EFFECT OF HIGH PRESSURE ON THE ACCUMULATION OF IMP AND ON THE STABILITY OF AMP DEAMINASE IN RABBIT SKELETAL MUSCLE

This study evaluated the effect of high pressure on rabbit skeletal muscle, specifically on the production of inosinic acid (IMP), one of “umami” components, and on the activity of adenosine triphosphate (AMP) deaminase, which plays a role in the conversion of AMP to IMP. By increasing the pressure (0.1 to 300 MPa), nucleotide analysis showed that IMP content in muscle increased instantly with a concomitant decrease in ATP content. The IMP content of muscle at 300 MPa was approximately 15% higher than with lower pressures (0.1–200 MPa) when stored for 1 week at 4C after pressurization. These results suggested that the metabolism of nucleotides in muscle was not significantly impaired by pressure treatment. At 300 MPa, AMP deaminase maintained approximately 70% of the activity at 0.1 MPa. In contrast, the activity of purified AMP deaminase was completely lost at 200 MPa, and irreversible conformational changes were observed by in situ fluorescence spectroscopy. These results indicated that purified AMP deaminase was irreversibly denatured under pressure as high as 300–400 MPa.     

HYDROLYSIS OF PHYTATE IN BROWN RICE-ADDED BREAD BY ADDITION OF CRUDE AND PURIFIED ASPERGILLUS NIGER PHYTASE PREPARATIONS DURING BREAD MAKING

Brown rice-added breads were prepared with and without crude and purified Aspergillus niger phytase preparations. By adding 30% (w/w) brown rice flour and no phytase preparation, the phytate (myo-inositol hexaphosphate; IP₆) content of the bread was increased and the loaf volume was reduced. The direct addition of a food-additive grade phytase preparation (3,000 U) resulted in a significant decrease in the IP₆ content. However, it collapsed the bread crust. The crude phytase preparation had significant protease and amylase activities. A simple chromatographic method for the separation of phytase activity from the protease and amylase activities was developed. By using purified phytase, the IP₆ content was reduced without any adverse effects on the rising of the bread, which indicates that protease and amylase may be responsible for the collapse of the crust by the commercial phytase preparation.

PRACTICAL APPLICATIONS

Phytate in unrefined cereals and beans lowers bioavailability of minerals. On the other hand, these materials are rich in health-promoting components. To reduce the phytate in them during processing, some commercially available phytase preparations are now used. However, we found that such preparation contains significant amylase and protease activities, which may cause adverse effect on the appearance and textural properties of final products. To solve these problems, a simple and inexpensive procedure for separation of phyatase from amylase and protease was developed in the present study. The purified phytase can reduce phytate in brown rice-added bread without adverse effect on rising of bread. These results would encourage prepare the phytase preparation in high purity in an industrial scale to improve nutritional value of unrefined cereal- and bean-based functional foods.     

RHYTHMIC AND IRREGULAR MOVEMENT OF THE FIRST MOLAR WHILE EATING FOODS WITH DIFFERENT TEXTURES

The three-dimensional movement of a tooth, any tooth, while naturally eating, was measured by an apparatus developed in our laboratory. The movement of the first molar on the usually used side is reported here. The mastication movements are divided into two parts, namely the rhythmical chewing period during which there are mastication pressure loads on the molar and the irregularly pulsated moving period in preparation for the swallowing followed by the rhythmical one during which there is no more pressure on it. The amplitudes of the up and down movements of the molar are 10–22mm for the rhythmical chewing period which are bigger than those for the irregularly moving period. The rhythmical chewing periods are distributed around 10–40 s depending on 14 kinds of food texture, and also on the size of the food, in a fairly similar manner for the participants. The period is longer for tough foods and bigger samples. The irregularly pulsated moving periods are widely distributed, 2–45s, and depend both on the food texture and on the participant. The irregular moving periods are longer for foods which scatter in the mouth or adhere to the teeth when chewing. The ingestion difficulty of the food was divided into two groups. One is where it is difficult to break down the food with the teeth and the other is where it is difficult to prepare for swallowing.     

The stumptailed macaque as a model for baldness: effects of minoxidil

Topical application of minoxidil in bald scalps of stumptailed macaques successfully induced regrowth of terminal hairs. The rate and degree of hair growth by minoxidil are much greater in the early stage of baldness in adolescent and young adults. Minoxidil also prevented the development of baldness when applied on non-bald scalps of peri-adolescent animals. Morphometric analysis of hair follicles (folliculograms) has brought a new aspect in observing cyclic dynamics and growth (transformation) of hair follicles. Using this analytic method and autoradiographic observation of DNA synthesis of hair follicles, the action of minoxidil appears to be a potent mitotic stimulator of the follicular as well as peri-follicular germinal (or reserve) cells, thus inducing an enlargement of vellus follicles through the process of cyclic growth and maintaining anagen follicles in the growing phases. Most importantly, minoxidil has no influence in epidermal keratinocytes, sebaceous glands and other dermal components. During almost 3 years of consecutive treatment, the animals showed no detectable local or systemic side effects when examined by laboratory tests of blood cells, chemistry, steroid hormones, measurement of blood pressure and EKG test.
Le macaque a queue courte: exemple de calvitie     

DYNAMIC VISCOELASTICITY AND STRESS RELAXATION IN STARCH PASTES

The dynamic viscoelasticity and stress relaxation of ten types of starch pastes were measured. The dynamic moduli increased with increasing frequency, and were different for each starch paste, changes in tan δ for cassava and potato starch pastes being about 0.5–0.6. The stress relaxation behaviour of all the samples tested could be represented by a four-element mechanical model. The relationship between spinnability and stress relaxation was determined, the spinning distance increasing with increased relaxation time (τ₂). No satisfactory linear relationship between spinning distance and relaxation time (τ₂) was apparent with the 10 starch paste samples.     

Correction Factor of Come-up Heating Based on Mass Average Survivor Concentration in a Cylindrical Can of Heat Conduction Food

A mathematical expression is derived to estimate a correction factor for come-up heating, which may be used to calculate mass average survival concentrations. For this derivation, analytical heat conduction formulae are used to estimate transient state temperature distributions in a cylindrical can of heat conduction food. Through the dimensional analysis of the derived analytical expression, 12 dimensionless groups are formulated in order to examine the Influence of various process conditions as well as of food properties on the correction factors. Theoretical correction factors are then computed for various numerical combinations of these dimensionless groups. Through the nonlinear regression analyses of these computed factors, we obtain algebraic equations for representing these factors as a quadratic function of the dimensionless groups. There is fair agreement between the correction factors estimated by using the algebraic equations and by using heat penetration data collected experimentally.     

群居空间里的单身部落

名古屋是日本第五大城市，而这间公寓就坐落在距离名古屋1小时车程的农村地区。公寓里面一共住着9个人，都是单身，他们各自为政。     

Image contrast enhancement of Ni/YSZ anode during the slice‐and‐view process in FIB‐SEM

Focused ion beam‐scanning electron microscopy (FIB‐SEM) is a widely used and easily operational equipment for three‐dimensional reconstruction with flexible analysis volume. It has been using successfully and increasingly in the field of solid oxide fuel cell. However, the phase contrast of the SEM images is indistinct in many cases, which will bring difficulties to the image processing. Herein, the phase contrast of a conventional Ni/yttria stabilized zirconia anode is tuned in an FIB‐SEM with In‐Lens secondary electron (SE) and backscattered electron detectors. Two accessories, tungsten probe and carbon nozzle, are inserted during the observation. The former has no influence on the contrast. When the carbon nozzle is inserted, best and distinct contrast can be obtained by In‐Lens SE detector. This method is novel for contrast enhancement. Phase segmentation of the image can be automatically performed. The related mechanism for different images is discussed.