The effect of different packaging methods on the formation of biogenic amines and organic acids in Kashar cheese

The effects of packaging methods (nonvacuum and vacuum) on biogenic amines (cadaverine, putrescine, tyramine, tryptamine, phenylethylamine, and histamine) and organic acids (citric, lactic, formic, acetic, propionic, and butyric) during storage for 180 d at 4°C were investigated in Kashar cheese. Dry matter, titratable acidity, total nitrogen, water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen, free amino group (proteolysis), pH, fat, and acid degree value were also determined. Storage period had a significant effect on all of the biogenic amines. When compared with vacuum packaging, nonvacuum packaging resulted in no large differences among the amounts of biogenic amines. Vacuum-packaged cheeses had more lactic, formic, acetic, and butyric acids than did cheeses packaged without vacuum. Water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen, proteolysis, pH, and acid degree values of the cheese samples increased continuously until the end of the ripening in all the samples. No significant change was observed in total nitrogen, dry matter, or fat content within the ripening period, whereas titratable acidity values changed significantly in vacuum-packaged cheese and decreased slightly in the non-vacuum-packaged cheeses. The results of this study showed that storage period and packaging method had significant effects on the quality of Kashar cheese.     

Hydrogen production by radio frequency plasma stimulation in methane hydrate at atmospheric pressure

Methane hydrate, formed by injecting methane into 100 g of shaved ice at a pressure of 7 MPa and reactor temperature of 0 °C, was decomposed by applying 27.12 MHz radio frequency plasma in order to produce hydrogen. The process involved the stimulation of plasma in the methane hydrate with a variable input power at atmospheric pressure. It was observed that production of CH₄ is optimal at a slow rate of CH₄ release from the methane hydrate, as analyzed by in light of the steam methane reforming (SMR) and the methane cracking reaction (MCR) processes in accordance with the content of gas production. In comparison with the steam methane reforming (SMR), it was found that methane-cracking reaction (MCR) was dominant in conversion of CH₄ into hydrogen. An H₂ content of 55% in gas production was obtained from conversion of 40% of CH₄ at an input power of 150 W. The results clearly show that hydrogen can be directly produced from methane hydrate by the in-liquid plasma method.     

Wear performance of self-glazed zirconia crowns with different amount of occlusal adjustment after 6 months of clinical use

ABSTRACT

The amount of enamel wear on the antagonist occlusal surfaces caused by self-glazed zirconia crowns was compared with that caused by contralateral natural teeth. Thirteen self-glazed zirconia crowns were placed in situ. The impressions of self-glazed zirconia crowns, their antagonists and the control teeth were taken and scanned at baseline and 6-month follow-up. The patients were divided into two groups, the self-glazed crowns in one group were subjected to a large amount of grinding with well polishing (LaP group, n?=?7), while the other group required a little amount of grinding with well polishing (LiP group, n?=?6). Statistics were analysed by two-sided paired Student’s t-tests to a significance level of p?<?.05. The results revealed that the maximum and mean enamel wear significantly different between the antagonists of self-glazed crowns and the control teeth (p?<?.05). Increased amount of enamel wear was found in LaP group (p?<?.05). The self-glazed zirconia crowns caused more enamel wear of antagonists than natural teeth after 6 months. Occlusal adjustment and polishing were considered as possible confounders which affected wear behaviour.     

岸堤水库岩溶坝基防渗处理

本文概述了岸堤水库大坝岩溶坝基帷幕灌浆施工工艺,结合水库历年观测资料分析,介绍一种岩溶地基处理防渗的经济有效、简便易行的施工工艺。     

Noise reduction capability of hybrid flax fabric-reinforced polypropylene-based composites

In recent years, natural fiber polymer composites have demonstrated great potential for reducing noise. This study reports sound transmission loss (STL) of hybrid flax fabric-reinforced polypropylene composites. The STL values were determined by the BSWA impedance tube and evaluated by ISO 10534 standard test procedure in the frequency range of 64 to 1600 Hz. Measurements show that the STL per areal density of flax/polypropylene is two times higher compared to aluminum. A noteworthy result is that upon hybridization with 13% carbon fibers (carbon-flax/polypropylene), the STL per areal density increases by 2.4 times. This study also presents the finite element (FE) simulation of sound transmission through the composites. Good agreement between FE predicted and experimentally measured STL is obtained. Moreover, parametric sensitivity studies are performed using the developed FE model to examine the effect of possible variation in the mechanical properties of the natural fiber composites on the STL performance. It is found that within 15% variation, no significant effect on STL is obtained and that STL is only sensitive to the in-plane elastic moduli.     

Water Ecological Restoration Practice of Cross-Administrative-Area Synergic Projects—Case Study on the Yuandang Lake Synergic Eco-Development Pilot Project,the Demonstration Zone of Green and Integrated Ecological Development of Yangtze River Delta

Today integrated regional development becomes a national agenda of China. The Demonstration Zone of Green and Integrated Ecological Development of Yangtze River Delta faces a task of exploring a more effective and localized coordination mechanism for the implementation of cross-administrative-area synergic projects under the current administrative regimes. This article reviews the current practice of cross-administrative-area synergic development at home and abroad, and summarizes corresponding mechanisms and key issues; then by focusing on the case of the Yuandang Lake Synergic Eco-Development Pilot Project that sits on the junction of Shanghai City and Jiangsu Province, this article sorts out the key issues and the solutions at each project stage, and proposes the “3P3S” coordination framework for the implementation of cross-administrative-area synergic projects. As an exploration of spontaneous bottom-up approach—instead of administrative orders—the “3P3S” coordination framework can efficiently promote project implementation under the current administrative regimes, providing reference for synergic implementation of regular cross-administration-area projects.     

Multiple-strain Lactobacillus-fermented soymilk with antioxidant capacity and delicate flavour

Soymilk is a high-quality fermentation substrate, but its flavour is not accepted by many consumers. In this study, soymilk was fermented under different fermentation conditions by different Lactobacillus strains. The antioxidant activity of the soymilk was explored using TOPSIS and the changes in flavour during fermentation were investigated by e-nose using PCA. The results of TOPSIS showed that Lactobacillus plantarum (LP) ranked first (0.734) and L. acidophilus (LA) ranked second (0.651). In addition, L. bulgaricus (LB) was the only strain that could increase ABTS antioxidant activity (by around 11%). The LP, LA and LB mixed fermentation sample (w/w/w, 1 : 1 : 1) provided 10 new kinds of flavour compounds and stronger antioxidant ability than the unfermented sample. In addition, storage at 4 °C after fermentation elicited beneficial changes in the content of key flavour substances. Therefore, multiple-strain Lactobacillus-fermentation of soymilk not only improved the antioxidant activity but also provided a delicate flavour.     

Effect of pH on betalain–anthocyanin mixture in bayberry juice: influences on pigments,colour, and antioxidant capacity

Betalains (mainly betanin, isobetanin, and phyllocactin) extracted from red–purple pitaya were blended with Chinese bayberry juice (rich in anthocyanins) to explore variation trends of two natural pigments in one system. The mixture showed higher anthocyanin contents at pH 4, 4.5, and 5. In this process, redness and colour saturation were also maintained to a greater extent compared to the control. The coexisting betalains and anthocyanins increased colour acceptability of the juice matrix and expanded the pH tolerance range. Interestingly, colour change (ΔE) showed the opposite trend. Besides, betalains showed the function of improving the antioxidant activity of juice matrix at pH 3, 4, and 4.5, which confirmed their biological activity. Betalain-added bayberry juice obtained a satisfactory ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging capacity for 62.52% at pH 5.