Electrophoretic analisys to detect and quantify additional whey in milk and dairy beverages

Polyacrylamide gel electrophoresis, SDS-PAGE system, was adjusted to detect the presence of additional whey in dairy beverages distributed in a Brazilian Government School Meals Program. Aqueous solutions of samples in 8 M urea were submitted to a polyacrylamide gel gradient (10% to 18%). Gel scans from electrophoresis patterns of previously adulterated milk samples showed that caseins peak areas decreased while peak areas of beta -lactoglobulin plus alpha -lactalbumin increased as the percentage of raw milk powder replaced by whey powder increased. The relative densitometer areas of caseins or beta -lactoglobulin plus alpha -lactalbumin plotted against the percentage of whey added to the raw milk showed a linear correlation coefficient square higher than 0.97. The caseins plot was used to determine the percentage of additional whey in 116 dairy beverages, chocolate or coffee flavor. Considering that the lowest relative caseins concentration found in commercial milk powder samples by the present method was 72%, the dairy beverages containing caseins percentages equal to or higher than this value were considered free of additional whey. Based on this criterion, about 49% of the coffee-flavor dairy beverages and 29% of the chocolate-flavor beverages, among all the samples analyzed were adulterated with whey protein to reach the total protein contents specified on their labels. The present method showed a sensitivity of 5% to additional whey.

Perception of thickness, mouth-coating and mouth-drying of dairy beverages by younger and older volunteer

Sensory perception has been found to change during ageing. The perception of mouth feel by older adults, and the role of ageing on the sensory perception of texture attributes is uncertain. . This study investigated perception of the textural attributes of thickness, mouth-coating and mouth-drying, in the context of dairy beverages, by older and younger adults. Just noticeable differences (JND) of a starch thickener and for cream concentration within milk were established for thickness and mouth-coating perception, finding no age-related differences between participant groups. Mouth-drying was assessed through the directional paired comparison of a mouth-drying milk beverage to a skimmed milk sample. The older adults were found to be more sensitive to mouth-drying (p=0.03) than the younger adults. This study found no age-related decline in texture perception with older adults finding perception of some attributes such as mouth-drying enhanced by ageing.

Effect of inulin and oligofructose on the physicochemical, microbiological and sensory characteristics of symbiotic dairy beverages

The aim of this study was to verify the effect of inulin and oligofructose on the physicochemical, microbiological and sensory characteristics of symbiotic dairy beverages. Four formulations were made: 1) a control (C); 2) a sample with added Lactobacillus paracasei (P); 3) a sample with added L. paracasei and inulin (PI); and 4) a sample with added L. paracasei and oligofructose (PO). The probiotic population, pH, and acidity of the products were evaluated once a week for 21 days while refrigerated (5 +/- 1 degrees C). Possible contaminating microorganisms (coliforms, E. coli, and Salmonella spp.) were investigated after three days of storage. Sensorial acceptance and purchase intention were evaluated seven days after manufacture. Dairy beverages presented with L. paracasei populations above 8.50 log CFU/mL during the whole storage period. Significantly (p<0.05) lower pH values were observed in P and PI, and higher acidity values were found in all formulations throughout storage. The dairy beverages were considered to be a promising matrix for the probiotic microorganism L. paracasei. The prebiotic additions (inulin and oligofructose) did not interfere with the overall acceptance and intention to purchase the beverages.

Starter cultures used in probiotic dairy product preparation and popular probiotic dairy drinks

Dairy products that contain probiotic bacteria are those that are produced with various fermentation methods, especially lactic acid fermentation, by using starter cultures and those that have various textures and aromas. Fermented dairy products are popular due to their differences in taste and their favourable physiological effects. Today, fermented dairy beverages in general are produced locally by using traditional methods. Recently, due to the increased demand for natural nutrients and probiotic products, fermented dairy beverages have reached a different position and are considered to have an important impact on human health and nutrition. In this article, probiotic bacteria and functional dairy products that are produced by using probiotic bacteria are discussed.

Investigation of milk proteins binding to the oral mucosa

High protein dairy beverages are considered to be mouth drying. The drying sensation may be due to the product protein content; however the mechanism of this mouth drying is uncertain. This study investigated the potential adhesion of milk proteins to porcine oral mucosal tissues and their resistance to wash out with simulated saliva was monitored using fluorescence microscopy. Cadein was found to be more adhesive to porcine mucosa then lactogloubulin. Some investigation into the reason for this difference in mucoadhesion was conducted by thiol-content analysis, rheology and zeta-potential measurements. The higher viscosity of casein solution and smaller zeta-potential is believed to be responsible for its better retention on mucosal surfaces. These findings suggest that casein and whey protein are both capable of binding and eliciting mouth drying in high protein dairy beverages.

CARACTERÍSTICAS FÍSICAS E QUÍMICAS DE BEBIDAS LÁCTEAS FERMENTADAS E PREPARADAS COM SORO DE QUEIJO MINAS FRESCAL

Nesta pesquisa procurou-se verificar as características físicas e químicas de bebidas lácteas preparadas com três concentrações de soro de queijo Minas Frescal (30, 40 e 50%), empregando-se dois tipos de culturas lácticas: uma tradicional para iogurte (YC-180) contendo cepas mistas de Streptococcus salivarus subsp. thermophilus, Lactobacillus delbrueckii subsp. lactis e Lactobacillus delbrueckii subsp. bulgaricus e outra (ABY-1) contendo cepas mistas de Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus acidophillus, Bifidobacteria e Streptococcus salivarius subsp. thermophilus. Constatou-se que as bebidas lácteas apresentaram diferença estatística no tempo zero para os teores de gordura e de extrato seco. À medida em que se elevou a proporção de soro em relação ao leite, os teores de gordura e de extrato seco diminuíram. O teor de proteína também diminuiu à medida em que se aumentou o teor de soro nas bebidas lácteas, embora a diferença não tenha sido tão acentuada quanto as observadas para os teores de gordura e de extrato seco. em relação à lactose, não se constatou diferença entre os tratamentos. Os teores de soro não influenciaram o índice de proteólise das bebidas lácteas. Verificou-se todavia que as bebidas elaboradas com a cultura probiótica ABY-1 apresentaram valores superiores para proteólise quando comparadas às bebidas elaboradas com as culturas YC-180. As bebidas lácteas elaboradas com 30% de soro apresentaram maiores valores para viscosidade. As bebidas elaboradas com a cultura YC-180 apresentaram valores superiores para viscosidade durante o período de armazenamento.

Efeito do teor de soro, açúcar e de frutooligossacarídeos sobre a população de bactérias lácticas probióticas em bebidas fermentadas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Características reológicas e sensoriais de bebidas lácteas funcionais

This research studied the effects of the independent variables whey protein concentrate - WPC (3.0; 3.5; 4.0%), skimmed milk powder - SMP (4.0; 5.0; 6.0%), and isolated soy protein - IPS (1.5; 2.0; 2.5%) on the rheological and sensorial characteristics of functional dairy beverages. In all tests 7% of sucrose was added to the ingredients. The rheological parameters were obtained in duplicate at the temperature of 10° C using a cone and plate rheometer, and fitted to the Power law model. The samples revealed a non-Newtonian fluid behavior both in the upward and downward curves, typical of a tixotropic fluid. The dairy beverages were submitted to a sensory analysis by a group of fifty untrained tasters who used a hedonic scale of nine points, the extremes being 1 - disliked extremely and 9 - liked extremely, in order to evaluate the following parameters: general acceptability; appearance and color; consistency; taste and aroma. The dairy beverage produced with 3% WPC, 6% SMP and 1.5% IPS, (treatment 3), was the one that obtained the best average score for those attributes and was preferred by the tasters. The variables SMP and IPS and the interaction between WPC and SMP presented a positive effect on the sensory consistency attributes: the higher amount of those ingredients in the formula the more the tasters liked the consistency.

Qualidade microbiológica e ocorrência de leveduras em bebidas lácteas fermentadas, com adição de polpas de frutas, comercializada na região de São José do Rio Preto - SP

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo da interação entre amido de mandioca e gomas e efeito de sua aplicação em bebida láctea fermentada

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de bebida láctea probiótica carbonatada: características físico-químicas, microbiológicas e sensoriais

Pós-graduação em Alimentos e Nutrição - FCFAR

Bebidas lácteas fermentadas: evolução da microbiota durante a fabricação, identificação de fungos leveduriformes e ação de culturas probióticas sobre os leveduriformes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Microbiota contaminante em bebidas lácteas fermentadas comerciais

Lately, the acceptability of fermented dairy beverages has been increased, due to the nutritional benefits, the practical consumption and the low cost of product for the manufacturers, and consequently for final market price to the consumers. During the manufacturing process, these products can be susceptible to microbiological contamination. The present study investigated the contaminant microbiota in fermented dairy beverages produced by small- and medium-sized companies, by means of analyses on moulds and yeasts counting, determination of the Most Probable Number (MPN) of total and thermo tolerant coliforms, Escherichia coli and Salmonella spp. detection, and determination of pH value. In spite of the absence of Salmonella spp., a high counts of yeasts and moulds were found, and E. coli was detected in five samples (16.67 %); and the sample were classified as “products in poor sanitary conditions”, because they showed thermo-tolerant coliforms counting higher than the standard established by the legislation in force. Therefore, quality programs such as Good Manufacturing Practices (GMP) and Hazard Analysis and Critical Control Points (HACCP) should be employed to prevent any contamination risk, in order to provide safe products to consumers.

Desenvolvimento de bebida láctea potencialmente probiótica carbonatada: características físico-químicas, microbiológicas e sensoriais

The goal of this work was to develop a strawberry fl avored dairy beverages carbonated and fermented with potential probiotic bacteria. Four formulations of dairy beverages were elaborated: Control (BL); Fermented (BLF); Carbonated (BLC) and Carbonated Fermented (BLFC). In samples submitted for carbonation, a carbonator was used for the carbon dioxide (CO2 ) gas injection dissolved in drinking water and the cultivation consisting of lactic bacteria Lactobacillus acidophilusLA-5®, Bifi dobacterium BB-12® and Streptococcus thermophilus (Biorich, Chr. Hansen) was employed on the fermented samples. The samples were characterized by physical and chemical, microbiological and sensory parameters. The BLC sample showed the presence of yeasts and coliform counts, but the counts indicated that it was suitable for consumption in 28 days time. The BL presented average coliform counts above the limit established by the law after 21 days of refrigerated storage. The presence of lactic bacteria and CO2 and their effects on lower proteolysis indexes, lower pH values and higher acidity values were correlated with signifi cant inhibitory effect of contaminated microorganisms in the BLF and BLFC. The carbonation was not stimulatory for the growth of lactic crops, mainly in the genus Bifi dobacterium spp. and Streptococcus spp. The BLF drink presented greater sensory acceptance and purchase intention test results, however the carbonated beverage presented positive results, with mean values greater than 50% in the acceptance tests with potential inclusion as sensory differential in dairy beverages. Just BLFC drink was considered potentially probiotic, by presenting minimum counts of Lactobacillus spp. during storage. Further studies should be conducted with the technology of carbonation, since it has been proven the correlation of the presence of CO2 with inhibitory effect of contaminated microorganisms and lower physical and chemical changes of dairy beverages.

Potential sources of mouth drying in beverages fortified with dairy proteins: a comparison of casein and whey-rich ingredients

Oral nutritional supplement drinks (ONS) are beverages high in dairy proteins that are prescribed to individuals at risk of malnutrition. Consumption of ONS is poor in elderly care facilities, with patients commenting that the sensory attributes of these drinks reduce their enjoyment and willingness to consume. Mouth drying is an attribute of ONS found to build with repeated consumption, which may further limit liking of these products. This study investigated the sources of drying sensations by sequential profiling, with a trained sensory panel rating a range of model milk systems and ONS over repeated sips and during after-effects. Sequential profiling found that fortification of milk with both caseinate and whey protein concentrate significantly increased the perception of mouth drying over repeated consumption, increasing by between 35 and 85% over consumption of 40mL. Enrichment of ONS with either whey protein concentrate or milk protein concentrate to a total protein content of 8.7% (wt/wt) resulted in whey and casein levels of 4.3:4.4% and 1.7:7.0% respectively. The product higher in whey protein was substantially more mouth drying, implying that whey proteins may be the most important contributor to mouth drying in ONS. However, efforts to mask mouth drying of protein-fortified milk by increasing sweetness or fat level were unsuccessful at the levels tested. Increasing the viscosity of protein-fortified milk led to a small but significant reduction in mouth drying. However, this approach was not successful when tested within complete ONS. Further analysis is required into the mechanism of protein-derived mouth drying to mask negative sensations and improve the enjoyment and consumption of protein-rich ONS.