玻璃态液氮速冻对蓝莓品质特性的影响  

Effect of Glassy State and Liquid Nitrogen Quick Freezing on the Quality Characteristics of Blueberries

作　　者：黄碧飞 李洋[1] 胡泽茜 HUANG Bifei;LI Yang;HU Zexi(College of Civil Engineering and Transport,Northeast Forestry University,Harbin 150040,China)

机构地区：[1]东北林业大学土木与交通学院,黑龙江哈尔滨150040

出　　处：《食品科学》2024年第6期225-232,共8页Food Science

基　　金：黑龙江省自然科学基金项目(LH2021C016)。

摘　　要：以‘北村’蓝莓为研究对象,构建蓝莓的状态图确定其特征玻璃化转变温度T_(g)’,在此基础上以蓝莓T_(g)’为冻结终点,对蓝莓进行超低温冰箱冷冻(-80℃)(记为RF-80℃组)、液氮浸渍速冻(-80、-100、-120℃)(记为LN-80℃、LN-100℃、LN-120℃组)处理,测定冷冻曲线、汁液流失、硬度、营养物质含量、细胞膜完整性、酶活性、微观结构等指标,探究液氮速冻结合T_(g)’对蓝莓品质特性的影响。结果表明,蓝莓T_(g)’为-52.55℃;与RF-80℃组相比,液氮速冻蓝莓的品质保持效果更佳,液氮速冻蓝莓的冷冻时间显著缩短,果实解冻后汁液流失减少,硬度保持得更好;可溶性固形物含量、可滴定酸含量、抗坏血酸含量和花青素含量与鲜果更接近;相对电导率和丙二醛含量更低,细胞膜的完整性破损程度更低;过氧化物酶和多酚氧化酶活性更低;微观结构的紧密型和完整性更强。液氮速冻的环境温度越低,冷冻效果越好,LN-120℃处理将冷冻蓝莓的品质劣化降至最低。综上所述,液氮速冻能够显著提高冷冻速率,结合T_(g)’有助于保持良好的冷冻蓝莓品质,研究结果可为蓝莓冷冻加工条件的选择提供理论基础。The glass transition temperature T_(g)’of‘Northcountry’blueberries was determined according to its state diagram.Using T_(g)’as the freezing end point,blueberries were frozen at−80℃using an ultra-low temperature freezer(RF−80℃),or at−80,−100 or−120℃by direct immersion in liquid nitrogen(LN−80℃,LN−100℃,and LN−120℃,respectively).Freezing curves,juice loss,hardness,nutrient contents,cell membrane integrity,enzyme activities and microstructure were measured to investigate the effects of liquid nitrogen quick freezing combined with T_(g)’on the quality characteristics of blueberries.The results showed that the T_(g)’of blueberries was−52.55℃;compared with RF-80℃,the quality of liquid nitrogen frozen blueberries was better maintained.The freezing time of liquid nitrogen quick freezing was significantly shortened,the frozen fruit lost less juice after thawing,and the hardness was better maintained.The contents of soluble solids,titratable acid,ascorbic acid and anthocyanin were closer to those of fresh fruit,the relative conductivity and malondialdehyde(MDA)content were lower,the integrity of the cell membrane was less broken,the activities of peroxidase(POD)and polyphenol oxidase(PPO)were lower,and the microstructural compactness and integrity were stronger.The lower the ambient temperature of liquid nitrogen quick freezing,the better the freezing effect,and LN-120℃minimized the quality deterioration of frozen blueberries.In conclusion,liquid nitrogen quick freezing significantly increased the freezing rate,and its combined with T_(g)’helped to maintain good quality of frozen blueberries.The results of this study can provide a theoretical basis for the selection of blueberry freezing conditions.

关 键 词：蓝莓 玻璃化转变温度 液氮速冻 品质 

分 类 号：TS255.3[轻工技术与工程—农产品加工及贮藏工程]