Cell fusion was examined using commercial Natto bacteria. An important point is the discrimination of fusants. Following results were obtained; (1) the optimum tonicity for protoplast regeneration (PR) of Bacillus was 0.2M, less than half as the ordinary methods, (2) PR is limited when amino acid-negative mutants were used because of the limitation of casamino acids (CA) content, and (3) an easy plate-count method, namely plating directly in hypertonic media, was possible. Based on above results, nucleic acid-negative mutants (NNM) not affected by CA, and a new protoplast reversion medium containing a low content of sodium succinate, a sufficient amount of CA and a little biotine as well as polyvinylpyrrolidone, were employed. The frequency of back mutation of NNM of Natto bacteria was 10^-6 level by the Miura strain with an adenine marker and 10^-5 level by the Takahashi strain with an uracil marker. Their PR occured efficiently by the easy plate-count method. The cell fusion between them was shown by giving five proofs in one series of experiments; protoplast formation, its reversion, check of back mutation, control number of fusion and fusant number. The fusion frequency was approximately 0.02%.

View full abstract

he degree of gelatinization, retrogradation and disintegration of starch in steamed glutinous rice, fresh glutinous rice cake dough, cooled glutinous rice cake dough and dried cut glutinous rice cake dough prepared under different conditions were estimated by their disperibility in a 0.04% SDS solusion. (1) The degree of gelatinization of starch in steamed glutinous rice increased with increasing moisture content of soaked glutinous rice and steaming time, and was the highest when steamed at 0.2kg/cmcm² steam pressure. (2) The degree of disintegration of starch granules in fresh glutinous rice cake dough prepared with a pounding type machine, a mixing type machine and a kneading type machine were 76.8%, 84.3% and 83.0%, respectively. (3) The degree of gelatinization of starch in the glutinous rice cake dough cooled at 5°C decreased rapidly in a day, and lowered gradually after that. No difference in the degree of gelatinization of starch in the glutinous rice cake dough could be found when cooled at 5-30°C for 24h. However, the degree of retrogradation in strongly bonding micelles of starch in those samples increased with increasing temperature above 10°C between 10 and 30°C. (4) When dried cut glutinous rice cake dough with 20-35% moisture content was placed at 30°C for 24h, the degree of gelatinization of starch in the samples with 30% and 35% moisture contents was a little lower than that with 20% and 25% moisture contents.

View full abstract

Pectic Polysaccharides (HXSP, from uncooked cotyledons; HWIP, from cooked ones; HWSP, from the cooking soup) and hemicelluloses were prepared from Adzuki beans stored for two years at 5°C and 30°C, and the pectic preparations were fractionated into neutral (I) and acidic (II, III and IV) fractions by DEAE-cellulose chromatography. The acidic fractions from the beans stored at 30°C, as compared with those from the beans stored at 5°C, exhibited some different properties: First, the uronate contents were low in all the acidic fractions. Second, the relative amounts of III and IV considerably increased in HXSP and HWIP. Finally, the molecular sizes of III and IV except those from HWSP decreased to some extent, although the molecular size of II from HWSP greatly decreased even in the beans stored at 5°C when compared to a similar fraction previously prepared from HWSP of fresh Adzuki beans. In addition, the total amount of HWSP in the stored beans at 30°C was somewhat smaller than that in the beans stored at 5°C. Neutral sugar compositions of II, III, IV and hemicelluloses showed no significant difference between the two temperatures of storing the beans. The major neutral sugar constituent was xylose in II-IV and the xylose content increased with increasing their adsorptive activities on the DEAE-cellulose column. In particular, the fraction IV was adsorbed most strongly on the column in spite of its small molecular size and low uronate content, and exhibited the highest xylose content of more than 80%.

View full abstract

"Model cheese" simply consisted of sodium caseinate, butter fat, and water was prepared in order to study effects of heat treatment on the meltability of processed cheese. When the model cheese was held at 80°C after cooking, the meltability decreased with the increase of holding time. During this process, the increase of water insoluble protein was observed with the decrease of meltability. The correlation coefficient value of -0.92 indicated significant relationship between water insoluble protein content and meltability. The formation of the insoluble protein was considered being caused by aggregation of the protein adsorbed to the surface of fat globules in the cheese held at 80°C, and associated with the decrease of meltability.

View full abstract

In the previous paper, we discussed the structure of polysaccharides extracted from Lyophyllum ulmarium with hot water. This paper discussed the chemical structure of polysaccharides extracted with 0.1N NaOH on 0.5N NaOH. Each extract was deproteinated by use of pronase and Sevag method, and subjected to column chromatography with Toyopearl HW-65F gel. Polysaccharide purified from the 0.1N NaOH extract was designated as P-4 and the other from 0.5N NaOH extract was designated as P-5. Homogeneity of P-4 and P-5 was confirmed by gel filtration and electrophoresis. Molecular weight of P-4 was about 105000, [α]²⁰_D was +0.27 (C=1, 0.5N NaOH) and its infrared spectrum showed absorption at 890cm^-1, suggesting the presence of β-dominant linkage. P-4 gave mannose, galactose and glucose in ratio of 1.0:1.8:4.2 after acid hydrolysis. Periodate consumption was 1.43mol/sugar residue and formic acid production was 0.61mol/sugar residue. Smith degradation products were glycerol and glucitol in a ratio of 2.6:1.0. Methylation analysis and partial acid hydrolysis sugested that P-4 possesses a highly branched structure, and the core of the molecule consisted mainly of glucose. P-5 was a glucan of molecular weight about 90000, [α]20D was +2.10 (C=1, 0.5N NaOH) and absorption was detected at 890cm-1 in infrared spectrum, suggesting the presence of β-dominant linkage. Periodate consumption was 0.45mol/sugar residue and formic acid production was 0.20mol/sugar residue. Smith degradation gave glycerol and glucitol in the ratio of 1.0:3.2. From these findings, it was assumed that P-5 possesses the structure with one branch in every 4 straight chains connected by (1→3) linkage.

View full abstract

Terpeneless (hydrocarbon-free) oils were produced from citrus peel oils by vacuum distillation method-The effects of operating temperature, time and other conditions on the extraction of terpene hydrocarbons were investigated. In an actual run, the operation was carried out at the pressure of 4-4.5mmHg. In binary system (d-limonene+citral), the boiling point remarkably rose as its volume fraction lowered. In ternary system (d-limonene+linalool+citral), the maximum concentration ratio of d-limonene was ca. 1/20 at the extracting temperature of 60°C. on the other hand, the content of linalool in terpeneless oil increased to 40°C, then had a gradual decrease to 70°C and a marked decrease hereafter; that of citral gradually increased with increasing in temperature. Lemon (Citrus limon Burm. f.) peel oil was deterpenified at the most appropriate conditions of 50°C for 30 min to yield the more predominant quality oil consisting of 7.49% d-limonene and 27.2% citral. A similar attempt to deterpenify Valencia orange (Citrus sinensis Osbeck) peel oil was performed at 50°C for 30min. Consequently, the content of linalool in terpeneless oil which highly comtributes to the orange flavor characteristics was ca. 7 times that of native peel oil.

View full abstract

Effects of mineral salts, vitamins, nucleic acid relating substances and phytohormones on the vegetative growth of kuritake mushroom [Naematoloma sublateritium (Kr.) Karst.] were investigated using a liquid culture medium. (1) The vegetative mycelium did not grow in the absence of KH₂PO₄ and MgSO₄·7H₂O. The vegetative mycelium yield was severely decreased by the omission of ZnSO₄·7H₂O. The other mineral salts [CaCl₂·2H₂O, FeSO₄·7H₂O, CuSO₄·5H₂O, MnSO₄·5H₂O, (NH₄)₆Mo₇O₂₄·H₂O] did not show any special effect for the vegetative growth. (2) The vegetative mycelium required thiamine for the growth. Each of the other vitamins (nicotinamide, riboflavin, pantothenic acid, pyridoxine, folic acid, cyanocobalamin, biotin, inositol) affected the vegetative growth. (3) Nucleic acid bases (adenine, guanine, cytosine, thymine, uracil, orotic acid), nucleosides (adenosine, guanosine, cytidine, inosine, uridine, thymidine) and nucleotides (adenylic acid, guanylic acid, cytidylic acid, uridylic acid) were effective for the vegetative growth. (4) The vegetative mycelium yield was increased in the basal medium containing 1mg/l of IAA (indole-3-acetic acid), NAA (1-naphthylacetic acid) and GA3 (gibberellic acid), but the vegetative mycelium yield was decreased in the basal medium containing 10mg/l of IAA and NAA.

View full abstract

The effects of processing conditions on the textural and/or rheological quality of Kan-tofu (Chinese pressed tofu) were studied. Constant apparent creep curve was obtained in the range of employed pressure, 3100-31000kg/mm², for the thin soy milk gel at 7min after the loads were given with a consolidation testing machine. Tensile strength, hardness and gumminess of Kan-tofu increased extremely up to 9300kg/mm² and water content decreased remarkably. The maximum values of these parameters were obtained when they were coagulated at 90°C. In general, the values of the parameters of various physical properties increased for longer period in the case of processing with higher pressure. It was found that the Kan-tofu of good quality was obtained when soy milk was prepared with soybean and water ratio of 1:10.

View full abstract

Since for infrared drying, drying materials are heated by radiant heat, their optical properties are important factors. In this paper, focusing on such optical properties as emissivity and reflectivity of the drying materials, we selected three kinds of wet granular beds as model foods, whose optical properties are different each other. These beds consisted of each one of the three kinds of powders (alumina, silver and stainless steel) and water. The emissivity of alumina is the highest among them and that of silver is the lowest. Based on far infrared drying experiments of these beds, a drying model for the granular beds by far infrared radiation was discussed to calculate the drying rate and the material temperature in the constant rate period. We introduced the optical properties of the drying materials (emissivity of powder, emissivity and reflectivity of water) to the model. The drying rate and the material temperature in the constant rate period for the alumina beds are the highest of three beds. The values calculated for each bed by the model agreed with the experimental values.

View full abstract

Investigations have been carried out to obtain calculation formulas for total free sugar, sucrose, raffinose plus stachyose, and stachyose contents of soybean seeds (dry matter basis) using estimated data of free type of total sugar content (dry matter basis) of 105 samples of 60 cultivars and 7 lines. The calculation formulas using free type of total sugar content (x) were as follows: Total free sugar content (y₁)=1.18+0.88x
Sucrose content (y₂)=-4.24+0.93x
Reffinose+stachyose content (y₃)=(y₁-y₂)×0.84
Stachyose content (y₄)=(y₁-y₂)×0.68

View full abstract

The composition of carotenoids in four flesh colored melon cultivars was studied. The carotenoids were separated by column, thin layer and high performance liquid chromatography and identified by order of absorption affinities on the column and by their absorption spectra. The contents and kinds of carotenoids were as follows: (1) The orange flesh colored melon cultivars 'Iroquois', 'Blenheim Orange', 'Birdie Red', 'Quincy' and 'Tiffany' contained about 9.2-18.0μg/g β-carotene as the major pigment; a small amount of phytofluene, α-carotene, ζ-carotene and xanthophylls were present. (2) The light orange flesh colored melon cultivar 'Hale's Best' contained about 4.0μg/g β-carotene; phytofluene, α-carotene, ζ-carotene and xanthophylls were also present in small amount. (3) The green flesh melon cultivar 'Earl's Favourite' and 'Fukunoka' and white flesh colored melon 'Barharman'; the components were β-carotene and xanthophylls.

View full abstract

Ascorbic acid content and several enzyme activities related to biosynthesis and metabolism of ascorbic acid, namely L-gulono-γ-lactone oxidase, monodehydroascorbate reductase, dehydroascorbate reductase, peroxidase, ascorbate oxidase and polyphenol oxidase, in potato tubers were examined to clarify the relationship between physiological condition of stored potatoes and their ascorbic acid content. During the first month of storage, ascorbic acid content decreased markedly irrespective of storage temperature, after which the decrease became gradual. Since several related enzyme activities also changed markedly during the first month, they are assumed to affect the ascorbic acid content of stored tubers. Changes in storage temperature had little effect on these changes. This study showed that a marked change in ascorbic acid content of potato tubers occurred during the initial period of dormancy irrespective of storage temperature.

View full abstract