It is not unusual for commonly encountered food processing technologies to have evolved from those originating in other fields. Consumer demand, in particular that for new foods, is a major driving force for the development of new food processing technologies. Here, I describe three case studies on the development and practical application of new technologies for processing high quality and high added value foods, designed to meet the varied requirements of consumers, which often change in accordance with social conditions. The first case study details a process using a twin-screw extruder that results in versatile, high water content texturized materials by an injection molding method, food materials for specific users like patient, and meat substitutes. The second case study describes processing technology for environmentally friendly agricultural products. The process involves the use of a twin-screw type device, includes efficient solid-liquid separation treatments (oil expression, dehydration, etc.), and results in the production of biodegradable materials by an injection molding method. The third case study describes Aqua-gas processing technology, which includes processing high quality agricultural products and foods for use in certain hospital settings through a heating media containing micro-water droplets in superheated steam. This paper covers in detail the progress made in the development of these technologies in response to consumer and industry requirements.

Drying is important for producing long shelf life food products such as vegetables, fruits and liquid foods. A batch hot air tray dryer is widely used for food drying as the equipment is simple and easy to use. The problem of the food drying process by such tray dryers is that it is difficult to determine the optimum drying program such as air temperature and humidity. A trial and error approach is commonly employed for determining the drying program, which is labor intensive and time-consuming. Another approach is to use mechanistic or hybrid models along with various monitoring devices, some of which can work as soft sensors. We have developed a laboratory drying setup, equipped with non-invasive temperature sensors, humidity sensors, a digital camera and an electronic balance. The weight of the sample, the air temperature, the air humidity, the sample temperature and the sample image can be recorded on-line by PC. A proto-type tray dryer having above-mentioned devices was also developed. As for the model, a water diffusion equation along with a heat balance equation considering the mass transfer through the interface was used. It is practically difficult to determine the optimum drying program (temperature step change) experimentally because a single drying experiment takes at least a few hours as high air temperatures cannot be used in order to avoid the quality loss of the food product. It is therefore best to use the model simulation for determining the optimum conditions with the data obtained by the dryer with various sensing devices. We have demonstrated that the dryer developed in this study was able to monitor the color change of the model food samples continuously, which might be related to the loss of free amino acid concentrations during the late stage of drying.

Phycobiliprotein (PB) produced by cyanobacteria exhibits an anti-inflammatory effect and anti-cancer effect, and is expected to be applied as pharmaceuticals. In this study, a PB-containing solution from Nostoc commune was concentrated and separated by an ultrafiltration (UF) membrane module (nominal molecular weight limit (NMWL) 150 kDa, 30 kDa and 10 kDa). When the PB-containing solution was permeated through an UF membrane module of NMWL 10 kDa at 0.07 MPa, the total protein content was concentrated up to 10 times in 30 minutes. To simulate the change in the concentration for the concentrate in the scaled-up treatment, the parameters of the formed cake layer were determined by a mathematical model. The concentration performance of the UF membrane modules was evaluated using the obtained parameters, indicating that the 150 kDa NMWL UF membrane modules were able to concentrate 100 liters of PB-containing solution by 10 times in 15 hours. The 30 kDa and 10 kDa NMWL UF membrane modules showed the possibility of PB separation, as well as protein concentration. The productivity of PB calculated by flux and selectivity was highest for the 30 kDa NMWL UF membrane module.