Vitamin E constituents of Weaning Foods from Germinated Cereals and Legumes

Four weaning food formulations prepared from 70% 72-hr germinated rice/corn and 30% 48-hr germinated mungbean/cowpea were studied for tocopherol constituents and compared to ungerminated controls. γ-TocopheroIs were the major constituents of the mungbean-supplemented samples. The cowpea-supplemented foods contained a predominance of δ-tocopherols followed closely by γ-tocopherols, α-Tocopherols were comparatively higher in corn- than in rice-formulations. Tocopherols in the weaning foods decreased due to germination especially the γ-tocopherols of germinated corn-mungbean.     

OCCURRENCE OF RUPTURES ON THE SURFACE OF FOODS DURING FRYING

An attempt was made to clarify the mechanism of ruptures on the surface of foods occurring during frying. Two different products were fried in a corn oil bath at a temperature of 160C or 180C. One of the products was ellipsoidal croquettes coated by the crust with different thicknesses ranging from 1 mm to 4 mm, while the other was ring doughnuts consisting of the three different compositions of a fixed size. The type of ruptures on the crust of croquette samples could roughly be divided into two categories according to the results obtained by the precise observations during the process of frying, i.e., a small hole and a crack. The small hole, like a pinhole, occurred in the crust of the croquette with 1 mm thickness early in the procedure, while the cracks could be observed with the crusts of croquettes more than 2 mm thicknesses after 120 s or more of frying time. The cracks also occurred on the curved surface of all the doughnut samples tested, although the location of cracks on the three surfaces, i.e., upper, outer and inner, was much influenced by the composition of the samples. A variety of measurements were made to obtain information on the changes in mechanical properties of the core region and crusted surfaces of the samples in the frying process so as to confirm generalized simple considerations assumed for the occurrence of ruptures.     

Antioxidant Activity of Fungus Suihs bovinus (L: Fr.) O. Kuntze

Two major antioxidative compounds were isolated from wild mushrooms, Suillus bovinus (L: Fr.) O. Kuntze, and studied for antioxidative activity by comparison with other antioxidants, BHA and tocopherol. One compound was an orange pigment identified as variegatic acid (3,3′,4,4′-tetrahydroxy puluvinic acid) and the other was an orange-red pigment, possibly diboviquinone-4,4. The variegatic acid had strong antioxidative activity in an emulsion system as shown by peroxide value (POV) of linoleic acid and in an oil system as shown by the POV of methyl linoleate and weight gain of soybean oil. The second compound was active only in the emulsion system.     

Abalone (Hariltis discus): Seasonal Variations in Chemical Composition and Textural Properties

Seasonal changes in adenosine 5′-triphosphate, total free amino acids, and total oligopeptides in abalone meat were analyzed. Levels were higher in summer and lower in winter. In both seasons, the most abundant free amino acid was taurine followed by arginine, glycine, glutamine, and glutamic acid. The largest peptide-bond amino acid was glutamic acid + glutamine. The collagen content decreased in summer and increased in winter. The breaking stress values of the meat were low in summer and high in winter, indicating that summer abalone would be more tender. Scanning electron microscopy revealed the collagen network was more compact in winter.     

Nitrogen-to-Protein Conversion Factors for Some Common Edible Mushrooms

Mushrooms (13) common to Japan were analyzed for total nitrogen (TN), amino acid nitrogen (AAN), amide-N and nonprotein nitrogen. The distribution of protein nitrogen averaged 67% to TN. Averaged nitrogen-to-protein conversion (N:P) factor was 5.99. Application of the factor for estimation of protein content resulted in a considerable difference from amino acid residue (AAres) levels, due to the high level of nonprotein nitrogen. A net N:P factor, defined as the proportion of AAN to TN, was proposed. The averaged value of 3.99 was derived from analytical TN and AAN data of mushrooms. Calculated protein values using this factor were in good agreement with AAres.     

Reaction of Strontium Carbonate with Anatase and Rutile

The kinetics of the solid-state reaction of strontium carbonate with anatase and rutile in air and carbon dioxide were studied by use of a thermobalance. The product was single-phase SrTiO₃ in all cases. The relation between fraction reacted and time was fitted to the Jander equation and to the Carter equation for both anatase and rutile. For anatase the rate constant in carbon dioxide did not differ from that in air. The reaction rates for rutile in air and in carbon dioxide were ⅓ and ⅛ that for anatase, respectively. The In k vs 1/ T relation for anatase gave two straight lines with different slopes having a break point at ∼820°C in both air and carbon dioxide. The Jander activation energies for anatase in the higher and lower temperature regions were ∼340 and ∼290 kj · mol⁻¹, respectively, and those for rutile in air and carbon dioxide were 340 and 390 KJ · mol⁻¹, respectively.     

辅助谐振变换极软开关逆变器分段定时间控制方法

辅助谐振变换极(auxiliary resonant commutatedpole,ARCP)是一种重要的软开关逆变器拓扑,其辅助开关的控制方法会影响到逆变器的效率及可靠性。传统定时间控制方法虽然简单易实现,但该控制方法下,逆变器的轻载效率表现不够理想。通过对定时间控制下ARCP逆变器的电流应力及损耗分布进行详细地分析,找出提高逆变器效率的关键途径,并提出一种新的分段定时间控制方法。该控制方法在不增加控制和电路复杂度的前提下,改善了ARCP逆变器的效率。最后在一台2kW/20kHz实验样机上验证了分析结果。     

n-Hexanol Formation from n-Hexanal by Enzyme Action in Soybean Extracts

n-Hexanal in soybean homogenates decreased during incubation at alkaline pH. When soybean extracts were dialyzed and then incubated with n-hexanal and cofactors [nicotinamide adenine dinucleotide (NAD⁺), the reduced form (NADH), nicotinamide adenine dinucleotide phosphate (NADP+), and the reduced form (NADPH)], NADH and NADPH stimulated the enzymatic reduction of n-hexanal with NADH being more effective than NADPH. When undialyzed preparations were incubated, all the cofactors stimulated enzymatic activity, with NADH being the most effective. The reaction product in all the incubation mixtures was n-hexanol; n-hexanal was reduced to n-hexanol stoichiometrically. It was suggested that alcohol dehydrogenase was responsible for the decrease of n-hexanal in soybean homogenate at alkaline pH.     

EFFECT OF HIGH PRESSURE TREATMENT ON CYTOPLASMIC 5'-NUCLEOTIDASE FROM RABBIT SKELETAL MUSCLE

We investigated the effect of high‐pressure treatment on the properties of cytoplasmic 5′‐nucleotidase (NT), which converts inosine monophosphate (IMP) into inosine. After pressure treatment at 400 MPa, the activity of purified IMP‐NT remained at almost 100%, but the activity of partially purified adenosine monophosphate (AMP)‐NT decreased to about 40%. These data suggest that there is a difference in the pressure stability between the enzymes. In situ fluorescence spectroscopy of IMP‐NT under pressure showed that its pressure‐induced denaturation was reversible. When the pressure was reduced from the highest pressure to ambient pressure, hysteresis was observed. This suggests that high pressure treatment may lead to a partial change in the affinity of the subunits for each other once they have dissociated. The activities of IMP‐NT and AMP‐NT extracted from pressure‐treated muscles decreased remarkably between 250 and 450 MPa, but IMP‐NT was more stable than AMP‐NT.