粗纺呢绒缩呢工艺的优化研究

粗纺缩呢工序是粗纺毛织物整理加工过程中的一项重要工序,对产品质量起着十分重要的作用。利用正交试验的方法,对纯毛麦尔登产品后整理的缩济用量、pH值、缩箱压力三因素进行正交试验,优选出最佳加工工艺参数为：缩剂用量4％,缩箱压力0．15MPa,pH值9．5。     

Toward predictive food process models: A protocol for parameter estimation

Mathematical models, in particular, physics-based models, are essential tools to food product and process design, optimization and control.

The success of mathematical models relies on their predictive capabilities. However, describing physical, chemical and biological changes in food processing requires the values of some, typically unknown, parameters. Therefore, parameter estimation from experimental data is critical to achieving desired model predictive properties.

This work takes a new look into the parameter estimation (or identification) problem in food process modeling. First, we examine common pitfalls such as lack of identifiability and multimodality. Second, we present the theoretical background of a parameter identification protocol intended to deal with those challenges. And, to finish, we illustrate the performance of the proposed protocol with an example related to the thermal processing of packaged foods.     

Evaluation and validation of an automatic jaw movement recorder (RumiWatch) for ingestive and rumination behaviors of dairy cows during grazing and supplementation

Observation of ingestive and rumination behaviors of dairy cows may assist in detecting diseases, controlling reproductive status, and estimating intake. However, direct observation of cows on pasture is time consuming and can be difficult to realize. Consequently, different systems have been developed to automatically record behavioral characteristics; among them is the RumiWatch System (RWS; Itin and Hoch GmbH, Liestal, Switzerland). Until now, the RWS has not been thoroughly validated under grazing conditions. The aim of the current study was to validate the RWS, against direct observation, in measuring ingestive and rumination behaviors of dairy cows during grazing and supplementation in the barn. A further objective was to examine whether it is possible to refine the algorithm used by the evaluation software RumiWatch Converter 0.7.3.2 to improve the accuracy of the RWS. The data were collected from an experiment carried out with 18 lactating Holstein cows in a crossover block design including 3 treatments and 3 measuring periods. All cows grazed night and day, 19 h/d, and were either unsupplemented or supplemented, with chopped whole-plant corn silage, or chopped whole-plant corn silage mixed with a protein concentrate. During the measuring periods, cows were equipped with the RumiWatch Halter, and their ingestive and rumination behaviors were recorded concurrently by the RumiWatch Halter and by direct observation (690 × 10 min). Comparison of concurrently measured data shows that the RWS detected jaw movements reliably, but classification errors occurred. A low relative prediction error of ≤0.10 for the number of rumination boluses, rumination chews, and total eating chews was found. A high relative prediction error of >0.10 was found for the number of prehension bites and time spent in prehension and eating. Both converter versions performed equally well in differentiating ingestive and rumination behaviors when cows were supplemented in the barn or when grazing and supplementation activities were combined. For grazing cows, with no supplementation, more reliable results for the total number of eating chews, rumination chews, prehension bites, and time spent in these activities were obtained, by using the RumiWatch Converter 0.7.3.11. In light of these findings, further research is warranted to improve the accuracy of the RWS and to allow a differentiation between mastication chews and prehension bites while eating.     

鱼腥草多糖活性炭脱色工艺研究

研究了鱼腥草多糖活性炭脱色的工艺。以多糖含量和脱色率为指标,在单因素筛选的基础上,采用正交试验法对脱色工艺进行优选。优化的脱色工艺为:在pH 4.0,20℃的条件下,加入0.4%活性炭,搅拌40 min。该脱色工艺适合工业化应用。     

转基因棉花MON88913转化体特异性定性、定量PCR检测方法

本文以我国批准商业化的转基因耐草甘膦棉花MON88913为研究对象,建立并验证了其转化体特异性定性、定量PCR检测方法.建立的定性PCR方法的检测极限是20个拷贝棉花单倍体基因组DNA,定量PCR方法的检测和定量极限分别是10和20个拷贝棉花单倍体基因组DNA.同时,我们组织了实验室5位研究人员对建立的定量PCR检测方法进行了协同验证.对5个盲样的定量分析结果显示与真实值的偏差介于1.59% 和10.12%之间,完全满足国际标准25%偏差范围的要求,完全可用于转基因棉花MON88913的实际样品检测.     

Rapid and non-destructive analysis of apricot fruit quality using FT-near-infrared spectroscopy

A non-destructive optical method based on near-infrared spectroscopy has been used for the evaluation of apricot fruit quality. Diffuse reflectance measurements (800–2500 nm), physical, physiological and biochemical measurements were performed individually on 877 apricot fruits from eight contrasted cultivars harvested at different ripening stages. Relationships between spectral wavelengths and quality attributes were evaluated by application of chemometric techniques based on partial least squares (PLS) on fruit set divided randomly into two groups: 598 fruits for calibration and 279 for validation. Good prediction performance was obtained for soluble solids and titratable acidity with correlation coefficients of 0.92 and 0.89 respectively and root mean square errors of prediction of 0.98% Brix and 3.62 meq 100 g⁻¹ FW respectively. For the other quality traits such as firmness, ethylene, individual sugars and organic acids, the prediction models were not satisfactorily accurate due to the high error of calibration and prediction.     

利用香菇菌丝体发酵藜麦及其发酵产物中粗多糖的抗氧化评价

以藜麦为固体培养基,利用香菇菌丝体将其发酵,通过正交试验设计探讨碳源、氮源、碳氮源添加比例、时间等因素对发酵产物中粗多糖含量的影响,测定最适发酵条件下发酵产物中粗多糖抗氧化活性。最终得出以粗多糖为目标产物的最适发酵条件为:碳源为淀粉,氮源为牛肉膏,碳氮源添加比例5:1,发酵时间15 d;在此条件下,香菇与藜麦的发酵产物中粗多糖含量达(58.89±1.33)mg/g,较未发酵藜麦提升了31倍;且其对DPPH·自由基和ABTS·^+自由基均表现出较好的体外清除效果,当粗多糖浓度为20 mg/mL时,其对DPPH·自由基和ABTS·^+自由基的清除能力均达到最高,分别为76.57%与60.16%。利用香菇菌丝体发酵藜麦后,能够大大提升藜麦培养基中多糖的含量,且发酵后的粗多糖具有较好的抗氧化能力,为发酵产物作为功能性食品的可行性提供一定数据支持。     

New approach for the quantification of processed animal proteins in feed using light microscopy

A revision of European Union's total feed ban on animal proteins in feed will need robust quantification methods, especially for control analyses, if tolerance levels are to be introduced, as for fishmeal in ruminant feed. In 2006, a study conducted by the Community Reference Laboratory for Animal Proteins in feedstuffs (CRL-AP) demonstrated the deficiency of the official quantification method based on light microscopy. The study concluded that the method had to be revised. This paper puts forward an improved quantification method based on three elements: (1) the preparation of permanent slides with an optical adhesive preserving all morphological markers of bones necessary for accurate identification and precision counting; (2) the use of a counting grid eyepiece reticle; and (3) new definitions for correction factors for the estimated portions of animal particles in the sediment. This revised quantification method was tested on feeds adulterated at different levels with bovine meat and bone meal (MBM) and fishmeal, and it proved to be effortless to apply. The results obtained were very close to the expected values of contamination levels for both types of adulteration (MBM or fishmeal). Calculated values were not only replicable, but also reproducible. The advantages of the new approach, including the benefits of the optical adhesive used for permanent slide mounting and the experimental conditions that need to be met to implement the new method correctly, are discussed.     

Determination of aflatoxin M1 in milk by triple quadrupole liquid chromatography-tandem mass spectrometry

A sensitive and reliable method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with an electrospray-positive ionization method was developed for the determination of aflatoxin M₁ in milk. This method includes simple extraction of the sample with acetonitrile by ultrasonic, separation on an MGIII-C₁₈ column using 0.01% formic acid buffer/acetonitrile (60 : 40, v/v) as mobile phase, and MS/MS detection using multiple reaction-monitoring mode. Average recoveries of aflatoxin M₁ from spiked samples at concentrations of 0.02 and 1 ng ml^?1 ranged from 77% to 94%, with a 6% relative standard deviation. The limit of detection and limit of quantification were 0.006 and 0.02 ng ml^?1, respectively. The standard curve was linear between 0.02 and 20.0 ng ml^?1. The recommended method is simple, rapid, specific and reliable for the routine monitoring of aflatoxin M₁ in milk.     

Development of an accelerated solvent extraction,ultrasonic derivatisation LC‐MS/MS method for the determination of the marker residues of nitrofurans in freshwater fish

A rapid method using accelerated solvent extraction (ASE) and ultrasound enhanced derivatisation has been developed for the quantitative determination of metabolites of nitrofurans, namely 3‐amino‐2‐oxalidinone (AOZ), 5‐morpholinomethyl‐3‐amino‐2‐oxalidinone (AMOZ), 1‐amino‐hydantoin (AHD) and semicarbazide (SEM), in muscle and skin of carp and finless eel. The target analytes were extracted using ASE, ultrasonic derivatisation for 1?h and then purified by solid phase extraction. Averaged decision limits (CCα) and detection capability (CCβ) of the method were in the range of 0.07–0.13 and 0.31–0.49?µg?kg^?1 in carp and finless eel, respectively. The accuracy in terms of recovery was in the range 77.2–97.4%. The simplified and traditional methods were compared with incurred residue samples. The simplified method reduced the derivatisation time and has been applied to the determination of nitrofurans residues in fish.