Characterization of Melanoidins and Color Development in Dulce de Leche, a Confectionary Dairy Product With High Sucrose Content: Evaluation of pH Effect, an Essential Manufacturing Process Parameter.

The effect on color of the initial pH employed in dulce de leche (DL) production was evaluated through physicochemical and spectroscopical characterization of the melanoidins formed in the process. Melanoidins originated at pH values of 6.5, 7.0, and 7.5, and they were released by the enzymatic hydrolysis of the protein backbone and purified by gel filtration. They showed a significant degree of polydispersity, in general, with molecular weights (MWs) below 1,800 Da. DL produced at a higher pH released melanoidins with higher average MW after the enzymatic hydrolysis. They also presented darker colors (dE*ab, C*), more closely resembling those typical of the commercial product. Analysis of the fractions isolated by gel filtration using HPLC-DAD and multinuclear NMR showed an heterogeneous and complex composition. Even though structurally related, the 1H NMR spectra of melanoidins showed a higher degree of aromaticity at higher pH values. In conclusion, the pH employed in DL production affects the amount and structure of the colored products originated by MR reactions, and thus the color of the final product.

Influence of sucrose reduction on fouling during the production of dulce de leche.

In this Research Communication we focus the food industry´s broad tendency to decrease sugar content in food products onto dulce de leche (DL) and examine the influence of sucrose reduction on the detrimental deposits formed during the production process. The method used to identify the impact produced directly on the heat exchanger during the production of this product with low sucrose content required varying the quantity of sucrose in the milk. Different percentages of sucrose (20, 15, 10, 5 and 0% w/w) were submitted to the DL concentration process in a process simulator. After concentration, the quantification of the deposits formed in each was carried out and these deposits were characterized according to their composition. Methods such as Kjeldahl, Pregl-Dumas and sem-EDS were used. Thus, the work highlights the need to change the product manufacturing process due to changes in the formulation that directly impact the formation of deposits in the equipment used (fouling). This deposit changes significantly in relation to its quantity as well as in relation to the composition and chemical characteristics as the gradual reduction of the sucrose content in the production takes place. Therefore, these impacts must be considered in order to maintain better manufacturing and ensure efficient cleaning of equipment.

Isolation and Characterization of Melanoidins from Dulce de Leche, A Confectionary Dairy Product.

Melanoidins, the brown-colored compounds formed through the Maillard reaction, are responsible for color development in dulce de leche (DL), a popular confectionary dairy product in the Río de la Plata region, particularly in Uruguay and Argentina. Color is a critical quality parameter that strongly influences consumer preference. This work aimed to develop a method to perform preliminary structural characterization of the chromophores produced by the Maillard reaction. Melanoidins are present in a water-insoluble fraction, linked to a protein backbone, conforming melanoproteins of high molecular weight. The insoluble melanoprotein fraction (10% total solids) was isolated, and the chromophores released by proteolysis and isolated by gel-permeation chromatography. The analysis of the products revealed that they present a high degree of molecular weight (MW) polydispersity, in a range of 300 to 2000 Da, where the compounds of higher molecular weight contributed the most to the color of the product. The isolated fractions were further analyzed by RP-HPLC using a diode array detector (DAD) detector. These results, together with H-NMR data, suggested that the chromophores isolated belonged to a relatively simple mixture of aromatic products with higher hydrophobic character relative to other products of the melanoprotein digestion.

Preference mapping of dulce de leche commercialized in Brazilian markets.

Dulce de leche samples available in the Brazilian market were submitted to sensory profiling by quantitative descriptive analysis and acceptance test, as well sensory evaluation using the just-about-right scale and purchase intent. External preference mapping and the ideal sensory characteristics of dulce de leche were determined. The results were also evaluated by principal component analysis, hierarchical cluster analysis, partial least squares regression, artificial neural networks, and logistic regression. Overall, significant product acceptance was related to intermediate scores of the sensory attributes in the descriptive test, and this trend was observed even after consumer segmentation. The results obtained by sensometric techniques showed that optimizing an ideal dulce de leche from the sensory standpoint is a multidimensional process, with necessary adjustments on the appearance, aroma, taste, and texture attributes of the product for better consumer acceptance and purchase. The optimum dulce de leche was characterized by high scores for the attributes sweet taste, caramel taste, brightness, color, and caramel aroma in accordance with the preference mapping findings. In industrial terms, this means changing the parameters used in the thermal treatment and quantitative changes in the ingredients used in formulations.

Dulce de Leche, a typical product of Latin America: characterisation by physicochemical, optical and instrumental methods.

The physicochemical profile of Dulce de Leche (DL) was determined by both routine analysis and others techniques (HPLC, GC-MS and ICP-OES). Seven Brazilian commercial brands were characterised for moisture content, protein, fat, ash, pH and titratable acidity, mineral content (sodium, potassium, calcium, and phosphorus), colour parameters and instrumental analysis (carbohydrates content and volatile compounds). Overall, extensive variability among all the parameters evaluated were observed, suggesting different operational procedures in the dairy factories along the DL processing. In this sense, an increase of intrinsic quality of DL is related closely the standardization of operational parameters using during the manufacture.

Avaliação das características físico-químicas e sensoriais de doce de leite pastoso, elaborado com diferentes tipos de leite / Evaluation of physicochemical and sensory characteristics of sweet milk paste, prepared with different types of milk

Existem diversos produtos no mercado além do doce de leite tradicional, porém não há opções de doce de leite produzido com leite de baixo teor de lactose. Tendo em vista a escassez de produtos deste tipo para as pessoas com intolerância à lactose, este trabalho teve o objetivo de comparar as características sensoriais e físico-químicas dos doces de leite tradicionais, fabricados com leite integral (Amostra A), desnatado (Amostra B) e com leite de baixo teor de lactose (Amostra C). Os atributos sensoriais avaliados foram: cor, aroma, sabor, consistência por meio de escala hedônica e intenção de compra. Observou-se diferença significativa entre as amostras (p

There are several products on the market besides the traditional dulce de leche, but there are no options of dulce de leche produced with milk with low lactose content. Given the scarcity of such products for people with lactose intolerance, this study aimed to compare the sensory and physico-chemical properties of traditional dulce de leche, made with whole milk (Sample A), milk (sample B) and milk with low lactose (Sample C). The sensory attributes evaluated were color, aroma, flavor, consistency of hedonic scale and intention to purchase. There was a significant difference between samples (p <0.05) for color and consistency, and the sample C was the least preferred for both color (4.94) and for consistency (4.42). ln the analysis of intention to purchase the sample A differed from samples B and C. Some values found in the physico-chemical composition are outside the standards of current legislation, probably due to the different characteristics of the raw materials used in this work. However, the candies produced had excellent sensory acceptance, and in general the averages were between "like slightly" and "like regularly". (AU)

Which dulce de leche is that? A discussion on the identity and quality standard of creamy dulce de leche / Que doce de leite é esse? Uma discussão sobre o padrão de identidade e qualidade do doce de leite pastoso

This study aimed at determining the quality of commercial creamy dulce de leche, and to discuss whether there is a mischaracterization of the traditional formula by the food industry, considering the identity and quality standards (PIQ–Brazilian abbreviation). Samples of five brands of creamy dulce de leche and a standard sample were evaluated, and coded as DL I, DL II, DL III, DL IV, DL V, and DL P. These samples were investigated by means of physical-chemical analyses of moisture, ash, lipids, and proteins, and analyses of color and texture parameters. The ingredient labels were analyzed and compared with the identity and quality standards. The results were treated by analysis of variance (ANOVA) and Tukey test with p < 0.05 in the 10.0 Statistica (StatSoft) software. The values obtained from analyzed samples when compared with the standard one, it suggests that the dulce de leche been modified over the years. However, even with the addition of non-traditional ingredients into dulce de leche, the final product has been in accordance with the parameters set by the identity and quality standards, which can be attributed to a permissiveness of the Brazilian legislation, allied with the food industry appropriation on the traditional product.(AU)

No presente trabalho foi determinada a qualidade do doce de leite pastoso comercial para discutir se há descaracterização do produto tradicional pela indústria de alimentos, considerando-se o padrão de identidade e qualidade (PIQ). Foram avaliadas cinco marcas de doce de leite pastoso e uma marca definida como amostra padrão, codificadas em DL I, DL II, DL III, DL IV, DL V e DL P. As amostras foram submetidas à análise físico-química de umidade, cinzas, lipídios, proteínas e análise dos parâmetros de cor e textura. Os ingredientes dos rótulos foram analisados e confrontados com o padrão de identidade e qualidade. Os resultados foram tratados pela análise de variância (ANOVA) e teste Tukey com p < 0,05 no software Statistica 10.0 (StatSoft). Os valores obtidos das amostras quando comparados com a amostra padrão sugerem que o doce de leite tem sido modificado ao longo dos anos. No entanto, mesmo com a adição de outros ingredientes não tradicionais ao doce de leite, o produto final está de acordo com os parâmetros estabelecidos pelo padrão de identidade e qualidade, o que pode ser atribuído a uma permissividade da legislação Brasileira, aliada à apropriação da indústria de alimentos sobre o produto tradicional.(AU)

Behavior of enterohemorrhagic, enteropathogenic and enteroinvasive Escherichia coli in ambrosia / Comportamento de Escherichia coli entero-hemorrágica, enteropatogênica e enteroinvasiva em ambrosia

Ambrosia is a type of Dulce de Leche hand-made with milk, eggs and sugar, widely consumed in South America, and it is commonly sold in street markets, supermarkets and candy shops. Food contamination by pathogenic micro-organisms usually occur during the processing steps, at the distribution centers, at the retail market or in the consumer home. This study aimed at evaluating the behavior of the pathogenic strains of Escherichia coli enterohemorrhagic (EHEC) ATCC 43895, enteropathogenic (EPEC) INCQS 00182 and enteroinvasive (EIEC) ATCC 43893 in ambrosia samples. Aliquots of ambrosia were experimentally contaminated by the strains analyzed in this study. Detections of the inoculated microorganisms were done at 0, 1, 2, 3, 4, 5, 10, 20 and 30 days of storage. EHEC was recovered from all of analyzed samples until five days after infection. EPEC survived in ambrosia and it was isolated until the fourth day of the experiment. EIEC strain remained viable during the 30 days of storage. The analyzed pathogenic strains of E. coli showed different behavior in ambrosia, but all of them demonstrated potential danger to the consumers health. This study works for warning to adopt appropriate hygiene and sanitary actions during the ambrosia production, packaging and manipulation.(AU)

Ambrosia é um tipo de doce de leite preparado artesanalmente com leite, ovos e açúcar, muito consumido na América do Sul, e comumente comercializado em feiras livres, supermercados e docerias. A contaminação de alimentos por micro-organismos patogênicos geralmente ocorre durante as etapas de processamento, nos centros de distribuição, no mercado varejista ou na casa do consumidor. Neste trabalho foi avaliado o comportamento dos agentes patogênicos Escherichia coli: entero-hemorrágica (EHEC) ATCC 4895, enteropatogênica (EPEC) INCQS 00182 e enteroinvasiva (EIEC) ATCC 43893 em amostras de ambrosia. Alíquotas de ambrosia foram experimentalmente contaminadas com as cepas analisadas no estudo. Foram realizadas pesquisas do micro-organismo inoculado após 0, 1, 2, 3, 4, 5, 10, 20 e 30 dias de estocagem. EHEC foi recuperada de todas as amostras até cinco dias após a contaminação. EPEC sobreviveu na ambrosia e foi isolada até o quarto dia do experimento. A cepa de EIEC conseguiu permanecer viável durante os 30 dias de estocagem. As cepas patogênicas de E. coli estudadas mostraram diferente comportamento em ambrosia, mas todos representam perigo potencial para a saúde dos consumidores. Este estudo serve como alerta em relação à necessidade da adoção de medidas higiênico-sanitárias apropriadas durante a produção, embalagem e manipulação da ambrosia.(AU)

Desenvolvimento e avaliação físico-química, sensorial e da estabilidade de ácido ascórbico de doce de leite com pimenta / Development of red pepper-containing dulce de leche and evaluation of its physico-chemical and sensorial characteristics, and ascorbic acid stability

O doce de leite é um alimento muito consumido em todo o Brasil, com sabor, cor, aroma e texturas características. A pimenta dedo-de-moça também está presente na mesa dos consumidores e é rica em ácido ascórbico (vitamina C), que é excelente antioxidante. No presente trabalho, foi elaborado o doce de leite adicionado de pimenta dedo-de-moça. No produto desenvolvido, foi determinada a composição centesimal, e foi avaliada a aceitação do doce quanto aos atributos sensoriais de cor, aroma, sabor, textura e aceitação global. O teor de ácido ascórbico foi quantificado em diferentes períodos de armazenamento(0, 30 e 60 dias). O doce de leite com pimenta preparado apresentou composição centesimal de acordo com a legislação vigente. O teor de ácido ascórbico mostrou-se praticamente estável durante o período de armazenamento, e o produto demonstrou boa aceitação na análise sensorial.(AU)

The dulce de leche or milk candy is a food widely consumed in Brazil, which shows typical characteristics of taste, color, flavor and texture. The lady-finger red pepper is regularly present on the Brazilian people table as this product contains a pungent flavor favoring various spices; and it is also rich in ascorbic acid (vitamin C) which is an excellent antioxidant. This study aimed at developing a dulce de leche containinglady-finger red pepper, and to determine the composition of the product. Also, the ascorbic acid contents were quantified in products stored for different periods (0, 30 and 60 days). The product acceptance by consumers on the sensory characteristics was evaluated by means of hedonic scale for color, aroma, flavor and texture attributes. The composition of the product was in accordance with the legislation in force, and the ascorbic acid contents were practically stable during the storage, and the sensory analyses indicated that the red pepper-containing dulce de leche was well accepted.(AU)

Adição de soro de leite e café na qualidade do doce de leite pastoso

This research was carried out with the objective to verify the effect of substitution of milk for whey and the addition effect of coffee in the quality chemical and sensory of dulce de leche. A full factorial was used 2², with two levels (± 1) with the addition of three central points (0) and two levels of axial points (±1.41). The data were analyzed by statistical methodology of response surface and the data obtained with the acceptance testing was assessed using preference mapping. The results indicated that the increased concentration of whey increased the moisture content and yield of sweet and decreased protein and fat. The addition of coffee changed the moisture of candy. The response surface analysis for the composition of sweets showed that the maximum substitution of milk whey to produce dulce de leche would be 37%. For the preference map, observed that the sweets preferred by consumers were the formulation 1 and 2. The determining factor in their choice of sweet was the concentration of coffee, since that consumers preferred the samples with low concentrations of coffee independent of the concentration of whey, enabling with this the use of whey in the manufacture of dulce de leche, thus obtaining a new product.

Este trabalho foi realizado com o objetivo de verificar o efeito da substituição de leite por soro de leite e o efeito da adição de café na qualidade química e sensorial do doce de leite. Foi utilizado um fatorial completo 2², com dois níveis (±1) com a adição de três pontos centrais (0) e dois níveis de pontos axiais (±1,41). Os resultados obtidos foram analisados pela metodologia estatística de superfície de resposta e os dados do teste de aceitação foram analisados pela metodologia de mapa de preferência. Os resultados indicaram que o aumento da concentração de soro de leite aumentou o teor de umidade e diminuiu o teor de proteína e de gordura. A adição de café alterou somente a umidade dos doces. A análise da superfície de resposta para a composição dos doces mostrou que o teor máximo de substituição de leite por soro para se fabricar doce de leite seria de 37%. Pelo mapa de preferência, observou-se que os doces preferidos pelos consumidores foram os da formulação 1 e 2. O fator determinante na escolha dos doces foi a concentração de café, visto que os consumidores optaram pelas amostras com baixas concentrações de café independente da concentração de soro, possibilitando com isso a utilização do soro de leite e do café na fabricação do doce de leite, obtendo assim um novo produto.

Adição de soro de leite e café na qualidade do doce de leite pastoso

This research was carried out with the objective to verify the effect of substitution of milk for whey and the addition effect of coffee in the quality chemical and sensory of dulce de leche. A full factorial was used 2², with two levels (± 1) with the addition of three central points (0) and two levels of axial points (±1.41). The data were analyzed by statistical methodology of response surface and the data obtained with the acceptance testing was assessed using preference mapping. The results indicated that the increased concentration of whey increased the moisture content and yield of sweet and decreased protein and fat. The addition of coffee changed the moisture of candy. The response surface analysis for the composition of sweets showed that the maximum substitution of milk whey to produce dulce de leche would be 37%. For the preference map, observed that the sweets preferred by consumers were the formulation 1 and 2. The determining factor in their choice of sweet was the concentration of coffee, since that consumers preferred the samples with low concentrations of coffee independent of the concentration of whey, enabling with this the use of whey in the manufacture of dulce de leche, thus obtaining a new product.

Este trabalho foi realizado com o objetivo de verificar o efeito da substituição de leite por soro de leite e o efeito da adição de café na qualidade química e sensorial do doce de leite. Foi utilizado um fatorial completo 2², com dois níveis (±1) com a adição de três pontos centrais (0) e dois níveis de pontos axiais (±1,41). Os resultados obtidos foram analisados pela metodologia estatística de superfície de resposta e os dados do teste de aceitação foram analisados pela metodologia de mapa de preferência. Os resultados indicaram que o aumento da concentração de soro de leite aumentou o teor de umidade e diminuiu o teor de proteína e de gordura. A adição de café alterou somente a umidade dos doces. A análise da superfície de resposta para a composição dos doces mostrou que o teor máximo de substituição de leite por soro para se fabricar doce de leite seria de 37%. Pelo mapa de preferência, observou-se que os doces preferidos pelos consumidores foram os da formulação 1 e 2. O fator determinante na escolha dos doces foi a concentração de café, visto que os consumidores optaram pelas amostras com baixas concentrações de café independente da concentração de soro, possibilitando com isso a utilização do soro de leite e do café na fabricação do doce de leite, obtendo assim um novo produto.

Viability of Staphylococcus xylosus during shelf-life of dulce de leche prepared by vacuum evaporation / Viabilidade de Staphylococcus xylosus na vida de prateleira de doce de leite elaborado em evaporador a vácuo

In this research an innovation in the manufacture of dulce de leche by vacuum evaporation is presented, based on the addition of Staphylococcus xylosus. The culture growth, lactic acid bacteria, pH, acidity, water activity, and lactose and sucrose contents were monitored. The cell counting of S. xylosus varied from log10 6.22cfu g-1 to log10 6.83cfu g-1. Lactic acid bacteria naturally occurring in the milk varied from log10 3.62cfu g-1 to log10 4.38cfu g-1 (90th day of storage). The pH was favourable to the growth of S. xylosus, showing the viability of using this culture in this kind of product.

Este trabalho apresenta uma proposta de inovação, que é a adição da cultura pura de Staphylococcus xylosus em doce de leite elaborado em evaporador a vácuo. Monitorou-se o desenvolvimento da cultura pura e das bactérias lácticas, o pH, a acidez, a atividade de água e os teores de lactose e sacarose. O número de colônias da cultura pura variou de log10 6,22ufc g-1 a log10 6,83ufc g-1, enquanto que as bactérias lácticas naturalmente presentes no doce variaram de log10 3,62ufc g-1 a log10 4,38ufc g-1 no 90° dia de armazenamento. O valor de pH foi favorável ao crescimento do S. xylosus, demonstrando a viabilidade do uso da cultura neste tipo de produto.

Viability of Staphylococcus xylosus during shelf-life of dulce de leche prepared by vacuum evaporation

In this research an innovation in the manufacture of dulce de leche by vacuum evaporation is presented, based on the addition of Staphylococcus xylosus. The culture growth, lactic acid bacteria, pH, acidity, water activity, and lactose and sucrose contents were monitored. The cell counting of S. xylosus varied from log10 6.22cfu g-1 to log10 6.83cfu g-1. Lactic acid bacteria naturally occurring in the milk varied from log10 3.62cfu g-1 to log10 4.38cfu g-1 (90th day of storage). The pH was favourable to the growth of S. xylosus, showing the viability of using this culture in this kind of product.

Este trabalho apresenta uma proposta de inovação, que é a adição da cultura pura de Staphylococcus xylosus em doce de leite elaborado em evaporador a vácuo. Monitorou-se o desenvolvimento da cultura pura e das bactérias lácticas, o pH, a acidez, a atividade de água e os teores de lactose e sacarose. O número de colônias da cultura pura variou de log10 6,22ufc g-1 a log10 6,83ufc g-1, enquanto que as bactérias lácticas naturalmente presentes no doce variaram de log10 3,62ufc g-1 a log10 4,38ufc g-1 no 90° dia de armazenamento. O valor de pH foi favorável ao crescimento do S. xylosus, demonstrando a viabilidade do uso da cultura neste tipo de produto.

Viability of Staphylococcus xylosus during shelf-life of dulce de leche prepared by vacuum evaporation

In this research an innovation in the manufacture of dulce de leche by vacuum evaporation is presented, based on the addition of Staphylococcus xylosus. The culture growth, lactic acid bacteria, pH, acidity, water activity, and lactose and sucrose contents were monitored. The cell counting of S. xylosus varied from log10 6.22cfu g-1 to log10 6.83cfu g-1. Lactic acid bacteria naturally occurring in the milk varied from log10 3.62cfu g-1 to log10 4.38cfu g-1 (90th day of storage). The pH was favourable to the growth of S. xylosus, showing the viability of using this culture in this kind of product.

Este trabalho apresenta uma proposta de inovação, que é a adição da cultura pura de Staphylococcus xylosus em doce de leite elaborado em evaporador a vácuo. Monitorou-se o desenvolvimento da cultura pura e das bactérias lácticas, o pH, a acidez, a atividade de água e os teores de lactose e sacarose. O número de colônias da cultura pura variou de log10 6,22ufc g-1 a log10 6,83ufc g-1, enquanto que as bactérias lácticas naturalmente presentes no doce variaram de log10 3,62ufc g-1 a log10 4,38ufc g-1 no 90° dia de armazenamento. O valor de pH foi favorável ao crescimento do S. xylosus, demonstrando a viabilidade do uso da cultura neste tipo de produto.