The generation of relatively high oil-film pressure in the small radial gap between two scroll wraps in a scroll compressor due to the inscribed rolling and sliding motions has long been hypothesized. However, neither the precise physical mechanism of this high oil-film pressure generation nor the significant characteristics of the oil-film pressure has been clearly identified. The current study presents the motion between two scroll wraps are represented by the superposition of rolling and sliding. Secondly, a theoretical analysis of the effects of oil viscosity on the oil-film pressure generated by the inscribed rolling and sliding motion between the scroll wraps is documented, where the oil film pressure and resultant oil film force are derived in a simplified form of the dimensionless expressions. Subsequently, the measurement of the oil-film pressure in a simplified equivalent physical model consisting of two circular cylinders undergoing inscribed rolling and sliding motions confirmed the theoretical results. Finally, the major characteristics of the oil-film pressure and resultant oil film force in a medium cooling capacity scroll compressor is calculated and demonstrates that the oil-film pressure acting on the outer periphery is sufficiently high to cause elastic deformation of scroll wrap.

Pizza dough baked at mild thermal conditions (pre-baked pizza crust) can be shipped and stored under refrigerated conditions, and enables a quick serving of pizza. Pre-baked pizza crust, however, easily collapses due to loading weight during shipping and storage. In addition, the texture of re-baked pizza crust becomes essentially harder due to the further reduction of water. The purpose of this study was to improve the physical strength of pre-baked pizza crust and the texture of re-baked pizza crust. The water content decreased and initial elasticity increased with increase in pre-baking time. Samples pre-baked for 15 and 20 min tended to have a lower deformation ratio than that pre-baked for 5 min. The rounded, thicker rim of the pizza crust became flattened, but the internal porous structure was maintained in samples that were pre-baked for 15 min. To control the texture of the re-baked pizza crust, rehydration was performed before the re-baking. The water content of the rehydrated pizza crust was almost equivalent to that of conventional (not pre-baked) pizza crust dough, and the rheological and sensory softness of the re baked pizza crust were significantly improved.

For environmental protection, low-GWP refrigerants are required in HVAC/R industries. To replace refrigerants with low GWP ones rapidly, reliable thermodynamic model that is essential for system performance calculation is also required. Recently, Extended Corresponding States (ECS) model is used for cycle simulation of various candidate refrigerants, however, reproducibility of property estimation by ECS model have not studied yet. In this work, by ECS model with parameters determined applicable to various refrigerants, estimation accuracy of saturated properties and theoretical performance is evaluated. The average absolute deviations for the saturated properties were 5.7 % for the vapor pressure, 11 % for the saturated liquid density, and 2.0 % for the latent heat of evaporation at Tr = 0.7. On the other hand, in the calculation of the theoretical refrigeration cycle performance, the accuracy was better than 1 % for COP, but the prediction accuracy for volumetric capacity was slightly lower, around 6.7 %.

In this study, we demonstrated the superiority of a heat pump system in heating an electric vehicle over an electric heater supported with other energy-saving measures; an EV heated with a heat pump system consumed less power and enabled better mileage than one heated with an electric heater. We developed a heat pump system which had enough heating efficiency for this experiment, installed it in an EV and measured the heating capacity and the energy consumption. As for an electric heater, we calculated its power consumption based on the measured figures of the EV with the heat pump system, setting the conditions of no ventilation and low temperature respectively as energy-saving measures. We compared the following four figures: the power consumption of heating with an electric heater, heating with an electric heater plus no ventilation, heating with an electric heater plus low temperature, and heating with a heat pump system. The comparison showed that a heat pump system consumes the least energy.

We aimed to investigate the de-oiling phenomenon of yellowtail on freezing using liquid nitrogen (LN2). The yellowtail samples were frozen at -30 °C (stationary freezing, SF) or soaked in LN2 to observe the de-oiling phenomenon. The thawed samples were left on a paper plate at 25 °C for 10 h. As a result, it was observed that the LN2 frozen sample was de-oiled more than the sample of SF. The raw yellowtail was frozen in a stocker at -30 ℃and soaked in LN2. The water and oil loss were obtained on thawing under running water the frozen yellowtail and stored at 10 ℃ or 25 ℃ for 18 h. The drip loss immediately after thawing was 0.4% lower in the sample with LN2 freezing. On the other hand, the drip loss of the LN2 frozen sample was higher than the frozen sample in SF after storage at 10 °C and 25 °C. After storage at 25 °C, the water loss was 7.6%, the oil loss was 5.5% in the LN2 frozen samples, which was significantly higher. From the results, we found that the amount of drip loss, especially the outflow of lipids, increases during storage after thawing.

We investigated the odor changes in frozen horse mackerel after thawing using an electronic nose. The samples were frozen rapidly and then thawed either at 10 ℃ or 25 ℃. In samples thawed at 25 ℃, higher levels of hydrocarbon, ester, and aromatic compound odor were detected. From the results of this study, it is possible to quantify the changes in odor intensity and quality due to thawing temperature by odor contribution and similarity. This study demonstrates the usefulness of an electronic nose to evaluate the odor changes in the fish meat after thawing.

Tempe is soybean-based fermented food from Indonesia. In countries outside Indonesia, including in Japan, tempe is mostly purchased in a frozen form because of its short shelf life. Inappropriate thawing may result in lowering the food quality. The study aims to investigate the effect of thawing conditions such as water immersion thawing (WIT), hot steam thawing (HS), ultrasound-assisted thawing (UAT), and microwave thawing (MT) on frozen tempe. This study showed that WIT had the longest thawing time and lowest hardness value. Although HS had a short thawing time, it had a lower hardness value compared to fresh samples. Furthermore, MT had the highest color difference (ΔE) and decreased in hardness value compared to fresh samples. UAT at 150W is considered as optimal thawing conditions because it not only significantly shortened the thawing time by 32% but also showed the best retention in the original hardness and color properties of fresh tempe compared to other thawing conditions. Thawing time had a significant negative correlation with thawing loss at the 5% level, and thawing loss had a positive correlation with yellowness (b*) (p<0.01) and color difference (ΔE) (p<0.01) values.

Evaluating the thawing level of frozen ingredients in food manufacturing processes is important for ensuring quality. In the present study, a new approach for measuring the ice fraction, an indicator of the thawing level of frozen foods, was developed using near-infrared (NIR) spectroscopy. In the NIR spectra (700–1100 nm), the OH band shifted to shorter wavelengths as the ice fraction decreased. Savitzky-Golay second-derivative treatment revealed that the peak intensity of ice decreased whereas that of water increased as the ice fraction decreased. Multiple linear regression models constructed using the second-derivative spectra provided prediction values that agreed well (determination coefficients of 0.96 for agar and 0.84 for pork) with the ice fractions determined using conventional calorimetry (0–71.6 % for agar and 0.3–67.4 % for pork). Thus, this NIR technique can be applied as a non-destructive and rapid method for confirming the thawing level of frozen foods.

We investigated the effect of freeze vacuum dry processing on the antibacterial activity of dried garlic against Escherichia coli and Streptococcus thermophilus by diffusion plate test. The diameters of the inhibition zones formed by these two bacteria were similar between raw garlic and freeze-dried garlic. When raw garlic was heated at various temperatures for 30 minutes, the diameters of the inhibition zones showed no decrease at temperatures of 30C to 60C but decreased remarkably over 20 minutes at 80C. A similar result was found for freeze vacuum dried garlic. These results suggest that the antibacterial activity of garlic is minimally affected by freeze vacuum dry processing.

Aging of fishes which has attracted interests recently, is generally widespread with its pretreatment method, the instant killng and blood removal nerve destruction technique. However, there are very few scientific research reports on its efficacy and safety. Therefore, using the high-grade flatfish barfin flounder, it was treated by the conventional blood removal nerve destruction method and the irrigation type nerve removal blood removal method, without denervation, and aged at 0˚C for month. As a result, the washed semi-dress of fish meat of barfin flounder was bacterially safe. On the other hand, regardless of the blood removal method, inosinic acid disappeared at the end of 1 month of aging, free amino acids did not increase, and a rich umami taste was not confirmed in the sensory test. It was estimated that the time to eat barfin flounder in the same treatment was from the day after the start of aging to the 6^th day.

Half frozen or thawed fish are widely used at fishery processing industry, but it is difficult to strictly determine the status required by processing machine. Therefore, we evaluated an in-line non-contact near infrared sensor for use in frozen-thawed status discrimination. As a result of linear discriminant analysis, the discrimination rates in the frozen, half-frozen, and thawed status were approximately 98 %, 85 %, and 100 %, respectively. This suggests that it is possible to determine the status in which mackerels progress from freezing to thawing. It is expected that the automation of status discrimination using this technology will contribute to the optimization of the fish processing process.

We analyzed lipid compounds and water soluble compounds of frozen farmed scallop and bottom-cultured Japanese scallop in Mutsu Bay Aomori Japan. As a result, lipids content was higher in bottom-cultured Japanese scallop compared with farmed scallop. On the other hands, there were no difference of free amino acids in each other. Further, a comprehensive analysis was also performed by metabolome analysis using a capillary electrophoresis-time-of-flight mass spectrometer (CE-TOF/MS). 138 ionic water soluble compounds were detected. However, no significant difference in characteristics was observed. These results suggest that there is no difference in water soluble compounds related to quality of sea food products between frozen farmed and bottom-cultured Japanese scallop.

The effect of sodium alginate addition on the recrystallization of ice crystals in 40% sucrose solution at -10 ^oC was experimentally determined. The dynamic state of the freeze-concentrated matrix was investigated by the dielectric relaxation measurements to discuss the mechanism of sodium alginate addition effect on the ice recrystallization. The recrystallization of ice crystals was significantly inhibited by the addition of 3%, 5%, and 10% alginate. And the recrystallization rate constant tended to decrease with increasing alginate concentration. The dielectric relaxation behavior of all samples was well fitted by the combined equation of the two Cole-Cole relaxations indicating the existence of two relaxation process with different relaxation time: fast and slow processes. Based on the preceding research, the fast one and slow one was interpreted as relaxation of free water and that of solute-coupled water, respectively. Increasing sodium alginate concentration, both the fast and slow relaxation time tended to become larger, indicating that slower water mobility in freeze-concentrated phase. This result suggested that the slower water mobility by addition of sodium alginate contributed to the ice recrystallization suppression.