This report shows the importance of food texture in attractive and palatable food. Specifically, I focused on the classification of food texture, including the perceptual and cognitive representations. Perceptual food texture is composed of the rheological, tribological, and morphological attributes. The cognitive food texture is represented by the combination of perceptual food texture during the mastication process. For example, the “Mochi-mochi”texture of a tapioca starch gel shows the typical cognitive representation. The cognitive food texture is “Kansei”, which is similar to sensitivity. In food development, a sensitivity food texture is desirable. Therefore, the sensitivity expression of the attractive and palatable food was analyzed by sensory evaluation, physical property measurement, and structural observation. I recommend that one approach to achieve delicious food texture is based on food structural engineering.
Friction index was introduced into the evaluation of food texture. A wedge-shaped probe was inserted into a food sample by a swing arm device for the acoustic measurement of food. Since total weight of the arm, balance weights and probe were known,initial kinetic energy of the inserting probe can be calculated. Displacement and time of the probe after insertion was monitored by a linear encoder. When the probe is stopped within the sample, a food friction index (FFI) was calculated by an equation, 3/4 ×(mv0)/Δl or 3/2 ×(m/Δt), where m is the total weight of the balance, arm and probe, v0 the initial probe velocity at insertion, Δl the probe travelling distance after insertion until the probe stop, and Δt the time from the insertion to the probe stop. FFIs (kg/s) of fresh and stored apple were 40.5 ± 0.8 and 44.1 ± 1.2, suggesting the fresh apple exhibits less FFI and is more crisp. The FFIs obtained by the first and second equation are not significantly different and different insertion velocity of the probe did not affect the results. FFIs of another species of fresh apple, persimmon and banana were 23.6 ± 0.7, 20.5 ± 0.8, and 12.4 ± 0.1, that corresponds to human sensory evaluation.
Due to the oral process is the complex action with fast movement and configuration changes, it is difficult to visualize the accurate bolus behavior. Physical quantities on human organ during oral and swallowing process are considered as important information for the development of the appropriate food product. The purpose of this work is to estimate physical quantities of bolus dynamically on the organ surface received from the food bolus during oral and swallowing process. In order to simplified measurement, the dynamic food bolus evaluation system “F-bology® analyzer”have been developed. This system contained inclined plate with customized the pseudo organ sheet. This pseudo organ sheet has similar specific wetting properties of human organ surface. The food sample was supplied on the sheet of this system by the piston pump, and it became bolus. The bolus flow down and the velocity on the sheet was measured by the disruption signal of laser sensors. The changes of the diffusion area of food bolus were calculated from movies recorded by the high speed micro scope. Physical quantities which include tribology properties were calculated from these measured values. Differences of physical quantities such as shear stress, energy density and diffusion area have been observed under the different viscosity, density samples. On the sensory evaluation, there are linear relationship between all physical properties taken from this system and sensory words. Physical measurement from this system and sensory evaluation were comprehensively linked and it can discuss to appropriate food properties for the target consumer such as patient for aspiration or elderly person.
The aged society has arrived in Japan. Though the mastication indicator of foods for elderly persons is established in Japan, it does not provide the information whether they can swallow or not. Moreover, we cannot know the characteristic texture of each food with the standard measurement methods. In this study, we corrected the standard methods of TPA and viscosity measurement to develop and to sell food for aged and person having difficulty in chewing. In addition, we tried to evaluate the mouthfeel of the food by static friction coefficients. The static friction coefficients showed a high correlation with collecting feel of bolus in the mouth.
As typical seals used for food machinery, this paper presents oil seals which are a kind of dynamic seals and ferrule gaskets which are a kind of static seals. These seals are required to comply with the Food Sanitation Act and to have high durability against the special oils and detergents peculiar to food machinery. Especially, in the case of oil seals, it is necessary to improve the sealing properties against low-viscosity water, and in the case of ferrule gaskets, it is necessary to take measures against the odor of various flavors. In response to these requirements, the development of fluorine-based rubber materials by special compounding and the improvement of the seal structure have been promoted.
Food safety management system such as “HACCP” is widely implemented in food industry to gain the trust from consumers. Along with this trend, NSF H1 lubricants are getting more common and required to have higher performance. High performance NSF H1 lubricants can contribute to improve food machinery performance by excellent lubricity and safety. This paper focuses on grease for food machinery and report the review of current grease trends. In addition, latest technological trends are reported from the viewpoint of thickener.
Deterioration of friction and wear due to particulate matter is one of the common lubrication problems. Lubrication failure due to soot generated by combustion in internal combustion engines frequently becomes a problem. In particular, abnormal wear of each part of the engine due to exhaust gas measures called EGR (Exhaust Gas Recirculation) is well known. EGR has a great effect on reducing nitrogen oxides, but abnormal wear occurs on piston rings and cylinder bores. This abnormal wear was actively studied about 20 years ago. Even today, the deterioration of friction and wear due to particulate matter is a serious problem. Here, the papers analyzed from different viewpoints are introduced in two explanations. This explanation is one of two explanations. This explanation summarizes the following contents. EGR increases the frictional force of the piston ring, thereby increasing wear. The cause of the change in frictional force is that particulate matter enters the back of the ring. The slap force of the piston is transmitted to the piston ring via the particulate matter. This force is the cause of increased wear on EGR.
Improving seizure resistance in plastic working is a major issue in tribology, but there are few clear guidelines for achieving this using surface treatment. This is likely due to the lack of a method for theoretically and quantitatively evaluating seizure resistance of tool surface treatments. Therefore, the authors focused on the adhesion strength between seizure and the tool surface as a quantitative index of seizure resistance. In this study, Friction pressure welding (FPW) was adopted as a measurement technique. And the effect of tool surface treatments on seizure resistance during hot rolling and FPW strength was investigated. The respective bonding mechanisms with the tool surface were also examined. The results showed the same orders of FPW strength and degree of seizure in hot rolling: polished surface < Cr plating < oxide film. Observation and analysis of bonding interfaces showed that the FPW interface had a higher temperature than the seizure interface during hot rolling, but the bonding mechanism was inferred to be very similar. These results show it is possible to quantitatively evaluate seizure resistance by evaluating seizure point strength using FPW with a controlled amount of friction heating.
Friction reduction by engine oil under low temperature as well as high temperature conditions are required because of the increasing number of hybrid vehicles where bulk oil temperature is low. Friction modifier (FM) technology to realize it is required. Friction performance of MoDTC, which works well at high temperature, used with adsorption type friction modifiers, which work well at low temperature, was investigated. Low molecular type, glycerol monooleate (GMO) inhibited friction reduction performance of MoDTC while polymer type FM showed little inhibition. Surface analysis indicated that the reaction film by MoDTC was not existed when the GMO was used together while it existed when it is used with polymer FM (PFM). The cause of the difference was studied by their adsorption performance examined by quartz crystal microbalance. GMO showed high adsorption density, while PFM showed low adsorption density compared to that of MoDTC. The result indicated that GMO competitively adsorbed on the surface, inhibiting the reaction film formation by MoDTC while polymer FM does not. The study indicated that use of the polymer FM with MoDTC is one of the solutions of FM design that works under both high and low temperature.