The Production, Benefits, and Applications of Monoacylglycerols and Diacylglycerols of Nutritional Interest

In light of the increasing interest in the development of functional food, several researches have focused on the production of food grade emulsifiers of nutritional interest, especially enriched in the eicosapentaenoic (EPA) and docosahexaenoic acids (DHA). The aim of this paper is to make a review of the production of monoacylglycerols (MAG) and diacylglycerols (DAG) obtained from different feedstock, mainly fish oil. A section of this paper is dedicated to the raw materials used as feedstock for these emulsifiers production. The health benefits of these partial acylglycerols are outlined. The chemical and enzymatic methods for producing these esters of glycerol are discussed, focusing on glycerolysis reactions. Recent advances on the lipase-catalyzed production of these partial acylglycerols in alternative reaction media and systems are also reviewed.     

Physicochemical Characterization of a Heat Treated Calcium Alginate Dry Film Prepared with Chicken Stock

Solid sodium alginate was dissolved into chicken stock in order to give a final alginate concentration of 0.9 percent (w/v). Calcium ions present in chicken stock were enough to induce ionic gelation. After drying, Fourier transform infrared spectroscopy, thickness and mechanical properties of films obtained were determined. Calcium alginate‐chicken stock films were heated at 130 °C for different times between 0 and 15 min. Mechanical and optical studies, differential scanning calorimetry, visual aspect and scanning electron microscopy were carried out to describe physicochemical properties of heat treated films. Heating developed a maroon ochre color and increased the brittleness (crispness) of the films related to the intensity of the treatment. Differential scanning thermometry and study on appearance of the films suggested that Maillard reactions may be responsible for the observed changes. Maillard reactions mainly occurred between reducing sugar monomers and free amino groups of gelatin peptides present in the chicken stock, and between alginate and gelatin peptides to a lesser extent. In addition, the plasticizing effect of fat added with chicken stock was also studied. These studies suggest a potential use of heat treated chicken stock films as a substitute of roasted chicken skin.     

Thermal and economic evaluation of heat recovery measures for indoor ice rinks

A comparative study of three ventilation systems supplying air to a typical Canadian indoor ice rink illustrates the power, energy and operating cost savings which can be achieved by using the relatively warm air from the air cooled condensers of the refrigeration system. The direct use of this warm air for ventilation results in a reduction of energy consumption during the winter amounting to 24.2% of the yearly consumption of the heating system. On the other hand, the use of a heat exchanger to heat the ventilation air results in energy consumption reductions throughout the year. Depending on the size of the heat exchanger these gains can be as high as 60.8% of the heating energy consumption by the existing system. Based on actual prices of electricity and the heat exchanger it is established that the cost savings over the life of the equipment are at least three times higher than the cost of the heat exchanger.     

The mitochondrial genome from the thermal dimorphic fungus Paracoccidioides brasiliensis

We present here the sequence of the mitochondrial DNA of the pathogenic thermodimorphic fungus Paracoccidioides brasiliensis, agent of an endemic disease in most South American countries. The sequenced genome has 71 334 bp and is organized as a circular molecule with two gaps of unknown size flanking the middle exon of the nad5 gene. We located genes coding for the three subunits of the ATP synthase (atp6, atp8 and atp9), the apocytochrome b (cob), three subunits of the cytochrome c oxidase enzyme complex (cox1, cox2 and cox3), seven subunits of the reduced nicotinamide adenine dinucleotide ubiquinone oxidoreductase (nad1, nad2, nad3, nad4, nad5, nad6 and nad4L) and the large (rnl) and small (rns) subunits of ribosomal RNA. Two maturases and a ribosomal protein (rms5) are located inside introns. Twenty-five tRNAs were identified with acceptors for all 20 amino acids. Seven polypurine/polypyrimidine tracts (140-240 bp) have been found in this genome. All genes are in the same orientation over the genome, while their order is closest to the mitochondrial genomes from Penicillium marneffei and Aspergillus nidulans.     

Application of Fast Gas Chromatography–Mass Spectrometry in Combination with the QuEChERS Method for the Determination of Pesticide Residues in Fruits and Vegetables

A fast gas chromatography–mass spectrometry method has been developed for multiresidue determination of up to 56 pesticides in fruits and vegetables in a chromatographic run time of <10 min, using a single quadrupole mass spectrometer operating in selected ion monitoring mode. The well-known acetate-buffering version of the QuEChERS method has been used for sample preparation. Programmable temperature vaporizer injection of 3 μL allowed reaching limits of detection between 0.15 and 15 μg/kg for most compounds in the sample matrices tested. The applicability of the method has been evaluated in apple, orange, carrot, and tomato. Recoveries at three fortification levels (0.01, 0.1 and 0.5 mg/kg) ranged from 70 to 120 % for most compounds, with relative standard deviations below 20 % in all cases. The developed method has been applied to fruit and vegetable samples from different Spanish provinces.     

Physico-chemical and sensory properties of yogurt from ultrafiltreted soy milk concentrate added with inulin

The total solids required for yogurt preparation were obtained by soy milk microfiltration and ultrafiltration. Inulin was incorporated at the level of 20–70 g/L, and the soy milk containing inulin was fermented using conventional microorganisms. The chemical, physical and sensory properties of the products were evaluated. The membrane concentration of soy proteins leads to yogurts with an increase of 59 g/L of proteins and 15 g/L of vegetable fats, reducing ash and anti-nutrients content. The clot had high stability and protein concentration generated a buffer effect smoothing the acidity and the flavor obtained is more agreeable. In addition, the proteins were concentrated without thermal treatment. As the inulin content increased, creaminess and viscosity increased as well. The products prepared presented nice smell, flavor and color, being the sample with higher global acceptability the yogurt with 50 g/L of inulin (P < 0.05).     

Optimization of alcohol‐free beer production by lager and cachaça yeast strains using response surface methodology

Alcohol‐free beers (AFBs) are an attractive segment of the beer market both for the brewing industry and for consumers. While AFBs produced by arrested/limited fermentation often suffer from a lack of volatile compounds, beer flavour can be improved by yeast selection and optimization of fermentation conditions. The yeast selection strategy was demonstrated by comparing traditional lager yeast with selected cachaça yeast strains. Correspondingly, response surface methodology was used to enhance the formation of the flavour‐active volatile compounds by optimization of the fermentation conditions (original wort extract, fermentation temperature, pitching rate). Statistical analysis of the experimental data revealed the relative significance of process variables and their interactions. The developed quadratic model describing the responses of total esters and higher alcohols to changes in process variables was used to predict the ideal fermentation conditions in terms of flavour formation. The predicted conditions were experimentally verified and alternative strategies of AFB production are suggested. Copyright © 2016 The Institute of Brewing & Distilling     

Uncertainty in particle number modal analysis during transient operation of compressed natural gas, diesel, and trap-equipped diesel transit buses

The relationships between transient vehicle operation and ultrafine particle emissions are not well-known, especially for low-emission alternative bus technologies such as compressed natural gas (CNG) and diesel buses equipped with particulate filters/traps (TRAP). In this study, real-time particle number concentrations measured on a nominal 5 s average basis using an electrical low pressure impactor (ELPI) for these two bus technologies are compared to that of a baseline catalyst-equipped diesel bus operated on ultralow sulfur fuel (BASE) using dynamometer testing. Particle emissions were consistently 2 orders of magnitude lower for the CNG and TRAP compared to BASE on all driving cycles. Time-resolved total particle numbers were examined in terms of sampling factors identified as affecting the ability of ELPI to quantify the particulate matter number emissions for low-emitting vehicles such as CNG and TRAP as a function of vehicle driving mode. Key factors were instrument sensitivity and dilution ratio, alignment of particle and vehicle operating data, sampling train background particles, and cycle-to-cycle variability due to vehicle, engine, after-treatment, or driver behavior. In-cycle variability on the central business district (CBD) cycle was highest for the TRAP configuration, but this could not be attributed to the ELPI sensitivity issues observed for TRAP-IDLE measurements. Elevated TRAP emissions coincided with low exhaust temperature, suggesting on-road real-world particulate filter performance can be evaluated by monitoring exhaust temperature. Nonunique particle emission maps indicate that measures other than vehicle speed and acceleration are necessary to model disaggregated real-time particle emissions. Further testing on a wide variety of test cycles is needed to evaluate the relative importance of the time history of vehicle operation and the hysteresis of the sampling train/dilution tunnel on ultrafine particle emissions. Future studies should monitor particle emissions with high-resolution real-time instruments and account for the operating regime of the vehicle using time-series analysis to develop predictive number emissions models.     

Effect of corn particle size on site and extent of starch digestion in lactating dairy cows

Two experiments were conducted to determine the effects of corn particle size (CPS) on site and extent of starch digestion in lactating dairy cows. Animals were fitted with ruminal, duodenal, and ileal cannulas. Dry corn grain accounted for 36% of dry matter intake. In experiment 1, 6 cows were used in a duplicate 3 x 3 Latin square design. Semiflint corn was used. Corn processing methods were grinding, medium rolling, and coarse rolling. The mean particle size of the processed corn was 730, 1807, and 3668 microm, respectively. Rumen digestibility of starch linearly decreased from 59% with ground corn to 36% with coarsely rolled corn. Similarly, small intestine digestibility linearly decreased with increased CPS, and consequently, the amount of starch digested in the small intestine was not affected by corn processing. In experiment 2, 4 cows were used in a 2 x 2 crossover design. Dent corn was used. Corn processing methods were grinding and coarse rolling. The mean particle size of the processed corn was 568 and 3458 microm, respectively. Rumen digestibility of starch decreased from 70% with ground corn to 54% with coarsely rolled corn. Small intestine digestibility of starch was not significantly affected by CPS, and the amount of starch digested in the small intestine tended to be greater for rolled than for ground corn. In both experiments, starch total tract digestibility decreased with increased CPS. In conclusion, CPS is an efficient tool to manipulate rumen degradability of cornstarch. In midlactation cows, the decrease in the amount of starch digested in the rumen between grinding and coarse rolling is partly compensated for by an increase in the amount of starch digested in the small intestine with dent genotype, but with semiflint genotype postruminal digestion is not increased and rumen escape starch is not utilized by the animal.