Experimental and parametric study on drying of green peas in spouted bed

Drying of Green Peas (Pisum sativum) was studied experimentally in a lab‐scale spouted bed. Experiments were carried out at different operating conditions, and the effect of inlet air temperature and its flow rate, bed height (initial mass of wet particles) and average diameter of particles were examined on performance of dryer and rate of drying. The obtained experimental results were fitted by an exponential form equation to model the drying kinetic behaviour of green peas in a spouted bed. The fitting parameters are presented in the form of mathematical correlations as a function of operating parameters. As expected, it was found that by increasing inlet air temperature and air‐flow rate, the rate of drying increases, but by increasing the bed height and diameter of particles, the rate of drying decreases. The results can help the design engineers to choose the optimum drying conditions for industrial applications.     

Bioactive compound retention in Echium amoenum Fisch. & C. A. Mey. petals: Effect of fluidized bed drying conditions

The dried petals of Echium amoenum Fisch. & C.A. Mey. are used for the treatment of many diseases but there are not any reports about the effects of drying conditions on their bioactive compounds. A complete 3² factorial design was used, where the independent variables were drying temperature (40°C–60°C) and air flow rate (0.5–1.0 m/s). The bioactive compounds studied were total phenolic, total flavonoid and anthocyanin contents, and antioxidant activity. The desirability index was used to predict the optimal drying conditions. Both independent variables were statistically significant. The optimal drying conditions were air velocity of 0.86 m/s at 60°C. The results show that the drying conditions play an important role in determining the final quality of the product, content of its bioactive compounds, and minimum drying time.     

干燥方式对油茶粉品质及挥发性风味物质的影响

目的：探究适合油茶粉的干燥方式,以便油茶食用和贮藏。方法：采用喷雾干燥、真空冷冻干燥、真空干燥3种干燥方式对油茶汤进行干燥处理,并对干燥后油茶粉的品质（水分含量、感官评价、色泽）及挥发性物质进行评价。结果：真空冷冻干燥油茶粉感官得分最高（93）,含水量最低（3.78%）,色泽较优（ΔE值49.74）。利用SPME-GC-MS技术从3种方式干燥油茶粉中共鉴定出104种挥发性物质,其中,影响油茶粉风味的有14种。冷冻干燥的特征风味物质（壬醛、癸醛、（Z）-2-癸醛、（Z）-2-壬烯醛、（E）-3,7-二甲基-2,6-辛二烯醛）呈现青香、油脂香,喷雾干燥和真空干燥的特有香气均为（Z）-3,7-二甲基-2,6-辛二烯醛、（E）-3,7-二甲基-2,6-辛二烯醛、癸醛,呈现青香、果香、蜡香。结论：真空冷冻干燥风味品质最佳。     

Effects of drying methods on colour,amino acids,phenolic profile,microstructure and volatile aroma components of Boletus aereus slices

This study is to investigate the effects of hot air drying (HD) at 60–80 °C (HD-60, HD-70 and HD-80), microwave pretreatment combined with HD (MHD), ultrasound pretreatment combined with HD (UHD) and vacuum freeze drying (FD) on the quality of Boletus aereus slices. Key characteristics, including colour, free amino acids, microstructure, volatile aroma components, phenolic profile and antioxidant activity, were studied. Amongst these drying methods, FD was the best way to preserve colour and volatiles of Boletus aereus slices. Fifteen amino acids were detected in Boletus aereus slices, and HD-60 showed a higher content of total amino acids than other drying regimes. Two phenolic acids were identified in Boletus aereus slices, namely, protocatechuic acid and p-hydroxybenzoic acid. MHD presented the highest content of phenolic compounds, followed by FD. Antioxidant capacity was positively correlated with phenolic compounds of Boletus aereus slices. Moreover, the cell structure of Boletus aereus slices was damaged after drying, and FD had a more porous structure than other drying methods. These results will be beneficial to the further industrial production of Boletus aereus slices.     

Image analysis and quality attributes of malting barley grain dried with infrared radiation and in a spouted bed

The impact of drying two spring barley cultivars (Mauritia and Prestige) in a spouted‐bed and in infrared radiation (IR) dryers on grain dimensions, colour, pigment content, vitality and malt quality was investigated. The results indicate that the investigated drying methods led to kernel dimension changes. Kernel shrinkage was typical of spouted bed drying, while kernel expansion was observed after IR drying at the intensity of 900 W m^?2. An increase in the intensity of yellowness (b*) on the surface of dried grain and a decrease in the yellowness intensity of kernel cross‐section were also observed. The aforementioned changes were associated with the decomposition of carotenoids (endosperm colour) and reduction of soluble proanthocyanidin and total phenolic compounds (surface colour). The drying processes also lowered germination energy and capacity, in addition to susceptibility to moisture diffusion into the endosperm. These adverse results were cultivar dependent and affected the quality of malt and wort only to a limited extent. The main changes were an increase in the Kolbach index in malt from Mauritia cv., and a fluctuation of the diastatic power of malt that did not exceed ±3%. Generally, drying of barley grain in spouted bed should be conducted at an inlet air temperature of 40 °C and using an IR drier at a radiation intensity of 600 W m^?2.     

Effect of hot air,vacuum and infrared drying methods on quality of rose hip (Rosa rubiginosa) leathers

For the development of fruit leathers, a formulation containing rose hip pulp, sucrose and citric acid was used as initial material for the drying process. Three dehydration techniques were tested: forced hot air, infrared and vacuum, all carried out at 60 and 70 °C. All methods led to flexible, translucent fruit leathers at both temperatures. Colour and water activity were not affected by the dehydration method nor by the temperatures tested. Nutritional parameters such as antioxidant capacity (TEAC) and content of phenolic substances were measured. The best retention was achieved with vacuum drying at 60 °C being of 57.5% and 25.1%, respectively. ESEM observations were conducted to assess the effect of drying methods and conditions on microstructure of leathers. Various extents of sucrose crystallisation were inferred from surface images. Cross‐sectional micrographs showed that the size of pores was affected by the drying technique but not by temperature in the range studied.     

热风干燥技术对贮存期大曲质量的影响

通过测定热风干燥大曲在贮存期的理化指标、生化指标、酶系指标、挥发性风味成分指标和微生物指标等的变化,探究热风干燥技术对大曲贮存期质量的影响。研究发现,经热风干燥后大曲的水分和水活度显著降低,在贮存期间对氨态氮的形成有一定抑制作用,在贮存后期对酯类和2,6-二甲基吡嗪含量有促进作用;实验室贮存条件下,热风干燥在大曲贮存后期也能促进其酒化力、液化力、糖化酶活力提高和增加细菌的数量;而热风干燥对大曲在贮存期淀粉的分解、酯化力、发酵力、蛋白酶活力没有影响。      

干燥方式对大球盖菇品质及挥发性风味成分的影响

目的:筛选最为合适的大球盖菇干燥方式。方法:选用冷冻干燥、热泵干燥、热风干燥和微波干燥对新鲜大球盖菇进行干燥处理,考察其理化性质。结果:粗蛋白、粗脂肪、灰分、钾、钙、总黄酮、必需氨基酸、呈味氨基酸以及总氨基酸含量方面以冷冻干燥的最高,16种氨基酸总量为16.88 g/100 g;复水率、色泽方面均为冷冻干燥的最佳;DPPH自由基清除率为热风干燥的最高达61.14%,清除率大小依次为热风干燥>热泵干燥>微波干燥>冷冻干燥;ABTS自由基清除率为热泵干燥的最高达67.97%,清除率大小依次为热泵干燥>热风干燥>微波干燥>冷冻干燥;大球盖菇单糖主要由葡萄糖和半乳糖组成,其中,冷冻干燥的葡萄糖含量最多,占总糖的36.79%;大球盖菇单糖分子量最大的为冷冻干燥的;不同干燥方式下大球盖菇挥发性风味存在差异,且与新鲜大球盖菇的差异较大,冷冻干燥大球盖菇中挥发性成分种类最丰富、部分成分含量较高。结论:冷冻干燥在营养成分、复水率、色泽、风味等方面较其他干燥方式均有优势,对大球盖菇品质影响最小,是最为合适的干燥方式。     

不同干燥方式对林芝松口蘑挥发性风味的影响

以不同干燥方式得到的西藏林芝产松口蘑干品为研究对象,采用电子鼻结合GC-MS技术对自然晾干、冷冻干燥、真空干燥、热风烘干得到的松口蘑干品的风味进行比较分析.结果表明:4种干燥方式所得松茸样品的传感器响应轮廓大致相同,但响应强度有所差别,4个样品的雷达响应值大小依次为真空干燥>自然晾干>冷冻干燥>热风烘干,其中真空干燥样...     

干燥方式对滁菊抗氧化、抑菌活性和挥发性风味物质的影响

以新鲜滁菊为原料,研究真空冷冻干燥、热泵干燥、热风干燥对滁菊抗氧性、抑菌活性、挥发性风味物质和感官品质的影响。结果表明:真空冷冻干燥滁菊(T1)自由基清除能力和脂质过氧化抑制能力最高,对金黄色葡萄球菌和大肠杆菌抑制作用最强,同时具有最好的感官品质。各样品活性和感官评分顺序为真空冷冻干燥滁菊(T1)热泵干燥滁菊(T2)热风干燥滁菊(T3)。运用固相微萃取—气相色谱—质谱联用对3种干燥方式的滁菊挥发性风味物质进行分析,T1、T2和T3分别鉴定出71,88,56种物质。萜烯类是3种干制滁菊的主体风味物质,相对含量均达到45%以上。因此,真空冷冻干燥工艺是滁菊最佳的脱水工艺。     

变温干燥处理对秋季绿茶品质的影响

目的 探究变温干燥处理对秋季绿茶品质的影响。方法 以茶树品种碧香早秋季一芽二叶为原料,在传统绿茶90℃烘二青、75℃烘至足干的干燥工艺基础上,提高烘二青温度至85～95℃2～4 min,烘三青温度至85～95℃2～3 min,从感官品质、呈味物质及香气物质3方面探讨变温干燥及其组合处理对绿茶品质的影响。结果 与传统绿茶干燥工艺相比, 90℃二青干燥17 min后升温至100℃干燥3 min、75℃三青10 min后,升温至95℃干燥3 min、最后回温至75℃烘至足干的变温干燥处理加工出的绿茶栗香高长、滋味醇厚且综合感官品质最佳,其茶多酚、咖啡碱、酯型儿茶素等苦涩滋味物质含量显著下降(P<0.05),醇类、酯类、杂环化合物等香气物质的相对含量分别增加了26.14%、38.95%、81.34%(P<0.05),其中苯甲醇、芳樟醇、水杨酸甲酯、2-正戊基呋喃等栗香特征性香气成分增幅较大,且新增加了植烯、金合欢醇、丁位癸内酯等甜香、花果香香气成分。结论 在秋季绿茶干燥过程中,烘二青、烘三青组合变温处理有利于提高秋季绿茶品质。     

热风微波联合干制对香菇品质及风味的影响

分析比较热风干燥、热风微波联合干燥对香菇干燥速率、复水比、色泽及风味成分的影响。结果显示,热风微波联合干燥其微波干燥阶段的干燥速率明显高于热风干燥后期干燥速率,热风微波联合干燥的香菇复水比好于热风干燥,热风微波联合干燥和热风干燥L*、b*值差异显著,而a*不显著。顶空固相微萃取和气相色谱质谱联用分析发现两种干制方式的香菇风味组成存在差异,主要体现在含硫化合物、醇类、酯类和烃类。热风微波联合干燥和热风干燥的香菇中含硫化合物分别为10.07%和5.60%;醇类分别为5.08%和12.09%;酯类分别为4.15%和10.16%;烃类分别为3.17%和0.68%。且热风微波联合干燥产生了干香菇重要风味化合物二甲基三硫醚、二甲基四硫醚及香菇素。因此,综合以上实验结果,热风微波联合干燥香菇品质优于热风干燥。      

猕猴桃切片流化床干燥特性与干燥动力学模型研究

为了提高猕猴桃切片制干品质、缩短干燥时间,采用流化床干燥技术对其进行干燥,研究温度(55,65,75,85℃)、风速(1.5,2.5,3.5,4.5m/s)和厚度(5,10,15mm)对猕猴桃切片热风干燥曲线、水分有效扩散系数以及干燥活化能的影响.结果表明:猕猴桃切片的整个干燥过程属于降速干燥,水分有效扩散系数为1.2...