摘要
Hyuganatsu is a typical Japanese citrus with desirous smell and edible albedo. The objectives of this study are to establish a method for softening hyuganatsu peel without heating and a process for making a high pressure-induced （HP-） marmalade and to compare with heat-induced （H-） marmalade and citrus shaddock family marmalade. Firmness of peel was （greatest to least） pressurized at 500 MPa for 30 min, soaked in citric acid solution at pH 2.7 for 24 h, and boiled for 10 min, respectively. The cell walls of flavedo and albedo did not loosen after pressurization. However, after soaking or heating, the middle lamella of albedo separated. When flavedo was soaked at pH 2.7, 9.3% of pectin was extracted. The amount of naringin was the least in hyuganatsu 〈 pummelo 〈 grapefruit）, and juice sacs 〈 flavedo 〈 segment walls 〈 albedo, respectively. Thus, marmalade was processed. Albedo, segment walls and juice sacs of hyuganatsu were homogenized with citric acid solution （pH 2.7） and mixed with sliced flavedo. Then it was soaked for 24 h at pH 2.7. Sucrose was then added （final sugar 50%）, vacuum packed, then pressurized for 30 min at 500 MPa or boiled for 10 min, respectively. There was no significant difference in sensory evaluation between HP- and H-marmalade. However, the color, transparency and total evaluation of HP-marmalade were better than H-marmalade. Consequently, total evaluation of hyuganatsu-HP-marmalade was rated highly. So, hyuganatsu was considered to be more suitable for marmalade because it was more palatable than the others.
