Effect of inulin as prebiotic and synbiotic interactions between probiotics to improve fermented milk firmness

Inulin behaved as a prebiotic to improve firmness of skim milk fermented by (a) pure cultures of Lactobacillus acidophilus (La), Lactobacillus rhamnosus (Lr), Lactobacillus bulgaricus (Lb) and Bifidobacterium lactis (Bl), (b) binary co-cultures of them with Streptococcus thermophilus (St), or (c) a cocktail containing all them. Inulin addition to co-cultures and cocktail enhanced products firmness, either after 1 day (D1) or 7 days (D7) of cold storage, likely due to the increase in microbial growth induced by metabolic interactions among lactic acid bacteria and partial inulin metabolization. Co-culture firmness did in fact range from 0.33 N without inulin (St-Lb) after D1 and 0.55 N with inulin (St-Lr) after D7. Also cocktail cultures exhibited high values of firmness, ranging, as an average, from 0.43 N (D1) to 0.46 N (D7), which suggests that they could have been potentiated by the reciprocal synergistic effects of microorganisms in complex mixture. (C) 2011 Elsevier Ltd. All rights reserved.

LPS Removal from an E. Coli Fermentation Broth Using Aqueous Two-Phase Micellar System

In biotechnology, endotoxin (LPS) removal from recombinant proteins is a critical and challenging step in the preparation of injectable therapeutics, as endotoxin is a natural component of bacterial expression systems widely used to manufacture therapeutic proteins. The viability of large-scale industrial production of recombinant biomolecules of pharmaceutical interest significantly depends on the separation and purification techniques used. The aim of this work was to evaluate the use of aqueous two-phase micellar system (ATPMS) for endotoxin removal from preparations containing recombinant proteins of pharmaceutical interest, such as green fluorescent protein (GFPuv). Partition assays were carried out initially using pure LPS, and afterwards in the presence of E. coli cell lysate. The ATPMS technology proved to be effective in GFPuv recovery, preferentially into the micelle-poor phase (K(GFPuv) < 1.00), and LPS removal into the micelle-rich phase (%REM(LPS) > 98.00%). Therefore, this system can be exploited as the first step for purification in biotechnology processes for removal of higher LPS concentrations. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 26: 1644-1653, 2010

A New Approach to Ammonium Sulphate Feeding for Fed-Batch Arthrospira (Spirulina) platensis Cultivation in Tubular Photobioreactor

Arthrospira platensis was cultivated in tubular photobioreactor using different photosynthetic photon flux densities (PPFD) and protocols of (NH(4))(2)SO(4) fed-hatch supply. Results were evaluated by variance analysis selecting maximum cell concentration (X(m)), cell productivity (P(x)), nitrogen-to-cell conversion factor (Y(X/N)) and biomass, protein and lipid contents as responses. At PPFD of 120 and 240 mu mol-photons/m(2) s, a parabolic profile of (NH(4))(2)SO(4) addition aiming at producing biomass with 7% nitrogen content ensured X(m) values (14.1 and 12.2 g/L, respectively) comparable to those obtained with NaNO(3). At PPFD of 240 mu mol-photons/m(2) s, P(x) (1.69 g/Ld) was 36% higher, although the photosynthetic efficiency (3.0%) was less than one-half that at PPFD of 120 mu mol-photons/m(2) s. Biomass was shown to be constituted by about 35% proteins and 10% lipids, without any dependence on PPFD or kind of nitrogen source. These results highlight the possible use of (NH(4))(2)SO(4) as alternative, cheap nitrogen source for A. platensis cultivation in tubular photobioreactors. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 26: 1271-1277, 2010

Effect of Polyethylene Glycol on the Thermal Stability of Green Fluorescent Protein

Green fluorescent protein (GFP) shows remarkable structural stability and high fluorescence; its stability can be directly related to its fluorescence output, among other characteristics. GFP is stable under increasing temperatures, and its thermal denaturation is highly reproducible. Some polymers, such as polyethylene glycol, are often used as modifiers of characteristics of biological macromolecules, to improve the biochemical activity and stability of proteins or drug bioavailability. The aim of this study was to evaluate the thermal stability of GFP in the presence of different PEG molar weights at several concentrations and exposed to constant temperatures, in a range of 70-95 degrees C. Thermal stability was expressed in decimal reduction time. It was observed that the D-values obtained were almost constant for temperatures of 85, 90, and 95 degrees C, despite the PEG concentration or molar weight studied. Even though PEG can stabilize proteins, only at 75 degrees C, PEG 600 and 4,000 g/mol stabilized GFP. (C) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 26: 252-256, 2010

Fed-Batch Production of Tetanus Toxin by Clostridium Tetani

This study deals with the effects of the initial nitrogen source (NZ Case TT) level and the protocol of glucose addition during the fed-batch production of tetanus toxin by Clostridium tetani. An increase in the initial concentration of NZ Case TT (NZ(0)) accelerated cell growth, increased the consumption of the nitrogen source as well as the final yield of tetanus toxin, which achieved the highest values (50-60 L(f)/mL) for NZ(0) > 50 g/L. The addition of glucose at fixed times (16, 56, and 88 h) ensured a toxin yield (similar to 60 L(f)/mL) about 33% higher than those of fed-batch runs with addition at fixed concentration (similar to 45 L(f)/mL) and about 300% higher than those obtained in reference batch runs nowadays used at industrial,scale. The results of this work promise to substantially improve the present production of tetanus toxin and may be adopted for human vaccine production after detoxification and purification. (C) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 26: 88-92, 2010

Thermal Behavior, Microstructure, Polymorphism, and Crystallization Properties of Zero Trans Fats from Soybean Oil and Fully Hydrogenated Soybean Oil

Blends of soybean oil (SO) and fully hydrogenated soybean oil (FHSBO), with 10, 20, 30, 40, and 50% (w/w) FHSBO content were interesterified under the following conditions: 20 min reaction time, 0.4% sodium methoxide catalyst, and 500 rpm stirring speed, at 100 A degrees C. The original and interesterified blends were examined for triacylglycerol composition, thermal behavior, microstructure, crystallization kinetics, and polymorphism. Interesterification produced substantial rearrangement of the triacylglycerol species in all the blends, reduction of trisaturated triacylglycerol content and increase in monounsaturated-disaturated and diunsaturated-monosaturated triacylglycerols. Evaluation of thermal behavior parameters showed linear relations with FHSBO content in the original blends. Blend melting and crystallization thermograms were significantly modified by the randomization. Interesterification caused significant reductions in maximum crystal diameter in all blends, in addition to modifying crystal morphology. Characterization of crystallization kinetics revealed that crystal formation induction period (tau (SFC)) and maximum solid fat content (SFC(max)) were altered according to FHSBO content in the original blends and as a result of the random rearrangement. Changes in Avrami constant (k) and exponent (n) indicated, respectively, that-as compared with the original blends-interesterification decreased crystallization velocities and modified crystallization processes, altering crystalline morphology and nucleation mechanism. X-ray diffraction analyses revealed that interesterification altered crystalline polymorphism. The interesterified blends showed a predominance of the beta` polymorph, which is of more interest for food applications.

Effect of inulin on growth and acidification performance of different probiotic bacteria in co-cultures and mixed culture with Streptococcus thermophilus

Inulin was used as a prebiotic to improve the quality and consistency of skim milk fermented by Lactobacillus acidophilus (La), Lactobacillus rhamnosus (Lr), Lactobacillus bulgaricus (Lb) and Bifidobacterium lactis (BI) with Streptococcus thermophilus (St), either in binary co-cultures or in cocktail containing all microorganisms. We compared, either in the presence of 40 mg inulin g(-1) or not, the results of the maximum acidification rate (V(max)) and the times to reach it (t(max)), to reach pH 5.0 (t(PH5.0)) and to complete the fermentation (t(f)). Post-acidification, lactic acid formation and cell counts were also compared after either 1 day (D1) or 7 days of storage at 4 degrees C (N). In co-culture, inulin addition to the milk increased V(max), decreased t(max) and t(f), favored post-acidification and exerted a bifidogenic effect. S. thermophilus proved to stimulate the metabolism of the other lactic bacteria and enhanced the product features. After D7, a significant prebiotic effect of inulin was observed in all co-cultures. Either after D1 or D7, the enumerations of Lr and BI in mixed culture markedly decreased compared to their respective co-cultures because of greater competition for the same substrates. (C) 2008 Elsevier Ltd. All rights reserved.

Effect of different prebiotics on the fermentation kinetics, probiotic survival and fatty acids profiles in nonfat symbiotic fermented milk

The simultaneous effects of different binary co-cultures of Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus rhamnosus and Bifidobacterium lactis with Streptococcus thermophilus and of different prebiotics on the production of fermented milk were investigated in this paper. In particular, we determined and compared the kinetics of acidification of milk either as such or supplemented with 4% (w/w) maltodextrin, oligofructose and polydextrose, as well as the probiotic survival, chemical composition (pH, lactose, lactic acid and protein contents), fatty acids profile and conjugate linoleic acid (CIA) content of fermented milk after storage at 4 degrees C for 24 h. Fermented milk quality was strongly influenced both by the co-culture composition and the selected prebiotic. Depending on the co-culture, prebiotic addition to milk influenced to different extent kinetic acidification parameters. All probiotic counts were stimulated by oligofructose and polydextrose, and among these B. lactis always exhibited the highest counts in all supplemented milk samples. Polydextrose addition led to the highest post-acidification. Although the contents of the main fatty acids were only barely influenced. the highest amounts of conjugated linoleic acid (38% higher than in the control) were found in milk fermented by S. thermophilus-L. acidophilus co-culture and supplemented with maltodextrin. (C) 2008 Elsevier B.V. All rights reserved.

Separation and partitioning of Green Fluorescent Protein from Escherichia coli homogenate in poly(ethylene glycol)/sodium-poly(acrylate) aqueous two-phase systems

The partitioning of Green Fluorescent Protein (GFP) in poly(ethylene glycol)/Na-poly(acrylate) aqueous two-phase systems (PEG/NaPA-ATPS) has been investigated. The aqueous two-phase systems are formed by mixing the polymers with a salt and a protein solution. The protein partitioning in the two-phase system was investigated at 25 degrees C. The concentration of the GFP was measured by fluorimetry. It was found that the partitioning of GFP depends on the salt type, pH and concentration of PEG. The data indicates that GFP partitions more strongly to the PEG phase in presence of Na2SO4 relative to NaCl. Furthermore, the GFP partitions more to the PEG phase at higher pH. The partition to the PEG phase is strongly favoured in systems with larger tie-line lengths (i.e. systems with higher polymer concentrations). The molecular weight of PEG is important since the partition coefficient (K) of GFP gradually decreases with increasing PEG size, from K ca. 300-400 for PEG 400 to K equal to 1.19 for PEG 8000. A separation process was developed where GFP was separated from a homogenate in two extraction steps: the GFP is first partitioned to the PEG phase in a PEG 3000/NaPA 8000 system containing 3 wt% Na2SO4, where the K value of GFP was 8. The GFP is then re-extracted to a salt phase formed by mixing the previous top-phase with a Na2SO4 solution. The K-value of GFP in this back-extraction was 0.22. The total recovery based on the start material was 74%. (c) 2008 Elsevier B.V. All rights reserved.

Moisture sorption isotherm characteristics of freeze-dried D-limonene emulsions in modified chitosan and maltodextrin

This article reports on modified chitosan as an alternative substance for protecting loss of volatile compounds during freeze drying. Moisture sorption isotherms of freeze-dried D-limonene emulsions in modified chitosan were determined at 15, 25, and 35 degrees C. The data were adjusted to the GAB model. Maltodextrin was used in a parallel experiment. Flavor released from microcapsules was measured. The monolayer humidity, the sorption heat, the diffusivity coefficients, and the surface area of freeze-dried D-limonene emulsions were determined.

Characterization of Brazilian lager and brown ale beers based on color, phenolic compounds, and antioxidant activity using chemometrics

BACKGROUND: Epidemiological studies have shown that beer has positive effects on inhibiting atherosclerosis, decreasing the content of serum low-density lipoprotein cholesterol and triglycerides, by acting as in vivo free radical scavenger. In this research, the antioxidant activity of commercial Brazilian beers (n = 29) was determined by the oxygen radical absorbance capacity (ORAC) and 1,1 -diphenyl-2-picrylhydrazyl (DPPH(center dot)) assays and results were analyzed by chemometrics. RESULTS: The brown ale samples (n = 11) presented higher (P < 0.05) flavonoids (124.01 mg L(-1)), total phenolics (362.22 mg L(-1)), non-flavonoid phenolics (238.21 mg L(-1)), lightness (69.48), redness (35.75), yellowness (55.71), color intensity (66.86), hue angle (59.14), color saturation (0.9620), DPPH(center dot) values (30.96% inhibition), and ORAC values (3,659.36 mu mol Trolox equivalents L(-1)), compared to lager samples (n = 18). Brown ale beers presented higher antioxidant properties (P < 0.05) measured by ORAC (1.93 times higher) and DPPH (1.65 times higher) compared to lager beer. ORAC values correlated well with the content of flavonoids (r = 0.47; P = 0.01), total phenolic compounds (r = 0.44; P < 0.01) and DPPH (r = 0.67; P < 0.01). DPPH values also correlated well to the content of flavonoids (r = 0.69; P < 0.01), total phenolic compounds (r = 0.60; P < 0.01), and non-flavonoid compounds (r = 0.46; P = 0.01). CONCLUSION: The results suggest that brown ale beers, and less significantly lager beers, could be sources of bioactive compounds with suitable free radical scavenging properties. (C) 2010 Society of Chemical Industry

Processing optimization of probiotic yogurt containing glucose oxidase using response surface methodology

Exposure to oxygen may induce a lack of functionality of probiotic dairy foods because the anaerobic metabolism of probiotic bacteria compromises during storage the maintenance of their viability to provide benefits to consumer health. Glucose oxidase can constitute a potential alternative to increase the survival of probiotic bacteria in yogurt because it consumes the oxygen permeating to the inside of the pot during storage, thus making it possible to avoid the use of chemical additives. This research aimed to optimize the processing of probiotic yogurt supplemented with glucose oxidase using response surface methodology and to determine the levels of glucose and glucose oxidase that minimize the concentration of dissolved oxygen and maximize the Bifidobacterium longum count by the desirability function. Response surface methodology mathematical models adequately described the process, with adjusted determination coefficients of 83% for the oxygen and 94% for the B. longum. Linear and quadratic effects of the glucose oxidase were reported for the oxygen model, whereas for the B. longum count model an influence of the glucose oxidase at the linear level was observed followed by the quadratic influence of glucose and quadratic effect of glucose oxidase. The desirability function indicated that 62.32 ppm of glucose oxidase and 4.35 ppm of glucose was the best combination of these components for optimization of probiotic yogurt processing. An additional validation experiment was performed and results showed acceptable error between the predicted and experimental results.

Effect of natural pigments on the oxidative stability of sausages stored under refrigeration

The objective was to use natural pigments to replace sodium erythorbate (NaEry), a synthetic compound used as an antioxidant in sausage formulations, and to evaluate the oxidative stability of the samples. Six assays were prepared in which sodium erythorbate (ERY) at 0.05 g/100 g was substituted by norbixin (NOR), lycopene (LYC), zeaxanthin (ZEA), beta-carotene (CAR) or dextrose (used as a control (CON)). Physical, chemical, color, texture and sensory parameters were measured on the first day and after 45 days of storage at 4 degrees C. All pigments used in the sausage formulations were able to maintain the oxidative stability of the sausages (MDA equivalents <038 mg/kg). Zeaxanthin and norbixin were the most efficient antioxidants of those tested. This antioxidant effect might be associated with the intermediate polarities of these two compounds, which would allow them to concentrate in the membrane lipids or emulsion interface, where lipid oxidation is most prevalent. Other volatile secondary products of oxidation besides MDA should be evaluated in further studies involving natural pigments and sensory oxidative stability. (C) 2009 Elsevier Ltd. All rights reserved.

A survey on the sanitary condition of commercial foods of plant origin sold in Brazil

The objective of the study was to evaluate the hygienic conditions and practices of commercial foods of plant origin in establishments and street marketed by street vendors in cities in the State of Rio de Janeiro, Brazil. Forty different sales points were evaluated (establishments that prepared and sold fruit juices and street vendors that commercialized fresh coconut water, sugarcane juice and orange juice) using a questionnaire with 12 items, divided into three blocks (salesmen/handlers, operations, installations). The results indicated that the activities related to the commerce of fruit beverages in the cities of Sao Goncalo and Rio de Janeiro required the elaboration of a set of actions by the Sanitary Vigilance Agency in order to improve the hygienic and sanitary level and minimize health risk to consumers. Important requirements in the legislation relevant to this type of food are still not followed; adequate packaging and storage of the raw material, obtaining the raw material from registered suppliers, hygiene of the handlers and adequate management of wastes produced during the activities in question are amongst the main items deserving attention. (C) 2009 Elsevier Ltd. All rights reserved.

Bioavailability of dietary sodium copper chlorophyllin and its effect on antioxidant defence parameters of Wistar rats

BACKGROUND: There has been growing interest in sodium copper chlorophyllin (Cu-Chl) as a food colourant and supplement owing to its beneficial biological activities. Studies have revealed that this green pigment inhibits experimental carcinogenesis and interacts with proteins and genotoxic agents. Health-related activities have also been associated with the prevention of lipid peroxidation. However, intestinal absorption of this pigment has been considered insignificant, raising questions of whether eventual biological properties are related to pre- or post-absorptive actions. In this study, intestinal absorption of Cu-Chl and its appearance in serum and organs were estimated by high-performance liquid chromatography analysis in rat feeding experiments. The effect of ingested Cu-Chl on lipid peroxidation was analysed by measuring thiobarbituric acid-reactive substances and antioxidant enzyme activities in hepatic and brain tissues of oxidative stress-induced rats. RESULTS: The two main components of commercial Cu-Chl, namely Cu-chlorin e(6) and Cu-chlorin e(4), showed different digestive behaviours, and only Cu-chlorin e4 was found in serum, liver and kidneys. Antioxidant activity in vivo could be observed in brain and seemed to be related to in situ protection but not to antioxidant enzyme modulation. CONCLUSION: As at least one of the major components of Cu-Chl is effectively absorbed, further pharmacolkinetic studies are encouraged to access absorption rates and the role of ingested copper chlorophyllins in mammals. (C) 2009 Society of Chemical Industry