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.     

喷动床在农产品干燥中的研究进展

农产品干燥是农产品加工业中一项非常重要的技术,为农产品原料的利用和新产品的开发提供了更多可能.能效和干燥产品的质量是农产品干燥的2个关键指标,喷动床干燥技术是这2个关键指标的有效提高途径之一.该文简述了喷动床技术在干燥农产品的应用中的研究进展,介绍了喷动床的结构、工作原理及其应用现状,分析了喷动床干燥农产品主要的优缺点...     

红外—喷动床联合干燥设备研制与分析

为较好地解决单一红外干燥均匀性差的问题,利用红外加热高效节能的特点,结合喷动床流动性好、传热均匀的特点,设计了红外联合喷动床干燥设备。该装置包括喷动床干燥系统、红外辐射加热系统、回风式空气调节系统、动力循环系统和控制系统等。并以新鲜毛豆为物料,对该装置干燥均匀性和产品品质进行试验验证。结果表明,单一红外干燥耗时270 min,而红外—喷动床联合干燥耗时160 min,与单一的红外干燥相比,红外—喷动床联合干燥时间缩短了40.7%;同时,红外—喷动床联合干燥设备减轻了毛豆仁干瘪皱缩现象,使干制品具有较好的豆香味和感官品质。     

基于电场分布的单波导矩形微波喷动床结构设计

针对矩形微波喷动床,基于喷动腔内电场强度及电场分布均匀性进行结构分析与优化。采用的评价指标为反映电场分布均匀性的变异系数COV、平均电场强度E_(mean)和反映电场局部集聚参数E_(max)/E_(mean)。利用多物理场耦合软件COMSOL Multiphysics对喷动腔内电场强度进行数值模拟,通过单因素和正交试验法分别分析喷动床结构参数a(喷动床宽)、H(波导位置)和L(喷动床高)对评价指标的影响。结果发现,a对COV和E_(max)/E_(mean)的影响最显著,H对E_(mean)的影响最显著;a与L的交互作用对COV,E_(mean)和E_(max)/E_(mean)的影响均显著。单波导矩形微波喷动床的优化结构为:a=427mm,H=200mm,L=1 000mm。     

红外辐射在谷物干燥中的应用

阐述了红外辐射干燥的基本原理,分析了红外辐射在谷物干燥中的应用形式,提出了今后的研究方向.     

红外干燥粮食机理浅析

介绍了红外干燥谷物的机理,分析了红外干燥谷物的传质情况以及影响干燥效果的因素,从理论上说明了红外干燥较热风干燥更具优势.     

Drying kinetics and quality of okara dried in a jet spouted bed of sorbent particles

Okara or soy residue is a byproduct of soymilk and tofu production process. Okara has high protein content and can be used as an ingredient in many food products or can be used as animal feed. However, okara deteriorates rapidly; hence raw okara must be dried as early as possible under appropriate conditions. Drying could also help eliminating undesirable antinutritional factors in okara. The present study investigated the feasibility of drying okara using a combined convection-sorption drying, i.e., the use of a jet spouted bed of sorbent particles. The effects of various parameters such as drying air temperature and velocity, mass ratio of sorbent particles to okara, and initial bed height of okara on the drying kinetics were investigated. Also, various quality attributes of okara viz. color, oxidation level, rehydration ability, urease activity and protein solubility as well as the specific energy consumption during drying were investigated in both low- and high-temperature ranges.     

Effect of constant and variable temperature drying processes on drying characteristics,quality, and volatile profile of rose petals in infrared-assisted spouted bed drying

The edible rose (Rosa Crimson Glory) petals were dried using infrared-assisted spouted bed drying technology. The effects of different drying temperature conditions (30, 35, 40, 45, and 50°C, as well as stepped heating drying [SHD] and stepped cooling drying) on the drying characteristics, physicochemical properties, antioxidant capacity, and changes in volatile flavor compounds of the rose petals were investigated. The results showed that the drying time was shortened with increasing drying temperature. Both variable temperature drying processes gave the shortest drying times. Optimal color retention of rose petals was achieved at a constant temperature of 40°C and SHD. Increased drying temperature resulted in higher water-soluble polysaccharide content in the dried rose petals, whereas lower temperatures facilitated anthocyanin preservation. The variable temperature drying processes favored the retention of water-soluble polysaccharides in rose petals, but not anthocyanins. Regarding antioxidant capacity, the samples dried at 40°C and those subjected to the two variable temperature drying processes performed better. This study also analyzed the differences in volatile flavor compounds of rose petals dried under different drying conditions. It was found that the majority of volatile flavor compounds in the rose petals dried by SHD exhibited higher content levels than the other drying conditions. Therefore, considering a thorough evaluation of all relevant factors, it was clear that utilizing the SHD process was the most efficient method for obtaining the best quality rose petals overall.     

脉冲喷动床微波冻干方便面品质与能耗研究

以湿面条为实验原料,进行脉冲喷动床微波冻干(PSBMFD)面饼品质与能耗研究,并与传统电加热冻干(CFD)方式进行对比分析。研究表明:PSBMFD面饼的复水时间、复水比及复水前后硬度值分别为150 s、3.07、4 692.36 g、520.45 g,水分、色差及收缩率的均匀度分别为94.51%、94.31%、92.23%,感观评价总分为8.2,干燥时间为3.5 h,干燥产品总耗能为8.05 kWh/kg。PSBMFD技术不仅提高冻干面饼的干燥均匀度,改善冻干面饼的品质,而且与CFD相比,能够明显地缩短冻干时间(58.83%),降低冻干能耗(66.63%)。     

Protein quality of dried enzymatic hydrolysate from anchovy produced in a spouted bed of inert particles

The anchovy (Engraulis anchoita) is a pelagic fish and due to its abundance in South America shows a sustainable exploitation. The enzymatic hydrolysis of anchovy protein associated to the drying technique in spouted bed was analysed in order to obtain products with the best characteristics. The drying conditions were inlet air temperature, concentration and flow rate of suspension. The degree of hydrolysis of the anchovy suspension was of 3.8%, and its available lysine and specific antioxidant activity were of 86 g kg^?1_protein and 4.31 mm _DPPH kg^?1 min^?1, respectively. In spouted bed drying, the lowest reduction in available lysine (9%) and loss of specific antioxidant activity (8%) were found at 90 °C, and suspension concentration and flow rate of 65 g L^?1 and 200 mL h^?1, respectively. The dried product was characterised as a protein source of high biological value due to the essential amino acids profile.     

近红外光谱分析技术在粮油品质评价中的研究应用进展

近红外光谱分析技术于20世纪60年代率先应用于美国农业领域,随着计算机技术的普及和化学计量学的发展,近年来国内也广泛应用到各个领域,在粮油收购过程中对质量的检控就应用了近红外光谱分析技术。简述近红外光谱分析技术的基本原理和操作流程,重点综述近年来近红外光谱分析技术在粮油品质评价方面的具体应用,分析其存在的不足,并展望其在粮油领域中的应用前景。     

The effects of middle infrared radiation intensity on the quality of dried tomato products

The effects of air temperature (T) (unheated and 35 °C), infrared radiation intensity (IP) (894, 1004, 1190, 1314 and 1410 Wm^?2) and air velocity (Av) (1.0, 1.5 and 2.0 ms^?1) on drying characteristics of tomatoes, drying time (DT), specific energy consumption (SEC) and quality parameters were investigated. DT and SEC varied between 114 and 249 min, 10.04 and 18.22 MJ kg^?1 water, respectively, and were significantly affected by process variables. Shrinkage ratio (S) and rehydration ratio (R_r) were varied between 0.129 and 0.214, 2.11 and 2.86 for all the drying conditions, respectively. Total colour change (ΔE) varied from 5.30 to 13.19. Vitamin C content decreased, while lycopene content increased with infrared drying. For optimum points, desirability of functions of all targets had satisfactory, very good and excellent desirability values and ranged between 0.54 and 0.99.     

Physical properties of parboiled wheat and bulgur produced using spouted bed and microwave assisted spouted bed drying

The main objective of this study was to compare the spouted bed and microwave assisted spouted bed drying on affecting physical properties of parboiled wheat and bulgur. Drying was performed at different temperatures (50 °C, 70 °C, 90 °C) and microwave powers (288 W, 624 W). Bulk and apparent density, bulk and apparent porosity, sphericity, color, microstructure and pore size distribution of parboiled wheat were investigated after drying. Yield and water absorption capacity were determined in bulgur samples. The effect of air temperature on physical properties of product except color was not significant in spouted bed drying. More porous structure was observed in wheat samples dried in microwave assisted spouted bed compared to air dried ones. Sphericity and bulk density were higher when high temperature was combined with high microwave power. In microwave assisted spouted bed drying, similar yield value but lower water absorption capacity of bulgur were observed as compared to spouted bed drying.     

美国引进酿造专用啤酒大麦产量及品质综合分析

对8种引进的美国啤酒大麦及当地主栽甘啤4号品种进行生育期、产量及品质综合比较。结果表明：生育期除MERIT品种外,其余均较对照甘啤4号早熟,株高整体较高,穗长较短,二棱品种分蘖成穗数高;所有参试品种籽粒蛋白质、千粒质量、饱满度、发芽率均达国家优级标准（蛋白质含量10.0%～12.5%、千粒质量≥37g、饱满度≥80%、发芽率≥97%）;各品种麦芽的水分、细粉浸出率、α-氨基氮、黏度、糖化力均达到国家优级标准（麦芽水分≤5.0%、细粉浸出率≥79%、α-氨基酸态氮≥150 mg/kg,黏度≤1.60 mPa·s,糖化力≥260 WK）。大麦品种Z090M066M平均产量9 466.31 kg/hm2,位居参试品种第一位;但参试品种均出现条纹病。综合分析,Z090M066M可以进行进一步试验示范推广。     

Use of a spouted bed to improve the storage stability of wheat germ followed in paper and polyethlyene packages

Stabilization of wheat germ by heating in a spouted bed for 180–540 s with air at 140–200 °C was studied. The lipase activity decreased by 6–65%. Wheat germ processed at 200 °C for 360 s was ranked highest in sensory evaluation, described as having ‘a golden color’ and ‘nutty flavor’, and its lipoxygenase activity had decreased by 91.2%. This product and raw wheat germ were stored in paper, polyethylene and vacuum‐packed polyethylene pouches at 5 °C, room temperature (18–26 °C) and 40 °C, and the moisture contents, water activities, free fatty acid contents and peroxide values were followed for 20 weeks. The increases were faster in paper pouches than in the polyethylene ones; vacuum packaging in polyethylene did not bring about significant improvement. The peroxide values of raw samples exceeded 10 meq O₂ kg^?1 oil after 3–23 days while those of the processed samples stored at room temperature or 5 °C were still less than 10 after 20 weeks. The free fatty acid content and peroxide value changes were expressed by zero order kinetics, resulting in similar activation energies for the raw and processed samples. Copyright © 2005 Society of Chemical Industry     

Relationship of ergosterol content and fungal contamination and assessment of technological quality of malting barley preserved in a metal silo using the near-ambient method

Environmental microbiologists frequently use ergosterol, a fungal-specific membrane lipid, as an indicator of fungal infection in grain and other plant materials. Microbiological loading and technological quality of barley was determined directly after harvest, after post-harvest drying, and during storage. The conventional plate count method was used to measure fungal contamination (CFU). Ergosterol concentration (ERG) was determined by extraction, saponification and quantification using high-performance liquid chromatography (HPLC) with UV detection. The laboratory malting method was used to determine technological quality of the malt. Results showed a significant correlation between ERG and CFU (the coefficient of correlation was 0.92). Analyses also indicated that the high germinative energy and technological quality of the malt produced from dried barley was retained.