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排序方式: 共有7722条查询结果,搜索用时 15 毫秒
921.
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923.
Rosalía López-Ruiz Roberto Romero-González José Luis Martínez Vidal 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2016,33(11):1685-1692
The development and validation of a method to determine flonicamid and its metabolites as TFNA (4-trifluoromethylnicotinic acid), TFNG (N-(4-trifluoromethylnicotinoyl) glycine) and TFNA-AM (4-trifluoromethylnicotinamide) in bell pepper samples by ultra-high-performance liquid chromatography coupled to Orbitrap mass spectrometry (UHPLC-Orbitrap-MS) was performed. A fast and simple extraction procedure with acidified acetonitrile and salts (magnesium sulfate and sodium chloride) was used. The methodology was validated, checking for specificity, recovery, precision, limits of detection (LODs) and limits of quantification (LOQs). The recoveries ranged from 84% to 98%, and precisions were lower than 17%. Finally, LODs ranged from 1 µg kg–1 (flonicamid) to 6 µg kg–1 (TFNA-AM), while LOQs ranged from 10 µg kg–1 (flonicamid) to 30 µg kg–1 (TFNA-AM). Bell pepper samples were analysed and concentrations up to 98 µg kg–1 (flonicamid) were detected, although the sum of flonicamid and metabolites did not exceed the maximum residue limit (MRL) set by the European Union. 相似文献
924.
Efficient very‐high‐gravity fermentation of sugarcane molasses by industrial yeast strains 下载免费PDF全文
Heloisy Suzes Barbosa Erick de Abreu Silveira Messias Miranda Jr. José Roberto Ernandes 《Journal of the Institute of Brewing》2016,122(2):329-333
In this study industrial strains were inoculated, in successive cycles, at high cell density into a sugarcane‐based juice containing normal (22%, w/v) and very high sucrose (30%, w/v) levels and supplemented with peptone as a nitrogen source. At 30 °C, in shaken cultures, in the normal gravity situation, efficient sucrose utilization occurred in both the supplemented and unsupplemented medium. At higher sugar concentrations, supplementation with peptone induced a more efficient fermentation compared with the unsupplemented medium, with higher biomass accumulation and maintenance of cell viability, and ethanol levels as high as 16% (v/v). Trehalose was also high during the cycles, probably as a necessary response of the yeast to the high stress fermentation conditions. This suggests that it is possible to increase ethanol production by using very‐high‐fermentation technology and that nutritional supplementation would have a positive effect on the fermentation, allowing for efficient sugar consumption and cell viability maintenance. Copyright © 2016 The Institute of Brewing & Distilling 相似文献
925.
926.
Marta Laranjo Ana Gomes Maria Eduarda Potes Maria José Fernandes Maria João Fraqueza Miguel Elias 《International Journal of Food Science & Technology》2016,51(5):1150-1158
Carne do alguidar is a Portuguese traditional pork fried meat, usually manufactured for self‐consumption purposes. This study developed a ready‐to‐eat (RTE) meat product, to meet today's consumers’ convenience, manufactured at the industrial scale evaluating its quality and shelf life, assessing the effect of vacuum packaging and the use of an antioxidant (50 ppm BHT) to enhance oxidative stability. Physicochemical and microbiological parameters were assessed, and a sensory analysis was performed. Interestingly, no significant differences were recorded between control (non‐BHT) and antioxidant (BHT) samples. Microbiological counts remained at low levels throughout the storage period, ensuring the product's required microbiological quality. At later storage stages, higher values of thiobarbituric acid‐reactive substances arose and off flavours and aromas were perceived. Still, overall appreciation was not affected until 12 months of storage and a significant depreciation was perceived only after 15 months. Fibrousness and rising of off flavours were negatively correlated with overall appreciation. 相似文献
927.
Beatriz Herranz Wenceslao Canet María José Jiménez Raúl Fuentes María Dolores Alvarez 《International Journal of Food Science & Technology》2016,51(5):1087-1098
Chickpea flour (CF)‐based muffin formulations were made with CF alone and with added biopolymers [whey protein (WP), xanthan gum (XG) and inulin (INL)] to evaluate their suitability to be a wheat flour (WF) substitute in muffins. Structural characteristics of the batters and muffins were studied by means of rheometry, microscopy, physicochemical properties, and texture and sensory analysis. Partial replacement of CF with XG, alone (at 0.5 and 1%) or blended with either WP or INL, significantly increased the batter viscoelasticity as denser matrices developed; moreover, the muffins with XG added at 1% had similar hardness to wheat gluten muffins. The replacement of WF decreased the springiness, cohesiveness, chewiness, resilience and specific volume of the muffin. However, baked muffins with added XG also showed higher sensory sponginess and moisture associated with numerous air bubbles in the batter and were perceived to be easier to swallow and to have better general appearance. 相似文献
928.
Eduardo J. Pires José A. Teixeira Tomás Brányik António A. Vicente 《Journal of the Institute of Brewing》2014,120(4):500-506
Developing a sustainable continuous fermentation reactor is one of the most ambitious tasks in brewing science, but it could bring great benefits regarding volumetric productivity to modern breweries. Immobilized cell technology is often applied to reach the large densities of yeast needed in a continuous fermentation process. However, the financial cost associated with the use of carriers for yeast immobilization is one of the major drawbacks in the technology. This work suggests that yeast flocculation could address biomass immobilization in a gas‐lift reactor for the continuous primary fermentation of beer. Nearly 25 g dry wt L?1 of yeast was flocculated in the reactor before interruption of the fermentation. Stable sugar consumption and ethanol production (4.5% alcohol by volume) from an 11°P wort was evidenced. The key esters and higher alcohols measured in the young beer met the standards of a finished primary beer fermentation. Copyright © 2014 The Institute of Brewing & Distilling 相似文献
929.
Antonio Caminero Enrique Calvo Eulogio Valentín José Ruiz‐Herrera Juan A. López Rafael Sentandreu 《Yeast (Chichester, England)》2014,31(4):137-144
This paper describes the results obtained by analysing the human pathogen Candida albicans cell wall subproteome by mass spectrometry, using extraction procedures aimed at releasing proteins bound by disulphide bridges (RAE‐CWP) or alkali‐labile ester linkages (ALS‐CWP). Ten of the total proteins released from the wall by β‐ME and/or NaOH contained a potential signal peptide, lacked a GPI cell wall hydrophobic C‐terminal domain and were identified as true wall proteins by in silico analysis, whereas four additional proteins were identified as bound to the plasma membrane. The results surprisingly demonstrated that, in addition to the expected RAE‐CWP and ALS‐CWP proteins, 16 GPI proteins were bound to the wall by disulphide or alkali‐sensitive bonds, since they were released by β‐ME and/or NaOH. The biological significance of these results is discussed in relation to the added complexity of the organization of the proteins in the C. albicans cell wall. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
930.
Antonio J. Pérez-López José Manuel López-Nicolás Angel A. Carbonell-Barrachina 《European Food Research and Technology》2007,225(2):255-260
Consumers demand organic products because they believe that the organic products are more flavorful and respectful to the
environment and human health. The effects of organic farming on the minerals contents and aroma composition of Clemenules
mandarin juices were studied. Minerals (Fe, Cu, Mn, Zn, Ca, Mg, K, and Na) were quantified using atomic absorption-emission
spectroscopy, while volatile compounds were extracted using the dynamic headspace technique and were identified and quantified
by GC–MS. In general, organic farming produced a mandarin juice with a higher quality than that produced by conventional agricultural
practices. Higher concentrations of both minerals and positive volatile compounds were found in the organic juice, while the
formation of off-flavors was higher in the conventional juice, although threshold values were not reached. 相似文献