Physical and Sensory Properties of Sweetpotato Puree Texturized with Cellulose Derivatives

We evaluated the physical and sensory characteristics of restructured sweetpotato puree texturized with methylcellulose (MC) or methylhy-droxypropylcellulose (MHPC). Samples were studied by instrumental texture profile (TPA), dynamic rheometric and sensory analyses, and scanning electron microscopy. Gelation of the gum-puree mixtures gave maximal values of the storage modulus (G^') at 60-70^°C. The TPA curves measured at 60^°C for the 0.50%MC or MHPC sample were similar to those of baked sweet potatoes (control). A texture profile panel rated the 60^°C samples of the 0.25-0.50%MC or MHPC product as nearly equal to baked roots for several texture notes. An untrained acceptability panel scored the 0.25%MC and MHPC samples significantly higher in flavor and overall acceptability than baked roots.     

基于Spark的并行化头脑风暴优化算法及复杂多峰函数优化

头脑风暴优化BSO算法是一种新型的群体智能优化算法,启发于众人集思广益求解问题的模式,适合求解复杂多峰函数优化问题。但是,BSO求解多峰极值时需进行重复的迭代运算,面对大规模数据集时会出现计算效率与求解精度过低的现象。为解决上述问题,设计并实现了一种基于Spark的并行化头脑风暴优化算法,通过将BSO算法中计算复杂度最高的聚类与新解产生过程并行化,以提高算法的加速比与计算效率。特别地,基于并行化思想,将种群划分为多个子群进行协同演化,每个子群独立产生新解来保持种群多样性,提高算法的收敛速度。最后,利用并行化BSO算法求解多峰函数。实验表明,在并行节点的总核心数为10的情况下,并行化BSO算法计算时间节省一半,计算精度和串行BSO算法基本持平,收敛速度明显提高,实验结果说明了并行化BSO的有效性。     

EFFECTS OF PUREE PROCESSING METHODS ON THE TEXTURAL CHARACTERISTICS OF AN ALGINATE- TEXTURIZED SWEET POTATO PRODUCT1

The objective was to determine the effect of sweet potato (SP) puree preparation methods on the properties of texturized SP products. The treatments were separated into two main types in which sliced SPs were cooked prior to puree preparation, or purees were prepared by grinding raw roots, followed by heat processing using steam injection. Purees from each treatment were texturized into cylinders 12.7 cm long and 5.5 cm in diameter, using an alginate-calcium system, and frozen. We found that cooked purees prepared by steam injection of raw purees had higher viscosities than did purees made from cooked SP. Texture Profile Analysis (TPA) revealed that texturized product made from SP cooked before puree preparation was the most fracturable and least springy of the texturized products. Sensory panelists did not express apreference for texturized product from any of the treatments, but 23% of the panelists noted a grainy texture and/or raw root aroma in products prepared by steam injection of raw purees. In view of these observations and the fact that puree preparation from cooked SP is the simplest process, this process appears to be the best for this type of texturized SP product.     

主动网络流水印技术研究进展

在匿名网络环境下通信双方关系确认、僵尸网络控制者追踪、中间跳板主机发现等方面,以被动网络流量分析（passive traffic analysis）为核心的传统入侵检测与流关联技术存在空间开销大、实时性差、识别率低、灵活性欠佳、难以应对加密流量等明显缺点。而将主动网络流量分析与数字水印思想相融合的主动网络流水印（ANFW, active network flow watermark）技术能有效克服传统被动网络流量分析方法的不足,已引起了国内外学者的广泛关注。首先阐述了ANFW机制的通用模型,总结了ANFW技术的分类及所涉及的角色关系;其次,详细综述了近年来提出的多种典型的基于不同网络流特征的ANFW技术,并进行对比性总结;最后,概述了当前ANFW技术自身安全威胁及应对措施现状,展望了其未来的研究方向。     

Texturization of Sweetpotato Puree with Alginate: Effects of Tetrasodium Pyrophosphate and Calcium Sulfate

The effects and optimum levels of tetrasodium pyrophosphate (TSPP), alginate and calcium sulfate (CaSO₄) on physical and sensory characteristics of texturized sweetpotato puree were studied using response surface methodology. Samples were subjected to instrumental texture profile analysis (TPA) and sensory evaluation. Prediction models to describe the effects of ingredients on TPA parameters were used to generate contour plots for optimization using TPA values of baked roots as the limits. The optimum formulations having textural characteristics of the baked roots were within the following identified regions: (a) at 0.12% TSPP, alginate, 0.20–0.25%, and CaSO₄, 0.4–0.70%; (b) at 0.18% TSPP, alginate, 0.2–0.55%, and CaSO₄, 0.22–0.42%. A taste panel scored representative formulations of the optimum regions similar to the baked roots for color, flavor, texture, and overall acceptability.