气相红外光谱无损检测臭鳜鱼中挥发性盐基氮

挥发性盐基氮(total volatile basic nitrogen,TVB-N)是衡量臭鳜鱼新鲜度的一项重要指标,而现有检测方法存在速度慢、对样品破坏性强的局限性。为实现TVB-N快速无损检测,该文利用气相傅里叶变换红外光谱获取不同贮藏条件下臭鳜鱼挥发物的光谱信息,采用高斯滤波、稳健局部加权回归(robust locally weighted regression,RLWR)、小波阈值去噪、模拟退火-偏最小二乘(simulated annealing-partial least squares,SA-PLS)等方法进行光谱预处理,偏最小二乘回归和支持向量回归算法构建预处理光谱与TVB-N之间的关联性模型。结果表明,与其它模型相比,经RLWR结合SA-PLS选择的特征波长光谱可建立最优预测模型,其决定系数(decision coefficient,R_p²)和相对预测误差分别为0.942 8和4.005 0,具有较高的精准度与鲁棒性。     

便携式气相色谱仪市场现状分析

便携式气相色谱仪因其实时、快速、高效等优点在环境质量抽查、应急检测、执法检测中发挥着重要作用.本文通过对市场上常用便携式气相色谱仪技术原理、仪器性能、通信运维以及价格等方面分析,总结不同便携式气相色谱仪的特点,以期为木材加工企业和质检机构选购便携式气相色谱仪提供帮助.     

不同成熟期蜜桔中酚酸的组成与分布

酚酸具有多种生理功能,在植物中广泛存在.柑橘可能是膳食酚酸的重要来源.采用HPLC-PDA测定了不同成熟期温州蜜桔中八种酚酸的含量,即绿原酸、咖啡酸、对香豆酸、阿魏酸、芥子酸、原儿茶酸、对羟基苯甲酸和香草酸.结果显示,果肉中酚酸含量随成熟度提高而减少,果皮酚酸含量在半成熟期最高;果皮中酚酸含量大大高于果肉;果皮果肉中都以肉桂酸型酚酸为主,苯甲酸型酚酸含量较少;蜜桔果实中绿原酸和阿魏酸是所测八种酚酸中含量最高的.对柑橘中酚酸组成与分布的研究可望应用于食品营养标识、柑橘品种的识别或加工果汗掺假的识别等.     

Estimation of Calcium Status in Selected Food Systems

Ionic and total dialyzable calcium in nonfat dry milk, soy protein isolate, and a 50:50 mixture of the two were estimated in dialysates before and after in vitro digestion by HCl/pepsin and pancreatin/bile. Heat pasteurization did not affect % ionic or % total dialyzable calcium, before or after digestion, for the three food systems. Digestion increased % ionic dialyzable calcium for non-fat dry milk and the mixture, and increased % total dialyzable calcium for all three food systems. After digestion, % total dialyzable calcium did not differ between the milk and the mixture. Soy protein did not bind substantial amounts of calcium from the milk.     

Non-destructive Assessment of Guava (<Emphasis Type="Italic">Psidium guajava</Emphasis> L.) Maturity and Firmness Based on Mechanical Vibration Response

Storage potential and eating quality of guava (Psidium guajava L.) fruit depend on its maturity. Segregation of guava according to maturity and firmness measured using non-destructive technologies would help the industry to designate ripe fruit to immediate market and less ripe fruit for distant market (e.g., exportation). This research was conducted to evaluate the potential of experimental resonant frequency (f _e) and elasticity index (EI) to estimate fruit firmness, which has been reported to be inversely correlated to its maturity. A maturity index (I _m) was calculated as the ratio of total soluble solids/titratable acidity (TSS/TA). It was proved that TSS, TA, and I _m were significantly correlated (P?<?0.05) to skin firmness (F _s), flesh firmness (F _f), stiffness (S), and analytical resonant frequency (ω _n ), being S the attribute best fitted to I _m (R ²?=?0.77). Since it was observed that f _e and EI were sensitive to changes in fruit firmness, both of them were explored as alternatives to predict F _s, F _f, S, and ω _n of guava fruit. In some cases, EI improved the models to predict guava firmness traits (e.g., F _s vs f _e had a coefficient of determination of R ²?=?0.58, whereas for F _s vs EI, it was R ²?=?0.62). The best model occurred when plotting ω _n vs f _e (R ²?=?0.86), followed by S vs EI (R ²?=?0.84), making these promising features for the development of a new practical application using frequency response measurement as a non-destructive method to assess guava maturity.     

基于引力场粒子滤波算法估算锂电池健康状态

针对粒子滤波算法(PF)估算锂电池健康状态(SOH)时易发生粒子退化的问题,提出基于引力场算法优化的粒子滤波算法估算锂电池SOH,估算锂电池SOH。实验与仿真结果表明,与优化前的粒子滤波算法估算结果比较,该混合算法的仿真结果有更多的数据落在合理区间[0.045,0.055]内,更具优越性。     

Meat is the Meal and Status is by Meat: Recognition of Rank, Wealth, and Respect Through Meat in Turkana Culture

Although milk is the main meal and major contributor to nutritional requirements of the Turkana nomads, livestock-meat increasingly becomes central to the diet whenever the milk supply declines, and as the dry season progresses. Major social obligations are performed and networks made, maintained, and extended using livestock-meat, whose apportionment is based on seniority and power, which are equated to age and the order of marriage for females at the homestead feast. Age, the position in the hierarchy of the generation-set, and wealth, are the considerations for meat distribution at the males-only meat feast. Being the rare, desirable and major food item donated, exchanged, or offered in social transactions and as the main food in the dry season elevates its status. The analysis suggests that livestock-meat, a high status food, reveals gender, rank, respect, and perceived status of the Turkana pastoralist on social occasions.     

Meat is the Meal and Status is by Meat: Recognition of Rank,Wealth, and Respect Through Meat in Turkana Culture

Although milk is the main meal and major contributor to nutritional requirements of the Turkana nomads, livestock-meat increasingly becomes central to the diet whenever the milk supply declines, and as the dry season progresses. Major social obligations are performed and networks made, maintained, and extended using livestock-meat, whose apportionment is based on seniority and power, which are equated to age and the order of marriage for females at the homestead feast. Age, the position in the hierarchy of the generation-set, and wealth, are the considerations for meat distribution at the males-only meat feast. Being the rare, desirable and major food item donated, exchanged, or offered in social transactions and as the main food in the dry season elevates its status. The analysis suggests that livestock-meat, a high status food, reveals gender, rank, respect, and perceived status of the Turkana pastoralist on social occasions.