Aiming to produce functional oligosaccharides such as di-D-fructose dianhydrides (DFAs) from inulin in subcritical water (the hot compressed water), the hydrolysis mechanism of inulin was investigated. The hydrolysis of inulin was conducted in carbon dioxide-the hot compressed water (CO2-HCW) created with a batch-type reactor (temperature: 100―150℃, pressure: 3.0―5.0 MPa). The inulin hydrolysate prepared with CO2-HCW were determined by electrospray ionization mass spectrometry and UV-Vis spectroscopy. The results showed that inulin is hydrolyzed to monosaccharides, disaccharides, fructooligosaccharides , and DFAs with CO2-HCW. The hydronium ion concentration ([H+]) formed in CO2-HCW was approximately estimated 100-fold higher than [H+] created in the hot compressed water without CO2. High [H+] is believed to be one of the factors that contributes to the hydrolysis of inulin ＜150 ℃. The generation of 5-hydroxymethylfurfural (HMF) occurred by intramolecular dehydration of fructose was suppressed due to low temperature process (＜150℃). CO2-HCW is one of the means to convert inulin into DFAs while suppressing the generation of HMF.
The mechanism for accelerating leaf lettuce growth by alternating irradiation of red (R) and blue (B) lights was investigated in this study. Leaf lettuce was cultivated under nine light conditions with different time ratios of R/B alternate irradiation; R0B24, R3B21, R6B18, R9B15, R12B12, R15B9, R18B6, R21B3 and R24B0. As a result, R21B3 treatment (21 hours of R irradiation and 3 hours of B irradiation, in an alternating pattern without a dark period) was determined to be the optimum condition for leaf lettuce growth, since shoot fresh weight under this treatment was significantly the highest. Moreover, photosynthetic ability and morphology were studied under alternating irradiation (R21B3 and R12B12) and simultaneous irradiation (RB24; simultaneous irradiation of R and B lights without a dark period). Photosynthetic ability of lettuce grown under R21B3 and R12B12 was significantly higher than that under RB24. A morphological index, PA/LA (Projected Area divided by Leaf Area), was greater in R21B3 and R12B12 than in RB24. This result suggested that alternating irradiation causes plants to have an effective posture for receiving light. Therefore, it seems reasonable to conclude that growth acceleration of plants under alternating radiation was caused by high photosynthetic ability and morphological superiority.
Tomatoes (Solanum lycopersicum L.) cultivated under salt-stress conditions offer enhanced contents of sugars, organic acids, and amino acids, and have a favorable taste. In this study, 3 tomato cultivars and the components of sugars (glucose, fructose, and sucrose), organic acids (citric acid and malic acid), and 17 amino acids of fruits cultivated under salt-stress (100 mM NaCl) conditions were investigated using HPLC systems. Taste was evaluated using a taste sensor and sensory evaluation. The taste sensor measured sourness, saltiness, bitterness, and astringency. In the sensory evaluation, the 5 basic tastes (sweetness, sourness, saltiness, umami, and bitterness), aroma, and texture were evaluated. Salt-stressed tomatoes undergo characteristic component changes due to the salt-stress, resulting in enhanced contents of glucose, fructose, citric acid, and several amino acids. The tendency toward increased saltiness in salt-stressed tomatoes was found by both the sensory evaluation and the taste sensor. Sourness was evaluated more sensitively and accurately by the taste sensor. To evaluate the objective tastes of a tomato, it is important not only to incorporate sensory evaluation but also to measure metabolic components using HPLC systems and to evaluate tastes using a taste sensor.
Role of raffinose family oligosaccharides (RFOs), sucrose and lipid in respiration metabolism during soybean seed germination were investigated to determine appropriate method for producing soybean sprouts containing high amount of RFOs. Soybean seed were soaked into 50 μM 1-deoxygalactonojirimycin (DGJ), which is a specific α-galactose inhibitor, for 90 minutes before and after germination preparation phase (GPP). Soybean seed without DGJ treatment was used as control. The growth rate, respiration rate, respiratory quotient, fatty acids and saccharides contents were measured during cultivation at 20℃. When DGJ was applied before GPP, the degradation of RFOs was significantly reduced, moreover the growth rate and respiration rate were suppressed due to the alternation of respiratory substrate from glucose to lipid in GPP. However, in the DGJ application after GPP, no difference was found from control although RFOs breakdown was functionally inhibited in subsequent radicle elongation phase (REP). These results suggest that RFOs are essential only in GPP as a source of respiratory substrate and lipids play the main role in respiration during REP. Therefore, prevention of RFOs degradation after GPP could be useful to maintain high amount of RFOs in soybean sprouts.
Plants of soybean cultivars ‘Fukuyutaka’, a popular cultivar in western Japan, and ‘Misato-zairai’, a local soybean cultivar in Mie Prefecture, were shaded after the beginning of bloom stage. To examine light utilization in a simple sinksource relationship between pods and leaves only, shoot apices on the main stem, branches, and new lateral buds were removed during the treatment. In both cultivars, shading decreased seed weight and the numbers of pod and seed. Seed weight and pod number were positively correlated. Total air-dried weight at maturity (total weight, including stem, pods, and seeds) was also decreased by shading and was positively correlated with pod number. Shading had no reproducible effects on 100-seed weight. Light utilization of ‘Misato-zairai’ plants without branching vegetation was similar to that of ‘Fukuyutaka’.
Paternal inheritance of mitochondrial DNA (mtDNA) of Cucumis hystrix Chakr. was revealed in the interspecific crosses of cucumber (C. sativus L.) x C. hystrix. The mtDNA was analyzed by RFLP analysis of a PCR amplified nad4 exon1 and nad4 exon2 region of the female parent C. sativus, male parent C. hystrix and the hybrids. All the hybrids showed the identical restriction pattern of C. hystrix. This indicated the paternal inheritance of mtDNA. A similar experiment with chloroplast DNA (cpDNA) was performed by RFLP analysis of a PCR amplified rbcL-ORF106 region. The results showed the identical restriction pattern of the female parent C. sativus in the same hybrids. This indicated the maternal inheritance of cpDNA. Paternal transmission of the mitochondrial genome of C. hystrix was newly discovered in the Cucumis hybrids.