Takaaki Satake

Comparison of Physical Properties of Wheat Starch Gels with Different Amylose Content

ABSTRACT The effects of amylose content and other starch properties on concentrated starch gel properties were evaluated using 10 wheat cultivars with different amylose content. Starches were isolated from grains of two waxy and eight nonwaxy wheat lines. The amylose content of waxy wheat lines was 1.4–1.7% and that of nonwaxy lines was 18.5–28.6%. Starch gels were prepared from a concentrated starch suspension (30 and 40%). Gelatinized starch was cooled and stored at 5°C for 1, 8, 16, 24, and 48 hr. The rheological properties of starch gels were studied by measuring dynamic viscoelasticity with parallel plate geometry. The low-amylose starch showed a significantly lower storage shear modulus (G′) than starches with higher amylose content during storage. Waxy starch gel had a higher frequency dependence of G′ and properties clearly different from nonwaxy starches. In 40% starch gels, the starch with lower amylose showed a faster increase in G′ during 48 hr of storage, and waxy starch showed an extremely s...

Rheological Properties of White Salted Noodles with Different Amylose Content at Small and Large Deformation

ABSTRACT The rheological properties of cooked white salted noodles made from eight wheat cultivars with varied amylose content were analyzed at small and large deformation. Their dynamic shear viscoelasticity was measured using a rheometer with parallel plate geometry. Compressive force and creep-recovery curves were measured using various probes and sample shapes. Noodles with lower amylose content showed a lower storage shear modulus (G′) and a higher frequency dependence of G′. The G′ values of noodles were highly correlated with amylose content in wheat flour and with G′ values of 30 and 40% starch gels. Remarkable differences in the characteristics of creep-recovery curves were observed between cultivars. The difference in amylose content in wheat flour reflected the creep-recovery properties of noodles. A negative correlation was demonstrated between amylose content and both maximum creep and recovery compliance. The compressive force required for 20, 50, 80, and 95% strains was compared. At 20 and ...

Steady state characteristics of acclimated hydrogenotrophic methanogens on inorganic substrate in continuous chemostat reactors

A Monod model has been used to describe the steady state characteristics of the acclimated mesophilic hydrogenotrophic methanogens in experimental chemostat reactors. The bacteria were fed with mineral salts and specific trace metals and a H(2)/CO(2) supply was used as a single limited substrate. Under steady state conditions, the growth yield (Y(CH4)) reached 11.66 g cells per mmol of H(2)/CO(2) consumed. The daily cells generation average was 5.67 x 10(11), 5.25 x 10(11), 4.2 x 10(11) and 2.1 x 10(11) cells/l-culture for the dilutions 0.071/d, 0.083/d, 0.1/d and 0.125/d, respectively. The maximum specific growth rate (mu(max)) and the Monod half-saturation coefficient (K(S)) were 0.15/d and 0.82 g/L, respectively. Using these results, the reactor performance was simulated. During the steady state, the simulation predicts the dependence of the H(2)/CO(2) concentration (S) and the cell concentration (X) on the dilution rate. The model fitted the experimental data well and was able to yield a maximum methanogenic activity of 0.24 L CH(4)/g VSS.d. The dilution rate was estimated to be 0.1/d. At the dilution rate of 0.14/d, the exponential cells washout was achieved.

Evolutionary programming for mix design

Abstract An evolution method for the solution of a mix design problem is proposed. It is an application of genetic algorithms in which the ratio of ingredients have evolved. In this paper, the evolution algorithm, new crossover methods and mutation schemes are introduced. The usual crossover operation was not used, instead one field of a superior chromosome was copied to an inferior chromosome. A mutation was generated by a combination of uniform random number and normal distribution random number and the mutation rate was very high ( 1 2 ). This approach can be applied to non linear optimization problems. The method has been successfully applied to the actual mix problem.

Quality Evaluation of Fresh Pork Using Visible and Near-Infrared Spectroscopy with Fiber Optics in Interactance Mode

The feasibility of evaluating color value, chemical components, and other physical characteristics of fresh, random thickness pork samples by visible/near-infrared (NIR) spectroscopy was determined. Wavelengths in the visible light region were used to perform calibration of color value. The correlation coefficients and RPD for CIE L*, a*, b*, hue, and chroma were 0.87 to 0.94 and 1.74 to 2.45, respectively. Wavelengths from 700 to 1100 nm were used to build the model of chemical components and other physical characteristics. The correlation coefficients for IMF, moisture, and protein were 0.98, 0.90, and 0.97, respectively. However, the correlation coefficients for WHC, drip loss, and pH were about 0.76 to 0.83. NIR spectroscopy using interactance mode can perform accurately with intact pork loin samples vacuum-packed in low-density polyethylene film. The color and chemical composition can be evaluated very accurately. It is possible to make rapid, nondestructive, and accurate pork quality evaluation using visible and near-infrared spectroscopy.

Temporal changes in occurrence frequency of bowel sounds both in fasting state and after eating

Food evaluation technology that takes into account the constitutional predisposition and health of an individual’s digestive system should aid in the development of value-added foods for patients and people who require health care. Based on the assumption that the degree of bowel activity changes depending on each individual’s constitutional predisposition, health, and tolerance of the consumed foods, we investigated bowel sounds as an index of bowel activity. We have developed a method for investigating changes in bowel activity by performing long-term continuous recording of bowel sounds and observing changes in the occurrence frequency of bowel sounds per unit of time. In order to obtain basic data, we made recordings of eight healthy adults. We observed that bowel sounds continued even after the most recently consumed food had been nearly completely digested. In addition, we found that the occurrence frequency of bowel sounds of normal intensity (stethoscope audible) did not synchronize with that of minimal intensity (amplifier audible) in the fasting state. In contrast, the former did synchronize with the latter during digestion.

Electrochemical microdevice for on-site determination of ricefreshness

An electrochemical microdevice was fabricated for on-site rapid freshness determination of rice. The activity of peroxidase was used as an indicator for freshness. With hydrogen peroxide and hydroquinone as substrates, the enzymatic reaction of peroxidase produced benzoquinone, which was subsequently reduced on a gold working electrode electrochemically. The progress of the enzymatic reaction could clearly be observed in the change of cyclic voltammograms. Distinct differences were observed in the current change between fresh rice and aged rice, reflecting the remaining activity of peroxide. The current also depended on the time at which rice grains were milled. The result agreed well with those obtained by the conventional fluorometric and guaiacol methods. Comparison of results obtained with different numbers of grains showed that even the measurement with a single grain provided fairly consistent data. Furthermore, the existence of grains of different freshness could be identified using a device with multiple sensing sites.

Basic study of occurrence frequency of bowel sounds after food ingestion

The human bowel produces bowel sounds characteristic of digestive activity. The changes in digestive activity of the bowel are reflected in the frequency and intensity of peristaltic action, and indirectly in variation in bowel sound. Approaching this process in reverse, we detected changes in bowel sound to capture variation in digestive activity of the bowel, aiming to develop a quantitative monitoring technique to trace the cause of the bowel sound variation back to a difference in consumed foods, to compatibility between the food and the individual, or to the health of the individuals digestive organs. In order to collect the basic data for developing such a technique, we carried out two experiments. Experiment 1 was an examination of frequency of bowel sounds after ingestion of easy-to-digest food in a complete fasting state. Experiment 2 was an investigation of how the bowel sound frequency changes according to the difference in foods eaten. Foods considered good for digestion as well as foods bad for digestion were used in Experiment 2. The results of the two experiments suggested that the frequency of bowel sounds is affected by health conditions or disruption of lifestyle rather than by differences in foods ingested.

Rapid measurement and prediction of bacterial contamination in milk using an oxygen electrode.

An oxygen electrode was used to measure oxygen consumption to determine bacterial contamination in milk. Dissolved oxygen (DO) measured at 10-35 degrees C for 2 hours provided a reasonable prediction efficiency (r > or = 0.90) of the amount of bacteria between 1.9 and 7.3 log (CFU/mL). A temperature-dependent predictive model was developed that has the same prediction accuracy like the normal predictive model. The analysis performed with and without stirring provided the same prediction efficiency, with correlation coefficient of 0.90. The measurement of DO is a simple and rapid method for the determination of bacteria in milk.

Microfluidic Device for Coulometric Detection of Organophosphate Pesticides

A microdevice for coulometric detection of organophosphate pesticides (OPs) was fabricated based on the measurement of the inhibition of an enzyme, acetylcholinesterase (AChE), by OPs. Thiocholine (TCh) produced in the enzymatic reaction of AChE with acetylthiocholine (ATCh) as a substrate was oxidized on a microelectrode array formed in a main flow channel. Volumes of plugs of necessary solutions were measured using a structure consisting of a row of rhombuses formed in an auxiliary flow channel. The plugs were merged and solution components were mixed at a T-junction formed with the main and auxiliary flow channels. A linear relationship was confirmed between the generated charge and the logarithm of the OP (malathion) concentration in a concentration range between 10(-6) and 10(-3) M with a correlation coefficient of 0.951. The lower limit of detection was 412 nM.