摘要
目的:采用低场核磁弛豫时间和低场核磁成像技术,研究在模拟冷库环境条件下,风循环冷却和雾化喷淋冷却过程中猪肉水分迁移规律。方法:选择宰后2 h内的整条带皮猪背最长肌(通脊)10条,沿肌肉走向垂直方向分切成4份14 cm×10 cm×6 cm的肉块,其中2份保留猪皮及皮下脂肪(带皮组),另2份则去除猪皮及皮下脂肪(不带皮组),带皮组和不带皮组肉块分别放入风循环冷却和雾化喷淋冷却的模拟冷库中进行冷却,并于0.0、1.5、3.0、4.5、6.0 h和7.5 h进行低场核磁共振横向弛豫时间(T_2)和低场核磁成像测定,同时记录肉块质量变化。结果:风循环冷却过程中猪肉中结合水峰面积A_(2b)和结合水占猪肉中总水分的百分比P_(2b)变化差异不显著(P>0.05)、不易流动水t_(21)显著降低(P<0.05),自由水A_(22)、P_(22)也显著降低(P<0.05);而在雾化喷淋冷却过程中,结合水A_(2b)、P_(2b)和不易流动水t_(21)、A_(21)、P_(21)变化差异不显著(P>0.05),自由水A_(22)、P_(22)则显著降低(P<0.05)。带皮猪肉和不带皮猪肉在冷却过程中水分迁移的变化过程相同,但水分损耗存在差异。结合图像分析,在冷却过程初期,猪肉干耗主要是自由水的损失;而冷却后期,猪肉干耗则主要是部分不易流动水的损失。雾化喷淋冷却通过补充外源水,来减小猪肉内部和外表的水势差而抑制不易流动水由内向外迁移,可有效降低冷却干耗。
Objective:This study was designed to explore the change in water mobility in skin-on and skin-off pork duringblast chilling and spray chilling.Methods:Ten skin-on pork loins were obtained at2h postmortem and each loin was cutinto4steaks(14cm×10cm×6cm),the skin of two of which was kept and the other two were skinless.Skin-on andskinless steaks were individually subjected to blast chilling and spray chilling.At0.0,1.5,3.0,4.5,6.0and7.5h of chilling,transverse relaxation time(T2)and magnetic resonance images(MRI)were determined by low-field nuclear magneticresonance(LF-NMR)and sample weight was measured.Results:The A2b and P2b changed without statistical significance(P>0.05),and the t21,A22and P22were significantly decreased during blast chilling(P<0.05),while spray treatmentsignificantly reduced A22and P22(P<0.05),but it had no significant effect on A2b,P2b,t21,A21or P21(P>0.05).The watermobility in skinless or skin-on pork under two chilling treatments was similar,while the evaporative loss was significantlyaffected by the treatments(P<0.05).At the initial stage of blast chilling,the evaporative loss was mainly derived from freewater,while it was immobilized water that contributed to the evaporative loss at the late stage.The spray chilling treatmentcould replace the immobilized water during the removal of heat from pork,resulting in a reduction of evaporative loss.
作者
张楠
庄昕波
黄子信
陈玉仑
李春保
周光宏
ZHANG Nan;ZHUANG Xinbo;HUANG Zixin;CHEN Yulun;LI Chunbao;ZHOU Guanghong(Key Laboratory of Meat Products Processing and Quality Control, Ministry of Education, Key Laboratory of Animal Products Processing, Ministry of Agriculture, Jiangsu Synergetic Innovation Center of Meat Processing and Quality Control,Nanjing Agricultural University, Nanjing 210095, China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2017年第11期103-109,共7页
Food Science
基金
“十二五”国家科技支撑计划项目(2014BAD19B01)
江苏省农业自主创新项目(CX(15)1006)
江苏省重点研发计划项目(BE2015372)
国家现代农业(生猪)产业技术体系建设专项(CARS36-11)
南京农业大学基本业务费专项(KYCYL201502)
江苏省优势学科PADP项目
关键词
低场核磁弛豫时间
低场核磁成像
冷却干耗
雾化喷淋冷却
风循环冷却
low-field nuclear magnetic relaxation time
low-field nuclear magnetic resonance imaging
evaporative loss
spray chilling
blast chilling
