We investigated the effects of heat treatment on the glucosinolate (GSL) content of Brassicaceae vegetables. The results obtained were as follows: 1. Highest decrease in the GSL content of watercress and broccoli was recorded on subjecting to a temperature of 50-60°C. 2. Residual amounts of aliphatic GSLs were found to be approximately 80% in broccoli that was subjected to an internal temperature of 95°C. Residual amounts of indolyl GSLs ranged between 20% to 75% depending on the kind of indolyl GSL. 3. The remaining amounts of both aliphatic and indolyl GSLs in boiled broccoli decreased with an increase in the boiling time. The boiling water retained only limited amount of GSLs, that is, approximately 7% of the aliphatic GSLs and approximately 18-20% of indolyl GSLs. 4. When broccoli was boiled in different volumes of water, the difference in the ratios of residual GSLs were found to be negligible. 5. No loss in the amount of GSLs content of the vegetables was recorded after heating to an internal temperature of 95°C with steam, superheated steam, or vacuum cooking.
We investigated the effect of fatty acid composition on the sensory characteristics of grilled beef steak. Beef steak samples with varying fatty acid composition were cooked by grilling, and then analysed for sensory qualities, breaking measurements, and cooking loss. Based on the sensory evaluation, samples with high content of monounsaturated fatty acid (MUFA) were found to have reduced “tenderness” and inferior “overall texture”. On the other hand, these samples had good “flavor intensity”. Additionally, these samples had high value of breaking characteristics and there was increased loss of fat and juice through cooking. It has been suggested that the fat in the samples with high MUFA melted at a lower temperature, and therefore, resulted in an increased outflow of fat and meat juice when the steak was grilled, leading to an inferior texture. Increases in the MUFA ratio of the beef steak adversely affected the texture. Consequently, we suggest that to be palatable, beef should have a suitable proportion of each fatty acid. We found that beef samples with good sensory qualities generally had a MUFA proportion of 56-59%.
This study investigated the effects of cooking and placement conditions, heat capacity of an oven plate, and thickness of meat samples upon change in their internal temperatures after oven cooking. In the condition wherein the oven plate was covered after oven cooking, the internal temperature of the samples was maintained at over 75°C. This temperature was maintained for a longer duration than that for the condition wherein the samples were not covered. The heat capacity of the oven plate (weight-to-area ratio) affected the retention time of the central temperature (over 75°C) of the samples. The thickness of the samples had negligible effect on the retention time. The retention time of the central temperature (over 75°C) of the samples was predicted using the improved calculation model. The values of the calculated time were similar to those obtained through actual measurement, which confirmed the validity of the heat transfer model.
This study analysed the effects of the heating capacity of oven plates and the heating ability of ovens on the internal temperature of meat after oven cooking at 230°C. The temperature of the samples increased with the increase in the heating ability of ovens. Further, the overall temperature after cooking increased with the increase in the heating capacity of the oven plates, and the time required to attain an internal temperature exceeding 75°C also increased. As the duration of covering the samples after heating was reduced, the percentage of weight reduction decreased, and the samples became softer. These findings revealed that covering the cooked meat until a maximum internal temperature was attained kept it hygienic and enhanced its taste.
We examined the gelatinisation, paste texture, and gel rupture properties of the fermented sweet potato product ‘Sen’, a traditional foodstuff of the Tsushima Island, in comparison with that of the sweet potato powder and sweet potato starch. Based on the chemical composition, starch was the most abundant component in Sen as well as in sweet potato powder and sweet potato starch. The contents of soluble and insoluble dietary fibres were 0.9%, 1.8% in Sen and 3.0%, 5.7% in sweet potato powder, respectively. The onset, peak, and termination temperatures for Sen gelatinisation were 65.3°C, 72.5°C, and 80.2°C, respectively. The gelatinisation properties of Sen were similar to those of sweet potato starch. The paste texture tests, with concentrations ranging from 1-12%, revealed that both the hardness and adhesiveness of Sen paste were relatively higher than those of the other two samples. Moreover, the gel rupture tests demonstrated that the Sen gel was harder and more elastic than the sweet potato powder gel. The rupture properties of Sen gel and sweet potato starch gel were similar.
Nine different grain flours were used to make cookies; soft wheat, soft wheat (whole), rice, brown rice, red-kernelled rice, maize, buckwheat, Japanese millet and foxtail millet. Cookies were made from raw as well as roasted flours. The cookies were assessed using sensory as well as objective methods such as a rheological instrument. The quality of cookies can be summarized as follows: (1) Roasting of flour reduced cookie hardness and resulted in a more crunchy product after baking as well as improved mouth feel. (2) Roasting of flour also improved the taste and after taste as well as flavor resulting in a good overall score. (3) The high score group with overall cookie quality were as follows: raw wheat flour, roasted wheat flour, roasted whole wheat flour, roasted brown rice flour, and roasted maize flour. (4) The roasting of grain flour also reduced product hardness as rheological quality particularly for rice flour.
This study was conducted to examine the ingredients of Zōni, a Japanese soup containing rice cakes and popular in Aichi Prefecture. In Aichi Prefecture, typical Zōni consisted of square-shaped rice cakes, favoured in eastern Japan, along with soy sauce and dried bonito flakes-based clear broth (which reflects the historical influence of the samurai society wherein people disliked miso-based broth). The ingredients of the traditional Zōni included Japanese mustard spinach (Mochina) (grown in the Owari district for good luck), minced and steamed fish (kamaboko or naruto), and dried bonito flakes. However, differences were observed between Zōni dishes in Owari and Mikawa districts. A larger amount of Japanese-style seasoning was used in Mikawa, where the proportion of working females was high. Compared to Zōni dishes in Owari, those in Mikawa contained a wider variety of local specialties as ingredients, such as Chinese cabbage, tofu, deep-fried bean curd, and carrot.
A questionnaire survey was conducted targeting registered dieticians and nutritionists working at each facility to study the required cooking training for individual fieldwork provided from training facilities for registered dieticians and nutritionists. The questionnaire consisted closed-ended and open-ended questions. The analysis compares the feature of the learning contents required by each type of facility, such as hospitals and elder care institutions and administrations. The results found that basic cooking knowledge and skills are important regardless of institutions type. Moreover, the required cooking skills and dishes depended on the institution at which a respondent now works. Especially required dishes were likely to differ by life stage of user whom each facility covers. The necessity for skills and knowledge in preparing soft dishes was high in hospitals, elder care institutions, nursery schools, and kindergartens. Compared to other institutions, the ability to prepare fish was most likely to be required by administrations, but not very likely in facilities that provide meals, such as hospitals and elder care institutions. Regarding knife skills, the necessity for the basic knife skills used to prepare daily food was high without indicating significant difference among facilities.
This study investigates the relationships of the mineral composition, pH, hardness, and other physical and chemical characteristics of tap water to its taste. Using principal components analysis, tap water from 20 areas in Japan is categorized by the extent of concentrations of Na, Ca, K, Mg, Si, and other physical and chemical properties. The tap waters with relatively positive ratings of taste have relatively low concentrations of Si and Ca, and their sources are surface water. The results of a discriminant analysis find that the concentrations of Si and Ca strongly contribute to categorizing tap water into two groups based on the taste test. The pH value also is an important factor in the discriminant analysis. Last, the discriminant analysis results are consistent with the results of the principal component analysis. These results suggest that the taste of tap water is related to the concentrations of Si, Ca, and the pH level.