In this study, changes in ascorbic acid (AA), phenolics, anthocyanins (ACNs) and antioxidant activity (AOA) were monitored during storage at − 25, 4, 10 and 20 °C to observe the stability of bioactive compound in strawberry juice concentrates (SJCs). Half-life periods (t_1/2) for ACN and AA degradations were 7.9 and 50 days at 20 °C, respectively. On the contrary, much higher t_1/2 values were found for the reduction in AOA and phenolics, i.e. 251 and 430 days at 20 °C, respectively. AOA and phenolics were more stable during storage than AA and ACNs. p-Coumaric acid was the major phenolic identified in SJC. p-coumaric acid (33.8%), catechin (23.1%), vanilic acid (18.6%) and epicatechin (16.1%), which constituted 91.6% of phenolics in SJC, followed by chlorogenic acid (4.9%) and caffeic acid (3.2%). Chlorogenic acid was the least stable phenolic in SJC stored at 20 °C. Strong correlations were found between AOA and ACNs (r = 0.99), phenolics (r = 0.94) and AA (r = 0.92) in SJC stored at 20 °C. Significant ACN and AA degradations occurred at storage temperature as low as 4 °C. Therefore, storage at − 25 ℃ was suggested for SJC to maximize the stabilities of especially ACNs and AA in SJC.

中文翻译：

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高温和低温储存的草莓浓缩汁中生物活性化合物的降解动力学和抗氧化活性

在这项研究中，在– 25、4、10和20°C下储存期间，监测了抗坏血酸（AA），酚类，花色苷（ACN）和抗氧化活性（AOA）的变化，以观察草莓汁浓缩物中生物活性化合物的稳定性（SJC）。在20°C下，ACN和AA降解的半衰期（t _1/2）分别为7.9天和50天。相反，发现AOA和酚类化合物的降低的t _1/2值更高，即在20°C时分别为251天和430天。AOA和酚类化合物在储存过程中比AA和ACN更稳定。对-香豆酸是SJC中鉴定的主要酚类。p-香豆酸（33.8％），儿茶素（23.1％），香草酸（18.6％）和表儿茶素（16.1％），占SJC中酚类的91.6％，其次是绿原酸（4.9％）和咖啡酸（3.2％） ）。绿原酸是在20°C下储存的SJC中最不稳定的酚类。发现 在20°C下储存的SJC中AOA和ACN（r  = 0.99），酚类（r  = 0.94）和AA（r = 0.92）之间有很强的相关性。在低至4°C的储存温度下，ACN和AA的降解显着。因此，建议在SJC的− 25℃下储存，以最大程度地提高SJC中ACN和AA的稳定性。