Effects of initial ammonium ion concentration on pullulan production by Aureobasidium pullulans and its modeling

Pullulan fermentations by Aureobasidium pullulans with various initial ammonium ion concentrations were evaluated in a 2-L bioreactor. The results demonstrated that A. pullulans produced highest pullulan (23.1 g/L) when the initial ammonium sulfate was 7 at 5 g/L. The purity of produced pullulan was 94.6%. Seven gram per liter of ammonium sulfate produced more biomass due to the higher level of nitrogen source, but the pullulan-degrading enzyme activity was detected after the depletion of sucrose, which reduced pullulan concentration. From the results of fed-batch fermentation, addition of 10 g/L of sucrose suppressed A. pullulans from producing pullulan-degrading enzyme. Additionally, the modified-Gompertz equation demonstrated its generality to fit all pullulan production, biomass production, and sucrose consumption curves at three ammonium sulfate levels. After incorporating the degrading factor, a re-modified-Gompertz equation was obtained that can adequately describe the decrease of pullulan at the late fermentation stage.     

Using spray-dried sugar beet molasses in ice cream as a novel bulking agent

In this study, it is aimed to investigate and evaluate the use of molasses which is a by-product of sugar production as a novel bulking agent in ice cream as a sugar replacer. Sugar beet molasses (75%) and 12 DE maltodextrin (25%) were converted into powder form by spray drying. Spray-dried sugar beet molasses (SDSM) was then used as a substitute of sugar in different ratios (0:100, 25:75, 50:50, 75:25 and 100:0) in the ice cream products. The increased amount of SDSM decreased the overrun, L*, whiteness index (WI) and melting behaviours and increased a*, b*, total phenolic content, consistency and viscosity. Meanwhile, thermal properties have not been affected by the use of SDSM (P < 0.05). The sensory findings have been particularly interesting especially when replacing above 50% sugar with SDSM, aroma, flavour and general acceptability decrease. According to the results of this study, substituting 25% of total sugar with SDSM as a bulking agent can decrease cost of the product and improve total phenolic content and some quality parameters without compromising sensorial properties.     

Fatty acids of the seeds of <Emphasis Type="Italic">Origanum onites</Emphasis> L. and <Emphasis Type="Italic">O. vulgare</Emphasis> L.

Seed oils of Origanum onites L. from the Antalya and Mugla regions and O. vulgare L. from the Kirklareli region of Turkey were extracted with hexane in a Soxhlet apparatus. The oil yields were 14.1–20.0 and 18.5%, respectively. FA compositions of the seed oils were determined by GC and GC/MS. Twenty FA were identified in both O. onites and O. vulgare seeds. The major FA of both species were linolenic (56.3–57.0%; 61.8%), linoleic (21.5–21.7%; 18.8%), oleic (8.7–8.9%; 5.9%), palmitic (5.9–6.5%; 5.5%), stearic (2.1–2.4%; 2.1%), and (Z)-11-octadecenoic (0.6–0.8%; 0.5%), respectively.     

Improved mechanical strength of p(AAm) interpenetrating hydrogel network due to microgranular cellulose embedding

Here, polyacrylamide [p(AAm)]‐based hydrogels were synthesized via redox polymerization technique in the presence of various amounts of microgranular cellulose (MGCell) such as 0, 10, 25, 50, 100, and 150 mg MGCell/g. The synthesized p(AAm)‐MGCell interpenetrating hydrogels were characterized spectroscopically by FTIR, thermally by TGA analysis, and mechanically via dynamic mechanical measurements. Furthermore, the effect of the amount of MGCell in p(AAm) hydrogels on swelling% (S%) degree and mechanical strength was investigated. It was found that the S% was decreased from 727 ± 9 to 667 ± 6, 642 ± 8 and 619 ± 10, 568 ± 6 for p(AAm)‐MGCell interpenetrating network hydrogels containing 10, 50, 100, and 150 mg MGCell, respectively. On the other hand, the Young modulus of p(AAm)‐based hydrogels increased from 2.8 ± 0.2 kPa to 3.1 ± 0.03, 3.4 ± 0.1, 3.6 ± 0.3 and 4.3 ± 0.3 kPa with the incorporation of 10, 50, 100, and 150 mg MGCell into p(AAm) hydrogels. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44854.     

Superporous cryogel/conductive composite systems for potential sensor applications

In situ synthesis of conductive polymers, poly(Aniline) (p(An)), poly(Pyrrole) (p(Py)), and poly(Thiophene) (p(Th)) within network of superporous cryogels with tunable functionalities as neutral poly(acrylamide) (p(AAm), anionic poly(acrylic acid) (p(AAc)), and cationic poly(4-vinylpyridine) (p(4-VP)) were carried out via oxidation polymerization technique. The highest conductivity values were measured for p(AAm)/p(An) semi-IPN cryogel with 1.4 × 10^?2 S.cm^?1 and for p(AAc)/p(Py) cryogel with 3.2 × 10^?4 S.cm^?1. In addition, to increase the amounts of conductive polymers within cryogel networks, reloading/polymerization cycle was carried out thrice, and found that there is no significant increase in the amounts of conductive polymers and the measured conductivity values. The prepared p(AAm), p(AAc), and p(4-VP) cryogels and their corresponding p(An), p(Py), and p(Th) composites were tested potential sensor materials against HCl and NH₃ vapor. The changes on conductivities for bare p(4-VP) cryogel were observed as 70 and 52-fold increase upon HCl and NH₃ gas treatment, respectively. The p(4-VP)/p(An) p(An) composites showed 7-fold conductivity decrease upon the treatments of HCl and NH₃ vapors. The p(AAm)/p(Py) composite responded 2-fold increase upon HCl vapor exposure and 50-fold decrease upon NH₃ vapor exposure. Furthermore, p(AAm)/p(Th) cryogel composite responded 7-fold decrease and 300-fold increase in their conductivities upon HCl and NH₃ vapor exposure, respectively.

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Effect of Gamma Irradiation on Biochemical Properties of Grape Seeds

In the present study, grape seed samples (Alicante Bouschet, Cabernet Franc, Cinsault, Merlot, Shiraz) were treated with 1.0, 3.0, 5.0, and 7.0 kGy of gamma radiation. Effect of irradiation dose on free fatty acids (FFA), peroxide value (PV), sterol, fatty acid composition, phenolic content, antioxidant activity of the seed oils, and chemical (dry matter, fat, ash, total sugar, invert sugar) changes of grape seeds were determined. Regarding fatty acid composition, oleic acid (C18:1) and linoleic acid (C18:2) levels decreased. β-sitosterol content with a highest percentage among sterols in grape seed oils decreased due to gamma irradiation. Generally gamma irradiation increased free fatty acids and peroxide value of the oils; however, phenolic content and antioxidant capacity of grape seeds decreased.     

Mechanically Corner-Coupled Square Microresonator Array for Reduced Series Motional Resistance

Substantial reductions in vibrating micromechanical resonator series motional resistance R_x have been attained by mechanically coupling and exciting a parallel array of corner-coupled polysilicon square plate resonators. Using this technique with seven resonators, an effective R_x of 480 Omega has been attained at 70 MHz, which is more than 5.9X smaller than the 2.82 kOmega exhibited by a stand-alone transverse-mode corner-supported square resonator, and all this achieved while still maintaining an effective Q>9000. This method for R_x-reduction is superior to methods based on brute force scaling of electrode-to-resonator gaps or dc-bias increases, because it allows a reduction in R_x without sacrificing linearity, and thereby breaks the R_x versus dynamic range tradeoff often seen when scaling. This paper also compares two types of anchoring schemes for transverse-mode square micromechanical resonators and models the effect of support beam parameters on resonance frequency     

Borates in hydrolysis of ammonia borane

Ammonia borane NH₃BH₃ (19.5 wt% H) is able to release hydrogen by hydrolysis in the presence of a catalyst in ambient conditions. This reaction has received considerable attention since 2006, with special focus on the catalytic material. In comparison, important aspects like the nature of the hydrolysis by-product(s) have been much less investigated while a good identification of the borate(s) is required for approaching recyclability. In this context, we present a work based on a systematic approach that aims at characterizing the hydrolysate, its stability in time, and the borate(s) recovered after drying. It is shown that the hydrolysate consists in aqueous B(OH)₃ and that the solution (catalyst-free) is stable when stored 6 months under argon atmosphere at 30 °C. The extraction of the water from the hydrolysate was performed at different conditions (vacuum, or air; from −50 to 500 °C). It is observed that the higher the temperature, the lower the hydration degree of the borates. The total dehydration, with the formation of B₂O₃, can be obtained at heating at 500 °C. The main problem with the hydrolysate is the release of NH₃ during the drying stage. A solution is to remove NH₃ after hydrolysis and to dry the NH₃-free hydrolysate. By this way, H₃B₃O₆ forms. Hence, B₂O₃ and H₃B₃O₆ could be recovered and recycled into ammonia borane. Besides the identification of the borates, the suitability of ammonia borane for hydrogen production by hydrolysis is discussed, especially in comparison with sodium borohydride NaBH₄.