Edimar Aparecida Filomeno Fontes

Yacon Flour and Bifidobacterium longum Modulate Bone Health in Rats

Yacon flour has been considered a food with prebiotic potential because of the high levels of fructooligosaccharides, which allows for its use in formulating synbiotic foods. The purpose of this study was to evaluate the effect of yacon flour and probiotic (Bifidobacterium longum) on the modulation of variables related to bone health. Thirty-two Wistar rats were divided into 4 groups: control, yacon flour, diet+B. longum, and yacon flour+B. longum. After euthanasia, the bones were removed for analysis of biomechanical properties (thickness, length, and strength of fracture) and mineral content (Ca, Mg, and P); the cecum was removed for analysis of the microbiota and short-chain fatty acids. Tibia Ca, P, and Mg content was significantly (P<.05) higher in groups fed diet+B. longum, yacon flour+B. longum than in the control group. An increase in fracture strength was observed in the yacon flour (8.1%), diet+B. longum (8.6%), and yacon flour+B. longum (14.6%) in comparison to the control group. Total anaerobe and weight of the cecum were higher (P<.05) in rats consuming the yacon flour diet compared with the other groups. Cecal concentration of propionate was higher in all experimental groups compared with the control (P<.05). Yacon flour in combination with B. longum helped increase the concentration of minerals in bones, an important factor in the prevention of diseases such as osteoporosis.

A mechanistical mathematical model to predict lactose hydrolysis by β-galactosidase in a permeabilized cell mass of Kluyveromyces lactis: validity and sensitivity analysis

Abstract The kinetics of lactose hydrolysis by intracellular β-galactosidase in a preparation of Kluyveromyces lactis cells permeabilized with ethanol was assessed in the presence of lactose and its hydrolysis reaction products galactose and glucose. Enzyme inhibition by the reaction products was tested using different concentrations of galactose (1, 5, 10, 20, 30 and 40 mM) and glucose (10, 30 and 50 mM) and a combination of both. Galactose was a competitive inhibitor. The competitive or non-competitive nature of the inhibition was defined by the smallest value presented by the residual sum of squares of regression as determined using the Marquardt iterative method of the non-linear regression (NLIN) program of the statistical analysis system (SAS). The kinetic constants V max , K m and K i , with values corresponding to 0.291±0.01 mM min −1 ; 2.536±0.412 mM and 10.88±8.86 mM, respectively, were also estimated by the same program. Enzyme activity was not affected by glucose at the concentrations tested. Glucose affected enzyme activity only when galactose was present. A mechanistic mathematical model was developed to describe lactose hydrolysis, taking into consideration the inhibitory effect of galactose. Sensitivity analysis of the coefficients of the model proposed was performed. Varying estimated K m and K i values by ±20% had no effect on lactose hydrolysis kinetics. However, with a 20% increase in the estimated V max value, the model more closely approximated the experimental data for initial concentrations of 30 mM glucose and 10 mM galactose. Model simulation closely approximated experimental data from lactose hydrolysis in a 5% phosphate-buffered lactose solution as well as in skim milk.

Composition and color stability of carbon monoxide treated dried porcine blood

Color stability of swine blood was studied over 12 weeks of storage in plastic bags, after pH (7.40, 6.70, or 6.00) adjustment, saturation with carbon monoxide (CO) and spray-drying. CO-treated dried blood presented a redder color and higher reflectance between 610 and 700 nm, compared to a brownish-red color and lower reflectance of untreated samples. As indicated by reflectance spectra, blood pH adjustment did not influence (P>0.05) the initial color of dried blood but influenced (P<0.05) its color stability (browning index). During storage, CO-treated blood showed a reduction in reflectance percentages as well as in CIE L(*) and a(*) values, which was more pronounced in polyethylene (OTR=4130 cm(3)/m(2)/day/atm) packaged samples. After 12 weeks of storage, CO-treated samples packaged in high OTR bags presented color indexes similar to those of the untreated dried samples. CO-treated samples packaged in nylon-polyethylene (OTR=30-60 cm(3)/m(2)/day/atm) bags showed a smaller rate of discoloration and color difference (DeltaE(*)) between the CO-treated and untreated samples. Even with some darkening, packaging CO-treated dry blood in low OTR bags still gives an acceptable reddish color after 12 weeks of storage while untreated dry blood has a brownish color just after drying.

Behaviour of polydiacetylene vesicles under different conditions of temperature, pH and chemical components of milk

Blue polydiacetylene vesicles were studied with regard to their behaviour under variations in storage temperature, heating, potentiometric titration and in the presence of chemical components of milk, to evaluate their application as a sensor in the food industry. Vesicles were prepared using 10,12-pentacosadienoic acid (PCDA)/1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC). Their changes were monitored using UV-Vis absorption. Temperatures not exceeding 25°C did not cause colour change in PCDA/DMPC vesicles for a period of up to 60days of storage. Heating for 10min at 60 and 90°C, exposure to pH higher than 9.0 and the simulant solutions of the whey proteins, β-lactoglobulin and α-lactalbumin, promoted colour change from blue to red for the vesicles studied. The effects of routine factors on the characteristics and stability of polydiacetylene vesicles is important in defining the parameters related to their application as a sensor for the food industry.

Evaluation of mortadella formulated with carbon monoxide-treated porcine blood.

The proximate composition and color of mortadellas containing carbon monoxide-treated (COTB), untreated (UNTB), or CO-treated dried blood (CODB) were compared to that of control mortadella. Blood addition did not affect (P>0.05) the proximate composition and TBARS. The mortadella containing 10% UNTB were brown and those containing COTB or CODB were red. Residual nitrite level, L*, a*, b* and c* values of the mortadella decreased (P<0.05) with an increase in the amount of blood; TBARs did not vary (P>0.05). Increasing the amount of blood increased (P<0.05) the hue angle (h*) and browning index (BI) of the mortadella containing UNTB. Increasing blood addition decreased (P<0.05) h* and did not affect (P>0.05) BI. Increasing storage length decreased (P<0.05) residual nitrite, affected BI and color coordinates and did not affect TBARS (P>0.05). Addition of CO-treated blood allows the production of better-colored sausages having lower residual nitrite levels.

Influência do processamento na qualidade proteica de novos cultivares de soja destinados à alimentação humana

OBJECTIVE: The aim of this study was to evaluate the effect of processing on the protein quality of new soybean cultivars intended for human food. METHODS: The diets were prepared from the cultivars Embrapa 48, BRS 213, BRS 155 and UFVTN 105. They were heat-treated in a vacuum oven at 130oC and 150°C, with subsequent removal or not of the hull for the production of soybean meals. A biological assay was done to determine the protein efficiency ratio, net protein ratio and true protein digestibility. RESULTS: Soybean meals had lower protein efficiency ratio, net protein ratio and digestibility than casein. Whole soybean meals treated at 150oC had a better protein quality index than refined soybean meals heat-treated at 130oC. The protein efficiency ratio and net protein ratio of Embrapa 48 and BRS 155 cultivars were higher (p<0.05) than the other ones. The UFVTN 105 cultivar had the highest digestibility (p<0.05) when treated at 130oC. Among the cultivars heat-treated at 150oC, the BRS 213 and BRS 155 cultivars had the lowest digestibility (p<0.05). Protein digestibility of the cultivar with low trypsin inhibitor content (BRS 155) was not better than that of the conventional Embrapa-48 cultivar. CONCLUSION: Heating and removal or not of the hull affected the protein quality of the new soybean cultivars intended for human food. Whole soybean meals heat-treated at 150oC for 30 minutes presented the best results. Heating improved the protein quality of the conventional soybean meals. Their protein quality was similar to that of the cultivars without trypsin inhibitor and better than that of the cultivars without lipoxygenases.

Applicability of a Voltammetric Assay Based on the Electroreduction of Oxygen to Evaluate the Antioxidant Capacity of Pequi (Caryocar brasiliense Camb.) Pulp

This study aimed to use a differential pulse voltammetric (DPV) assay, based on the electroreduction of oxygen, to evaluate the antioxidant capacity of pequi pulp. The results were expressed in coefficient of antioxidant capacity (K), at different pH values and in trolox equivalent antioxidant capacity (TEAC), and were compared to the 2,2’-azinobis(3-ethylbenzothiazoline6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) spectrophotometric assays. The principal component analysis showed higher K for pequi pulp extract and pH tending to 7.15. The antioxidant capacity was related to the presence of gallic acid in its composition. Regarding the TEAC value, the best result was obtained by the DPV test (53.43 ± 5.14 μmol trolox g pulp). The pequi pulp showed antioxidant capacity, compared to the standard antioxidant compounds evaluated. It was concluded that the voltammetric protocol was efficient to assess the total antioxidant capacity of pequi pulp and can be an alternative to conventional spectrophotometric assays, for the analysis of food matrices.