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Zhu F.,Zhejiang University | Zhang H.,Zhejiang University | Shao Y.,Zhejiang University | He Y.,Zhejiang University | And 2 more authors.
Food and Bioprocess Technology | Year: 2014

A nondestructive and rapid method using near-infrared (NIR) hyperspectral imaging was investigated to determine the spatial distribution of fat and moisture in Atlantic salmon fillets. Altogether, 100 samples were studied, cutting out from different parts of five whole fillets. For each sample, the hyperspectral image was collected with a pushbroom NIR (899-1,694 nm) hyperspectral imaging system followed by chemical analysis to measure its reference fat and moisture contents. Mean spectrum were extracted from the region of interest inside each hyperspectral image. The quantitative relationships between spectral data and the reference chemical values were successfully developed based on partial least squares (PLS) regression with correlation coefficient of prediction of 0.93 and 0.94, and root mean square error of prediction of 1.24 and 1.06 for fat and moisture, respectively. Then the PLS models were applied pixel-wise to the hyperspectral images of the prediction samples to produce chemical images for visualizing fat and moisture distribution. The results were promising and demonstrated the potential of this technique to predict constituent distribution in salmon fillets. © 2013 Springer Science+Business Media New York.

Zhang X.,Zhejiang University | He Y.,Zhejiang University | He Y.,Key Laboratory of Equipment and Informatization in Environment Controlled Agriculture
Industrial Crops and Products | Year: 2013

In this study we developed a technique to early and rapidly estimate seed yield using hyperspectral images of oilseed rape leaves in the visible and near infrared (VIS-NIR) region (380-1030. nm). Hyperspectral images of leaves were acquired four times from field trials in China between seedling until pods stage. Seed yield data on individual oilseed rape plants were collected during the local harvest season in 2011. Partial least square regression (PLSR) was applied to relate the average spectral data to the corresponding actual yield. We compared four PLSR models from four growing stages. The best fit model with the highest coefficients of determination (RP2) of 0.71 and the lowest root mean square errors (RMSEP) of 23.96 was obtained based on the hyperspectral images from the flowering stage (on March 25, 2011). The loading weights of this resulting PLSR model were used to identify the most important wavelengths and to reduce the high dimensionality of the hyperspectral data. The new PLSR model using the most relevant wavelengths (543, 686, 718, 741, 824 and 994. nm) performed well (RP2=0.71, RMSEP = 23.72) for predicting seed weights of individual plants. These results demonstrated that hyperspectral imaging system is promising to predict the seed yield in oilseed rape based on its leaves in early growing stage. © 2012 Elsevier B.V..

Shen F.,Zhejiang University | Shen F.,Key Laboratory of Equipment and Informatization in Environment Controlled Agriculture | Wu J.,Shaoxing Testing Institute of Quality Technical Supervision | Ying Y.,Zhejiang University | And 3 more authors.
Food Chemistry | Year: 2013

Discrimination of Chinese rice wines from three well-known wineries ("Guyuelongshan", "Kuaijishan", and "Pagoda") in China has been carried out according to mineral element contents in this study. Nineteen macro and trace mineral elements (Na, Mg, Al, K, Ca, Mn, Fe, Cu, Zn, V, Cr, Co, Ni, As, Se, Mo, Cd, Ba and Pb) were determined by inductively coupled plasma mass spectrometry (ICP-MS) in 117 samples. Then the experimental data were subjected to analysis of variance (ANOVA) and principal component analysis (PCA) to reveal significant differences and potential patterns between samples. Stepwise linear discriminant analysis (LDA) and partial least square discriminant analysis (PLS-DA) were applied to develop classification models and achieved correct classified rates of 100% and 97.4% for the prediction sample set, respectively. The discrimination could be attributed to different raw materials (mainly water) and elaboration processes employed. The results indicate that the element compositions combined with multivariate analysis can be used as fingerprinting techniques to protect prestigious wineries and enable the authenticity of Chinese rice wine. © 2013 Elsevier Ltd. All rights reserved.

Tang W.,Zhejiang University | Tang W.,Key Laboratory of Equipment and Informatization in Environment Controlled Agriculture | Wu J.,Zhejiang University | Wu J.,Key Laboratory of Equipment and Informatization in Environment Controlled Agriculture
Analytical Methods | Year: 2014

An amperometric method for the detection of organophosphorus pesticide based on acetylcholinesterase inhibition is reported. A silver electrode is used and shows an inherent advantage in determination of pesticides, which can monitor the activity of the enzyme in real time by electrochemical oxidization of thiocholine at low potential. Cyclic voltammetry and amperometry were used to evaluate the performance of silver electrode for thiocholine detection. Spectrophotometry was conducted to optimize the parameters for the enzymatic reaction. Cyclic voltammetry shows the advantages of silver over others (platinum, glassy carbon and gold) electrodes, when detecting thiocholine at low potentials. The silver electrode could linearly respond to thiocholine in the range from 5.2 × 10-7 to 2.6 × 10-5 M at 0.08 V. The measurement displayed a detection limit of 6.2 ppb. The analytical feasibility was investigated further via determination of paraoxon in Chinese cabbages and Fuji apples, which shows recovery rates of 92.05% and 106.11%, respectively. The results indicate the capability of the proposed method for pesticides monitoring in real samples. © 2014 The Royal Society of Chemistry.

Fan K.,Zhejiang University | Fan K.,Key Laboratory of Equipment and Informatization in Environment Controlled Agriculture | Wu J.,Zhejiang University | Wu J.,Key Laboratory of Equipment and Informatization in Environment Controlled Agriculture
Analytical Methods | Year: 2013

A new carbon paste electrode based on the use of an ionic liquid as the binder is introduced. The composite electrode consists of graphite and n-octylpyridinium hexafluorophosphate (an ionic liquid). The behavior of the n-octylpyridinium hexafluorophosphate carbon paste electrode (OPFP-CPE) towards [Fe(CN)6]3-/4- was tested. This novel electrode has conductivity similar to glassy carbon electrode (GCE). It shows low background current and well defined voltammograms for the [Fe(CN)6] 3-/4-. The oxidation of nitrite was studied on the OPFP-CPE in aqueous solution using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry (CA). The proposed method was used for determination of nitrite in food samples (ham sausage) containing nitrite. Nitrite can be determined in the ranges of 1.0 × 10-4 to 1.0 × 10-3 M by CV, 1.0 × 10-6 to 2.0 × 10-4 M by DPV and 7.6 × 10-6 to 1.4 × 10 -4 M by CA, with the detection limits of 3.0 × 10-5 M, 1.0 × 10-7 M, and 4.0 × 10-7 M (calculated by 3σ) for CV, DPV, and CA, respectively. The recovery of spiked nitrite to the ham sausage extract was from 90.00% to 109.76%. © 2013 The Royal Society of Chemistry.

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