Studies on Off-Flavor Formed during Storage of Satsuma Mandarin Juice (Part V)

The relationship between pulp content and quantitative changes in volatile components during storage was investigated. Juice processed by the In-line Extractor contained about 1 ppm of α~ tocopherol derived from peel. The ^-tocopherol content was constant during 50 days storage at 40°C, but α-tocopherol had no effect on the essential oils from peel in juice. The decrease in α-limonene during storage was proportional to the amount of d-limonene in liquid (serum) fraction, that means the essential oil undergoes a change in serum. The distribution coefficients of major volatile compounds between pulp and serum fraction in juice were determined: terpene hydrocarbons; 60~70, linalool; 5. 4, citronellal; 3. 8, geranyl acetate; 32. Every component is distributed more in pulp than in serum fraction, which is favorable for the preservation of the flavor. In juice with lower pulp content, the formation of α-and β-terpineol and fenchyl alcohol increased with a rapid decrease in terpene hydrocarbons and the flavor deteriorated remarkably. Juice, therefore, may as well contain much pulp for the preservation of the flavor.