The effect of blanching on quality attributes of dehydrated carrots during long-term storage

 The effect of blanching on the retention of β-carotene and ascorbic acid, and non-enzymatic browning (NEB) during storage of dehydrated carrot slices was studied. Blanched carrots contained higher β-carotene but lower ascorbic acid than their unblanched counterpart just after drying, whereas NEB was unaffected by blanching. During storage of dehydrated carrots a decrease in β-carotene and ascorbic acid content with an increase in NEB values was observed. Blanching was helpful in limiting the loss of quality parameters irrespective of storage and packaging conditions. Received: 22 May 2000 / Revised version: 11 October 2000     

竹编胶合板双面自动喷胶干燥设备

本文提出一种新型的立式双面自动喷胶干燥设备，和卧式单面自动喷胶设备比较更为有效、快捷，并增加了干燥系统。此设备自动化程度大为提高，且降低了涂胶量。     

Influence of pre-treatment and storage temperature on the evolution of the colour of dried persimmon

Drying could be a way of increasing in the value of the large quantity of persimmon that is rejected for fresh consumption, being the colour one of the main attributes of the product. Although the use of sulphites is one of the most widely extended methods of preservation their undesirable effects on asthma sufferers currently limit their application. An interesting alternative could be to use citric acid combined with an adequate storage temperature. To that end, dried persimmon slices were stored at 4 temperatures (2, 10, 18 and 28 °C) for 409 days. Before drying, one group of samples was pre-treated (15 min) in a solution of potassium meta-bisulphite (3% w/w), other two groups (15 and 35 min respectively) in a solution of citric acid (3% w/w) and the last group (control) was untreated. The L, a and b CIE-Lab coordinates were measured during storage and the colour change, ΔE, was estimated. The experimental results were modelled using first-order kinetics and Peleg’s model. The citric acid pre-treatment turned out to be an interesting alternative to SO₂ taking into account that its effect was more effective at temperatures lower than 18 °C. No significant differences were found between the two citric acid pre-treatments, being, therefore, the shortest pre-treatment the most interesting one. More experiments are necessary to establish an optimum content of citric acid in samples.     

Mechanistic study of drying of alkyd resins using (Z,Z)- and (E,E)-3,6-nonadiene as model substances

The cobalt-catalysed autoxidative drying of alkyd resins was studied using (Z,Z)-3,6-nonadiene and (E,E)-3,6-nonadiene as model compounds. A large number of reaction products were isolated from the autoxidation mixture using HPLC and preparative size exclusion chromatography and identified with ¹H- and ¹³C-NMR. The identified compounds comprised C₉ hydroperoxides, endoperoxides, epoxides, aldehydes and ketones and some other oxidation products. Their chemical structures pointed to three different types of oxidation processes taking place. Besides the main radical autoxidation reaction, evidence was found for photo-sensitized oxidation involving singlet oxygen. Thirdly, epoxidation occurs via peracids or hydroperoxides formed as intermediates. Because of the large number of possible isomers having very similar physical properties, isolation of dimers required considerable effort. Nevertheless, two dimers were isolated and characterized. Their structures indicate crosslinking to occur by recombination of radicals as termination reaction.     

An experimental approach for the analysis of early-age behaviour of high-performance concrete structures under restrained shrinkage

This paper presents a systematic approach for the experimental testing and analysis of the early-age thermo-mechanical behaviour of large prismatic high-performance concrete specimens under restrained autogenous shrinkage and realistic temperature conditions. The loading system can apply a partial degree of restraint in order to enable the characterisation of high-performance concrete specimens without premature termination of the test in case of significant restrained shrinkage. The instrumentation system can measure the strains and other parameters from the setting time with high accuracy and reliability. The analysis method takes into account the temperature effects on the measured properties and provides equations to determine the time-evolution of shrinkage, thermal expansion, stiffness and creep of the concrete. Results from the testing of 200 × 200 × 1000 mm specimens made with a 0.34 water-cement ratio concrete are presented, analysed and discussed in the paper to demonstrate the application of the proposed approach.     

Experimental and numerical investigation of heat and mass transfer during drying of Hayward kiwi fruits (Actinidia Deliciosa Planch)

In this paper we undertake an experimental and numerical study on heat and mass transfer analysis during drying of kiwi fruits. In the experimental part, the effects of various drying conditions in terms of air velocity, temperature and relative humidity on drying characteristics of kiwi fruits are investigated. In the numerical part, the external flow and temperature fields are studied using a commercial CFD package. From these fields, the local distributions of the surface convective heat transfer coefficients for the fruits are determined to predict the local convective mass transfer coefficients through the analogy between the thermal and concentration boundary layers (known as the Chilton–Colburn analogy). In addition, the time-dependent temperature and moisture distributions for different cases are obtained using the code developed to investigate heat and mass transfer aspects inside the fruits. Numerical results are then compared with experimental data and a considerably high agreement is obtained.     

US-Assisted Convective Drying of Biological Materials

The aim of this work is to promote ultrasound as an energy source that is suitable for the enhancement of drying processes, and in particular of biological materials. The study aims at a more profound recognition of the interaction between ultrasonic (US) waves and the tissues of fruits and vegetables, which may contribute to an intensification of moisture removal during their drying. Absorption of acoustic energy causes heating and structural changes of the drying material due to a series of rapid material compressions and decompressions. The research hypothesis is based on the expectation that the ultrasound waves may enhance moisture removal from the fruits and vegetables during drying due to a special “heating effect,” “vibration effect,” and “synergistic effect.” Convective ultrasonic-assisted drying tests were conducted experimentally on a new hybrid dryer with ultrasonic equipment, and the effects of ultrasonic enhancement by drying are presented based on a drying model and assessed numerically.     

Drying of Herbal Product in Closed System

A new product from a low temperature drying method that reduces the loss of highly volatile essential oils is presented. The proposed drying method consists of evaporation/sublimation of water and aromatic substances in a dryer with a closed drying agent cycle. In parallel, the evaporated compounds are continuously condensed in a heat exchanger. As a result of the drying process, high-quality dried plants and Fluidolat as liquid phase containing water and volatile organic compounds are obtained. The aim of presented investigations was to optimize the developed technology for the herb lavender.     

精心设计、制造高效节能型干燥设备

该公司从事干燥设备的设计及制造,贯彻节能减排的方针设计开发多种优质、高效、节能型干燥设备及装备满足不同颜料生产的要求,其中：节能型带式干燥机,在生产能耗、用时、产品外型、粉尘含量等指标领先于同类干燥设备。