Different Concentrations Of Sugar Research Articles

Influence of sucrose concentration on electric conductivity of banana pulp during ohmic heating.

Ohmic heating is a substitutive rapid heating method for food products. In this study, banana pulp with different concentrations of sugar is ohmically heated and the influence of sucrose concentration on electrical conductivity was investigated. The electrical conductivity, pH, total soluble solids, acidity, ascorbic acid content before and after ohmic heat treatment were also analysed. As the sucrose concentration increased, heating time at various voltage gradients 13.33, 20 and 26.66 V/cm increased, and the electrical conductivity decreased. As the voltage gradient increased, the pH and TSS of treated pulp with different sugar concentration increased followed by decrease in colour and acidity.

Fermentation of oat and soybean hull hydrolysates into ethanol and xylitol by recombinant industrial strains of Saccharomyces cerevisiae under diverse oxygen environments

In this study, we evaluated the capacity of recombinant industrial Saccharomyces cerevisiae YRH 396 and YRH 400 strains to ferment sugars from oat hull and soybean hull hydrolysates into ethanol and xylitol. The strains were genetically modified by chromosomal integration of Pichia stipitis XYLI/XYL2 genes and the overexpression of S. cerevisiae XKS1 genes, in order to have the ability to metabolize xylose, one of the main sugars in lignocellulosic biomass. The strains YRH 396 and YRH 400 were tested by fermenting acid and enzymatic hydrolysates of oat and soybean hull, with different concentrations of sugars, in orbital shaker under conditions of anaerobiosis and oxygen limitation. The YRH 396 strain showed the best kinetic parameters for the production of ethanol and xylitol, thus its metabolism was further studied in bioreactor cultivations. Under anaerobiosis, the maximum consumption of xylose was approximately 35% when using hydrolysates containing similar concentrations of glucose and xylose, whereas when hydrolysates mainly composed of xylose were used, this strain showed a consumption of 73% of the xylose, reaching yields of ethanol of 0.33 g g−1. In bioreactor cultivations under oxygen limitation, xylose consumption reached approximately 65%, and the main product was xylitol, reaching a final concentration of 8.17 g L−1. These results suggest that, in addition to an adaptive evolution process, molecular modifications are necessary for an industrial application of these type of genetically modified strains.

Storage longevity of passion fruit squash

The present investigation on the storage longevity of passion fruit squash was carried out in the Experimental laboratory of the Department of Pomology and Post Harvest Technology, Faculty of Horticulture, Uttar Banga Krishi Vishwavidyalya, Pundibari, Cooch Behar during 2007-08. Four treatment combinations of both yellow and purple passion fruit squash with different concentrations of sugar and preservatives were evaluated for extending the storage life of squash. In yellow passion fruit squash T 3 (6.38 °Brix) and in purple passion fruit squash T 4 (8.23 °Brix) were found to have very less percentage change of TSS over initial value after six month of storage. The acidity value among various treatments, T 3 for yellow passion fruit squash and T 4 for purple passion fruit squash had recorded minimum percentage change in acidity over initial after six month of storage. The ascorbic acid content in different treatments for both yellow and purple passion fruit squash were found to decrease throughout the storage period. Considering mould count after six month of storage, T 3 was found best treatment both for yellow and purple passion fruit squash. The effect of KMS was better for suppressing mould growth than sodium benzoate. It was observed that hedonic score for yellow and purple passion fruit squash was decreased with increase in storage period. The yellow passion fruit squash prepared with 250 ml juice + 460 g sugar + 290 ml water + 1 g citric acid + 0.6 g KMS as preservative and the purple passion fruit squash prepared with 250 ml juice + 475 g sugar + 275 ml water + 2.5 g citric acid + 0.75 g sodium benzoate as preservative have been found to be the best treatment for the storage life.

Itaconic and Fumaric Acid Production from Biomass Hydrolysates by Aspergillus Strains.

Itaconic acid (IA) is a dicarboxylic acid included in the US Department of Energy's (DOE) 2004 list of the most promising chemical platforms derived from sugars. IA is produced industrially using liquid-state fermentation (LSF) by Aspergillus terreus with glucose as the carbon source. To utilize IA production in renewable resource-based biorefinery, the present study investigated the use of lignocellulosic biomass as a carbon source for LSF. We also investigated the production of fumaric acid (FA), which is also on the DOE's list. FA is a primary metabolite, whereas IA is a secondary metabolite and requires the enzyme cis-aconitate decarboxylase for its production. Two lignocellulosic biomasses (wheat bran and corn cobs) were tested for fungal fermentation. Liquid hydrolysates obtained after acid or enzymatic treatment were used in LSF. We show that each treatment resulted in different concentrations of sugars, metals, or inhibitors. Furthermore, different acid yields (IA and FA) were obtained depending on which of the four Aspergillus strains tested were employed. The maximum FA yield was obtained when A. terreus was used for LSF of corn cob hydrolysate (1.9% total glucose); whereas an IA yield of 0.14% was obtained by LSF of corn cob hydrolysates by A. oryzae.

Influence of concentration of sugar on mass transfer of pineapple slices during osmotic dehydration

Osmotic drying is a partial dehydration process to give the product a quality improvement over the conventional drying process. The experiment was conducted for studying water loss(WL), sugar gain(SG), weight reduction(WR) and total solid(TS) during osmotic dehydration of pineapple slices (10 mm thick) in different concentration of sugar (40%, 50% and 60%) up to 6 hours at room temperature. It was found that increasing the concentration of the sugar solution used resulted in increased rates of water loss. The water loss at 40% sugar solution of pineapple slices were found to be significantly lower (p=0.05) than that of at 60% sugar solution. It was found there were rapid rates of water loss, sugar gain, weight reduction for first four hour of the osmotic process. DOI: http://dx.doi.org/10.3329/jbau.v12i1.21415 J. Bangladesh Agril. Univ. 12(1): 221-226, June 2014

Duplication of Genes in an ATP-binding Cassette Transport System Increases Dynamic Range While Maintaining Ligand Specificity

Many bacteria exist in a state of feast or famine where high nutrient availability leads to periods of growth followed by nutrient scarcity and growth stagnation. To adapt to the constantly changing nutrient flux, metabolite acquisition systems must be able to function over a broad range. This, however, creates difficulties as nutrient concentrations vary over many orders of magnitude, requiring metabolite acquisition systems to simultaneously balance ligand specificity and the dynamic range in which a response to a metabolite is elicited. Here we present how a gene duplication of a periplasmic binding protein in a mannose ATP-binding cassette transport system potentially resolves this dilemma through gene functionalization. Determination of ligand binding affinities and specificities of the gene duplicates with fluorescence and circular dichroism demonstrates that although the binding specificity is maintained the Kd values for the same ligand differ over three orders of magnitude. These results suggest that this metabolite acquisition system can transport ligand at both low and high environmental concentrations while preventing saturation with related and less preferentially metabolized compounds. The x-ray crystal structures of the β-mannose-bound proteins help clarify the structural basis of gene functionalization and reveal that affinity and specificity are potentially encoded in different regions of the binding site. These studies suggest a possible functional role and adaptive advantage for the presence of two periplasmic-binding proteins in ATP-binding cassette transport systems and a way bacteria can adapt to varying nutrient flux through functionalization of gene duplicates.

The effect of addition of different concentrations of sugar and honey in physical, chemical and sensory parameters of low-fat frozen yogurt.

<p>The appeal of consumers for different products is a reflex of much information about alimentary market. The present work had as objective to produce low fat probiotic frozen yogurt in different concentrations of honey to substitute part of sugar in order to find out the effect of this variable in the physicochemical and sensory characteristics of the final product. In order to prepare the frozen yogurt, skimmed milk, glucose, sugar, honey, skimmed powder milk, powder whey, modified starch, thicken additive, neutral mixture, emulsifier and blended culture of <em>Lactobacillus acidophilus, Bifidobacterium ssp and Lactobacillus casei </em>were used. From a central rotational delineation compound, eleven formulas were defined for the study, having as variables the addiction of sugar and honey in two treatments, base and sauce, using the response surface methods. The samples were examined for the concentrations of total solids, fat, proteins, pH, acidity, simpler carbohydrates, overrun and sensorial evaluation to be checked through the acceptance tests and purchase intention of the consumers. Among all the analysis, only reducing simpler carbohydrates and the sensory tests differed significantly (p ≤ 0.05), proving the influence of honey in the evaluated parameters. It is possible to produce icy edible food with reduced fat value without interfering in the identity and quality standards established by the Brazilian legislation. The honey performed negative effect in the acceptance of the product showing to be doable only when added in the sauce with a maximum proportion of 2.0 %.</p><p> </p><p>DOI: http://dx.doi.org/10.14685/rebrapa.v3i2.79</p>

New development of Pasteurised Roselle (Hibiscus sabdariffa L. 'UKMR-2) pickles

The limited utilization of roselle in food products had encouraged this study to be done. This study was conducted to develop the most acceptable pickling formulation for roselle pickles. Sensory evaluation was conducted on six pickling formulations which involved different concentration of sugar (30, 40 and 50 °Brix) and acidity (0.5 and 1.0%). Sensory attributes evaluated were colour, aroma, texture, sweetness and sourness, and overall acceptability. The formulation C (50 °Brix, 0.5% acidity) was the best formulation in terms of texture and it was used for preparation of fresh pasteurized, fresh unpasteurized, stored pasteurized and stored unpasteurized pickles, and then proceeded with physico-chemical (pH, ascorbic acid, anthocyanin, energy, ash, fiber, protein, and texture) and microbiological analysis. From fresh calyces to pickles, there were significant increased (p 0.05) in energy and protein content. Microbial counts found in all samples were under safe limit. Since there are not much difference in the physico-chemical and microbiological properties of pasteurized and unpasteurized roselle pickles, for both fresh and stored, therefore pasteurization process is not a necessary step in the production of roselle pickles.

Neuronal and grey modelling of milk drying in spouted bed

AbstractThe chemical composition of pastes is one of the factors responsible for the behaviour of the paste during the drying process in spouted bed. Therefore, the aim of this study was to analyse the drying process of paste in spouted bed for four types of milk: whole, skimmed, semi‐skimmed and low lactose content milk, which have different concentrations of sugar and fat. A neuronal model was proposed in order to describe the influence of the presence of pastes on the spouted bed fluid dynamics. The change of moisture content of the powder during the drying process and of the heat and mass transfer phenomena were estimated using a hybrid model based on the global balance of mass and energy and a phase‐coupling term given by a neural network.

Ideal sweetness of mixed juices from Amazon fruits

Ready-to-drink fruit juices represent a large share of the market and are an important target for product development. The mixture of fruits can bring about improvements to nutritional and sensory aspects of these beverages while making used of the wide variety of exotic fruits from the Amazon region. Therefore, it is necessary to select mixed fruits and determine their ideal sweetness according to consumer acceptance. Consumers in the city of Belém (Brazil) evaluated five different concentrations of sugar using the just-about-right scale in two blends selected by preference ranking. For the cupuassu-acerola-açai blend, the optimum concentration of sugar was 9.5 g/100 mL, and for the soursop-camucamu-yellow mombin blend, it was 10.7 g/100 mL.

Enhancing Thermal Stability of Immobilized Raw Starch Digesting Amylase (RSDA)Using Different Additives

Enhancing Thermal Stability of Immobilized Raw Starch Digesting Amylase (RSDA) Using Different Additives Industrial and large scale applications of biocatalysts are often limited by lack of thermostability. Raw starch digesting amylase(RSDA) of Aspergillus carbonarius was immobilized on cyanogen bromide to facilitate mild covalent attachment. To improve thermal stability of immobilized and soluble RSDA different concentrations of sugar (trehalose) and polyols (polyethylene glycol, glycerol and mannitol) under varying conditions; temperature, pH and buffer ionic strength was studied.

Use of granulated sugar therapy in the management of sloughy or necrotic wounds: a pilot study

To determine the in vitro antimicrobial efficacy of three types of sugar and conduct a pilot clinical study with a view to developing a protocol for a randomised controlled trial (RCT). In the in vitro studies three types of granulated sugar (Demerara, granulated beet sugar and granulated cane sugar) were tested to determine their minimum inhibitory concentrations (MICs) against 18 Gram-negative and Gram-positive bacteria in a micro-titre broth dilution assay; growth inhibition of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa in different concentrations of sugar (0.38-25%) was also tested over 12-hours in an agar diffusion assay. The pilot clinical study selected patients from a vascular surgical ward and a vascular outpatient department. All had acute or chronic exuding wounds, some of which were infected. White granulated sugar was applied to the wounds. The following parameters were assessed: surface area; wound characteristics including pain, malodour, appearance (slough/granulation); exudate level; pain level and bacterial load. Patients with diabetes had their blood sugar levels checked daily. All patients completed a short health questionnaire at the start and end of the study. Staff completed a satisfaction questionnaire at the end of the study. The study period was 21 days. In vitro tests demonstrated that sugar inhibits bacterial growth. All three types of sugars had MICs ranging from 6-25% in the bacterial strains tested. The diffusion tests showed that strains were able to grow well in low concentrations of sugar but were completely inhibited in higher concentrations. The two granulated sugars were found to be slightly more effective than Demerara sugar, so the latter was excluded from the clinical pilot study. Twenty-two patients (20 inpatients and two outpatients) with sloughy or necrotic wounds were recruited into the clinical study. Two patients had MRSA and two had Staphylococcus colonisation at baseline. Blood sugar levels remained stable in the seven patients with insulin-dependent diabetes mellitus. All wounds were clean/debrided in a mean of 11.13 days. Pain and malodour reduced markedly. Patient and staff surveys revealed overwhelming support for the sugar therapy. The pilot study achieved its aim of developing a protocol for a RCT. Preliminary data suggest that sugar is an effective wound cleansing and is safe to use in patients with insulin-dependent diabetes. In vitro studies demonstrate that sugar inhibits bacterial growth. None.

Digestive efficiency of Knysna and purple-crested turacos fed varying concentrations of equicaloric and equimolar artificial fruit

Avian frugivores have been somewhat poorly studied with regards to the effects that different fruit sugar types and concentrations have on their digestive efficiencies. Therefore, two relatively large South African frugivores, the Knysna turaco (Tauraco corythaix) and the purple-crested turaco (Gallirex porphyreolophus), were fed artificial fruit that contained equicaloric and equimolar concentrations of different sugars, to determine their daily food and energy intake, digestive efficiencies and digestive transit times. The artificial fruit contained 6.6, 12.4 or 22%, or 0.42, 0.83 or 1.66 mol l(-1) sucrose or glucose. Food intake of both turaco species increased with decreasing sugar concentration and molarity, irrespective of sugar type, suggesting compensatory mechanisms for energy requirements. Apparent assimilation efficiencies of both turaco species ranged from 61.4-90.0% and 60.2-92.4% for equicaloric and equimolar artificial fruit diets, respectively. Digestive transit times for both turaco species were slowed with an increase in sugar concentration and molarity, irrespective of sugar type. Consequently these two frugivores appear to be tolerant of sugar type and would be expected to select fruits based on energy yields. Future studies of the composition of indigenous forest fruit sugars may give insight into food preferences of the turaco species and their role as potential seed dispersers of fruiting tree species.

Controlled germination to enhance the functional properties of rice

The production of prebiotic oligosaccharides during germination of rice has been investigated. Germination of waxy (RD6) and non-waxy (RD17) rice was compared by evaluating the total reducing sugars, free amino nitrogen, pH and enzyme activities over a 7-day period. An increment of amylolytic enzymes and chemical changes were observed in both varieties. RD6 showed higher levels of total reducing sugars and also higher amylolytic activities including α-amylase and α-glucosidase, which reached maximum values at the third day of germination. However, the amount of free amino nitrogen in RD6 was lower than in RD17. Sugar analysis indicates that RD6 produces higher concentration of sugars and oligosaccharides during germination. Based on these results, germinated RD6 at different times was used to produce malted rice syrup through mashing. After saccharification, the malted rice syrup contained different concentrations of sugars and oligosaccharides, particularly isomaltose, panose and isomaltotriose, which have been reported to have prebiotic properties.

Changes in physical and thermo-physical properties of sugarcane, palmyra-palm and date-palm juices at different concentration of sugar

The process of making jaggery from three natural juices by boiling could be divided into three zones: rise in temperature to boiling (Zone I), slow rise in both boiling temperature and total soluble solids (TSS) (Zone II) followed by rapid rise in boiling temperature with concomitant increase in viscosity and TSS (Zone III). The juice samples in Zone III exhibited changes in boiling temperature, viscosity and TSS from 105 to 121 °C, 4.5 to 988 mPa s and 54.6 to 81.9 (% w/w) for sugarcane ( Saccharum officinarum); from 104 to120 °C, 41.6 to 559 mPa s and 46 to 81 (% w/w) for palmyra-palm ( Borassus flabellifer L.); and from 103 to 121 °C, 22.9 to 417 mPa s and 51 to 81 (% w/w) for date-palm ( Phoenix sylvestris L.). Colour change Δ E Δ ( % w / w ) was rapid in Zone III. Difference in colour among these jaggery samples might be attributed to amount of reducing sugars present initially and respective changes in properties during juice concentration.

Preservation of Cauda Epididymis in Powder of Salt or Sugar at Room Temperature.

The generally accepted method for sperm preservation is by freezing in liquid nitrogen at -196 EC. However, this requires a constant replacement of liquid nitrogen for long-term preservation. Development of preservation techniques for male gametes at room temperature would allow us to store them with a simple and cost-effective manner. It has been known that food can be preserved in salt for long periods at room temperature. Therefore, in this study, we have tried to develop a new sperm preservation method at room temperature using a powder of salt and sugars. Whole cauda epididymides of mature B6D2F1 mouse were placed directly in a powder of pure salt (NaCl), sugars (glucose, raffinose or trehalose) or without any additives (untreated control) for 1 day to 1 month, at room temperature. Epididymides were then rehydrated with Hepes-CZB or NIM medium for 15 min at 4EC, and the sperm were collected by disrupting the epididymis using tweezers. In some experiments, cauda epididymides were gradually dehydrated using different concentrations of sugars in water, to avoid the rapid water replacement damage, and rehydration time was extended to avoid insufficient rehydration. The quality of stored spermatozoa was evaluated by their oocyte activation capacity and developmental potential after intracytoplasmic sperm injection (ICSI). When the cauda epididymis was stored for 1 week, there were no significant differences in the oocyte activation capacity of spermatozoa when compared to the fresh control, irrespective of storage conditions (stored: n= 533, fresh: n= 328; 88 to 100% vs 98%). However, when the cauda epididymis was stored for 1 month, the rate of activated oocytes decreased significantly in the untreated control (n= 130; 5%), whereas the cauda epididymis stored in salt or sugar showed that most spermatozoa still retained oocyte activation capacity after ICSI (n= 251; 83 to 95%). Activated oocytes formed male and female pronuclei which appeared normal and extrudes a second polar body 6 h after ICSI. We also examined pronuclear morphology and methylation status of histone H3 lysine 9 (H3K9) in zygotes by immunofluorescence staining, but we did not observe any differences between zygotes fertilized with stored and fresh spermatozoa (stored: n= 71, fresh: n= 30). However, the developmental ability of zygotes generated by ICSI using stored sperm showed a significant decrease. When epididymides were stored in glucose or raffinose for 1 day at room temperature, only 2% and 17% of embryos developed to blastocyst (glucose: n= 203, raffinose: n= 132), and after transfer into recipient females, only 1% and 7 % of them developed to full term (glucose: n= 208, raffinose: n= 182), respectively. However, when epididymides were stored for 1 month in glucose or raffinose, or stored in salt or trehalose for 1 day, none of embryos developed to the blastocyst stage. This could not be improved even when the epididymis was dehydrated gradually (n= 162) and rehydration time was extended (n= 259). We examined the cause of developmental arrest in embryos injected with sperm stored for 1 day and found that 100% (NaCl) or 87.8% (glucose) embryos showed aberrant chromosome segregation at the 2-cell stage (fresh: 7%). In conclusion, although the activation factor(s) is maintained in sperm preserved with salt or sugar for at least 1 month at room temperature, their developmental capacity were lost due to the abnormal distribution of the chromosomes.

Effect of Different Sugars on Shoot Induction in CV. Basmati

Effect of various concentrations of different sugars was investigated for induction of root and shoot from basmati rice. Explant, seeds (grains) were transferred in ½ MS basal media fortified with different concentrations of carbon source like sucrose, maltose, and dextrose. In vitro regenerated rice plantlets were healthy and attained a length of 16.17cm at 0.25 % concentration within a week. Only low concentration (0.25%) of dextrose exhibited the maximum shoot and root growth, out of three sugars. Maltose showed the moderate growth response of shoot and root length in all the concentrations.

Quantitative and Qualitative Aspects of Dissolved Organic Carbon Leached from Senescent Plants in an Oligotrophic Wetland

We conducted a series of experiments whereby dissolved organic matter (DOM) was leached from various wetland and estuarine plants, namely sawgrass (Cladium jamaicense), spikerush (Eleocharis cellulosa), red mangrove (Rhizophora mangle), cattail (Typha domingensis), periphyton (dry and wet mat), and a seagrass (turtle grass; Thalassia testudinum). All are abundant in the Florida Coastal Everglades (FCE) except for cattail, but this species has a potential to proliferate in this environment. Senescent plant samples were immersed into ultrapure water with and without addition of 0.1% NaN3 (w/ and w/o NaN3, respectively) for 36 days. We replaced the water every 3 days. The amount of dissolved organic carbon (DOC), sugars, and phenols in the leachates were analyzed. The contribution of plant leachates to the ultrafiltered high molecular weight fraction of DOM (>1 kDa; UDOM) in natural waters in the FCE was also investigated. UDOM in plant leachates was obtained by tangential flow ultrafiltration and its carbon and phenolic compound compositions were analyzed using solid state 13C cross-polarization magic angle spinning nuclear magnetic resonance (13C CPMAS NMR) spectroscopy and thermochemolysis in the presence of tetramethylammonium hydroxide (TMAH thermochemolysis), respectively. The maximum yield of DOC leached from plants over the 36-day incubations ranged from 13.0 to 55.2 g C kg−1 dry weight. This amount was lower in w/o NaN3 treatments (more DOC was consumed by microbes than produced) except for periphyton. During the first 2 weeks of the 5 week incubation period, 60–85% of the total amount of DOC was leached, and exponential decay models fit the leaching rates except for periphyton w/o NaN3. Leached DOC (w/ NaN3) contained different concentrations of sugars and phenols depending on the plant types (1.09–7.22 and 0.38–12.4 g C kg−1 dry weight, respectively), and those biomolecules comprised 8–34% and 4–28% of the total DOC, respectively. This result shows that polyphenols that readily leach from senescent plants can be an important source of chromophoric DOM (CDOM) in wetland environments. The O-alkyl C was found to be the major C form (55±9%) of UDOM in plant leachates as determined by 13C CPMAS NMR. The relative abundance of alkyl C and carbonyl C was consistently lower in plant-leached UDOM than that in natural water UDOM in the FCE, which suggests that these constituents increase in relative abundance during diagenetic processing. TMAH thermochemolysis analysis revealed that the phenolic composition was different among the UDOM leached from different plants, and was expected to serve as a source indicator of UDOM in natural water. Polyphenols are, however, very reactive and photosensitive in aquatic environments, and thus may loose their plant-specific molecular characteristics shortly. Our study suggests that variations in vegetative cover across a wetland landscape will affect the quantity and quality of DOM leached into the water, and such differences in DOM characteristics may affect other biogeochemical processes.

Investigation of the properties of decaoxyethylene n‐dodecyl ether, C12E10, in the aqueous sugar‐rich region

AbstractInterfacial, thermodynamic, and morphological properties of decaoxyethylene n‐dodecylether [CH3 (CH2)11(OCH2CH2)10OH](C12E10) in aqueous solution were analyzed by tensiometric, viscometric, proton nuclear magnetic resonance (NMR), and small‐angle neutron scattering (SANS) techniques. Dynamic and structural aspects at different temperatures in the absence and presence of sugars at different concentrations were measured. Critical micelle concentrations (CMC) were determined by surface tension measurements in the presence of ribose, glucose, and sucrose. The heat capacity (ΔCp.m.), transfer enthalpy (ΔHm.tr.), transfer heat capacities (ΔCp.m.tr.), micellization constant (Km), Setchenow constant (KSN), and partition coefficient (q) were determined and discussed as an extension of the usual thermodynamic quantities of micellization and adsorption at the air‐water interface. An enthalpy‐entropy compensation effect was observed with an isostructural temperature (Tc) of about 310 K for both micellization and interfacial adsorption. SANS measurements were taken to elucidate structural information, viz., aggregation number (Nagg), shape, size, and number density (Nm) on C12E10 micelles in D2O at different concentrations of sugars (0.05, 0.02, 0.3, and 0.5 M) and temperatures (30, 45, and 60°C). Intrinsic viscosity gave the hydrated micellar volume (Vh), volume of the hydrocarbon core (Vc), and volume of the palisade layer of the oxyethylene (OE) unit (VOE). SANS, as well as rheological data, supported the formation of nonspherical micelles with or without sugars. By SANS, we also observed that at the studied temperature intervals, oblate ellipsoid micelles changed into prolate ellipsoids and the number density of micelles decreased with an increase in temperature both in the presence and in the absence of sugars and also on increasing the concentration of sugars. Proton NMR showed a change in chemical shift of the OE group of micelles above the CMC. We also studied the phase separation of C12E10 by sugars in cloud point measurements.

Influence of starter cultures and sugar concentrations on biogenic amine contents in chorizo dry sausage

The production of biogenic amines in chorizo dry sausage by using different decarboxylase negative starter cultures and different concentrations of sugar added in its manufacture has been studied. Biogenic amines were determined as dansyl derivates by high-performance liquid chromatography (HPLC). Putrescine and tyramine were the most significant biogenic amines in the final product, followed by cadaverine and tryptamine. The highest concentrations of biogenic amines were found at the end of the ripening process in the control sausage with no starter culture irrespective of the use of different sugar concentrations. However, when a starter culture and sugar concentrations equal to 0.5% or 1% were used, the presence of biogenic amines in the sausage decreased considerably in comparison with control and low sugar concentration chorizos. Among all starter cultures tested Lactobacillus sakei K29 was really efficient in reducing the amine production since this strain caused a quick pH drop during sausage fermentation. On the other hand, the production of high amounts of putrescine (223–252 mg/K) and tyramine (64–102 mg/K) was not avoided when the concentration of sugar in the sausage was only 0.1%, even in sausages with a starter culture. Therefore, the use of decarboxylase negative lactic acid bacteria as starter cultures, which produces a rapid decrease on the pH of the meat mixture, and the use of a sugar concentration (mainly glucose) in a range of 0.5–1%, are two important factors to be considered in order to reduce the levels of biogenic amines in chorizo dry sausage.