Effect of [6,6]‐phenyl‐C61‐butyric acid methyl ester on the morphology of poly(3‐hexylthiophene) film

The change of morphology of poly(3‐hexylthiophene) (P3HT) film as a result of blending with [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PCBM) was studied using a freeze‐dry method. A porous structure was observed as the P3HT/PCBM solution was freeze‐dried. The pore size decreased as the proportion of PCBM increased in the P3HT/PCBM blended film. Additionally, the freeze‐dried P3HT/PCBM film was more resistant to the formation of PCBM crystals than that prepared by a spin‐coating method during the thermal annealing process. Homogeneous distribution of PCBM in the freeze‐dried P3HT/PCBM film was the main reason for the reduction of large PCBM crystal formation. Copyright © 2011 Society of Chemical Industry     

Freeze drying and vacuum impregnating characteristics of Nostoc sphaeroides Kützing

ABSTRACT

Nostoc sphaeroides Kützing (N. sphaeroides) is a kind of edible algae widely growing in China. The paper is aimed at developing a novel snack food of N. sphaeroides using vacuum impregnation. The samples from freeze drying (FD) have large volume and loose structure, which were found suitable for processing. With nuclear magnetic resonance and imaging, the water signal of N. sphaeroides was measured in FD, and different drying-stage raw N. sphaeroides were selected to impregnate by different solutions, when the products’ impregnated mass, water activity, and flavor difference were analyzed. Results indicate that the water distribution in FD was uniform. Sucrose impregnated product was stable with large impregnated mass and low water activity, whereas trehalose impregnated product was easy to separate from the solution with low sweetness. For the products with the raw N. sphaeroides dried for 9 and 12?h, no obvious difference was found in water activity and flavor. Result shows that N. sphaeroides dehydrated for 9?h in FD is suitable for vacuum impregnation, and different impregnated products are acceptable from the point of view of flavor and storage stability.     

Effect of previous frozen storage on quality changes of grass carp (Ctenopharyngodon idellus) fillets during short‐term chilled storage

The effect of chilled, frozen and freeze‐chilled storage on quality of grass carp fillets and soups was evaluated by sensory score, total aerobic counts and biochemical quality. Fish fillets were stored at 4 °C for 6 days (T1), ?40 °C for 12 h and then at ?20 °C for 5 days (T2), ?40 °C for 12 h and then at ?20 °C for 5 days, followed by at 4 °C for 4 days (T3). T1 showed higher sensory score, salt‐soluble protein content, better colour and texture qualities than T2 and T3 within 3 days. All fillets kept good quality based on the acceptable limit of sensory score, total volatile basic nitrogen and total aerobic count during storage time. According to the transportation and retail time, chilled storage is appropriate when it is within 3 days. If it extends for 5 days, freeze‐chilling treatment keeps better quality, but later chilled fillets should be retailed within 4 days.     

Ice‐Templated Scaffolds with Microridged Pores Direct DRG Neurite Growth

Successful spinal cord repair is thought to be promoted with hierarchically structured scaffolds. These should combine aligned porosity with additional linear features on the micrometer scale to guide axons across multiple length scales. Such scaffolds are generated through the carefully controlled directional solidification of an aqueous biopolymer solution, followed by lyophilization. Under specific freezing conditions this yields a highly regular and aligned lamellar architecture. This architecture exhibits uniform ridges of controlled height and width on the lamellar surface. These ridges run parallel to the pore axis, serving as secondary guidance features. The ridges are capable of linearly aligning 62.4% of chick dorsal root ganglia neurites to within ±10° of the ridge direction. Notably, neurites sprouting perpendicular to the ridge are guided into alignment with these microridged features.     

Effect of rice ageing and freeze‐thaw cycle on textural properties of cooked rice (Oryza sativa L.) cv. Khao Dawk Mali 105

This study investigated the effect of rice grain ageing (0.7–12 months) and freeze‐thaw 1–5 cycles on the textural properties of cooked rice. The cooked rice from aged rice grains was freezing and thawing up to five cycles. Ageing of the rice grain increased the hardness and decreased the stickiness of the cooked rice. Repeated freeze‐thaw cycles caused an increase in hardness and a decrease in stickiness of aged cooked rice. Scanning electron micrographs showed a rough surface on the cooked rice after repeated freeze‐thaw cycles, especially for cooked rice from rice aged for 12 months. Differential scanning calorimetry and X‐ray diffraction showed increased starch retrogradation with increased freeze‐thaw cycles. The gelatinisation temperature and gelatinisation enthalpy increased when rice was aged for longer periods. Thus, ageing of rice and the number of freeze‐thaw cycles influence the textural properties of cooked rice.     

Sorption isotherms and thermodynamic properties of freeze‐dried colostral whey powders with different additives

Moisture adsorption isotherms of colostral whey (CW) powders with different additives (maltodextrin and sucrose) were determined using gravimetric static method at 15–35 °C in the water activity range of 0.067–0.76. The moisture adsorption isotherms obtained were typical sigmoid curves, and the modified‐Halsey and Guggenheim–Anderson–de Boer (GAB) equations gave the best fit to experimental data among five well‐known equations. Addition with maltodextrin into CW powders could effectively decrease equilibrium moisture content (EMC), whereas addition with sucrose increased EMC in the water activity of 0.43–0.76 at 15 and 25 °C and in the water activity of 0.21–0.76 at 35 °C, respectively. Thermodynamic properties including net isosteric heat of sorption and differential entropy were determined from adsorption data using Clausius–Clapeyron equation. The results showed that net isosteric heat of sorption of all the samples decreased exponentially with increasing EMC. Enthalpy–entropy compensation theory was applicable for adsorption process of all the samples, and the adsorption processes were enthalpy‐driven.     

喷气燃料冰点试验出现悬浮物的探讨

某公司加氢裂化装置生产的喷气燃料在冰点试验时发现了悬浮物，并且悬浮物在回温过程中消失。虽然通过调整原料中催化裂化柴油（简称催化柴油）、外购原料、常三线柴油的掺炼情况，减少原料中芳烃及正构烷烃的含量，但是在冰点试验时依然发现了悬浮物；其次，通过调整反应深度和分馏塔分离效果（喷气燃料馏程），以及对影响喷气燃料质量的其他因素进行排查，仍然未找到出现悬浮物的原因；最后通过化验分析方法排查发现，在干燥环境（没有湿空气的影响）下进行喷气燃料冰点试验时，可以避免产生絮状物，说明空气中的水是喷气燃料冰点试验中产生絮状物的直接原因。因此，在进行喷气燃料冰点试验时要采取措施隔绝水分。     

具有全自动（半自动）进出料等功能最新型真空冷冻干燥机研发报告

主要介绍了上海千山远东制药机械有限公司最新研发的具有全自动（半自动）进出料功能真空冷冻干燥机的概况，从四个方面描述了在功能、质量上的提高，使国产真空冷冻干燥机真正符合新版GMP要求。     

Effect of blanching and drying treatments on quality of bamboo shoot slices

The enzymes activity, texture, pectin, microstructure and colour change in bamboo shoots (Dendrocalamus latiflorus) were examined to evaluate the effect of blanching and drying treatments on quality of bamboo shoot slices (BSS). Peroxidase (POD), phenylalanine ammonia‐lyase and polyphenol oxidase in BSS will become completely inactive at 95 °C for 6‐, 9‐ and 12‐min blanching treatments, respectively. The hardness and protopectin (PP) content decreased after the blanching treatment. Meanwhile, the content of water‐soluble pectin increased initially and then decreased gradually during the blanching. After the blanching treatment, the L* and a* of BSS decreased, while b* increased, ΔE > 2. The hardness of rehydrated BSS decreased by 43.57% after freeze drying (FD), which, however, decreased more after hot air drying (HAD). The pectin of rehydrated BSS was also determined to explain the hardness change in BSS. The BSS acquired similar microstructure of fresh samples after FD, while microstructure of BSS was severely damaged after HAD. The colour of BSS changes significantly after drying treatment. However, FD can maintain better colour of BSS than HAD. The results may provide a reference for industrial production of BSS.