The dietary fiber in rhubarb was determined and some properties of the pectic substances were investigated. The proportion of total dietary fiber by Kainuma's modified method was 2.79-3.73% in three kinds of rhubarb.
The content of pectic substances in dietary fiber was 40.1±2.0% hemicellulose and cellulose were 24-30%each, and lignin was only 5%. The boiling water-soluble fraction in pectic substances comprised about 80%, therefore, it is interesting that the dietary fiber in rhubarb had functional properties. The crude pectic substances in rhubarb consisted of 71.1-79.2% of galacturonic acid with 6.3-6.9% of methoxyl groups, and the presence of rhamnose, galactose, arabinose and xylose was confirmed.

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In order to investigate the decrease in the residual SO₂ amount following the opening bottles, six wine vinegars produced in Europe were tested.
1. The highest amount of acetaldehyde was detected in sherry vinegar, then in balsamic vinegar, white wine vinegar, and red wine vinegar in that order.
2. Tartaric acid accounted for some 50% of the total non-volatile organic acids in the wine vinegars. Pyruvic acid was detected at concentrations of 10-25 μg/g in four samples, and in trace amounts in the remaining two samples. No α-keto glutaric acid was detected.
3. Most of the SO₂ in the wine vinegars was of the bound type. Little or only a trace amount of free SO₂ was detected.
4. The amounts of SO₂ in both the bound and free types were higher in wine than in wine vinegar.
5. The total amount of residual SO₂ in the wine vinegar decreased following the opening of the bottles in a similar pattern for five samples, while a rapid decrease was observed in one sample of red wine vinegar.
6. The total SO₂ amounts decreased faster in the wine vinegars than in the wine. It was suggested that the decrease depended on the type and amount of wine vinegar components that could be bound to SO₂, as well as that the low pH value could be a factor.

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Experiments were carried out to elucidate the cooking properties of Thai rice (Oiyza sativa L. var. indica) comparing with those of Japanese rice, Chiyonishiki (Oryza sativa L. var. japonica, cultivar, Chiyonishiki). The effect of cooking with pressure cooker on improving palatability of Thai rice was also determined.
Amylose content of Thai rice was higher (28.6%) than that of Chiyonishiki, on the other hand its water absorption rate during soaking was lower. These rices were cooked with regular cooker and with pressure cooker adding various amount of water. The amounts of added water for Thai rice cooked with regular cooker were 1.5,1.6 and 1.9 times (added water weight/rice weight). The amount of added water for Chiyonishiki and for Thai rice cooked with pressure cooker was 1.5 times each. On hardness and stickiness measured by a texturometer as to the cooked rice with regular cooker, the hardness of Thai rice was harder than that of Chiyonishiki and its stickiness was less on cooking with the same added water. By adding more water to Thai rice up to 1.9 times, the hardness was nearly equal to that of Chiyonishiki, whereas its maximum stickiness was about 50% of that of Chiyonishiki. In case of cooking with pressure cooker, the stickiness of Thai rice by a texturometer was increased to about 70% of Chiyonishiki. Panel members judged Thai rice to be more preferable both texture and total quality than that cooked with regular cooker. On the observation of an ultrastructure by SEM, Thai rice cooked with regular cooker had less reticular structure in the surface area and poor networks in the cross section. By cooking with pressure cooker, it was observed that these structures were improved.

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The flow properties of roux prepared from wheat flour and butter at the different cooking temperatures(100°C,120°C,140°C,160°C,180°C)and the sauce made from the roux were determined by rotary viscometer at 50°C. It was revealed that each roux, remarkably uncooked mixture of wheat flour and butter, and the roux cooked to 100°C, showed non-Newtonian and time-dependent thixotropic characters. On the other hand, each sauce made from uncooked sample and the roux cooked to 100°C-140°C, showed almost same flow behavior as the roux, that is non-Newtonian and thixotropic characters, but those sauces when the materials were cooked to the temperatures of 160°C or 180°C, were gradually closing to non-thixotropic and Newtonian characters.
As the results of sensory tests for the sauces conducted by 29 female students, it was found that the taste and flavor compared with the viscosity in sensory attributes were more positively correlated with overall acceptaace in each sauce from the different roux, and the sauce from the roux cooked to 140°C, i. e. the intermediate of white and brown sauce, was evaluated most highly in the overall acceptance.

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Jam was prepared from fresh rhubarb, and its properties and sensory characteristics were compared with fourteen kinds of manufactured jam.
The pH value of the rhubarb jam was 3.55, a higher value than those of the other sample jams, its hardness was relatively low, and its cohesiveness and adhesiveness were about average.
The sensory attributes of the jam samples were investigated by a factor analysis of the results of a sensory evaluation that was conducted by the semantic differential (SD) method.
A profile of the sensory attributes was obtained by the SD method, using 20 parameters concerning appearance, flavor and texture. The factor analysis by the principal factor method of the intensity of sensory attributes ranked appearance first, taste and odor second.
The factor analysis based on “like or dislike” of the sensory attributes, indicated that the first factor was taste and odor, and the second was appearance. The two-dimensional spatial diagram of the samples was made from the scores of these two factors as a correlation diagram, and the fifteen kinds of jams classified into two groups. The rhubarb jam was classified in the group of fruits and vegetables excepting table fruits.

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Vol. 28 (1995) No. 2 p. 84-89

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