanotecnologia , Óleos/química , Ondas Ultrassônicas , Água/química , Cinética
12.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1044-1045: 17-23, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28064065

RESUMO

In this study, a supermacroporous polyacrylamide cryogel was produced by cryo-polymerization and activated with Tris(hydroxymethyl)aminomethane (Tris-cryogel) to be applied as an affinity ligand for a one step purification of lysozyme (LYZ), directly from chicken egg white (EW). The Tris-cryogel presented interconnected pores with size varying in the range of 20-80µm and swelling capacity of 19.6±0.9g/g. The axial dispersion of the Tris-cryogel was analyzed at different flow velocities and mobile phase viscosities. It was verified that higher viscosity resulted in a higher degree of dispersion, causing the HETP values to increase from 0.04cm to 0.8cm. Adsorption isotherms were measured at 15°C and 35°C at pH 7.5. A Langmuir model was fitted to the equilibrium data, with a maximum adsorptive capacity of 285mg/g at 15°C and 363mg/g at 35°C. Thermodynamic analysis based on the Van't Hoff relationship showed that the process was spontaneous and enthalpically driven. Lysozyme was purified directly from egg white in a one step purification process at different pH values (7.5, 8.5 and 9.5). Independent of the pH, the specificity of Tris-cryogel for lysozyme adsorption was confirmed. At pH 7.5, yield and purification fold were higher (30% and 45). In addition, the effect of the dilution rate on egg white and flow velocity were also analyzed and it was shown that flow velocity did not affected purification and column efficiency, and that diluting the egg white increased yield to 70% with a purification fold of 23. Results show Tris-cryogel is a promising matrix for use in high throughput purification of lysozyme from egg white.


Assuntos
Cromatografia de Afinidade/métodos , Criogéis/química , Clara de Ovo/química , Muramidase/isolamento & purificação , Animais , Galinhas , Eletroforese em Gel de Poliacrilamida , Concentração de Íons de Hidrogênio , Modelos Lineares , Muramidase/análise , Muramidase/química
13.
Food Res Int ; 76(Pt 3): 561-566, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28455038

RESUMO

The existing methodologies for determining thresholds generate unreliable estimates of the point at which the intensity of a stimulus begins to compromise acceptance or result in sensory rejection of a product. Thus, a new methodology was proposed for determination of two new sensory thresholds: the compromised acceptance threshold (CAT) and the rejection threshold (RT). In this new methodology, increasing or decreasing series of stimulus intensity are measured together with a standard stimulus (control sample) by means of acceptance tests. In the present study, the CAT and RT were determined for sucrose concentrations in grape nectar, demonstrating that when reducing the sucrose concentration of grape nectar form 9.00% (w/v) to 6.87% there begins to occur impairment of product acceptance (CAT), and when reducing the sucrose concentration from 9.00% to 3.83% there begins to occur sensory rejection (RT) of the product. When compared to existing threshold determination methodologies, the proposed methodology permitted for calculating, with greater reliability, the points at which compromise of acceptance (CAT) and sensory rejection (RT) of the product begin to occur. In addition to the case study presented, the proposed methodology has a wide range of applications in science and in the food, cosmetic and pharmaceutical industries.

14.
Food Chem ; 174: 1-7, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25529644

RESUMO

A rapid method for the detection and quantification of the adulteration of milk powder by the addition of whey was assessed by measuring glycomacropeptide protein using mid-infrared spectroscopy (MIR). Fluid milk samples were dried and then spiked with different concentrations of GMP and whey. Calibration models were developed using multivariate techniques, from spectral data. For the principal component analysis and discriminant analysis, excellent percentages of correct classification were achieved in accordance with the increase in the proportion of whey samples. For partial least squares regression analysis, the correlation coefficient (r) and root mean square error of prediction (RMSEP) in the best model were 0.9885 and 1.17, respectively. The rapid analysis, low cost monitoring and high throughput number of samples tested per unit time indicate that MIR spectroscopy may hold potential as a rapid and reliable method for detecting milk powder frauds using cheese whey.


Assuntos
Contaminação de Alimentos/análise , Proteínas do Leite/análise , Leite/química , Espectrofotometria Infravermelho/métodos , Animais , Calibragem , Caseínas/análise , Análise dos Mínimos Quadrados , Fragmentos de Peptídeos/análise , Pós/análise , Análise de Componente Principal , Espectrofotometria Infravermelho/normas , Proteínas do Soro do Leite
15.
Ciênc. rural ; 44(1): 174-180, Jan. 2014.
Artigo em Português | LILACS | ID: lil-697013

RESUMO

As indústrias de alimentos vêm inovando e desenvolvendo novos produtos e processamentos, e os consumidores estão mais conscientes e preocupados em relação às novas tecnologias alimentares, o que pode influenciar a aceitação dos alimentos. Nesse contexto, objetivou-se disponibilizar para a língua portuguesa o questionário originalmente desenvolvido em inglês que avalia a neofobia em relação à tecnologia de alimentos, denominado Food Technology Neophobia Scale (FNTS). O instrumento original composto por treze afirmações foi inicialmente traduzido para o português por três indivíduos bilíngues, de forma independente; na sequência, as versões em português foram traduzidas novamente para o inglês por outros três indivíduos bilíngues, também de forma independente. Procedeu-se então à análise das versões e ajustes para se obter uma única versão em português com equivalência conceitual e linguística, a qual recebeu o nome de Escala de Neofobia em relação à Tecnologia de Alimentos. As versões original e traduzida foram aplicadas a 30 indivíduos bilíngues para avaliação da confiabilidade e reprodutibilidade do questionário. Os resultados obtidos demonstraram que a tradução do instrumento foi adequada e confiável, podendo, portanto, ser empregada em estudos com consumidores brasileiros.


The food industries have been innovating and developing new products and processes.Consumers are aware and well concerned about new food technologies, which can influence food acceptance . In this context, the objective was to provide a portuguese version of the questionnaire developed in English to evaluate neophobia for food technology called Food Technology Neophobia Scale (FNTS). The original instrument consists of thirteen items and was initially translated into Portuguese by three bilingual individuals independently. Following the Portuguese versions were translated back into English by three other bilingual individuals, also independently. Analysis of versions and adjustments were performed to obtain a single version in Portuguese with linguistic and conceptual equivalence, which was called "Escala de Neofobia em relação à Tecnologia de Alimentos". The original and translated versions were applied to 30 bilingual individuals to evaluate the reliability and reproducibility of the questionnaire. The results showed that the translation of the instrument was adequate and reliable, therefore can be used in studies with Brazilian consumers.

16.
Food Res Int ; 64: 289-297, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30011653

RESUMO

The optimized descriptive profile (ODP) is a new descriptive methodology which proposes an optimized sample evaluation by no trained assessors. To permit that assessors with a low degree of training quantitatively evaluate samples consistently, this method proposes the presentation of reference materials ("weak" and "strong") together with all set of samples at the time of evaluation. The attribute-by-attribute protocol is recommended on the ODP technique to allow for comparison among the samples and avoid fatigue, since only one attribute is evaluated at a time. Simultaneous presentation of the samples, together with the reference materials, is the "key point" of the ODP, and therefore the number of samples may be a limiting factor in this technique. The purpose of the present study is to determine if the balanced incomplete block design (BIBD), used in descriptive techniques traditionally, may be an alternative for data collection on this specific methodology, the optimized descriptive profile (ODP). The BIB design does not allow for comparison among all samples together, but only among a fraction of them. Therefore an assessment of the data quality obtained through this design is necessary to increase the applicability of the ODP. In this experiment a specific set of grape juice formulations was used, which presented variations in pulp and sugar contents. Sensory evaluation was conducted with two independent panels, where each panel evaluated the samples using the ODP protocol in a specific design. Thus, one panel evaluated the samples using the balanced complete blocks design (BCBD) and the other panel the balanced incomplete blocks design (BIBD). The data obtained by the two designs were compared in relation to analysis of variation, F-test power and regression models. Data obtained by the ODP conducted in the BIBD was very similar to that of the ODP in the BCBD. In the ANOVA, the formulations differed (p<0.05) in relation to all attributes, showing a test power (1 - ß) greater than 0.95. The regression models obtained in the different designs indicated overlapping of the confidence intervals (CI 95%). Therefore, the BIBD presents itself as an alternative for data collection in the ODP without loss in quality of the results.

17.
Ciênc. rural ; 42(12): 2272-2279, dez. 2012. ilus, tab
Artigo em Português | LILACS | ID: lil-658032

RESUMO

Alimentos isentos ou de baixo nível de gordura constituem um desafio para a indústria de alimentos. Nesse contexto, este trabalho teve como objetivo estudar o efeito da adição de concentrado proteico de soro (CPS) nas características sensoriais e aceitabilidade de sobremesas lácteas sem gordura. Quatro formulações foram desenvolvidas com diferentes concentrações de CPS (0%, 1,5%, 3,0% e 4,5% m v-1) e caracterizadas sensorialmente por meio da Análise Descritiva. A aceitabilidade das formulações foi avaliada por 94 consumidores que utilizaram escala hedônica de nove pontos. As sobremesas foram caracterizadas por oito atributos sensoriais: cor, firmeza, resistência ao corte, brilho, consistência, gomosidade, aroma e sabor de baunilha. As formulações contendo 3,0 e 4,5% de CPS apresentaram maior intensidade de todos os atributos sensoriais. A adição de CPS foi efetiva na composição da textura das sobremesas lácteas diet, além de realçar a cor, sabor e aroma do produto. As formulações contendo 1,5 e 3,0% de CPS foram as mais aceitas, evidenciando que a utilização do CPS nessas concentrações favoreceu a aceitabilidade do produto, proporcionando características sensoriais agradáveis aos consumidores.


Foods free or low-fat constituted are a challenge for the food industry. Thus, the objective of this research was to study the effect of the addition of whey protein concentrate (WPC) in the sensory profile and acceptability of dairy desserts free-fat. Four formulations had been developed with different WPC concentrations (0%, 1.5%, 3.0% or 4.5%, mass%) and sensory characterized by Descriptive Analysis. The acceptability of the formulations was evaluated by 94 consumers who had used the nine-point hedonic scale. Dairy desserts were characterized by eight sensory attributes: color, firmness, resistance to cut, brightness, thickness, gumminess, aroma and vanilla flavor. The formulations containing 3.0 and 4.5% of WPC presented greater intensity of all the attributes. The addition of WPC was effective in the composition of the texture of free-fat dairy desserts and enhances color, flavor and aroma of the product. The formulations with 1.5 and 3.0% WPC had been most accepted, showing that the use of WPC in these concentrations favored the acceptability of the product, providing pleasant sensory characteristics to consumers.

18.
Food Chem ; 135(3): 1078-82, 2012 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-22953827

RESUMO

The present work reports the development and validation of an analytical method for lactic acid quantification in milk by ion exclusion-HPLC with UV detection. This method showed good precision (variation coefficient <7.0%) and good accuracy (97.6-99.6%). Calibration curves were linear (R(2)>0.996) at the tested range of 5.0-25.0mmolL(-1); and the detection and quantification limits were 0.5 and 1.0mmolL(-1), respectively. Analysis of lactic acid in fermented milk (FM) or NaOH neutralised fermented milk (FNM) was performed using samples obtained during 9h of fermentation. An ANOVA analysis combined with the Tukey test was used to show that the method was insensitive to the differences between FM and FNM. The proposed method therefore proved to be a useful quality control tool in laboratories because it was able to determine milk acidity even in adulterated samples.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Ácido Láctico/análise , Leite/química , Animais , Bovinos , Cromatografia Líquida de Alta Pressão/instrumentação
19.
Rev. Inst. Adolfo Lutz ; 71(1): 118-126, jan.-mar. 2012. tab, graf
Artigo em Português | LILACS, Sec. Est. Saúde SP, SESSP-CTDPROD, Sec. Est. Saúde SP, SESSP-ACVSES, SESSP-IALPROD, Sec. Est. Saúde SP, SESSP-IALACERVO | ID: lil-680447

RESUMO

Neste trabalho, foi avaliada a influência dos teores de gordura e água na textura e na aceitação de requeijão light adicionado de concentrado proteico de soro, determinando-se os teores de gordura, água, proteína, carboidratos, cinzas e extrato seco desengordurado (ESD). As formulações foram analisadas instrumentalmente por meio da análise do perfil de textura, e a aceitabilidade sensorial foi avaliada por100 consumidores. Os resultados foram examinados por meio da análise de variância, ajuste de modelos de regressão e mapa de preferência interno. O modelo de regressão linear de primeiro grau apresentou melhor ajuste aos dados em nível de 10% de probabilidade. Os constituintes gordura e água contribuíram inversamente para a intensidade das propriedades de textura. Os requeijões originados de diferentes combinações de proporção de gordura e água, com ESD de aproximadamente 19,30%, apresentaram intensidades intermediárias de textura e obtiveram melhor aceitação pelos consumidores; e este evento indicou que o equilíbrio no ESD otimizou a aceitabilidade sensorial. Este estudo evidencia que a redução de gordura em requeijão deve ser aliada ao aumento do teor de água, para que a indústria possa oferecer diversidade de produtos que atendam às expectativas dos consumidores e ainda por menor custo de produção.


Assuntos
Alimentos Industrializados , Gorduras , Água
20.
Ciênc. rural ; 42(2): 360-366, fev. 2012. ilus, tab
Artigo em Português | LILACS | ID: lil-618101

RESUMO

O requeijão cremoso é um tipo de queijo fundido originalmente brasileiro, fabricado em todo território nacional com algumas variações de tecnologia. Este é um dos principais tipos de queijos produzido e consumido no Brasil e apresenta como característica o elevado teor de gordura. Por outro lado, a gordura apresenta papel fundamental na aparência, sabor e textura de requeijão, portanto desenvolver um produto light com qualidade sensorial semelhante à versão tradicional é um grande desafio à indústria de alimentos. Nesse contexto, o objetivo deste trabalho foi avaliar a composição química e a aceitabilidade sensorial de requeijão cremoso light, com diferentes níveis de redução de gordura, em relação à textura e impressão global. O experimento seguiu um delineamento de superfície de resposta, o Delineamento Composto Central Rotacional (DCCR) com dois fatores (gordura e umidade). A aceitabilidade sensorial foi avaliada por 100 consumidores, utilizando a escala hedônica de nove pontos. Os resultados obtidos demonstraram que os requeijões com diferentes níveis de redução de gordura apresentaram aceitabilidade sensorial semelhante quando combinados a um aumento proporcional do teor de umidade. Os produtos que apresentaram extrato seco desengordurado (ESD) de aproximadamente 19,3 por cento, originados de diferentes combinações entre gordura e umidade, foram os que apresentaram melhor aceitação por parte dos consumidores, demonstrando a importância do ESD na aceitabilidade sensorial.


Cream cheesecurd is a type of processed cheese, originally Brazilian, produced throughout the entire Brazilian territory with some technological variations. This is one of the main types of cheese produced and consumed in Brazil and it is known for presenting an elevated fat content. On the other hand, the fat plays a fundamental role in appearance, flavor and texture of cheese, then developing a light product with sensory quality similar to the traditional version is a major challenge to food industry. In this context, the objective of this study was to evaluate the chemical composition and sensory acceptability of light cream cheesecurd with different levels of fat reduction for texture and overall impression. The experiment followed a design of response surface, the Central Composite Rotatable Design (CCRD) with two factors (fat and moisture). The sensory acceptability was evaluated by 100 consumers, by the hedonic scale of nine points. The results showed that the cheesecurds with different levels of fat reduction had similar sensory acceptability when combined with a proportional increase in moisture content. The products that presented dry defatted extract (DDE) of approximately 19.3 percent, originated from different combinations of fat and moisture, were those with better acceptance by consumers, demonstrating the importance of DDE in sensory acceptance.

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