Archive - Abstract

Vol.51 No.1 (March, 2020)

  • Research Paper (Japanese)
  • Study on Evaluation Indicators of Hop Aroma for Craft Beer Brewers in Japan
  • Masatsugu Tamura, Kana Komata, Daigo Inoue and Takahiro Saito
  • The object of present study was to establish indicators to visualize sensory-evaluated hop aroma. Sensory evaluation of aroma of 7 varieties hop was characterized by 5 craft beer brewers in Tochigi prefecture, and was examined for its visualization method. Aroma of eight varieties of hop was prepared as an original aroma (OA) and an extracted aroma (EA) simulating dry hopping. The hop aroma index simulated the beer brewing process was verified by sensory evaluation of 9 craft beer brewers in Tochigi prefecture using OA and EA. Questionnaire surveys were conducted in October 2016 (n=79) and January 2017 (n=27) targeting craft beer brewers from all over Japan. As a result, it was revealed that hops for the brewers were highly important and that there was little information of aroma at the time of purchase. Furthermore, a visual hop aroma indicator was desired by 89% of the brewers. Therefore, a hop package example of a 6-level scale radar chart consisting of five sensory evaluation terms (fruity, floral, herbal, spicy, citrus) with a text explanation was proposed as an indicator of hop aroma during brewing.

Keywords: Craft beer, Hops, Aroma, Sensory evaluation, Questionnaire survey


  • Research Paper (Japanese)
  • Control of Tomato Diseases by Night Time Dehumidification using Heat pumps in Autumn and Spring
  • Fumiyuki GOTO, Hitoshi TERAZOE, Atsushi YOMOTA, Hideki MORIYA and Kazuhiro SHOJI
  • The occurrence of leaf mold disease and other diseases is a concern in greenhouses, especially in spring and autumn because relative humidity in greenhouses rises at night. It is known that a heat pump has multiple functions not only heating but also air conditioning, dehumidification, and air blowing. We carried out comparative tests using two isomorphic greenhouses for tomato cultivation: a greenhouse equipped with two heat pumps (test area) and the other a kerosene heater (control area). Cultivation tests of tomato was carried out in autumn and spring in order to investigate the effect of dehumidification using two heat pumps. One heat pump was used for heating and the other for cooling. Both heat pumps were driven for 30 min. in 4 times at night. Leaf mold disease was seldom observed in the greenhouse installed with heat pumps for dehumidification. On the contrary, in the control greenhouse, leaf mold disease was observed in every experiment. No difference was observed between the two greenhouses in the weight of fruits, flowering time, number of flowers and the Brix value. The energy consumption of the control and test greenhouses during the cultivation period of spring was 10,817 MJ and 4,618 MJ, respectively. Approximately 27% of the energy consumption in the test greenhouse was used for dehumidification. In conclusion, dehumidification using heat pumps was effective for tomato cultivation by preventing leaf mold disease.

Keywords: dehumidification, greenhouse, heat pump, leaf mold disease, tomato


  • Technical Paper (Japanese)
  • Changes in Temperature and Relative Humidity, and the Freshness-keeping Effects of a Low-temperature Keeping System for Fruits and Vegetables using Refrigerant Plates
  • Takuma GENKAWA, Pankaj kumar GARG, Tofael AHAMED and Ryozo NOGUCHI
  • The performance of a low-temperature keeping system for fruits and vegetables was investigated using a refrigerant plate, the melting point of which is configurable within the chilled range. Young leaves of Japanese mustard spinach and the fruits of strawberry were sealed in a film bag and stored in an insulating container with refrigerant plates for a few days, and the temperature, relative humidity (RH), and qualities before and after storage were measured. The results indicated that the interior of the insulating container was maintained at a low temperature and a high RH for a few days, and that the fluctuations in temperature and RH were smaller than those obtained by mechanical refrigeration with an on-off control and defrosting. Moreover, there was no difference in qualities before and after storage. From these results, it was shown that the low-temperature keeping system using the refrigerant plates is a powerful tool for filling gaps in the cold chain logistics of exporting Japanese fruits and vegetables.

Keywords: Refrigerant, fruits and vegetables, low temperature keeping, cold chain, freshness keeping, exportation


Vol.51 No.2 (July, 2020)

  • Research Paper (Japanese)
  • Development and evaluation of wireless sensor network for measuring thermal air environment in large-scale greenhouses
  • Fumiyuki Goto, Norihiko Ito, Kazuhiro Shoji
  • In Japanese greenhouses, hot air generated by oil heaters or heat pumps generally is used for heating. Hot air heating is more likely to result in non-uniform temperatures in the greenhouses than heating with hot water pipes, so extra energy is used and uneven crop growth occurs. However, the details of the degree and mechanism of temperature non-uniformity caused by hot air are not well understood. To clarify them, it is effective to use a wireless sensor network (WSN) that can simultaneously measure the temperature at multiple points in the greenhouse for a long time. In this study, we developed a sensor node that measures the temperature distribution of greenhouses at multiple points simultaneously, considering the communication environment and power supply in the greenhouse. Further, WSN was evaluated by measuring the room temperature in a commercial greenhouse. TWELITE, which consumes less power during communication, was used as a communication method. TWELITE is one of the wireless systems that use 2.4 GHz band. Solar cells and capacitors were used as a power supply to eliminate the need for battery replacement. The developed WSN secured a communication distance of 100m in field measurement. The solar cells sufficiently generated electric power even in a greenhouse, and successfully transmitted radio waves from the sensor node for at least half a year or more. Seventy sensor nodes installed in a 0.5 ha tomato cultivation greenhouse showed the change over time of room temperature in detail, indicating that WSN functions effectively.

Keywords: Wireless sensor network, Greenhouse, Thermal environment, Tomato, Temperature, Photovoltaic cell


  • Technical Paper (Japanese)
  • Composting Characteristics of Semi-solid Dairy Manure after Solid-liquid Separation in Two-line Treatment System of Anaerobic Digestion and Composting
  • Kenichi FURUHASHI,Akihiro TANAKA, Kazutaka KURODA, Naoki FUKUJU
  • The objective of this study was to investigate composting characteristics and odor emission control of semi-solid dairy manure from loose housing system in two-line treatment system of anaerobic digestion and composting after solid-liquid separation. By the separation, bulk density of the solid fraction from the manure was improved, but the contents of the persistent organic matter were increased. In the pilot-scale composting experiments, the same degree of the fermentation temperature and the decomposition of organic matter were observed in both of composting of the solid fraction obtained from the solid-liquid separation and the sawdust-added material to adjust the moisture content. During composing in two-line treatment system, total ammonia emission was reduced by 55% and odor emission amount calculated by multiplying odor index equivalent value and air flow rate was reduced by 44.9% and 37.2% in first and second week, respectively, compared with composting of whole amount of the original manure.

Keywords: Dairy manure, Composting, Solid-liquid separation, Anaerobic digestion, Biomass, Odor emission control


Vol.51 No.3 (October, 2020)

  • Research Paper (Japanese)
  • Recording Small Sounds of Bemisia tabaci in Greenhouse
  • Hirotaka SATO, Hiroki NAKABAYASHI , Tadashi EBIHARA , Koichi MIZUTANI, Naoto WAKATSUKI , Kenji KUBOTA
  • Bemisia tabaci are one of the agricultural pests causing damage to valuable crops such as tomatoes, peppers, eggplant, cucumbers, and other vegetables. Bemisia tabaci are classified based on their biotypes having different pesticide resistance. Our research group established a biotype classifier by using the acoustic method. On the other hand, it was challenging to record sounds of Bemisia tabaci quickly in a greenhouse because the sounds of Bemisia tabaci are very small and a measurement space with low noise was mainly used. In this research, we clarified the characteristics of noise in a greenhouse and constructed a prototype for recording sounds of Bemisia tabaci quickly in such environments. We also evaluated the performance of the prototype at a specific greenhouse by experiments. The obtained results suggest that the proposed system can reduce noise in the greenhouse and can record sounds of Bemisia tabaci successfully.

Keywords: Bemisia tabaci, signal processing, sound, greenhouse


  • Research Paper (Japanese)
  • Effect of Shading Rate and Duration in Summer-Fall Protected Cultivation on Yield and Fruit Quality of Sweet Pepper (Capsicum annuum L.)
  • Shinsuke FURUNO, Hiroyuki FUJISHIMA
  • Questionnaire survey about shading and fruit quality for farmers growing sweet pepper in summer-fall protected cultivation were conducted. Most farmers expanded shading screen from late May to early October. After that, the rate of expanding farmer decreased gradually, and the farmer who answered that sunscald has occurred increased. The greenhouse that was expanded the shading screen until early October (Removal-greenhouse) and greenhouse that was expanded one continuous until late December (Continuous-greenhouse) were compared. Inside temperature of Removal-greenhouse was higher than Continuous -greenhouse only 0.8 °C, and there was no difference in ripening between them. The other hand, russetting fruits from Continuous -house decreased compared to Removal-greenhouse. The greenhouse that expanded shading screen which shading rate was 30% (30%-greenhouse) and the greenhouse that expanded one which shading rate was 50% (50%-greenhouse) were compared. The number of fruit setting on 30%-greenhouse was higher than 50%-greenhouse. The product fruit yield on 30%-greenhouse was higher than 50%-greenhouse too. These results reveal that the shading screen which shading rate is 30% should be expand from after the rainy season to the end of cultivation in summer-fall protected cultivation of sweet pepper.

Keywords: fruit setting, sweet pepper, questionnaire survey, russetting, sunscald


  • Note (Japanese)
  • Rice Husk Briquette, Wood Charcoal, Rapeseed Oil Cake and Combustion in a Wood Boiler for a Grain Dryer
  • Genta KANAI and Yoshimichi YAMASHITA
  • To assess biomass solid fuel use for grain drying, we assessed wood charcoal, rapeseed oil cake, and rice husk briquette, combustion in a wood boiler used for a grain dryer. For rice husk briquettes, the heat output and conversion efficiency were found to be sufficient with additional fuel feeding and forced air supply into the kiln. Furthermore, rice drying was achieved with the rice husk briquettes. However, after combustion of 120.9 kg fuel, the kiln had too much ash to allow further feeding of fuel. Furthermore, drying stopped before the moisture content was sufficiently low. Methods to avoid filling of the kiln by ash appear to be unavoidable for long-run drying: reducing ash by using not only rice husk briquettes but also wood or other low-ash fuels, removing ash from the kiln before filling or using a boiler having sufficient kiln size. For wood charcoal, 30 kg of initial feeding showed the duration as greater than 7 h with sufficient heat output (greater than 10 kW). Furthermore, grain drying the can finish without additional fuel feeding. Greater initial fuel feeding showed higher heat conversion efficiency. Wood charcoal can maintain combustion without forced air supply into the kiln, as firewood can. Rapeseed oil cake was found to require a forced air supply into the kiln to maintain combustion. With the forced air supply, it showed sufficient heat output for grain drying.

Keywords: wood boiler, grain dryer, rice husk, wood charcoal, oil cake


Vol.51 No.4 (December, 2020)

  • Research Paper (Japanese)
  • Relationship Between Electrical Impedance Characteristics and Physical Property of Cooked Meats
  • Akihito KOBAYASHI, Koichi MIZUTANI, Naoto WAKATSUKI, Yuka MAEDA, Tadashi EBIHARA, Yasumasa ANDO
  • This study aims to show the relationship between the electrical impedance characteristics of meats and the physical properties in order to establish a evaluating method of heating process of meats.The pork tenderloin with 10 mm thickness was heated at a constant temperature, then the Impedance characteristics and cooking loss of the heated samples were measured. However, no correlative relationship was found between the two values.The impedance (100 kHz - 1 MHz) of the sample heated and immediately cooled down showed good correlation between cooking loss and fracture characteristics. The impedance values at 250 kHz was found to be correlated with the cooking loss(R = 0.91321),the shear force with deformation of 50% (R = 0.8595),the fracture position (R = -0.7902). Impedance ZCL calculated from three factors: the impedance of the heated sample,the temperature of the sample in impedance measurement and the raw impedance, were highly correlated with cooking loss (R = 0.8513).The present study showed that the cooking loss and the fracture characteristics of meat can be estimated from the impedance values during heating process.

Keywords: Electrical impedance,Pork tenderloin,Heat process,Vacuum Cooking, Fracture characteristics,Cooking loss