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对香椿干燥过程中水分迁移规律进行研究,同时考察不同热处理条件对香椿的特征香气有机化合物之一2-巯基-3,4-二甲基-2,3-二氢噻吩(2-Mercapto-3,4-Dimethyl-2,3-Dihydrothiophene,MDD)稳定性的影响,分析MDD热降解的动力学以及热力学规律。结果表明:热处理温度越高,香椿干燥速率越快,符合传统的干燥速率变化规律。MDD降解过程符合一级动力学反应规律和Arrhenius模型,反应速率常数介于0.0155~0.0345min-1之间,并且随着处理温度的升高而增大,不同温度下半衰期分别为44.719、32.239、20.091 min,随着干燥处理温度的升高而呈现出减少的变化趋势,反应的活化能(Ea)为39.052 kJ/mol。焓变(ΔH)为正值说明MDD热降解过程是吸热反应,吉布斯自由能(ΔG)也为正值,说明MDD热降解反应为非自发反应。研究可为有效控制香椿加工生产过程特征风味物质的降解提供理论依据。 相似文献
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对6 种板栗的基础营养成分、风味物质进行测定,并对质地进行分析。6 种板栗的营养成分呈现品种和地区差异性,河南大板栗的淀粉、总酸含量较高,而在蛋白质、脂肪、还原糖、VC含量方面河北品种含量较高,各品种的脂肪与还原糖、VC含量呈显著正相关,VC与蛋白、还原糖呈显著正相关,淀粉与VC含量呈显著负相关。各品种板栗氨基酸种类齐全,含量较高的为谷氨酸和天冬氨酸,第1、第2限制氨基酸为半胱氨酸和甲硫氨酸,大板红总氨基酸含量最高达32.72 g/kg。检测出46 种香气成分,香气物质种类最高的为大板栗(25 种),其次为早丰和遵玉(均17 种),大板红、塔丰及红油栗(16 种),相对含量高的成分均为醛类达50%以上。板栗各质地参数间的相关性表明,硬度与咀嚼性、胶黏性呈显著正相关,内聚性与胶黏性、咀嚼性呈极显著正相关,弹性与胶黏性、咀嚼性呈一定的负相关,大板红及大板栗在果仁的硬度、弹性、胶黏性、咀嚼性大于其他几个品种。综合分析认为大板红品质比较优良,由于各地气候条件也有差异,应根据不同地理条件、产品用途等选择合适的品种进行种植及产品加工。 相似文献
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与鲜青豆进行比较,研究煮制青豆、烤制青豆、冻干青豆对青豆粉的基本成分、抗氧化性能和香气成分的影响。结果表明:不同加工工艺的青豆粉的淀粉、粗蛋白、总黄酮和总酚含量差异显著(p<0.05),冷冻干燥青豆粉中总黄酮和总酚含量分别为0.40 g/g和0.96 mg/g;煮制青豆中总黄酮和总酚含量分别为0.30 g/g和0.71 mg/g;冷冻干燥、煮制后的青豆所得青豆粉的自由基清除力、还原力能力较高,而炒制所得青豆粉的抗氧化能力最低。运用固相微萃取-气相色谱-质谱联用对鲜青豆和3种加工工艺的青豆粉的香气物质进行分析,鲜青豆、煮制后热风干燥的青豆粉、烤制干燥青豆粉和冷冻干燥青豆粉各自鉴定出17、20、41种和21种挥发性香气成分。综合分析,冷冻干燥和煮制后干燥的青豆粉抗氧化能力较高,能够较好的保存青豆的营养价值,对于青豆的香气也有较好的保留和增加。众所周知冷冻干燥会能耗较大,因此,可选择煮制后热风干燥制作青豆粉。 相似文献
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High lipid and high protein infant formula milk powders were stored at water activity of 0.11, 0.33 and 0.53 for up to fourteen weeks at 40 °C to investigate the effect of storage water activity on physicochemical properties and formation of volatiles to thereby recommend optimal storage water activity conditions. Water activity of the powders was determined during storage together with surface colour, glass transition temperature combined with dynamic headspace sampling followed by gas chromatography/mass spectrometry. The principal component analysis (PCA) showed that the optimal water activity for storage of high lipid infant formula milk powder, for which lipid oxidation was found to be the critical quality parameter, is aw = 0.33 with lowest lipid oxidation, while for high protein infant formula milk powder, for which protein degradation was found to be the critical quality parameter, aw = 0.11 is optimal to limit formation of Maillard reaction products. 相似文献
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In this study, microbes were isolated from the rice slurry of a fermented rice cake to obtain lactic acid bacteria and yeast species. These species were identified using microbial physiology and gene sequence analyses. As the growth of the lactic acid bacterial strain R-2b and the yeast J-3a strains were found to be the best, a composite starter comprising these microbes was used for the preparation of fermented rice cakes. Based on single factor and orthogonal experiments, when the proportion of Lactobacillus plantarum, Saccharomyces cerevisiae, and Candida humilis was 1:3:6, the optimal fermentation conditions were addition of sugar and starter amounts of 20% and 6%, respectively, a fermentation temperature of 32 °C, and fermentation time of 8 h. The fermented rice cake with this optimum ratio had the most abundant volatile components and qualified physicochemical and microbial indexes. Additionally, the overall quality was better than that of commercially available products. 相似文献
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