Вы искали: syneresis (Английский - Испанский)

syneresis
sinéresis

vitreous syneresis
degeneración vítrea

prevention of syneresis
prevención de la sinéresis

vitreous syneresis (finding)
degeneración vítrea

in yoghurts it is used as stabilizer thus avoiding syneresis and promoting a smooth and soft texture.
se aplican en yogures como estabilizantes, evitando la sinéresis y dándoles una textura lisa y suave.

the interaction is marked by a considerable increase in the gel strength, an improve in water binding capacity, a change in gel texture from brittle to elastic, and a reduction in the degree of syneresis.
el gel obtenido de la mixtura de carragenina con lbg presenta un considerable aumento de fuerza de gel, mejora en la capacidad de retención de agua, reducción de sinérisis y una alteración de la textura del gel de quebradiza para elástica.

evaluation of a functional soy product with addition of soy fiber and fermented with probiotic kefir culture tahis regina baú; sandra garcia and elza iouko ida* departamento de ciência e tecnologia dos alimentos;universidade estadual de londrina; londrina - pr - brasil abstract the objective of this study was to evaluate the chemical, sensory properties and stability of a functional soy product with soy fiber and fermented with probiotic kefir culture. the product was characterized by the chemical composition, color and sensory analysis. the stability of the product was evaluated by ph, acidity, viscosity, firmness, syneresis measurements and cells counts. the functional soy product presented better chemical composition and difference in color compared to the fermented product without fiber. sensory analysis showed that the functional soy product had good acceptance and had better firmness and reduced syneresis compared to fermented product without fiber. the lactic acid bacteria counts decreased slightly during 28 days at 4°c of the storage and the product showed good microbiological stability. the functional soy product due to high lactococcus lactis counts could be considered as a probiotic for the entire storage period. key words: soy fiber, kefir culture, functional fermented soy product, storage, probiotic product introduction the development of non-dairy probiotic products is a challenge to the food industry in its effort to use the abundant natural resources by producing high quality functional products (charalampopoulos et al. 2002). most probiotic foods at the markets worldwide are milk-based and very few attempts are made to the development of probiotic foods using other fermentation substrates such as cereals (angelov et al. 2006). soybean and its derivatives have good potential for application in the functional food industry, because they contain a large quantity of components that are beneficial to health, such as proteins, isoflavones, fiber, essential fatty acids, oligosaccharides, etc (liu 1997). despite its excellent nutritive value, soybean grains have not been accepted in many western countries due to its undesirable flavors and characteristics tastes (silva et al. 2010). however, soy fermentation can improve its acceptability. overall, functional foods, or beverages are fortified through the addition of exogenous functional compounds, or using the microorganisms that produce biogenic compounds, or having probiotic features (servili et al. 2011). fermented soy products may be supplemented with the compounds claiming to have functional properties, such as fibers and probiotics. kefir is a complex mixture of bacteria and yeast (urdaneta et al. 2007) that co-exist in a symbiotic association and can be used for acid and alcohol fermentation. kefir production using kefir grains is difficult to put into practice. attempts have been made toward standardizing kefir production using the defined cultures. because of its microbial complexity and the benefits derived from its use, kefir may be considered an adequate source of potential probiotic microorganisms (romanin et al. 2010). to confer health benefits, probiotic products should provide a minimum count of 106 cfu/g in the fermented product (shah 2007; ramchandran and shah 2010). during the storage of fermented soy products, some studies indicate that there is a reduction in the growth ad number of microorganisms. according to liong (2011), the challenge of these products is to ensure probiotic stability. many studies have indicated that soymilk fermented with kefir could be beneficial to the human health (kwon et al. 2006; apostolidis et al. 2007). fermentation approaches have been attempted extensively to develop various fermented products and thus overcome the limitations in the consumption of soy products. however, studies about the fermented soymilk were concerned with the bacterial growth, or the taste of the product, but not with the totality of characteristics evaluation as a probiotic food with soy fiber. still, the effect of using fibers from alternative sources in fermented milk products has been widely investigated. however, there are no published studies about the functional soy product with the addition of soy fiber and fermented with probiotic kefir culture. the objective of this study was to evaluate the chemical and sensory properties and stability of a functional soy product with the addition of soy fiber and fermented with probiotic kefir culture. materials and methods materials and starter culture soymilk was prepared with lipoxygenase-free brs 257 soybean. for the formulation of the fermented soy product, the following commercial ingredients were used: soy fiber, sucrose, antifoaming and artificial milk and vanilla flavoring. for fermentation, lyophilized kefir starter culture (sacco®-lyofast tm 036 lv) composed of a mixed stock of lactococcus lactis spp lactis, lactococcus lactis spp lactis diacetylactis, lactobacillus brevis, leuconostoc spp and saccharomyces cerevisiae was used. soymilk and fermented soy product preparation soymilk was prepared after soybean screening and washing. the soybeans in a ratio of 1:10 (w:v; soybean grains:water) were soaked for 14 h, triturated and filtered to obtain the soymilk. the residue was discarded. formulations containing 87.7% soymilk (w/w), 3.0% soy fiber (w/w), 9.0% sucrose (w/w) and 0.1% antifoam (w/w) were subjected to heat treatment at 95°c for 15 min according to ferragut et al. (2009). after cooling to 25°c, 0.2% milk and vanilla flavorings (w/w) were added and the mixture was dispensed into 600 ml glass vials. the mixture was fermented at 25°c with kefir culture (0.01 uc/l) until a ph of 4.5 ± 0.1 was attained. the vials were cooled to 4°c, homogenized for 6 min at constant speed (homogenizer contrac, mod 1000) and stored for at least 12 h before the analysis. from optimization studies on the formulation of fermented soy products with kefir and soy, oat and wheat fibers, the optimal formulation (kf) containing 3.0% soy fiber (w/v) was established. the formulated product was stored for 28 days at 4°c. at 7 days intervals, the ph, acidity, viscosit y, firmness and syneresis characteristics were evaluated and kefir microorganisms counts. the product without soy fiber (kc) was prepared for comparison purposes and soymilk volume was adjusted to 90.7%. chemical characterization and sensory analysis protein, fat, ash, moisture and total dietary fiber contents were determined in triplicate in fermented products (aoac, 2006), and the results expressed in dry basis (d.b.). color (10 replicates) was measured with a minolta cr-400 colorimeter (konica minolta sensing, incorporation), with lighting d65, and the results were expressed in the cielab system (l*, a* and b*). for sensory analysis, the study was approved by the ethics committee of institution (opinion no. 0163.0.268.000-10) and samples were analyzed for coliform at 45°c, bacillus cereus and salmonella spp counts, according to brasil (2003). the sensory analysis was performed by the acceptance test with 68 untrained consumers. the consumers received 30 g of the product at 10°c in plastic drinking cups coded with three-digit random numbers. the formulations were evaluated for color, aroma, texture, flavor and overall acceptability attributes. the panelists used a 9-point hedonic scale, ranging from "dislike extremely (1)" to "like extremely (9)" (stone and sidel 2004). evaluation and stability during storage fermented and stored products were evaluated for ph, lactic acid content, viscosity, firmness, syneresis and kefir microbial counts every 7 days until day 28. the ph of the fermented products was determined with a digital potentiometer (hanna, hi 223). the lactic acid content was measured by titration with naoh (0.1 mol/l) and expressed in g lactic acid in 100 g of sample. viscosity was determined using a digital brookfield viscometer with a plus spindle 4, speed of 1.26 rad/s (12 rpm) and a 600 ml sample at 4 ± 1°c; the results were expressed in centipoise (cp). centipoise corresponds at 10-3 pa s (si unit). syneresis was measured (five replicates) according to a modification of guirguis et al. (1984) methodology and was used with the fabric tunnel overlapped under a bolter for drainage. syneresis was expressed as ml exudate in 100 g of sample. the firmness was evaluated by the measurements carried out in a ta-xt2i texturometer (stable micro systems), with a cylindrical acrylic probe acrylic p 25/l, 10 mm compression depth, sensor compression speed 2 mm/s, trigger force of 0.05 n and time of 0.5 s. firmness was expressed in newtons (n). cell counts for lactococcus lactis (irigoyen et al. 2005), leuconostoc spp and yeast (fontán et al. 2006; zajsek and gorsek 2010) were carried out and the results were expressed as log cfu/g of the fermented product. data analysis data regarding the chemical composition, color and sensory analysis were subjected to a t-test for comparison of the kc and kf products. the storage stability data of the fermented products was also subjected to a t-test for comparison of the kc and kf products at the same storage period. the analysis of variance (anova) and the tukey test (p<0.05) were performed to compare the changes in ph, acidity, viscosity, firmness, syneresis and microbial kefir counts during the storage of kc or kf products. results and discussion chemical composition and sensory acceptance the chemical composition on dry basis (table 1) of fermented soy products with kefir and with addition of soy fibers (kf) presented protein, dietary fiber, carbohydrates and ash contents higher than the product without soy fibers (kc). these increases in the components content were due the 3% soy fiber addition and the chemical composition of soy fiber. the lipid content did not differ in the kc and kf product (table 1). color parameters (table 1) in soy products fermented with kefir and with the addition of soy fibers (kf) and without soy fibers (kc) showed significant differences, and judges preferred the color of the product without fibers (fig. 1). the higher l* parameter in the kc product indicated a lighter color than in the kf product. the a* parameter (red-green component) was higher in the kc product. the a* negative values were also obtained by cruz et al. (2007) for soymilk. the b* parameter (yellow-blue component) was lower in the kc product; the addition of 3% soy fiber conferred a yellowish kf product.
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