摘要
利用低场核磁共振(low-field nuclear magnetic resonance,LF-NMR)技术研究了冻融后松茸水分的存在形式及相对含量,比较了冻融次数对解冻损失率、色泽和硬度等品质指标的影响,利用多层自旋回波(multi-slice spin echo,MSE)序列获得样品质子密度成像,进而分析冻融过程松茸内部水分的变化。结果表明,松茸中存在结合水、不易流动水和自由水,对应的横向弛豫时间分别为T_(21)(0.01~10 ms)、T_(22)(10~100 ms)和T_(23)(100~1 000 ms)。冻融过程中松茸不易流动水、结合水、自由水相对含量分别为88.7%~92.2%、6.2%~9.8%、0.7%~1.9%,随着冻融次数增加,自由水和不易流动水含量不断下降,结合水含量先增加后减少;松茸解冻损失率增大,亮度L值、红度a~*值和黄度b~*值逐渐降低,硬度先下降后上升,松茸品质下降。MRI结果表明,冻融5次后,菌柄失水较菌伞严重,菌柄部分区域已无自由水存在。相关性分析表明,冻融次数与T_(22)、T_(23)、a~*、b~*和解冻损失率极显著相关(p<0.01)。T_(22)、T_(23)与a~*值、b~*值和解冻损失率显著相关(p<0.05)。因此,应用LFNMR对松茸水分状态及组分含量的测定可以作为考察松茸品质的指标。
The moisture state and content of Tricholoma matsutake after freeze-thaw were analyzed by low-field nuclear magnetic resonance（ LF-NMR） technology. The effects of freeze-thaw cycles on the thawing loss rate,color and hardness were compared. To learn the effect of the freeze-thaw process on Tricholoma matsutake moisture distribution,during the experiment period,the proton density weighted images of the sample were obtained with multi-slice spin echo（ MSE） pulse sequence. The results showed that the water states in Tricholoma matsutake included free water,immobilized water and bound water,which were T_（21）（ 0. 01-10 ms）,T_（22）（ 10-100 ms）,T_（23）（ 100-1 000 ms）,respectively. With the increasing of freeze-thaw cycles,the free water content and immobilized water content was decreased gradually,bound water content was increase slightly and then decreased; The thawing loss rate increased,L values（ lightness）,a＊（ redness） and b＊（ yellowness） values decreased,hardness decreased first and then increased,causing a decline in quality. MRI results showed that water loss of stipe was more serious than that of pileus,some areas of stipe hardly existed free water after 5 cycles of freeze-thaw. The correlation analysis showed that the times of freeze-thaw had a significant correlation（ p 〈0. 01） with T_（22）,T_（23）,a~＊（ redness）,b~＊（ yellowness） and thawing loss rates. The T22 and T22 had a significant correlation（ p 〈0. 05） with thawing loss rates,a~＊（ redness） and b＊（ yellowness）. Therefore,application of using LF-NMR in the determination of water content and composition of Tricholoma matsutake could be used as reference indexes for the quality control.
作者
石芳
廖霞
李福香
杨雅轩
吴素蕊
明建
SHI Fang1 LIAO Xia1 LI Fu-xiang1 YANG Ya-xuan1 WU Su-rui2 MING Jian1,2,3 1(College of Food Science, Southwest University, Chongqing 400715, China） 2（Kunming Edible Fungi Institute, All China Federation of Supply and Marketing Cooperatives, Kunming 650223, China） 3 （ Chongqing Engineering Research Center for Special Foods, Chongqing 400715, China)
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2018年第7期89-95,共7页
Food and Fermentation Industries
基金
国家自然科学基金面上项目(31471576)
云南省科技厅科技创新人才计划(2008OC008)
重庆市社会民生科技创新专项(cstc2015shmszx80019)
重庆市特色食品工程技术研究中心能力提升项目(cstc2014pt-gc8001)
关键词
松茸
冻融
低场核磁共振
品质
Tricholoma matsutake
treeze-thaw
low-field nuclear magnetic resonance
quality
