摘要
为了提升新鲜桑叶制成桑叶茶的品质,通过测定桑叶茶中的多糖、总黄酮、1-脱氧野尻霉素(DNJ)等活性成分含量,研究不同加工工艺和反复冻融对桑茶活性成分含量的影响。结果表明,桑叶茶加工过程中对桑叶茶活性成分含量有显著影响的是杀青和烘干工序,揉捻对桑叶茶的DNJ含量无显著影响。高温杀青有利于总糖和黄酮的积累,90 ℃烘干提香的茶样总糖、多糖、黄酮和DNJ含量最高,显著高于60 ℃和120 ℃制成的茶样(P<0.05)。冻融组桑叶茶中的多糖、黄酮和DNJ含量显著高于传统桑叶茶,即冻融处理能有效提高桑叶茶的活性成分。反复冻融能降低DNJ的损失率,并提高桑叶茶DNJ的溶出率。综上所述,在漂烫杀青30 s、220 ℃滚筒杀青、反复冻融3次、轻压10 min、重压15 min、90 ℃烘干提香的加工条件下,制成的桑叶茶多糖、黄酮等活性成分的保留度及DNJ浸出率相对较高,更利于发挥桑叶茶降血糖功效。
In order to further enhance the quality of mulberry leaf tea prepared with fresh mulberry leaves,the effects of processing technique and repeated freeze-thaw on contents of active ingredients in mulberry leaf tea were analyzed by taking contents of polysaccharides,total flavonoids,1-deoxynojirimycin (DNJ) in mulberry leaf tea as the evaluation indexes.The results indicated that the fixation and roasting treatment had a significant effect on the nutritional components of mulberry leaf tea,but rolling had no significant influence to DNJ content in mulberry leaf tea.High temperature fixation was beneficial to the accumulation of total sugar and flavonoids.The contents of total sugar,polysaccharide,flavonoids and DNJ in mulberry leaf tea dried at 90 ℃ were the highest,which were significantly higher than those of mulberry tea made at 60 ℃ and 120 ℃ (P<0.05).The contents of polysaccharides,flavonoids and DNJ in mulberry leaf tea prepared by repeated freezing and thawing were significantly higher than those in the control group,indicating that freeze-thaw treatment can effectively improve the active components of mulberry leaf tea.That is to say,repeated freezing and thawing could improve the dissolution rate of DNJ in mulberry leaf tea.In?conclusion,the prepared mulberry leaf tea had high retention rate of nutritional components including polysaccharides and flavonoids and the extraction amount of DNJ under the process conditions of blanching in boiling water for 30 s,fixation temperature 220 ℃,freeze thaw for 3 times,slight twisting time 10 min,heavy twisting time 15 min,firing temperature 90 ℃.This is more conducive to the hypoglycemic effect of mulberry leaf tea.
作者
吴劲轩
殷浩
夏文银
李兰英
王智文
王香君
夏川林
WU Jinxuan;YIN Hao;XIA Wenyin;LI Lanying;WANG Zhiwen;WANG Xiangjun;XIA Chuanlin(Sericultural Research Institute,Sichuan Academy of Agricultural Sciences,Nanchong 637000,China;Tea Research Institute,Sichuan Academy of Agricultural Sciences,Chengdu 610066,China;School of Chemical Engineering&Technology,Tianjin University,Tianjin 300072,China)
出处
《食品科技》
CAS
北大核心
2021年第4期57-63,共7页
Food Science and Technology
基金
四川省科技计划重点研发项目(2019YFN0114)
四川省财政创新能力提升工程项目(2016TSCY-006)
国家重点研发计划项目-科技助力经济2020(SQ2020YFF0403388)
南充市科技成果转化项目(19CGZH0003)。
关键词
桑叶茶
反复冻融
加工工艺
活性成分
1-脱氧野尻霉素
mulberry leaf tea
freeze-thaw cycle
processing technique
active ingredient
1-deoxynojirimycin
