title: CO₂ processing and hydration of fruit and vegetable tissues by clathrate hydrate formation.
abstract: CO2 hydrate can be used to preserve fresh fruits and vegetables, and its application could contribute to the processing of carbonated frozen food. We investigated water transformation in the frozen tissue of fresh grape samples upon CO2 treatment at 2-3 MPa and 3°C for up to 46 h. Frozen fresh bean, radish, eggplant and cucumber samples were also investigated for comparison. X-ray diffraction indicated that after undergoing CO2 treatment for several hours, structure I CO2 hydrate formed within the grape tissue. Phase-contrast X-ray imaging using the diffraction-enhanced imaging technique revealed the presence of CO2 hydrate within the intercellular spaces of these tissues. The carbonated produce became effervescent because of the dissociation of CO2 hydrate through the intercellular space, especially above the melting point of ice. In addition, suppressed metabolic activity resulting from CO2 hydrate formation, which inhibits water and nutrient transport through intercellular space, can be expected.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565, Japan. Electronic address: s.takeya@aist.go.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takeya
authors.affiliation: Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan. Electronic address: knakano@gifu-u.ac.jp.
authors.forename: Kohei
authors.initials: K
authors.lastname: Nakano
authors.affiliation: Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Manasikan
authors.initials: M
authors.lastname: Thammawong
authors.affiliation: Institute of Vegetable and Tea Science (NIVTS), 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8666, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Umeda
authors.affiliation: Hitachi Ltd., 1-280 Higashi-koigakubo, Kokubunji-shi, Tokyo 185-8601, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Yoneyama
authors.affiliation: Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan.
authors.forename: Tohoru
authors.initials: T
authors.lastname: Takeda
authors.affiliation: High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Hyodo
authors.affiliation: The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Matsuo
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D003461:Crystallography; D005519:Food Preservation / Q000379:methods*; D005638:Fruit / Q000737:chemistry*; D044367:Phase Transition; D014675:Vegetables / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D014867:Water; D002245:Carbon Dioxide
keywords: CO(2) hydrate; Diffraction enhanced imaging; Food preservation; Gas storage; Phase-contrast imaging