Kiyohiko Toyoda

Near-infrared spectroscopy for biomonitoring: influence of somatic cell count on cow's milk composition analysis

The influence of milk with high somatic cell count on the accuracy of near-infrared spectroscopic determination of fat, protein and lactose content of non-homogenized milk was investigated. Transmittance spectra of 258 milk samples were obtained by the NIRSystem6500 spectrophotom eter in the 700–1100 nmregion. The best accuracy for fat, protein and lactose content determination was found for calibration equations, derived from samples with low somatic cell count (SCC). The standard error of prediction increased and the correlation coefficient decreased significantly, both when equations, derived fromsam ples with low SCC milk were used to predict the content of the examined components in samples with high SCC, and when equations, obtained for samples with high SCC were used to predict the content of the components in samples with low SCC. Therefore, milk samples with high SCC in a data set used for calibration or prediction highly influenced the accuracy of fat, protein and lactose determination. r 2001 Elsevier Science Ltd. All rights reserved.

Selective degradation of tetracycline antibiotics present in raw milk by electrochemical method.

The dairy industry disposes of a large volume of waste milk with antibiotic residues, which is a great cause of much concern in soil and water environments. In this study, the electrochemical oxidation of tetracycline antibiotics (TCs) in cows milk was investigated. Milk contains a high concentration of organic matter, and the concentrations of TCs residues are extremely low. The effects of anode materials and electrolytes on the degradation of oxytetracycline (OTC) were investigated. A higher degradation rate for the OTC was attained using the inactive anode or a NaCl electrolyte. It was found that a physically adsorbed oxidant on the surface of the anode and indirect oxidation using electrogenerated hypochlorite could enhance the degradation of OTC in raw milk. The organic components in milk samples affected the removal rate of the OTC. The removal rate constants for the OTC in raw milk were 2.8-7.7 times higher than the chemical oxygen demand values. It was found that electrochemical oxidation could decompose low concentrations of TCs in high concentrations of organic matter solutions selectively. The results indicate that electrochemical oxidation is an effective method for the treatment of TCs in waste milk.

MEASUREMENT AND ANALYSIS OF MOISTURE CHANGES IN AGRICULTURAL PRODUCTS USING FFT NOISE IMPEDANCE SPECTROSCOPY

ABSTRACT Macroscopically, cellular foods including agricultural products are regarded as the electrical systems in which cell membranes isolate intracellular electrolytes from extracellular electrolytes. Moisture movement in the materials during drying causes the changes in moisture of the intracellular and extracellular electrolytes. Therefore, the moisture movements can be detected by an electrical measurement The authors measured the impedance of carrot roots during drying by a FFT (fast Fourier transform) noise impedance method at frequency of 40 Hz to 100 kHz. The equivalent circuit model agreed with the measured impedance. The parameters in the model were determined as the intracellular and extracellular resistances and membrane capacitance As a result, it was found that the increase in the extracellular resistance showed a good correlation with a decrease in moisture content between 200 and 400% d.b (dry basis) and that the membrane capacitance had the maximum near the second critical moisture cont...

Magnetic separation of antibiotics by electrochemical magnetic seeding

Magnetic separation of several classes of antibiotics was investigated using electrochemical magnetic seeding. Electrocoagulation with a sacrificial anode followed by addition of magnetite particles was applied for the magnetic seeding of antibiotics. With electrochemical magnetic seeding using an iron anode, tetracycline antibiotics (oxytetracycline, chlortetracycline, doxycycline and tetracycline) and cephalosporin antibiotic (cefdinir) were rapidly removed from synthetic wastewater by magnetic separation using a neodymium magnet. Iron and aluminium anodes were suitable for magnetic seeding of the antibiotics. The results indicated that the ability of antibiotics to form strong complex with iron and aluminium allowed the higher removal by magnetic separation. This method would be appropriate for rapid treatment of antibiotics in wastewater.

CHARACTERIZATION OF OSMOTIC DEHYDRATION AND SWELLING OF APPLE TISSUES BY BIOELECTRICAL IMPEDANCE SPECTROSCOPY

The electrical impedance of apple strip samples immersed in osmotic medium was investigated to characterize a dehydration process with sucrose solution and a swelling (hydration) process with deionized distilled water. The impedance measured at frequencies of 10 Hz to 100 kHz could be fitted well by an electrical equivalent model ‘Hayden model’. Symplasmic (intracellular) resistance and apoplasmic (extracellular) resistance assumed in the model showed a specific increase or decrease which corresponded to a dehydration or swelling (hydration) process respectively. Consequently, the changes in the resistances were suggested to be caused by an increase or a decrease in moisture content in extracellular and intracellular volumes. Furthermore, the time variation of the resistance values could be represented approximately by a first-order response equation. Therefore, it was concluded that bioelectrical impedance spectroscopy (BIS) was applicable to the simple detection of dehydration and swelling and that it was a helpful and effective method to monitor dehydration and swelling processes nondestructively and continuously.

The possibility of near infrared spectroscopy for evaluation of microbial nitrogen content of in sacco feed residues and duodenal digesta of sheep

This study aimed to estimate by near infrared (NIR) spectroscopy the microbial nitrogen content (MN) of feed residues from in sacco degradability trails and duodenal digesta of sheep. NIR spectra from 50 samples of duodenal digesta, and from in sacco residues—110 samples of alfalfa hay and 38 samples of maize silage were obtained using an NIRSystems 4250 spectrophotometer. The microbial nitrogen (MN) content of part of the alfalfa hay in sacco residues (78 samples) was calculated from the percentage of 15N enrichment compared to enrichment in the original samples; for the rest of the alfalfa samples and samples of maize silage residues were determined by diaminopimelic acid (DAPA) as a bacterial marker, and MN of duodenal digesta samples by the purine N (RNA equivalent) content as a microbial marker. The calibration equations were developed by modified least squares as the calibration method. The microbial content of all kinds of samples was accurately calibrated and cross-validated. A standard error of cross validation (SECV) of 0.418 g microbial N kg−1 DM, a coefficient of determination for the cross validation of 0.925 and a ratio of standard deviation of population and the SECV of 3.88 were obtained for the alfalfa 15N labelled hay residues. For maize silage residues, the corresponding values were 0.832, 0.938 and 3.90, and for duodenal digesta samples the values were 1.05, 0.962 and 5.19, respectively. Prediction of MN as percentage of total N of the samples gave approximately the same level of accuracy. For example, the SECV was 2.35% units, cross-validation R2 was 0.953, SD/SECV was 4.60 for alfalfa 15N labelled hay residues. Despite the different origin of the analysed samples (feed residues and duodenal digesta), the NIR spectroscopy determination of MN content of all samples was based on spectral data at very similar wavelengths. The study indicated that NIR spectroscopy has the potential to predict microbial nitrogen content and to distinguish MN from total N content of in sacco feed residues and duodenal digesta.

Nitrogen and energy balances of a combined anaerobic digestion and electrochemical oxidation process for dairy manure management

Anaerobic digestion and electrochemical oxidation were investigated for their potential to recycle carbon and degrade nitrogen from dairy manure; the energy balance of this combination of treatments was also evaluated. Anaerobic digestion is a sustainable technology that allows recovery of biomass energy and treatment of animal wastes for carbon recycling. Since the anaerobic digestion process performs denitrification poorly, almost all nitrogenous substances are discharged in digested effluent as ammonia. The ammonium nitrogen in anaerobically digested effluent is degraded by electrochemical oxidation with an unsacrificial anode. The electrochemical oxidation requires inputs of electricity. We evaluated the feasibility of using electricity generated by a full-scale biogas plant, producing biogas from dairy manure, for the electrochemical oxidation of ammonium nitrogen in anaerobically digested effluent. Data on the amount of electricity generated by such a plant were compared with data on the electricity requirements of the electrochemical oxidation process to determine the energy balance of the two processes. The results indicated that electricity generated from a biogas plant was able to supply 24 to 33% of the electricity required for the electrochemical oxidation.

Impedance Spectroscopic Analysis in Agricultural Products

The relationship between the impedance characteristics and the physical and physiological properties of agricultural products was investigated by an equivalent electrical model. The impedance of several agricultural products, measured over a range of alternating-current frequencies from 40 Hz to 110 MHz, was analyzed by the modified Hayden model taking account of the four parameters (apoplasmic resistance Ra, symplasmic resistance Rs, membrane capacitance Cm and constant-phase angle ϕ).

Measurement of Freezing Process of Agricultural Products by Impedance Spectroscopy

Abstract Analysis by bioelectrical impedance spectroscopy was conducted to pursue the behavior of cell tissues in apple fruits during freezing. The relationships between the parameters in an electrical equivalent model of the cell tissues and the progress of freezing were investigated. The extra- and intra-cellular resistance of the model showed the well correlation with a frozen ratio calculated from Planks equation and these parameters were found to be useful to detect the beginning and the end of the freezing and the progress of freezing of the cell tissues of agricultural products.

Comparison of Different Models Used in Fixed Bed Drying Processes

Abstract Different black-box and white-box models were used to compare results of fixed bed drying processes. The main purpose of this report is to demonstrate the differences of these methods and to show which one to use under different circumstances. Well defined and known models were used as a basis. Calculations have been performed with the help of i/o models (ARX, ARMAX, etc.), deep bed modeling technique with neglecting some dynamic changes and a block oriented way. It was found that block oriented approaches have advantages comparing to other methods. Solving differential equations is impossible with traditional methods, but it is very simple with the help of block oriented technique. In other case, if the purpose is only to control the dryer, the black-box modeling is much faster, but it may be solved by using physically based modeling with neglecting some dynamic changes.