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• Low HMF/furfural and high AA contents were determined at moderate temperature. • Formation of HMF/furfural and AA degradation depend mainly on thermal process time. • HMF formation rate was higher than furfural during thermal process and storage. • Storage temperature affects remarkably accumulation of HMF/furfural in OJ. • Shelf-life values were higher for OJs treated at mild temperature and kept at 4 °C. In this study, changes in ascorbic acid-(AA), hydroxymethylfurfural-(HMF) and furfural content of orange juice (OJ) were investigated during processing with different thermal treatments and storage conditions. According to the AA degradation kinetics; the half-lifes of thermally processed OJ at 70, 75, 80, 85 and 90 °C ranged between 666.5–1136.3 s. D- values for the same temperatures were calculated as 3774.7, 3337.1, 2914.7, 2646.6 and 2214s, respectively. z , Ea and Q 10 -values of AA were also calculated as 86.32 °C, 26.87 kJ mol−1, and 1.31; respectively. HMF formation kinetics showed that the doubling time of thermally processed OJ (70−90 °C) were determined between 42.0 and 77.0 s. D -values at those temperatures ranged from 139.6–255.8 s. z , Ea and Q 10 -values of HMF were also calculated as 75.98 °C, 31.34 kJ mol−1, and 1.35, respectively. For furfural formation kinetics, doubling time of thermally processed OJ at 70−90 °C was determined between 52.1–74.5 s. The D -values of furfural were calculated between 173.1–274.1 s at the same temperatures. z , Ea and Q 10 -values of furfural were also calculated as 100.21 °C, 24.98 kJ mol−1, and 1.26, respectively. The most obvious changes were determined during storage at 25 °C for the investigated compounds when compared to 4 °C. OJ samples processed at moderate temperatures performed better AA retention, and lower HMF and furfural formation was determined for those samples during shelf-life. [ABSTRACT FROM AUTHOR]

In this study, effects of various gas atmosphere (O 2 , CO 2 and N 2) and holding times (15, 30, 45 and 60 min) on changing of bioactive compounds (limonin, nomilin, hesperidin, neohesperidin, naringin, chlorogenic acid, ascorbic acid and total carotenoid, total phenolic content) were investigated in four different citrus varieties (Washington Navel, Valencia, Kozan Yerli and sour orange). When all gas atmospheres were evaluated, the effects of atmospheric gases on ascorbic acid, chlorogenic acid, naringin, neohesperidine, limonin contents were insignificant. Whereas the effects of different atmospheric conditions on total carotenoid, total phenolic, hesperidin, naringin contents were found significant. N 2 gas had a protective effect on total carotenoid content of Washington Navel, Kozan Yerli, sour orange and total phenolic content of all citrus varieties. The highest content of ascorbic acid was detected for the samples kept under CO 2. The bitter constituents (naringin, limonin, nomilin and neohesperidin) were found mostly in sour orange juice. • Effects of gas atmosphere on bioactive compounds of juice was revealed. • N 2 gas had a protective effect on total carotenoid/phenolic content of citrus juice. • Highest ascorbic acid content was detected in juice under CO 2 gas. • Limonin contents of juices increased with time for all citrus varieties. • Effect of atmosphere gas on CA content was found significant for all varieties. [ABSTRACT FROM AUTHOR]