The lactic acid bacteria Lactobacillus gasseri was recently reclassified based on the average nucleotide identity (ANI) value, calculated based on the identity of the whole genome sequence, and a subset was reclassified as Lactobacillus paragasseri. L. gasseri shows high extracellular D-amino acid production ability; thus, we assessed alr, racX, murI encoding alanine racemase, aspartate racemase, and glutamate racemase, and compared the nucleotide sequences of these amino acid racemase genes between L. gasseri and L. paragasseri. Both alr and murI genes extracted from 88 genome sequences exhibited restriction fragment length polymorphisms (RFLP) in a species-dependent manner. In 4 L. gasseri and 18 L. paragasseri strains pre-identified using pheS and rpoA genes, the DNA fragments of alr and murI from these 22 strains also exhibited RFLP by DraI and BamHI digestion in a species-dependent manner. Therefore, RFLP found in the alr and murI genes is useful for rapid differentiation of these two species.
We conducted a fluid analysis of ovomucoid (OM) from chicken egg white and the effect of its addition on the formation of mixed gels with globulin from rice embryo (RγG) using rheological measurement, ultrasound spectroscopy, scanning electron microscopy (SEM), Fourier transform-infrared analysis and SDS-PAGE. Although it is known that OM is a relatively heat-stable protein, when mixed with RγG it formed a gel with comparable dynamic rheological properties and microstructure to the RγG gel. Alterations in ultrasonic attenuation suggested that hydrogen bonding contributed more to gel formation for the OM and RγG mixture. Particle size analyses of the mixed protein gel using the ultrasonic attenuation value and SEM observation revealed that the mixed gel was composed of smaller aggregates compared to the RγG gel. These results indicate that the mixed protein system containing OM is applicable as a material for creating processed foods with novel textures.
The purpose of this study was to examine the effect of the application of eggshells to rice fields for calcium fortification on the quality of the cooked rice. The protein content and the amylose rate of each polished rice sample were not different from those of the control sample, and the taste analyzer values were almost the same. No clear difference in the calcium content of rice endosperm could be confirmed. However, the surface and overall hardness of the cooked rice grown with 100 or 200 kg of eggshell/10 a were increased in comparison to those of the control, and the stickiness of the surface also tended to be increased. Moreover, the characteristic value of the expansion volume of the cooked rice was increased, and it was inferred that the thermal behavior of the cell wall had changed, which affected the hardness and graininess of the cooked rice. In addition, the enzyme activity of the rice endosperm was lower than that of the control, and the absorbance at the maximum absorption wavelength of the iodine absorption spectrum of the eluted starch during cooking was increased. From these results, it was demonstrated that the application of eggshells to rice fields improved the graininess of the cooked rice and tended to increase the stickiness. It was also suggested that the effect of eggshell application on the cooked rice was not due to an accumulation of calcium in rice endosperm, but a complex and indirect effect on metabolic changes.
The main component of eggshells is calcium carbonate, which has been used for Ca research in rice cultivation in Japan. The effectiveness of Ca ions on rice was discovered in the 1 960 s by means of hydroponics, but the effect of Ca application on soil-grown rice has not yet been studied. The high-temperature ripening disorder of paddy rice in Japan in recent years is a sterility phenomenon caused by the failure of assimilation products produced in the leaves to be transferred to the ears. Therefore, to maintain the translocation of assimilated products produced in rice leaves, supplying Ca continuously even in small amounts is more important than increasing the Ca concentration in the plant. If research can be conducted on not only calcium carbonate, the main component of eggshells, but also the translocation rate of assimilates in paddy rice, and if high-temperature ripening disorders caused by weather conditions can be avoided, eggshells can be used as an agricultural material that contributes to food security in Japan.