【摘要】 以‘北村’蓝莓为研究对象，根据其最大冷冻浓缩状态的玻璃化转变温度（T_g’）、冻结曲线与玻璃化转变温度曲线的交点温度（T_g”）和特征冻结终点温度（T_m’），将蓝莓的冷冻状态划分为橡胶态（T>T_m’）、部分冻结浓缩态（T_g”<T<T_m’）和玻璃态（T<T_g”）。将蓝莓在液氮-120℃条件下速冻后，分别设置两组实验：无状态改变组分别处于橡胶态（-18℃，T>T_m’）、部分冻结浓缩态（-40℃，T_g”<T<T_m’）和玻璃态（-80℃，T <T_g”）条件下冻藏；状态改变组在玻璃态（-8 0℃）条件下冻藏后进行温度变化处理，以达到橡胶态（-30℃，T>T_m’）、达到部分冻结浓缩态（-40℃，T_g”<T<T_m’）和达到玻璃态（-50℃，T_g’<T<T_g”;-60℃，T<T_g’）为温度变化终点，并设无温度变化对照。测定汁液流失、硬度、营养物质含量、细胞膜完整性、酶活性等指标，探究不同冷冻状态及状态改变对冻藏蓝莓品质的影响。结果表明：玻璃态条件下冻藏的蓝莓品质保持最佳；发生状态改变的蓝莓品质劣变更明显，温度变化跨度越大，蓝莓果实发生的汁液流失、硬度降低、营养物质流失和细胞完整性受损越严重，过氧化物酶和多酚氧化酶活性越高。综上所述，玻璃态冻藏（T_g’以下温度）能够较好地维持蓝莓果实的品质，但要尽量避免冻藏过程中发生温度变化导致果实的冷冻状态改变。更多还原

【Abstract】 Frozen ‘Beicun’ blueberry fruits were classified based on three key temperatures: the glass transition temperature(T_g’) at their maximum cryo-concentration, the intersection temperature(T_g”) between the freezing curve and the glass transition temperature curve, and the characteristic freezing endpoint temperature(T_m’) into three states: rubbery(T > T_m’),partially frozen concentrated(T_g” < T < T_m’), and glassy(T < T_g”). Blueberry fruits were quickly frozen in liquid nitrogen at-120 ℃ and separated into two storage groups. One group, without any state changes, was stored under rubbery(-18 ℃,T > T_m’), partially frozen concentrated(-40 ℃, T_g”< T < T_m’), or glassy state(-80 ℃, T < T_g”) conditions. The other group,with state changes, was initially stored at the glassy state temperature(-80 ℃) and then switched to the rubbery(-30 ℃, T >T_m’), partially frozen concentrated(-40 ℃, T_g” < T < T_m’), or lower glassy state temperature(-50 ℃, T_g’ < T < T_g”;-60 ℃,T < T_g’). Besides, a control group was set up without any temperature changes. Juice loss, hardness, nutrient contents,membrane integrity, and enzyme activities were determined to explore the effects of different freezing states and state changes on the quality of frozen blueberry fruits. The results indicated that frozen blueberry fruits in the glassy state exhibited the best quality. State transitions resulted in more pronounced quality deterioration in blueberry fruits; greater temperature changes led to higher juice loss, hardness reduction and nutrient loss, more serious cell integrity damage, and higher activities of peroxidase and polyphenol oxidase. Therefore, glassy state freezing(at temperatures below T_g’) could better maintain the quality of blueberry fruits; however, it is crucial to avoid state transitions caused by temperature fluctuations during frozen storage.更多还原