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草业学报 ›› 2016, Vol. 25 ›› Issue (7): 104-111.DOI: 10.11686/cyxb2015448

• 研究论文 • 上一篇    下一篇

放牧时间对羊肉多不饱和脂肪酸沉积及氧化稳定性的影响

金艳梅1, 张晓庆2, *, 王冲1, 李美1, 王燚1, 严沁1   

  1. 1.山东大学威海海洋学院,山东 威海 264209;
    2.中国农业科学院草原研究所,内蒙古 呼和浩特 010010
  • 收稿日期:2015-09-23 修回日期:2015-11-16 出版日期:2016-07-20 发布日期:2016-07-20
  • 通讯作者: zhangxiaoqing@caas.cn
  • 作者简介:金艳梅(1978-),女,甘肃金塔人,讲师,博士。E-mail: jinym2001@sohu.com
  • 基金资助:
    国家自然科学基金项目(31402119)和中央级公益性科研院所基本科研业务费专项(1610332015014)资助

Effects of grazing duration on polyunsaturated fatty acid deposition and oxidative stability of lamb meat

JIN Yan-Mei1, ZHANG Xiao-Qing2, *, WANG Chong1, LI Mei1, WANG Yi1, YAN Qin1   

  1. 1.Faculty of Marine Studies, Shandong University at Weihai, Weihai 264209, China;
    2.Grassland Research Institute, Chinese Academy of Agricultural Sciences, Hohhot 010010, China
  • Received:2015-09-23 Revised:2015-11-16 Online:2016-07-20 Published:2016-07-20

摘要: 分析不同放牧时间对羊肉抗氧化性能的影响。选择40只乌珠穆沁去势公羔,按照体重和出生月份接近的同质原则随机分成5个处理组:舍饲组(0H,对照),放牧2 h组(2H)、放牧4 h组(4H)、放牧8 h组(8H)和放牧12 h组(12H)。舍饲组圈养,4个放牧组在清晨6:00出牧,依组次分别在8:00、10:00、14:00和18:00归牧。试验期102 d,预试期15 d,正式期87 d。放牧试验结束后,从各组挑选体重接近的6只屠宰,取背最长肌,测定多不饱和脂肪酸(PUFA)和抗氧化物浓度。结果表明,1)放牧时间显著影响羊肉中抗氧化物的浓度。舍饲组的丙二醛(MDA)含量显著(P<0.001)高于4个放牧组,且4个放牧组之间差异不显著。放牧4~12 h组的谷胱甘肽过氧化物酶(GSH-Px)显著(P=0.020)低于舍饲组,但其超氧化物歧化酶(SOD)显著(P<0.001)高于舍饲组。总抗氧化能力(T-AOC)在各组间差异不显著。2)放牧时间与羊肉中的MDA、SOD水平呈二次曲线关系,MDA先降低,至放牧10 h后升高,SOD先升高,至放牧10 h后降低;GSH-Px水平与放牧时间呈负线性关系,放牧时间越长其值越低。3)放牧4,12 h组的PUFA和高度氧化多不饱和脂肪酸(HP-PUFA)均显著高于放牧2 h和舍饲组(P<0.01)。PUFA和HP-PUFA沉积量与抗氧化物浓度之间关系密切。绵羊每天放牧2~10 h,可以改善羊肉的氧化稳定性,防止PUFA氧化,从而延长高品质羊肉的保质期。

Abstract: The aim of this research was to investigate the effects of the grazing duration on polyunsaturated fatty acids (PUFA) deposition and oxidative stability of lamb meat. Forty castrated male Ujumuqin lambs were randomly assigned to five groups with similar liveweight and age, and then subjected to the following treatments: (i) no grazing (0H, control), (ii) 2 h grazing (2H), (iii) 4 h grazing (4H), (iv) 8 h grazing (8H), and (v) 12 h grazing (12H). Each day, the lambs began to graze at 6:00, and stopped grazing at 8:00, 10:00, 14:00 and 18:00, respectively. The lambs were raised for 102 days, comprising a 15-d feed adaptation period and an 87-d experimental period. Six lambs with similar liveweight from each group were slaughtered at the end of experiment. The longissimus dorsi muscles were sampled from each lamb to measure PUFA contents and antioxidant properties. The results showed that the grazing time significantly affected antioxidant parameters. The meat of lambs fed concentrate in stalls had a higher (P<0.001) malondialdehyde (MDA) content than those in the meat of lambs grazed for 2-, 4-, 8- and 12-h, but there was no significant difference in meat MDA content among the lambs in the four grazing treatments. The meat of lambs grazed for 4-12 h had significantly higher (P<0.001) superoxide dismutase (SOD) activity, but significantly lower peroxidase (GSH-Px) activity (P=0.020) than those in the meat of lambs exclusively fed in pens. There was no significant difference in the total antioxidant capacity (T-AOC) among the five groups. The MDA content and SOD activity showed quadratic curve relationships with grazing time. The MDA content decreased up to 10-h of grazing time, and increased after that. In contrast, SOD activity increased up to 10-h of grazing time, and then decreased. The GSH-Px activity was negatively related to grazing time. The groups grazed for 4-h and 12-h had significantly higher PUFA and peroxidizable fatty acids (HP-PUFA) contents in the meat, compared with the 2-h and 0-h grazing groups (P<0.01). There were multiple linear relationships between antioxidant activity and PUFA (R2=0.586, P<0.001) and HP-PUFA (R2=0.602, P<0.001) contents. In conclusion, the meat of lambs grazed for 2-10 h showed better oxidative stability as a result of compounds that counteract oxidative reactions. This has important consequences for extending the shelf-life of lamb meat.