Chrysosporium species, potential spoilage organisms of chocolate

Standard methods of analysing foods for the presence of moulds are inadequate for thedetection of genera such as Chrysosporium which do not grow at the high wateractivities of most mycological media. The use of malt, yeast, 50% glucose agar (MY50G) insealed containers as an enrichment medium allowed time for germination and growth ofheat-stressed spores. Three Chrysosporium spp., C. xerophilum Pitt, C. inops (Carmichael) and C. farinicola (Burnside) Skou, were isolated fromcommercial chocolate bars with a water activity (a _w ) of approximately0·28. Chrysosporium inops was isolated from commercial milk crumb and anew Chrysosporium sp. was isolated from Ghanaian cocoa beans. In chocolates madeby coating MY50G agar (a_w = 0·89) with chocolate (a_w = 0·27) containing C. inops arthroconidia, two types of deterioration were seenafter storage. The first was fat bloom due to recrystallization of the cocoa butter on the outer andinner chocolate surface. The second was growth of C. inops which occurred on theinside chocolate surface adjacent to the MY50G agar filling and on the outside surface afterholding at 92% equilibrium relative humidity (erh) for 12 d. There was some evidence that C. inops could grow on the outside of chocolates held at 5·7% erh after 4months' storage at 25 °C. The appearance of the white fungal growth was not unlikefat bloom to the naked eye but was clearly different with the electron microscope.     

Crystallization Kinetics and Mechanical Properties of Nougat Creme Model Fats

Fat crystal networks result from a crystallization process, forming interlinked crystal aggregates of viscoelastic character. Palm oil-based fat crystal networks, such as chocolate and nougat spreads, often show liquid oil separation during storage because the fat crystal network is too weak to retain the liquid oils trapped within its structure. To explore the relationship between crystallization kinetics and subsequent mechanical properties, i) palm oil from three different geographical origins and with diverging crystallization properties, ii) mixtures of Ghanaian palm oil with gradually increasing additions of hazelnut oil, and iii) blends of Ecuadorian palm oil with palm stearin as a tripalmitin (PPP)-rich fraction were investigated. Kinetic parameters were acquired from an extended Avrami model by isothermal differential scanning calorimetry measurements, and the results combined with the elastic properties measured by oscillation rheology since studying crystallization kinetics alone insufficiently informs about the mechanical/structural properties needed to overcome liquid oil separation. Rate constants of all investigated fats followed bell-shaped curves, with curve progression strongly dependent on the lipid composition. Ameliorating crystallization properties entailed enhanced elastic properties. The higher the maximum rate constants, the higher the elastic modulus and the gel rigidity of the respective fats. However, two different linear regions of elastic modulus versus PPP or solid fat content resulted, depending on whether palm oil was diluted with hazelnut oil or blended with a PPP-rich fraction. Hazelnut oil strongly diluted crystallizable portions of the structuring fat, thereby decreasing the mechanical properties in a power-law fashion, because the fat crystal network became less connected between fat crystal aggregates.

     

The effects of low fat chocolate milk on postexercise recovery in collegiate athletes

Spaccarotella, KJ and Andzel, WD. The effects of low fat chocolate milk on postexercise recovery in collegiate athletes. J Strength Cond Res 25(12): 3456-3460, 2011-Drinking chocolate milk between exercise sessions may improve recovery. The purpose of this study was to examine the effects of low fat chocolate milk vs. a carbohydrate-electrolyte beverage (CE) on recovery between preseason practice sessions among 5 male and 8 female Division III soccer players. The study used a randomized crossover design: between morning and afternoon practices, athletes received either an amount of chocolate milk that provided 1 g carbohydrate per kilogram body weight or an equal volume of CE (mean volume of 615 ± 101 ml). After their afternoon practice, they completed a shuttle run to fatigue. Data were analyzed using the Wilcoxon paired rank-sign test (for shuttle run time) and the paired samples t-test (for dietary intake). No significant differences in run time were reported for the group. For the men only, there was a trend of increased time to fatigue with chocolate milk compared with the CE (exact p = 0.03). Low fat chocolate milk may therefore be as good as a CE at promoting recovery between training sessions during preseason.     

Quantification of oil binding capacity of structuring fats: A novel method and its application

A robust, well-defined and reproducible method to accurately measure the oil binding capacity (OBC) of structuring fats was developed. The method was validated using two oil/fat model systems, i.e., fully hydrogenated canola oil (FHCO) in canola oil (CO) (FHCO/CO) and fully hydrogenated soybean oil (FHSO) in CO (FHSO/CO). The mixtures were crystallized from the melt down to three different temperatures (15, 25 and 35 °C) at constant rates of cooling and the OBC was measured after different periods of storage time. The critical concentration of hard fat at which the solid fat network is stable and effectively binds oil has been also measured for mixtures crystallized at temperatures close to room temperature, i.e., 25 °C. Crystal structure, melting behavior, microstructure, and solid fat content of these binary systems have been investigated in relation to the OBC of the solid fat network using X-ray diffraction (XRD), differential scanning calorimetry (DSC), polarized light microscopy (PLM), and wide-line pulsed nuclear magnetic resonance (pNMR) techniques. The two model systems exhibited similar trends in OBC over time, a behavior attributed to their similar TAG composition and polymorphism. However, relatively smaller OBC values were achieved by the CO/FHSO compared to CO/FHCO samples, largely due to differences in their solid network structure. Four successive decreasing linear segments, identifying successive mechanisms of oil migration/binding, were observed in the experimental OBC versus fat weight fraction curves. The critical concentration of hard fat, at which the solid fat network is effective in binding oil, was also determined and found to be ～6 wt% for both systems.     

Presence of the cannabinoid receptors, CB1 and CB2, in human omental and subcutaneous adipocytes

To investigate the expression of the endocannabinoid 1 and 2 receptors by human adipocyte cells of omental and subcutaneous fat tissue, as well as to determine whether these receptors are functional. The expression of CB1 and CB2 receptors on human adipocytes was analyzed by western blotting, immunohistology and immunocytology. We also investigated intracytoplasmic cyclic AMP level modulation following CB1 and CB2 receptor stimulation by an enzymatic immuno assay. All mature adipocytes, from visceral (epiploon) and subcutaneous fat tissue, express CB1 and CB2 on their plasma membranes. We also demonstrate in this study that adipocyte precursors (pre-adipocytes) express CB1 and CB2 on their plasma membranes and that both receptors are functional. Activation of CB1 increases intracytoplasmic cyclic AMP whilst CB2 activation leads to a cyclic AMP decrease. Here we demonstrate, for the first time, that adipocytes of human adipose tissue (mature adipocytes and pre-adipocytes) express functional plasma membrane CB1 and CB2 receptors. Their physiological role on the adipose tissue is not known. However, their major involvement in the physiology of other tissues leads us to suppose that they could play a significant role in the homeostasis of the energy balance and/or in the regulation of adipose tissue inflammation.     

Food Intake‐independent Effects of CB1 Antagonism on Glucose and Lipid Metabolism

Overactivity of the endocannabinoid system (ECS) has been linked to abdominal obesity and other risk factors for cardiovascular disease and type 2 diabetes. Conversely, administration of cannabinoid receptor type 1 (CB1) antagonists reduces adiposity in obese animals and humans. This effect is only in part secondary to the anorectic action of CB1 agonists. In order to assess the actions of CB1 antagonism on glucose homeostasis, diet‐induced obese (DIO) rats received the CB1 antagonist rimonabant (10 mg/kg, intraperitoneally (IP)) or its vehicle for 4 weeks, or were pair‐fed to the rimonabant‐treated group for the same length of time. Rimonabant treatment transiently reduced food intake, while inducing body weight loss throughout the study. Rats receiving rimonabant had significantly less body fat and circulating leptin compared to both vehicle and pair‐fed groups. Rimonabant, but not pair‐feeding, also significantly decreased circulating nonesterified fatty acid (NEFA) and triacylglycerol (TG) levels, and reduced TG content in oxidative skeletal muscle. Although no effects were observed during a glucose tolerance test (GTT), rimonabant restored insulin sensitivity to that of chow‐fed, lean controls during an insulin tolerance test (ITT). Conversely, a single dose of rimonabant to DIO rats had no acute effect on insulin sensitivity. These findings suggest that in diet‐induced obesity, chronic CB1 antagonism causes weight loss and improves insulin sensitivity by diverting lipids from storage toward utilization. These effects are independent of the anorectic action of the drug.     

Cocoa butter-like lipid production ability of non-oleaginous and oleaginous yeasts under nitrogen-limited culture conditions

Applied Microbiology and Biotechnology - Cocoa butter (CB) extracted from cocoa beans is the main raw material for chocolate production. However, growing chocolate demands and limited CB production...     

TEMPORAL ASPECTS OF HEDONIC RESPONSES1

Continuous measurement of degree of liking for chocolate milk varying in milkfat (0–36%) showed significant fluctuations over the 80 s test period. For 17 judges, samples with intermediate fat levels received maximum liking 20–30 s after placement in the mouth then declined to neutral (neither like nor dislike). The nonfat sample gave a flat, neutral response across time while the 36% fat sample was initially neutral, reached maximum dislike at approximately 20 s then gradually returned to neutral. For 5 judges, increasing degree of liking was expressed for increasing fat levels. For both groups, maximum and minimum time-intensity (T-I) measurements correlated significantly with results from conventional hedonic scaling on a 20-cm line. Degree of liking was unaffected by swallowing or expectorating samples by either T-I or scaling. Thus, similar to perceived intensity, hedonic responses are not static, but show systematic changes during tasting, i.e., from the time the sample is placed into the mouth, through expectoration (or swallowing) until a steady (usually neutral) state is reached.     

Effect of Crystallization State on the Gel Properties of Oleogels Based on β-sitosterol

Oleogels based on three different oils (sunflower oil, solid coconut oil and liquid coconut oil) were formulated using β-sitosterol. In general, an observed increase in crystallinity was correlated with an increase in the gel storage modulus and hardness. Addition of lecithin promoted the formation of needle-like crystals of β-sitosterol with a corresponding increase in strain tolerance and oil-trapping capacity for oleogels produced with liquid oils. However, the incorporation of β-sitosterol crystals with or without lecithin into oleogels containing solid coconut oil reduced its strain tolerance by interrupting the formation of continual radiolitic crystal structures. The use of sunflower oil (long chain fatty acids) was more favourable to the packing and growth of gelator crystals and the formation of an elastic gel, in comparison to liquid coconut oil (short chain fatty acids). Overall, the type and physical state of oil influence the formation of oil crystal network, thus affecting its gel properties. These findings allow the better understanding of β-sitosterol-based oleogels, providing opportunity to design for the application as a fat-replacer and lowering solid fat content.

     

Coxsackievirus B3 adapted to growth in RD cells binds to decay-accelerating factor (CD55).

A coxsackievirus B3 (CB3) isolate adapted to growth in RD cells shows an alteration in cell tropism as a result of its capacity to bind a 70-kDa cell surface molecule expressed on these cells. We now show that this molecule is the complement regulatory protein, decay-accelerating factor (DAF) (CD55). Anti-DAF antibodies prevented CB3 attachment to the cell surface. Radiolabeled CB3 adapted to growth in RD cells bound to CHO cells transfected with human DAF, whereas CB3 (strain Nancy), the parental strain, did not bind to DAF transfectants. These results indicate that growth of CB3 in RD cells selected for a virus strain that uses DAF for cell surface attachment.     

A continuous culture study of the phosphorus nutrition of Rhizobium trifollii WU95, Rhizobium NGR234 and Bradyrhizobium CB756

With continuous cultures in a fully defined minimal salts medium steady states were achieved at both limiting and non-limiting concentrations of phosphate in the inflowing medium for Rhizobium trifolii WU95, cowpea Rhizobium NGR234, and Bradyrhizobium CB756.Millimolar growth yields obtained from P-limited cultures varied over 2-fold from 3.2 g dry weight·(mmol P)^-1 for WU95 to 5.3 g dry weight·(mmol P)^-1 for CB756 and 7.2 g dry weight·(mmol P)^-1 for NGR234.For both WU95 and NGR234 growth under P-excess conditions resulted in elevated levels of total biomass P and the storage compound polyphosphate, compared with P-limited cultures. However, P-limited cultures of these two strains still contained significant quantities of polyphosphate. The P-status for CB756 cultures did not affect either total biomass P or polyphosphate levels. Alkaline phosphatase was maximally derepressed in P-limited cultures of WU95 and NGR234. However, in CB756 alkaline phosphatase was not detected at significant levels regardless of its P supply.These data suggest that growth of rhizobia is controlled predominantly by the attainment of a critical internal P level.Abbreviation HEPES N-2-hydroxyethylpiperazine-N-2-ethane sulphonic acid     

Attenuated response of the serum triglyceride concentration to ingestion of a chocolate containing polydextrose and lactitol in place of sugar

We examined the effects of ingesting a non-sugar chocolate containing polydextrose and lactitol in place of sucrose and lactose on the concentrations of plasma glucose and serum insulin and triglyceride in humans. A regular chocolate was used as the control. A crossover study was employed, and the subjects each ingested 46 g of the control or non-sugar chocolate in the experiments. Alterations in the blood components were monitored for a period of 150 min after ingestion. The control chocolate elevated the concentrations of plasma glucose and serum insulin, with the peak occurring 30 min after ingestion, but the non-sugar chocolate had a very minor effect. The serum triglyceride concentration gradually increased after ingesting the control chocolate, but was only slightly elevated 150 min after ingesting the non-sugar chocolate. An animal study also showed an attenuated response of serum triglyceride to the administration of a fat emulsion containing polydextrose and lactitol, suggesting that the triglyceride transit through the gut was promoted by these compounds. These results suggest that, compared to regular chocolate, fat absorption in the gut was less after ingesting the non-sugar chocolate, presumably resulting in less effect on body fat deposition.     

Changes in the titer of the female-predominant storage protein (81K) during larval and pupal development of the waxmoth,galleria mellonella

The levels of an 81K storage protein in the waxmoth, Galleria mellonella, were monitored during the course of development using rocket immunoelectrophoresis. During the fifth and sixth larval stadia, 81K protein levels increased during feeding and growth but sharply declined at each larval molt. During the fifth and sixth stadia hemolymph levels of the 81K protein increased to about 1 and 2.5 mg/ml, respectively, with no discernible differences between levels in males and females. Neither the fat body nor the remainder of the carcass contained the 81K protein, indicating that the accumulation of this protein during the intermolt period was exclusively in the hemolymph and redistribution of the 81K protein into other tissues does not occur at the final two larval molts. During the seventh (final) larval stadium the absolute quantities of the 81K protein increased from 23 μg per insect to over 1,600 μg in females and to 300 μg in males. The hemolymph concentration of the 81K protein reached 28 mg/ml in females and 6 mg/ml in males with only low levels found in the remaining tissues. Shortly after pupal apolysis, marked by eyespot retraction, the fat body in both sexes rapidly and quantitatively sequestered the 81K protein from the hemolymph. The 81K protein in the hemolymph of both males and females rapidly dropped to nearly zero concentration by pupation. The 81K storage protein remained localized in the fat body cells after uptake occurred, even though the fat body cells disaggregate and reaggregate during metamorphosis. During pharate adult development the 81K storage protein disappeared from the fat body without entering the hemolymph. At adult eclosion 81K was virtually absent from the tissues of both males and females.     

Parasitic versus nutritional regulation of natural fish populations

Although parasites are expected to affect their host's fitness, quantitative proof for impacts of parasitism on wild populations is hampered by confounding environmental factors, including dietary resource. Herein, we evaluate whether the physiological conditions of European perch (Perca fluviatilis) in three large peri‐alpine lakes (Geneva, Annecy, and Bourget) depend on (a) the nutritional status of the juvenile fish, as revealed by stable isotope and fatty acid compositions, (b) the prevalence of the tapeworm Triaenophorus nodulosus, a parasite transmitted to perch through copepod preys, or (c) interactive effects of both factors. At the scale of lake populations, the deficit in growth and fat storage of juvenile perch during their first summer coincides with a high parasite prevalence and also a low quality of dietary resource. Yet, at the individual level, parasites had no evident effect on the growth of the juvenile perch, while impacts on fat storage appeared only at the highest prevalence of the most infected lake. Fatty acid and stable isotope analyses of fish tissue do not reveal any impact of T. nodulosus on diet, physiology, and feeding behaviour of fish within lakes. Overall, we found a low impact of parasitism on the physiological condition and trophic status of juvenile perch at the end of their first summer. We find instead that juvenile perch growth and fat storage, both factors tied to their winter survival, are under strong nutritional constraints. However, the coinciding nutritional constraints and parasite prevalence of perch juveniles in these three lakes may result from the indirect effect of lake nutrient concentrations, which, as a major control of zooplankton communities, simultaneously regulate both the dietary quality of fish prey and the host–parasite encounter rates.     

The effect of a lipid-lowering diet on plasma lipids and lipoproteins in mildly hypercholesterolaemic subjects: a potential role for occasional treats

The aim of the study was to compare the effect of a lipid-lowering diet containing chocolate confectionery with an equivalent diet that is chocolate-free. In a parallel design trial, 42 free-living subjects (19 men and 23 women), aged 46.9 yr, mildly hypercholesterolemic (6.9 mmol/L) were allocated to an American Heart Association/National Cholesterol Education Program Step 1 diet that included chocolate confectionery or an identical regimen containing no chocolate. Blood samples for the analysis of plasma lipids were obtained initially, then at 6 and 12 weeks after dietary therapy. Both groups of subjects showed a trend toward a reduction in saturated fat, with those allowed chocolate reaching borderline significance (P < 0.057). Plasma cholesterol and low density lipoprotein cholesterol concentrations were significantly lower (P < 0.03) whereas plasma triacylglycerol was significantly higher (P < 0.02) in the control group compared with the chocolate group. High density lipoprotein cholesterol was reduced in both groups. Subgroup analysis on patients with the apo E3/E3 phenotype showed that the response was identical between the control and chocolate groups. The inclusion of a modest amount of chocolate confectionery did not detract from the response of a lipid-lowering diet.     

Cytochalasin B slows but does not prevent monomer addition at the barbed end of the actin filament

We used Limulus sperm acrosomal actin bundles to examine the effect of 2 microM cytochalasin B (CB) on elongation from both the barbed and pointed ends of the actin filament. In this paper we report that 2 microM CB does not prevent monomer addition onto the barbed ends of the acrosomal actin filaments. Barbed end assembly occurred over a range of actin monomer concentrations (0.2-6 microM) in solutions containing 75 mM KCl, 5 mM MgCl2, 10 mM Imidazole, pH 7.2, and 2 microM CB. However, the elongation rates were reduced such that the rates at the barbed end were approximately the same as those at the pointed end. The association and dissociation rate constants were 8- to 10-fold smaller at the barbed end in the presence of CB along with an accompanying twofold increase in critical concentration at that end. Over the time course of experimentation there was little evidence for potentiation by CB of the nucleation step of assembly. CB did not sever actin filaments; instead its presence increased the susceptibility of actin filaments to breakage from the gentle shear forces incurred during sample preparation. Under these experimental conditions, the assembly rate constants and critical concentration at the pointed end were the same in both the presence and the absence of CB.     

Repair of impurity-poisoned protein crystal surfaces

The surface morphology of Bence-Jones protein (BJP) crystals was investigated during growth and dissolution by using in situ atomic force microscopy (AFM). It was shown that over a wide supersaturation range, impurities adsorb on the crystalline surface and ultimately form an impurity adsorption layer that prevents further growth of the crystal. At low undersaturations, this impurity adsorption layer prevents dissolution. At greater undersaturation, dissolution takes place around large particles incorporated into the crystal, leading to etch pits with impurity-free bottoms. On restoration of supersaturation conditions, two-dimensional nucleation takes place on the impurity-free bottoms of these etch pits. After new growth layers fill in the etch pits, they cover the impurity-poisoned top layer of the crystal face. This leads to the resumption of its growth. Formation of an impurity-adsorption layer can explain the termination of growth of macromolecular crystals that has been widely noted. Growth-dissolution-growth cycles could be used to produce larger crystals that otherwise would have stopped growing because of impurity poisoning.     

Endocannabinoid system in Xenopus laevis development: CB1 receptor dynamics

This study investigates for the first time the dynamics of endocannabinoid system appearance during low vertebrate Xenopus laevis development. We observed that the CB1 gene started to be expressed during the organogenesis period (+/- 1 dpf, st. 28) and expression persisted throughout the three further stages analyzed. Attention was focused on the localization of the CB1 messenger that was found both at the central level (in romboencephalon and in olfactory placods) and at the peripheral level (in the gastrointestinal tract) at +/- 3 dpf (st. 41), +/- 4 dpf (st. 46) and +/- 12 dpf (st. 49). We also considered the synthesis of CB1 protein that occurred from st. 41 onwards and, from this stage, we tested the receptor functionality in response to anandamide using cytosensor microphysiometry. CB1 functionality increased with development at both central and peripheral level. These data provide sufficient evidence to encourage further analysis on endocannabinoid physiological roles during embryonic and larval X. laevis growth.     

Regulating the Catalytic Dynamics Through a Crystal Structure Modulation of Bimetallic Catalyst

The surface of solid catalysts is one of the most important factors where the interface with reaction products governs the reaction kinetics. Herein, the crystal phase of palladium–copper nanoparticles (PdCu NPs) is controlled to modulate their surface atomic arrangement, which will govern the growth dynamics of discharge products on their surfaces and thus the catalytic performances in non‐aqueous lithium–oxygen (Li‐O₂) batteries. First‐principles calculations and experimental validations reveal that homogeneous nucleation and distribution of discharge products are observed on the surface of body‐centered cubic PdCu NPs, promoting the oxygen reduction/evolution reaction (ORR/OER) activities in Li‐O₂ batteries. However, the agglomerates formed on the surface of its face‐centered cubic homologue deteriorates ORR/OER activities, which worsen the battery performances. For the first time, this work theoretically and experimentally demonstrates how the crystal phase modulation regulates the nucleation behaviors and growth dynamics of discharge products for ORR/OER.