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1.
Crit Rev Food Sci Nutr ; : 1-15, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38818634

RESUMO

This review systematically explores the pivotal role of food science and technology as a support for Phenylketonuria (PKU) dietary management. It delves into the genetic and metabolic underpinnings of PKU, highlighting the crucial need for stringent dietary regulation to manage phenylalanine levels and mitigate neurological complications. Through bibliometric analysis and current product evaluations, it identifies trends in PKU food research, emphasizing recent innovations in food formulations such as glycomacropeptide (GMP) supplements and higher appealing low-phenylalanine food products. Furthermore, it accentuates the sensory and consumer aspects of PKU dietary solutions, underscoring the importance of palatability for adherence. Notably, the review introduces 3D food printing as an emerging technology for creating personalized, nutrient-optimized, and sensory-appealing foods for PKU patients, offering a new horizon in dietary management. This comprehensive assessment underscores the dynamic interplay between nutritional science, food technology, and sensory evaluation in improving the quality of life for individuals with PKU.

2.
Foods ; 11(13)2022 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-35804660

RESUMO

This research aimed to develop new hazelnut and pumpkin seed oil-based creams and to assess the effect of different fat and sugar phases on the structure and physical properties of those creams at different refining degrees. In this study, three novel spreadable creams were prepared in a stirred ball-mill: CBS with cocoa butter, pumpkin seed oil and saccharose; OS with pumpkin seed oil and carnauba wax-basedoleogel and saccharose; OLS with oleogel, saccharose and Lucuma powder. OS and CBS creams reached a D90 value lower than 30 µm at 150 min of refining, the OLS cream showed the highest D90 value, with a particle size distribution and a rheological behaviour little affected by the refining time. The OS and CBS creams differed in yield stress, indicating that the attractive particle-particle interactions are affected not only by the particle size, but also by fat composition. Moreover, all the creams showed solid-like behaviour and a good tolerance to deformation rate, a high oil-binding capacity and a good physical stability. Thus, it is possible to reformulate spreadable creams with healthier nutritional profiles.

3.
Food Chem ; 375: 131805, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34942502

RESUMO

This study aimed to understand the effect of fatty acid composition and viscosity of vegetable oils on network formation mechanism and physical properties of oleogels. To this purpose, 12 oleogels were prepared, by choosing 6 seed oils and two waxes, at a fixed oleogelator concentration (6%). The modified Avrami model correctly describes the crystallization profile (R2 > 0.98) and the oil type did not affect the Avrami index that ranged from 1.00 to 1.43. Independently from oleogelator, rice and hemp seed oils followed a 3-D network formation mechanism, while almond oil a 2-D mechanism. The strength and yield stress of carnauba wax oleogels increased with increasing saturated fatty acid amount, while in beeswax-based oleogels a more interconnected structure was associated with the length of the saturated fatty acid chain. Thus, the oleogels formation mechanism was closely related to the chemical composition of the solvent, even in highly monounsaturated or polyunsaturated oils.


Assuntos
Ácidos Graxos , Ceras , Cristalização , Cinética , Compostos Orgânicos , Óleos de Plantas
4.
Foods ; 10(5)2021 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-34066774

RESUMO

The study aimed to investigate the role of sensitivity to flowability on food liking and choice, the relationship between sensitivity to flowability and food neophobia, and its role in food liking. Five chocolate creams were prepared with different levels of flowability, and rheological measurements were performed to characterise them. One hundred seventy-six subjects filled in the Food Neophobia Scale and a food choice questionnaire (FCq). The FCq was developed to evaluate preferences within a pair of food items similar in flavour but different in texture. Secondly, the subjects evaluated their liking for creams (labelled affective magnitude (LAM) scale) and the flowability intensity (generalised labelled magnitude (gLM) scale). The subjects were clustered into three groups of sensitivity and two groups of choice preference. The effect of individual flowability sensitivity on food choice was investigated. Finally, the subjects were clustered into two groups according to their food neophobia level. The sensitivity to flowability significantly affected the liking of chocolate creams and the solid food choice. The liking of chocolate creams was also affected by the individual level of neophobia (p = 0.01), which, in turn, was not correlated to flowability sensitivity. These results confirm that texture sensitivity and food neophobia affect what a person likes and drives what a person chooses to eat.

5.
J Food Sci ; 85(4): 1265-1273, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32249412

RESUMO

Ready-to-use therapeutic foods (RUTFs) are special foods used to encourage rapid weight gain in 5-year-old malnourished children, avoiding hospitalization. The factors affecting sensory characteristics and acceptability of RUTFs have been not adequately described. The aim of this work was to evaluate both the sensory properties and volatile compounds of four alternative RUTFs, varying in soy and sorghum, icing sugar, and oil content. Nine nonoral sensory attributes were evaluated by nine selected and trained assessors. The perceived intensity of five oral sensory attributes and the overall liking were assessed by 100 adult consumers. The volatile compounds were extracted and concentrated by solid phase microextraction and analyzed by gas chromatography/mass spectrometry. RUTF formulations significantly differed for graininess between fingers (size of granules) (P = 0.007), viscosity (P = 0.013), adhesiveness to the spoon (P < 0.044), and meltability (P = 0.005), but in consumers' opinion, they differed only for difficulty in swallowing, intensity of global odor, flavor, and sweetness. A positive correlation between overall liking and sweetness was found. Volatile compounds arising from lipid oxidation (hexanal and octanoic acid) were positively correlated with global odor and flavor. These attributes negatively affected the overall liking and were mainly contained in one out of the four formulations. Sensory and instrumental characterization identified key attributes for this kind of food, such as difficulty in swallowing, global odor, and sweetness, suggesting how to formulate an alternative RUTF to be used for a future clinical trial on malnourished children. PRACTICAL APPLICATION: Starting from the world's need to fight child malnutrition, the present study tried to characterize alternative ready-to-use therapeutic foods (RUTFs), special foods used to encourage rapid weight gain in 5-year-old malnourished children, from several points of view, such as acceptability, stability, technological, and overall quality. Results obtained will be an aid to setup the technological conditions and scale-up parameters for local productions of RUTFs to be tested in real trials on malnourished children. Indeed, key sensory attributes that drive consumer acceptance for this special food, such as sweetness and difficulty in swallowing, came out from the present study.


Assuntos
Transtornos da Nutrição Infantil/dietoterapia , Fast Foods , Alimentos Formulados , Paladar , Adulto , Criança , Pré-Escolar , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Microextração em Fase Sólida
6.
J Texture Stud ; 51(2): 242-251, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31598970

RESUMO

Considering the lack of the literature and the need for developing a valid method to measure the texture sensitivity, in this study, we investigated the individual sensitivity to discriminate among different levels of graininess. With this purpose, five samples of cocoa-based creams were prepared, by changing the refining time. Samples were first characterized in terms of particles size distribution, by means of laser diffraction. Then, 59 subjects evaluated the cream sample graininess intensity, by using gLM scales, and their liking, by using LAM scales. The graininess scores of each subject were fitted with a power model, already observed with the instrumental results, estimating both the power law exponent and the R2 coefficient, and using them as clustering parameters. Subjects were then clustered into three groups: high sensitivity; moderate sensitivity; low sensitivity. First, as it was hypothesized, results showed a significant difference between the three groups in terms of perceived graininess. Second, even though results showed a significant difference between the three groups in terms of perceived graininess, only little differences were found in terms of liking scores. Indeed, all the samples were equally liked for both the moderate and low sensitivity groups, whereas a significant trend was observed for the highly sensitive subjects who liked more the most refined samples. No significant relationships were found with age, and only a little trend was observed with gender: females seemed to be more sensitive than males. Texture attributes discrimination ability, as for example sensitivity to graininess, could affect food rejection or preferences and choice, but it is poorly investigated. This exploratory study, proposes a method to cluster consumers, based on their sensitivity. A statistical methodology has been developed to discriminate among consumer sensitivity levels. The results provide useful information about graininess sensitivity suggesting that the used methodologies could be applied to other texture properties resulting in a valid tool for the industry in the development and optimization of tailored new products.


Assuntos
Laticínios , Grão Comestível , Alimentos , Sensação , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
7.
Food Sci Nutr ; 6(1): 153-159, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29387373

RESUMO

Visual inspection is an important part of quality control not only for manufacturers but also for retailers and consumers. The object of this investigation was to determine fat content in sliced salami by means of image analysis. The image analysis procedure is applied to digital images of sliced Italian salami produced in 16 different salami factories (A-P). The image analysis method described in this work is nondestructive and the necessary equipment is cheap. It extracts directly interpretable parameters of fat particle morphology (e.g., area, roundness) and number of fat particles from 15 digital images for each sample (A-P). The correlations between the fat features extracted from the images with the chemical fat content measured on the samples were also studied. Good relationships were found between the fat particle characteristics measured by image analysis procedure and the percentage of chemically extractable fat by correlation (R2=0.75) and principal component analysis.

8.
J Sci Food Agric ; 98(11): 4003-4013, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29412472

RESUMO

Mycotoxins are secondary metabolites produced by moulds in food that are considered a substantial issue in the context of food safety, due to their acute and chronic toxic effects on animals and humans. Therefore, new accurate methods for their identification and quantification are constantly developed in order to increase the performance of extraction, improve the accuracy of identification and reduce the limit of detection. At the same time, several industrial practices have shown the ability to reduce the level of mycotoxin contamination in food. In particular, a decrease in the amount of mycotoxins could result from standard processes naturally used for food processing or by procedures strategically introduced during processing, with the specific aim of reducing the amount of mycotoxins. In this review, the current methods adopted for accurate analyses of mycotoxins in cereals (aflatoxins, ochratoxins, trichothecenes, fumonisins) are discussed. In addition, both conventional and innovative strategies adopted to obtain safer finished products from common cereals intended for human consumption will be explored and analysed. © 2018 Society of Chemical Industry.


Assuntos
Grão Comestível/química , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Micotoxinas/análise , Grão Comestível/microbiologia , Fungos/metabolismo , Humanos , Micotoxinas/metabolismo
9.
Food Funct ; 9(1): 476-484, 2018 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-29235594

RESUMO

This study aimed to evaluate whether salivary endocannabinoid (EC) and N-acylethanolamine (NAE) concentrations upon mastication of a semisolid food were involved in the sensory perception of fat taste, food liking and appetite in humans. A fat-enriched (FEP) and a low-fat control (CP) pudding were developed and used in a randomized cross-over study with 19 healthy volunteers. The study protocol combined a Modified Sham-Feeding (MSF) with a multiple-spoon Temporal Dominance of Sensations method. Subjects masticated and expectorated 10 spoons of the pudding and selected the dominant sensations among a list of attributes. Saliva samples, appetite and food liking scores were collected at baseline, immediately after the MSF of the pudding and every 5 min until 20 min after MSF. Salivary concentrations of all monitored ECs and NAEs increased during pudding mastication compared to baseline (except for palmitoylethanolamide with FEP). The raise was lower with FEP than with CP for all compounds except for 2-arachidonoylglycerol whose increase was higher than the other compounds and independent of pudding type. Salivary N-arachidonoylethanolamine, linoleoylethanolamide and palmitoylethanolamide were significantly lower at 10 and 20 min after MSF of FEP than CP. Fatty taste at the 2nd spoon and creaminess at the 5th spoon were perceived as dominant with FEP whereas only wateriness was dominant with CP at the 2nd spoon. No difference between puddings for individual appetite or food liking over the 20 min of the protocol was recorded. During mastication of a semisolid fat-enriched food, the fatty taste and the creaminess were perceived as dominant. Salivary ECs and NAEs were not associated with the individual perception of fatty taste, pudding liking and appetite sensations.


Assuntos
Apetite , Endocanabinoides/metabolismo , Etanolaminas/metabolismo , Saliva/química , Paladar , Adulto , Endocanabinoides/análise , Etanolaminas/análise , Feminino , Análise de Alimentos , Humanos , Masculino , Mastigação , Saliva/metabolismo , Adulto Jovem
10.
J Dairy Sci ; 100(12): 9539-9550, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28987582

RESUMO

Sweeteners and flavors are generally added to yogurt to make them more palatable. However, the addition of these ingredients may affect the fermentation process of yogurt as well as its physical and sensory characteristics. Consumers prioritize yogurt products that are "natural." A modified single-chain form of the natural sweet protein monellin extracted from the fruit of Dioscoreophyllum cumminsii, called MNEI, could be a useful alternative to artificial sweeteners. The aim of the present work was to evaluate new rapid sensory methods in combination with rheology to assess the viability of using MNEI to develop sweetened yogurts without the calories of sugar. We studied the gelation and cooling kinetics of 4 yogurt samples (unsweetened or sweetened with MNEI, aspartame, or sucrose) by using a rheometer. Furthermore, the 4 yogurts, with and without addition of a flavoring agent, were characterized from a sensory perspective using a combination of 2 rapid sensory methods, ultra flash profile and flash profile. Rheological results showed that, when added at typical usage levels, aspartame, sucrose, and MNEI did not generally affect the yogurt fermentation process or its rheological properties. Sensory results demonstrated that texture attributes of yogurts with aspartame and sucrose were strongly linked to sweetness and flavor perception, but this was not true for MNEI-sweetened yogurts. In contrast to results obtained from samples sweetened with sucrose and aspartame, MNEI protein did not sweeten the yogurt when added before fermentation. This study highlights the enhancing effect of flavor on sweetness perception, supporting previous reports that noted synergistic effects between sucrose or aspartame and flavors. Hence, future studies should be conducted to determine how sweet proteins behave in yogurt when added after fermentation.


Assuntos
Aspartame/análise , Sacarose/análise , Edulcorantes/análise , Paladar , Iogurte/análise , Adulto , Animais , Feminino , Fermentação , Frutas/química , Humanos , Masculino , Reologia
11.
J Texture Stud ; 48(2): 103-113, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28370108

RESUMO

Natural sweet proteins may be used as sugar replacer in simple liquid food systems but their applicability in more complex matrices has not been investigated yet. Gelling agent nature and texture characteristics as well as type and distribution of a stimulus in a gel could affect taste perception through inhibition or enhancement of tastants migration to the receptors. The mechanical, nonoral texture and time-intensity sweetness characteristics of sweet proteins MNEI and super sweet Y65R mutant, aspartame and saccharin added at a concentration iso-sweet to 40 g/L of sucrose in three agar gel concentrations (1%, 1.5%, and 2%) were evaluated. The results have shown that agar concentration and agar sweetener interaction particularly affect mechanical fracture stress and non oral hardness of the sweetened gels. Time intensity results illustrated that unlike in solution, the intensity of sweet taste in a gelled system over time decreases. Indeed, the behavior of the sweet proteins differed greatly in the gelled system compared to when they are in solution. PRACTICAL APPLICATIONS: MNEI has been proved to be a high-potency sweetener for beverages, but the possibility to use it in semisolid foodstuff was not investigated yet. This study represented a preliminary characterization of two variants of natural sweetener monellin, MNEI and Y65R in semisolid model foodstuff. The data were an important scientific contribution to the knowledge of sweet proteins in agar-based gels and could be useful in order to extend the possible application of these sweet proteins as low calorie sweeteners in semisolid foodstuffs. Some problems concerning their delivered sweetness in agar gels were underlined and their application should be optimized in order to improve sweetness conveyed.


Assuntos
Ágar/química , Géis/química , Proteínas de Plantas/química , Edulcorantes/química , Aspartame , Bebidas , Proteínas Mutantes/química , Sacarina , Sacarose , Percepção Gustatória , Fatores de Tempo
12.
BMC Plant Biol ; 17(1): 66, 2017 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-28347287

RESUMO

BACKGROUND: The environment has a profound influence on the organoleptic quality of tomato (Solanum lycopersicum) fruit, the extent of which depends on a well-regulated and dynamic interplay among genes, metabolites and sensorial attributes. We used a systems biology approach to elucidate the complex interacting mechanisms regulating the plasticity of sensorial traits. To investigate environmentally challenged transcriptomic and metabolomic remodeling and evaluate the organoleptic consequences of such variations we grown three tomato varieties, Heinz 1706, whose genome was sequenced as reference and two "local" ones, San Marzano and Vesuviano in two different locations of Campania region (Italy). RESULTS: Responses to environment were more pronounced in the two "local" genotypes, rather than in the Heinz 1706. The overall genetic composition of each genotype, acting in trans, modulated the specific response to environment. Duplicated genes and transcription factors, establishing different number of network connections by gaining or losing links, play a dominant role in shaping organoleptic profile. The fundamental role of cell wall metabolism in tuning all the quality attributes, including the sensorial perception, was also highlighted. CONCLUSIONS: Although similar fruit-related quality processes are activated in the same environment, different tomato genotypes follow distinct transcriptomic, metabolomic and sensorial trajectories depending on their own genetic makeup.


Assuntos
Frutas/genética , Frutas/metabolismo , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Parede Celular/genética , Parede Celular/metabolismo , Qualidade dos Alimentos , Frutas/fisiologia , Dosagem de Genes , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Genótipo , Itália , Metaboloma , Biologia de Sistemas/métodos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcriptoma
13.
J Sci Food Agric ; 95(13): 2579-87, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25783568

RESUMO

Pasta is a traditional Italian cereal-based food that is popular worldwide because of its convenience, versatility, sensory and nutritional value. The aim of this review is to present a step-by-step guide to facilitate the understanding of the most important events that can affect pasta characteristics, directing the reader to the appropriate production steps. Owing to its unique flavor, color, composition and rheological properties, durum wheat semolina is the best raw material for pasta production. Although pasta is traditionally made from only two ingredients, sensory quality and chemical/physical characteristics of the final product may vary greatly. Starting from the same ingredients, there are a lot of different events in each step of pasta production that can result in the development of varieties of pasta with different characteristics. In particular, numerous studies have demonstrated the importance of temperature and humidity conditions of the pasta drying operation as well as the significance of the choice of raw material and operating conditions on pasta quality.


Assuntos
Dessecação/métodos , Grão Comestível , Farinha/análise , Manipulação de Alimentos/métodos , Valor Nutritivo , Triticum , Culinária/métodos , Humanos
14.
Food Chem ; 173: 1179-86, 2015 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-25466141

RESUMO

Sweet proteins represent a class of natural molecules, which are extremely interesting regarding their potential use as safe low-calories sweeteners for individuals who need to control sugar intake, such as obese or diabetic subjects. Punctual mutations of amino acid residues of MNEI, a single chain derivative of the natural sweet protein monellin, allow the modulation of its taste. In this study we present a structural and functional comparison between MNEI and a sweeter mutant Y65R, containing an extra positive charge on the protein surface, in conditions mimicking those of typical beverages. Y65R exhibits superior sweetness in all the experimental conditions tested, has a better solubility at mild acidic pH and preserves a significant thermal stability in a wide range of pH conditions, although slightly lower than MNEI. Our findings confirm the advantages of structure-guided protein engineering to design improved low-calorie sweeteners and excipients for food and pharmaceutical preparations.


Assuntos
Proteínas de Plantas/química , Relação Estrutura-Atividade , Edulcorantes/química , Dicroísmo Circular , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Simulação de Dinâmica Molecular , Proteínas Mutantes/química , Conformação Proteica , Paladar
15.
Food Chem ; 139(1-4): 515-20, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23561139

RESUMO

Radio frequency (RF) heating has been used for numerous applications in the food industry such as baking, thawing or pasteurisation. It reduces cooking time, and it helps to retain acceptable food colour and texture. In this paper, chemical and sensory data obtained from broccoli, potatoes, salmon and cocoa cakes cooked using an innovative RF oven were reported. The oven has an algorithm able to monitor the energy feedback from the cavity and to adjust the energy output accordingly. The different foods were cooked to the same end point and the concentration of phytochemicals, vitamins and acrylamide were assessed. Results demonstrated that RF oven preserved ascorbic acid and increased glucosinolates concentration in broccoli and it decreased the formation of acrylamide in roasted potatoes more than 50%. The total amount of vitamins B was 30% and 50% higher in RF cooked salmon than conventionally cooked salmon prepared at 55 and 75°C, respectively.


Assuntos
Culinária/métodos , Análise de Alimentos , Paladar , Animais , Culinária/instrumentação , Humanos , Produtos da Carne/análise , Ondas de Rádio
16.
Appl Environ Microbiol ; 79(12): 3779-85, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23584774

RESUMO

In the last few years the need to produce food with added value has fueled the search for new ingredients and health-promoting compounds. In particular, to improve the quality of bakery products with distinct nutritional properties, the identification of new raw materials, appropriate technologies, and specific microbial strains is necessary. In this study, different doughs were prepared, with 10% and 20% flour from immature wheat grain blended with type "0 America" wheat flour. Immature flour was obtained from durum wheat grains harvested 1 to 2 weeks after anthesis. Doughs were obtained by both the straight-dough and sourdough processes. Two selected exopolysaccharide-producing strains of lactic acid bacteria (LAB), Leuconostoc lactis A95 and Lactobacillus curvatus 69B2, were used as starters. Immature flour contained 2.21 g/100 g (dry weight) of fructo-oligosaccharides. Twenty percent immature flour in dough resulted in a shorter leavening time (4.23 ± 0.03 h) than with the control and dough with 10% immature flour. The total titratable acidity of sourdough with 20% immature flour was higher (12.75 ± 0.15 ml 0.1 N NaOH) than in the control and sourdough with 10% immature wheat flour (9.20 ml 0.1 N NaOH). Molecular analysis showed that all samples contained three LAB species identified as L. lactis, L. curvatus, and Pediococcus acidilactici. A larger amount of exopolysaccharide was found in sourdough obtained with 20% immature flour (5.33 ± 0.032 g/kg), positively influencing the exopolysaccharide content of the bread prepared by the sourdough process (1.70 ± 0.03 g/kg). The addition of 20% immature flour also led to a greater presence of fructo-oligosaccharides in the bread (900 mg/100 g dry weight), which improved its nutritional characteristics. While bread volume decreased as the concentration of immature wheat flour increased, its mechanical characteristics (stress at a strain of 30%) were the same in all samples obtained with different percentages of fructo-oligosaccharides. These data support the use of immature wheat grain flour, and exopolysaccaride-producing lactic acid bacteria in formulating functional prebiotic baked goods whose nutritional value can be suitably improved.


Assuntos
Pão/análise , Farinha/microbiologia , Lactobacillus/metabolismo , Leuconostoc/metabolismo , Polissacarídeos Bacterianos/metabolismo , Prebióticos/análise , Triticum/microbiologia , Eletroforese em Gel de Gradiente Desnaturante , Farinha/análise , Tecnologia de Alimentos/métodos , Processamento de Imagem Assistida por Computador , Itália , Lactobacillus/genética , Leuconostoc/genética , Pediococcus/genética , Pediococcus/metabolismo , Polissacarídeos Bacterianos/biossíntese , Triticum/química
17.
Appl Environ Microbiol ; 78(8): 2737-47, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22307283

RESUMO

After isolation from different doughs and sourdoughs, 177 strains of lactic acid bacteria were screened at the phenotypic level for exopolysaccharide production on media containing different carbohydrate sources. Two exopolysaccharide-producing lactic acid bacteria (Lactobacillus curvatus 69B2 and Leuconostoc lactis 95A) were selected through quantitative analysis on solid media containing sucrose and yeast extract. The PCR detection of homopolysaccharide (gtf and lev) and heteropolysaccharide (epsA, epsB, epsD and epsE, and epsEFG) genes showed different distributions within species and strains of the lactic acid bacteria studied. Moreover, in some strains both homopolysaccharide and heteropolysaccharide genes were detected. Proton nuclear magnetic resonance spectra suggest that Lactobacillus curvatus 69B2 and Leuconostoc lactis 95A produced the same exopolysaccharide, which was constituted by a single repeating glucopyranosyl unit linked by an α-(1→6) glycosidic bond in a dextran-type carbohydrate. Microbial growth, acidification, and viscoelastic properties of sourdoughs obtained by exopolysaccharide-producing and nonproducing lactic acid bacterial strains were evaluated. Sourdough obtained after 15 h at 30°C with exopolysaccharide-producing lactic acid bacteria reached higher total titratable acidity as well as elastic and dissipative modulus curves with respect to the starter not producing exopolysaccharide, but they showed similar levels of pH and microbial growth. On increasing the fermentation time, no difference in the viscoelastic properties of exopolysaccharide-producing and nonproducing samples was observed. This study suggests that dextran-producing Leuconostoc lactis 95A and Lactobacillus curvatus 69B2 can be employed to prepare sourdough, and this would be particularly useful to improve the quality of baked goods while avoiding the use of commercially available hydrocolloids as texturizing additives.


Assuntos
Microbiologia de Alimentos , Lactobacillus/crescimento & desenvolvimento , Leuconostoc/crescimento & desenvolvimento , Polissacarídeos Bacterianos/análise , Triticum/microbiologia , Fermentação , Análise de Alimentos , Lactobacillus/química , Lactobacillus/classificação , Lactobacillus/genética , Leuconostoc/química , Leuconostoc/classificação , Leuconostoc/genética , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Polissacarídeos Bacterianos/genética , Análise de Sequência de DNA
18.
Food Microbiol ; 25(2): 335-47, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18206776

RESUMO

In this study, three starter formulations including Lactobacillus curvatus and Staphylococcus xylosus strains selected in vitro on the basis of their lipolytic and proteolytic activities were employed for the manufacture of traditional fermented sausages of southern Italy. Microbial population, proteolysis, lipolysis, changes in free amino acids (FAA) and free fatty acids (FFA) and development of characteristic taste and flavor of the final product were investigated. Proteolysis and lipolysis were observed in sausages inoculated with proteolytic and lipolytic S. xylosus coupled with L. curvatus, while the sausage started with only S. xylosus without lactobacilli was identical to the non-inoculated control, indicating that the proteolysis could be due to both microbial activity and endogenous proteases activated by the decrease in pH. The statistical analysis applied to the instrumental and sensory data showed that there was an effect of the starter used on the characteristics of the sausage obtained. In particular, the control samples showed very close features different from the sausages obtained by adding starter cultures. Finally, analyzing the sensory parameters the sausages ripened without starter addition and those started without the L. curvatus AVL3 showed similar features indicating an influence of the presence of the lactobacilli on the final organoleptic quality of the sausages. An appropriate choice of a combination of strains in a starter formulation is fundamental to obtain products of the expected quality.


Assuntos
Manipulação de Alimentos/métodos , Lactobacillus/metabolismo , Produtos da Carne/microbiologia , Staphylococcus/metabolismo , Paladar , Tecido Adiposo/metabolismo , Aminoácidos/análise , Animais , Contagem de Colônia Microbiana , Ácidos Graxos não Esterificados/análise , Fermentação , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Lipólise , Produtos da Carne/normas , Proteínas Musculares/metabolismo , Peptídeo Hidrolases/metabolismo , Análise de Componente Principal , Suínos , Água/metabolismo
19.
Meat Sci ; 76(2): 295-307, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22064299

RESUMO

In this study, two strains of Staphylococcus xylosus isolated from traditional fermented sausages of Vallo di Diano (Southern Italy) were used in combination with an acidifying strain of Lactobacillus curvatus as starter culture for the production of fermented sausages. Two starter formulation were developed combining the proteolytic but not lipolytic (prt(+), lip(-)) S. xylosus CVS11 with the L. curvatus AVL3 (starter S1) and the S. xylosus FVS21 (prt(-), lip(+)) with the same strain of L. curvatus (starter S2). Proteolysis and lipolysis were observed during ripening by the increase in total free amino acids (FAA) and free fatty acids (FFA), respectively. Such activities were observed in both started and non started sausages (control). Moreover, the proteolytic and lipolytic activities were detected in products started by both formulations irrespective of the presence of such activities in the strains used. Therefore, it was not possible to conclude whether the effect of proteolysis and lipolysis during ripening of the started fermented sausages was due to the activity of the starter cultures or to the action of meat endogenous enzymes.

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