Changes of Aldehyde Levels in Defatted Soybean Extract

Aldehyde levels in defatted soybean extracts were measured by using aldehyde dehydrogenase. The level increased during incubation of flour-water suspension and its centrifuged extract at pH 6.5, while it decreased markedly at alkaline pHs. This aldehyde-eliminating activity was observed in 1:5 flour:water ratio, but was not in 1:20 flour:water ratio. ¹⁴C-labelled acetaldehyde added to 1:5 flour:water extract was converted into acetic acid. Fractionation of the extract indicated that a heat-labile protein and a heat-stable compound with low molecular weight were required for the aldehyde-eliminating activity.     

Influence of pulsed electric field on enzymes,bacteria and volatile flavor compounds of unpasteurized sake

A pulsed electric field(PEF) was applied to unpasteurized sake at constant temperatures, at which α-amylase was not inactivated. We adjusted the input energy to be identical for the temperatures by changing the number of PEF application, because the current significantly increased with the temperature, even the amplitude of the applied voltage was identical. As a result, the α-amylase was seemed to be inactivated by PEF application, not due to thermal effect.The glucoamylase was significantly inactivated by PEF. Moreover, the acid carboxypeptidase was inactivated by PEF at 4 °C but significantly activated at 25 °C. These results show that the sensitivity of enzyme to PEF application differs depending on the types of enzyme and treatment temperature. On the other hand, the colony number of bacteria was remarkably decreased, but the amount of the volatile flavor compounds was not decreased by PEF application.     

An inspection policy for a deteriorating single-unit system characterized by a delay-time model

This paper develops a method for determining the discrete time points of inspection for a deteriorating system which is under condition-based maintenance. The system is regarded as a single component unit, and it has the following states: a normal state, a symptom state and a failed state. A delay-time model is utilized in order to describe the transition of the states. The transition time from a normal state to a symptom state and the transition time from a symptom state to a failed state are assumed to obey independent and identically distributed probability density functions respectively. Two types of probabilities with respect to inspections are considered: failed-dangerous (FD) probability or type I error that a system is wrongly diagnosed as in a normal state when the system is actually in a symptom state and failed-safe (FS) probability or type II error that a system is wrongly diagnosed as in a symptom state when the system is actually in a normal state. The determination method is formulated to minimize the long-run average cost per unit time with a constraint on inspection time. The nature and sensitivity of the proposed method is investigated under varying FD and FS probabilities and coefficients of variation.     

HYPOTENSIVE ACTIVITY OF MUSCLE PROTEIN AND GLUTEN HYDROLYSATES OBTAINED BY PROTEASE TREATMENT

Protein hydrolysates obtained by treatment with papain, trypsin, chymotrypsin and actinase all exhibited inhibitory activity (IC50: 3.4–41.8 mg%) toward angiotensin‐converting enzyme (ACE) (EC 3.4.15.1). In particular, the protein hydrolysate obtained by treatment with papain showed the highest inhibitory activity (3.7–5.3 mg%). The ACE inhibitory activity of the gluten hydrolysate obtained with actinase was mainly due to peptides of less than 500 Da in molecular mass. On the other hand, the ACE inhibitory activity of the myofibrillar protein hydrolysate obtained with papain was due to peptides of both less and more than 500 Da in molecular mass. The blood pressure of spontaneously hypertensive rats (SHR) administered the myofibrillar protein hydrolysate was significantly reduced at 2 h after administration. The blood pressure of SHR was also reduced at 2 h after administration of the gluten hydrolysate, and this effect continued until 6 h. These hydrolysates may potentially be useful as antihypertensive food materials.     

THERMOELASTIC POTENTIAL FUNCTIONS IN TRANSVERSELY ISOTROPIC SOLIDS AND THEIR APPLICATIONS

An explicit solution composed of two thermoelastic potential functions is proposed in cylindrical coordinates and is applied to an analysis for steady-state, axially asymmetric thermal stresses in a long hollow cylinder. The solution is obtained with no assumptions of temperature fields. The temperature and stress fields in the long hollow cylinder made of magnesium are analyzed for the sake of application of the solution.     

Failure diagnosis of a servovalve by neural networks with new learning algorithm and structure analysis

This paper considers a failure diagnosis of a pneumatic servovalve used in automated production systems. The valve is monitored by an accelerometer. Six parameters characterizing the vibration data are extracted, and fed into neural networks to solve four types of diagnosis problems. A conjugate gradient followed by a variable metric method is demonstrated as an effective learning algorithm. Neural network structures are analysed through Boolean expressions summarizing network simulation results for given learning patterns. The neural networks are found to utilize majority voting mechanisms. Irrelevant neurons can be identified and removed without degrading the diagnosis performance.