An efficient method to extract and recover hesperidin from satsuma mandarin peel residue was developed. The fresh peel residue was degraded and liquefied with a commercial enzyme, prepared from Aspergillus niger, including pectinase, cellulase and hemicellulase activities, prior to the extraction. One and a half volumes of water was added to the residue and its pH was adjusted to 4.0. The enzyme reaction was carried out at 40°C for 20h. The hesperidin content was not affected by the enzyme activities during this process. After the enzyme reaction, the centrifugal residue was suspended in water and adjusted to pH 12.0 with Ca(OH)₂ and NaOH. Clear solution was obtained by centrifugal separation and filtration from the suspension. The solution was adjusted to pH 5.0 and hesperidin was crystallized. By this process the extraction time and crystallization time were shortened and the yield of hesperidin was increased. In the optimal condition, the recovery of hesperidin was about 75 %, and its purity was over 90%. It is most likely that the enzyme treatments improved both of crystallization and release of hesperidin from cells. When Ca(OH)₂ was added, higher purity was obtained.

View full abstract

Bacillus natto was cultured in the liquid media containing various carbon sources, and effects of carbon sources on the formation of pyrazines were examined. Reexamination of culture conditions revealed that shaking was better than standing on cell growth and pyrazine production. Fourteen pyrazines were identified by GC and GC-MS. The highest yield of pyrazines was obtained on addition of glucose, and the total pyrazines was more than 42mg/l of culture broth. Seventeen carbon sources were divided into five groups (A, B, C, D, E) by the pyrazine formation pattern. In the case of group A (D and L-arabinose, xylose, galactose and sorbose), 2-methylpyrazine was the main product. In group B (glucose, fructose, mannose, sucrose and mannitol), trimethyl and tetramethyl derivatives were the main products. The main product of the group C (trehalose and sorbitol) was 3-ethyl-2, 5-dimethylpyrazine, and that of group D (raffinose and stachyose) was 2, 5-dimethylpyrazine. Group E (L-rhamnose, maltose and lactose) was the group which could not belong to any other groups. Yields of pyrazines in the culture broths were parallel to cell growth in each group, except group E.

View full abstract

Drying rates of tuna flesh were measured at several conditions such as temperature, thickness of flesh, air velocity. Relationships between the drying rate and w/w_o, a ratio of moisture content at any time to the initial based on equilibrium, were asymptotic to a straight line independently of flesh thickness at a constant temperature. It was supposed from this result that a layer of an approximately same thickness with steep gradient of moisture content was formed at the surface of flesh in the early stage of drying. Then assuming that a drying rate is determined by a resistance of moisture through the layer, a rate equation was derived. The equation was well coincidence with experimental results. The rate was inversely proportional to the thickness of flesh, different from most of previous workers.

View full abstract

The successive treatments with acid and alkali or the single treatment with alkali were applied to disintegrate the edible tissues of vegetables and potatoes as follows. The samples were immersed in hydrochloric acid at 35°C for 1 or 24hours, where the pH values of the supernatant were 1.0-1.5. The samples treated with acid were stirred in a sodium hydroxide solution by a magnetic stirrer at room temperature for 2hours, where the pH values of the supernatant were 12.5-13.0. The degree of disintegration was calculated on the basis of the weights of the tissues used and those remained after the treatments. It was found that the single treatment with alkali disintegrated almost completely the tissues of tomato, squash and sweet potato. The successive treatments with acid and alkali disintegrated almost completely the tissues of cucumber, eggplant, sweet pepper, onion, garlic, lily root, taro, and potato. The successive treatments disintegrated 50-100% of the tissues of cabbage, chinese cabbage, lettuce, spinach, green asparagus and broccoli. The large scatter of the disintegration degree was assumed to be due to the heterogeneity of the tissues and fibrous tissues which may be difficult to be disintegrated by the treatments. The tissues of Japanese radish, carrot, burdock, lotus root, ginger and arrowhead, were found to be difficult to be disintegrated by the successive treatment, in which the degree of disintegration was less than 28%. From these results it was assumed that the relative difficulty of disintegration of tissues by the treatments may reflect a difference in the mechanism of adhesion or the strength of adhesion of tissues.

View full abstract

We analysed the isothiocyanates in Chinese wasabi, Cruciferae species, Hilliella shuangpaiensis, with GC and GC-MS. For analyzing the isothiocyanates, wasabi paste was extracted with ether. Gas chromatography and GC-MS analyses revealed allyl, β-phenyl-ethyl, 3-butenyl, 4-pentenyl and 5-hexenyl isothiocyanate as main components and 6-methylthiohexyl, 7-methylthioheptyl and 8-methylthiooctyl isothiocyanate, which are important flavor components in wasabi, as minor ones. These results show that Chinese wasabi is the interesting food which has the characteristic nature of both wasabi and horse radish.

View full abstract

In ordinary cases, brined ume fruit with Ca(OH)₂ becomes hard in texture, but in some cases wrinkles appear on the peel of the brined fruit, and such fruit has been called shrunk fruit. The shrunk fruit decreases in yield of hardened ume fruit and becomes soft in texture, so loses completely the value as hardened and brined ume fruit. Because the valuable way to prevent the shrinking was not found yet, we studied the way of preventing the shrinking and found the available way for it. The results obtained were as follows: (1) At the bigining of the brineing, the ume fruit added 0.15 % Ca(OH)₂ in the ratio against the fruit shrank, but the fruit added 0.30% Ca(OH)₂ did not shrink. (2) The ume fruit added 0.15% Ca(OH)₂ after the brineing did not shrink, but became soft in texture along with a delay of Ca(OH)₂ addition. (3) The ume fruit added 0.15% Ca(OH)₂ at 1 week after the brineing hardened enough in texture. (4) The fruit added Ca(OH)2 increased Ca contents. (5) HSP (HCl soluble pectin) decreased in the ratio against total pectin along with delay of Ca(OH)₂ addition, and the hardness also decreased. Thus, the prevention of the shrinking of brined ume fruit might occur under the inhibition of the change of HSP resulting with a crosslinkage between Ca of added Ca(OH)₂ and pectin.

View full abstract

In the courses of the study on an industrial scale system for hesperidin recovery from the peel residue of satsuma mandarin (Citrus unshiu Marc.), we have screened commercially available enzyme preparations to degrade the peel residue. Screening was designed to obtain the enzyme which concentrates hesperidin effectively in the enzyme-treated residue without changes of its chemical structure. Forty-seven commercially available enzymes were examined. They included pectinase, cellulase, hemicellulase, amylase, protease and lipase activities. An enzyme, prepared from Aspergillus niger, including pectinase, cellulase and hemicellulase activities, was the most effective among the examined enzymes. The optimal condition of this enzyme was as follows: initial pH, pH3.0-4.0; reaction temperature, 40°C. When the residue was treated for 24h, hesperidin in the residue was concentrated 2.2-fold and recovery of hesperidin was 94.1%.

View full abstract

The yolk-added emulsified product prepared from sardine meat had a more viscoeiasdic strucdure than the 'whole egg'-added product because it deveioped large G', G" values and large shear stress. However, the yolk-added product showed a smaller value of yield stress and a markedly smaller value was shown at asoybean oil to sardine meat ratio of 1.1. The consistency and flow behavior indexes of increasing shear rate determination were larger in the yolk-added product than in the 'whole egg'-added product. In the yolk-added product, the oil droplets were smaller, more uniform and larger in number. Therefore, the sum of the interactions between the oil droplets was larger. This microstrucdure is reiaded to the above rheological results. A drastic change in shear response was found between a soybean oil ratio of 1.1 and 1.7 in both the'whole egg'-added and the yolk-added products but was more pronounced in the yolk-added product. When the shear rate vs. shear stress hysteresis loop of the yolk-added product was considered in comparison with that of the 'whole egg'-added product, at a low oil ratio the strucdure breakdown was not induced by the shear, and at a high oil ratio a great structure breakdown was induced. This result means that the three dimensional structure developed with the high oil ratio was broken down by the shear. In the products with higher oil radios of 1.7 and 2.5, the relative amount of emulsifier do oil was very small. Therefore, the emulsifying layer around an oil droplet was thin, and the oil droplets tended to coalesce without the shear. If shear was applied, the emulsion was easily broken down due to the further progress of coalescence. From microscopic observation, it was found that many large oil droplets were present in the products with higher oil radios of 1.7 and 2.5.

View full abstract

Prevention of the caking of KCl-NaCl powder produced by a spray-dryer was investigated. The spray-dried powders of both a simple KCl-NaCl mixture and a mixture of KCl and NaCl with an amino acid that was less soluble than KCl and NaCl and that had hydrophobic functional groups were obtained in the form of particles that were hollow spheres. When stored in high humidity, the first powder soon caked, but the second did not. This difference could be explained by the solubility and polarity of the amino acid added. When the solubility of the amino acid added was higher than that of KCl or NaCl, the surface of the spray-dried particles was crystalline and porous. When the amino acid had hydrophobic functional groups and its solubility was lower than that of KCl or NaCl, the surface of the spray-dried powder was smooth and not porous; this result suggests that the surface of the spray-dried particles was covered with amino acid molecules. We concluded that the solubility and the functional groups of the amino acids that were added to a KCl-NaCl mixture could be used to control caking of the spray-dried powder.

View full abstract

Rapeseed oils from Japanese old type rapeseed varieties are rich in erucic acid. Rapeseed oil with high erucic acid content is said to be harmful in nutrition. Therefore, rapeseeds with low content or whithout erucid acid have been developed in Japan and many countries of the world. The fatty acid composition of rapeseeds of Japanese old type varieties was examined. Main fatty acid composition of Towada rapeseeds grown in Aomori prefecture in 1982 was as follows: Oleic acid, 16%; linoleic acid, 13%; linolenic acid, 8%; icosenoic acid, 10% and erucic acid, 45%. The fatty acid composition of the same rapeseeds in the same area in 1983 was similar to that in the previous year. The fatty acid composition of Oomi rapeseeds grown in Kagoshima prefecture in 1982 was similar to that in Aomori prefecture in same year. Of the twelve old type varieties of rapeseeds which were grown in Iwate prefecture, eleven contained erucic acid in seeds oils at levels ranging from 42 to 49% and oleic acid from 11 to 17%. There was a negative correlation between percentages of erucic and oleic acids. There was a linear relationship (r=0.795) (1) between oleic (Y) and erucic (X) acids percentage, except for 'Aomori-1'.
Y=(-0.7246X)+47.24(1)
There was also a linear relationship (r=0.847) (2) between percentages of oleic (Y) and erucic (X) acids in all rapeseeds analyzed and reported data.
Y=(-0.4348X)+34.25(2)

View full abstract