Sandra Garcia

Dry-fermented chicken sausage produced with inulin and corn oil: physicochemical, microbiological, and textural characteristics and acceptability during storage.

This study aimed to evaluate the effect of oil content reduction and the addition of inulin as a partial oil substitute on the physicochemical, microbiological, and textural characteristics and acceptability during the storage (4 °C for 45 days) of dry-fermented chicken sausage produced with corn oil. Reducing the oil content did not influence the characteristics evaluated but tended to produce sausage with a dark reddish coloration. The addition of inulin did not change the physicochemical and microbiological parameters or the acceptability of the products, but resulted in an altered texture profile and a tendency toward lighter and less reddish coloration, similar to products with standard oil content. Fermented chicken sausages produced with standard amounts of corn oil, reduced amounts of corn oil, and inulin as a partial oil replacement remained stable without a significant loss of physical, chemical, microbiological, or sensory attributes during storage at 4 °C for 45 days.

Patulin biodegradation using Pichia ohmeri and Saccharomyces cerevisiae

The effectiveness of Pichia ohmeri and Saccharomyces cerevisiae in the biodegradation of patulin was evaluated in vitro. Patulin is a toxin produced by Penicillium expansum, the predominant fungal contaminant in post-harvest apple. The biodegradation experiment was carried out in culture medium (Yeast Medium broth, YM) and commercial apple juice. These substrates were artificially contaminated with patulin previously produced by P. expansum strain 2 in malt extract broth and purified over a silica gel column. The YM broth was inoculated with P. ohmeri 158 with proved anti-P. expansum activity, whereas the apple juice was inoculated with dried Saccharomyces cerevisiae cells. The residual patulin in contaminated substrates was determined by reversed-phase HPLC. P. ohmeri 158 in YM broth degraded over 83% of the initial 223 µg (8.92 µg/ml) of patulin after incubation at 25 °C for two days under static conditions; after five days of incubation, this percentage was greater than 99%, and patulin levels fell bel...

In vitro fermentation of juçara pulp (Euterpe edulis) by human colonic microbiota.

This study was carried out to investigate the potential fermentation properties of juçara pulp, using pH-controlled anaerobic batch cultures reflective of the distal region of the human large intestine. Effects upon major groups of the microbiota were monitored over 24h incubations by fluorescence in situ hybridisation (FISH). Short-chain fatty acids (SCFA) were measured by HPLC. Phenolic compounds, during an in vitro simulated digestion and fermentation, were also analysed. Juçara pulp can modulate the intestinal microbiota in vitro, promoting changes in the relevant microbial populations and shifts in the production of SCFA. Fermentation of juçara pulp resulted in a significant increase in numbers of bifidobacteria after a 24h fermentation compared to a negative control. After in vitro digestion, 46% of total phenolic content still remained. This is the first study reporting the potential prebiotic effect of juçara pulp; however, human studies are necessary to prove its efficacy.

Effect of starter culture and inulin addition on microbial viability, texture, and chemical characteristics of whole or skim milk Kefir

The effect of inulin addition and starters (Kefir grains or commercial starter culture) on the microbial viability, texture, and chemical characteristics of Kefir beverages prepared with whole or skim milk was evaluated during refrigerated storage. The type of starter did not influence microbial viability during the storage of the beverages, but the chemical and textural changes (decreases in pH, lactose concentration, and inulin and increased acidity, firmness, and syneresis) were more pronounced in the formulations fermented with grains than those fermented with the starter culture. The addition of inulin did not influence acidity or viability of lactic acid bacteria, but in general, its effect on the survival of acetic acid bacteria, Lactococcus and yeasts, firmness, and syneresis depended on the type of milk and starter culture used. Generally, the yeast, acetic acid bacteria, and Leuconostoc counts increased or remained unchanged, while the total population of lactic acid bacteria and Lactococcus were either reduced by 1 to 2 logs or remained unchanged during storage.

Changes in soymilk during fermentation with kefir culture: oligosaccharides hydrolysis and isoflavone aglycone production

Abstract The objective of this study was to evaluate the changes in oligosaccharides and isoflavone aglycone content in soymilk during fermentation with commercial kefir culture. Soymilk was fermented with kefir culture at 25 °C for 30 h. The counts of lactic acid bacteria, Lactococcus lactis, Leuconostoc sp and yeasts; measurements of pH, acidity, α-galactosidase and β-glucosidase activity, sugar and isoflavone contents were performed at the intervals of time. In the fermented soymilk, the lactic acid bacteria counts increased from 7.6 log to 9.1 CFU g−1, pH reached to 4.9 and lactic acid reached 0.34 g 100  g− 1. The α-galactosidase was produced (0.016 AU g−1) with 100% raffinose and 92% stachyose hydrolysis being observed after the depletion of galactose, glucose and sucrose. Kefir culture produced β-glucosidase (0.0164 AU g−1), resulting in 100% bioconversion of glycitin and daidzin and 89% bioconversion of genistin into the corresponding aglycones. The fermented soymilk presented 1.67 μmol g−1 of daidzein, 0.28 μmol g−1 of glicitein and 1.67 μmol g −1 of genistein.

Evaluation of a functional soy product with addition of soy fiber and fermented with probiotic kefir culture

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.

Petit suisse from black soybean: bioactive compounds and antioxidant properties during development process

Abstract This study aimed to evaluate the antioxidant properties, bioactive compounds and other physico-chemical parameters from black soybean and its derivatives over 30 days under refrigeration at 4 °C and develop a probiotic petit suisse produced from black soybean. The soymilk showed the highest levels of isoflavones (109 mg/100 g), total phenolics (600 mg/100 g) and total anthocyanins (388 mg/100 g) with the highest response in the tests with DPPH• and ABTS+• on a dry basis. There was a significant increase (p ≤ 0.05) in antioxidant activity during storage due to the hydrolysis of isoflavone glycosides to aglycones in soymilk sample, having a strong linear correlation between the concentration of isoflavone aglycones and the antioxidant activity for ABTS+• (R = 0.9437, 0.9624 and 0.9992) and DPPH• (R = 0.9865, 0.9978 and 0.9911), respectively, for soymilk, quark and petit suisse. The conversion of isoflavone was influenced directly by the characteristics of each sample, inhibiting or promoting the action of the enzyme. The petit suisse developed is an alternative for consumers, providing isoflavones and anthocyanins, possessing probiotic average counts (108 CFU g−1) during storage.

Optimization of a fermented soy product formulation with a kefir culture and fiber using a simplex-centroid mixture design

Abstract The objective of this work was to optimize a fermented soy product formulation with kefir and soy, oat and wheat fibers and to evaluate the fiber and product characteristics. A simplex-centroid mixture design was used for the optimization. Soymilk, soy, oat and wheat fiber mixtures, sucrose and anti-foaming agent were used for the formulation, followed by thermal treatment, cooling and the addition of flavoring. Fermentation was performed at 25 °C with a kefir culture until a pH of 4.5 was obtained. The products were cooled, homogenized and stored for analysis. From the mathematical models and variables response surface and desirability an optimal fermented product was formulated containing 3% (w/w) soy fiber. Compared with the other formulations, soy fermented product with 3% soy fiber had the best acidity, viscosity, syneresis, firmness and Lactococcus lactis count.

Dried Probiotics for Use in Functional Food Applications

The increasing consumer demand for foods with health benefits has led the food industry to diversify its products. Most of the foods containing probiotic bacteria are dairy products, although there is a rapidly growing demand for incorporating probiotics in other segments of the food industry. According to Food and Agriculture Organization (FAO, 2002), probiotics are live microorganisms that, when administered in adequate amounts, confer health benefits on the host. In order to produce such health benefits, it is essential that live probiotic bacteria survive after passing through the gastrointestinal tract and reach their site of action intact. Foods containing probiotic microorganisms are expected to have a promising future, but will require the development of new technologies, specifically developed to enable their use in innovative products in a wide range of industries. The challenge for the industry is to produce large enough amounts of viable and stable probiotic cultures for use as inoculums or to be introduced directly into a dried food. Although specific numbers are not mentioned at the FAO definition, some studies demonstrated that high levels of viable microorganisms are recommended in probiotic foods for efficacy (Meng et al., 2007). However, maintaining such counts throughout preparation, processing and storage requires constant study by the scientific and industrial community. Drying process are often used as a means to stabilize probiotics and facilitate storage, handling, transportation and subsequent use in functional foods (Santivarangka et al., 2008). Drying by spray-drying and freeze-drying are the most commonly used techniques for dehydrating probiotic cultures and lactic acid bacteria starter cultures (Betoret et al., 2003), although other methods such as vacuum oven drying, fluid bed drying or combinations of these may also be used. Drying processes are a major cause of loss of viability of probiotics, and in the specific case of freeze-drying, the freezing step causes additional stress on the bacterial cells, making the

Evaluation of the isoflavone and total phenolic contents of kefir-fermented soymilk storage and after the in vitro digestive system simulation.

This study aimed to evaluate the isoflavone and total phenolic contents in kefir-fermented soymilk storage and after the in vitro digestive system simulation (DSS). Soymilk was fermented with kefir culture (0.02UC/L) at 25°C for 15h and stored at 4°C for 4days. After the fermentation and storage, the isoflavone and total phenolic contents were quantified by high performance liquid chromatography and spectrophotometry, respectively. The cell viability of lactic acid bacteria and yeast was evaluated. Fermentation promoted an increase of approximately 3log CFU/g cycles of the microorganisms and the storage process did not alter the aglycone isoflavones and total phenolic contents. The content of aglycone isoflavones increased 2-fold, and the total phenolic content increased 9-fold. Therefore, kefir-fermented soymilk is a good source of aglycone isoflavones and phenolics, since the content of these substances was increased significantly after the in vitro digestive system simulation of the product.