摘要
研究了降低水分活度对荞麦半干面保质期的影响。采用水分活度仪和低场核磁共振技术测定荞麦半干面中水分活度、形态与分布的变化,同时检测储藏期间荞麦半干面微生物指标、理化特性、质构特性和感官品质的变化。结果表明,不同水分活度降低剂的作用效果不同,复合组水分活度降低剂显著地将水分活度从0.940降至0.850(P<0.05),等温吸湿曲线上移,核磁共振弛豫峰左移,弛豫时间变短,面条中水分子自由度降低。核磁共振成像显示,与空白相比,储藏期间实验组水分迁移和内部结构劣变趋缓。空白组菌落总数在9 d时已超过检测阈值(106CFU/g),而实验组在36 d时才超过阈值。此外,较低的水分活度抑制荞麦半干面酸化的速度,保持其质构特性和感官品质。因此,降低水分活度、促进游离水分结构化的技术,能提高荞麦半干面的储藏稳定性,延长其保质期。
The present study investigated the effect of lowering water activity （ aW） on the sheff - life of semi - dried buckwheat noodles （SBWN）. Changes in aw, water state and distribution were determined by using aw meter and low- field nuclear magnetic resonance, meanwhile, the samples were submitted to microbiological, physico- chemical and sensory evaluations during the storage. Results indicated that different kinds of aw lowering agents ex- hibited the different lowering effects on the aw of SBWN, and the compound group of aw lowering agents significantly reduced the a, of SBWN to 0. 850 （ from 0. 940） , with increased water sorption isotherm, left shifted NMR transverse relaxation peak, reduced relaxation time, as well as the decreased molecular mobility of water in SBWN （P 〈 0.05 ）. Magnetic resonance imaging （MRI） showed that water migration and texture deterioration of test group were sup- pressed during the storage time, when compared to the eontrol group. The total plate counts （TPC） in control group had exceeded the level of 106 CFU/g （microbial threshold） at the storage time of 9 days, nevertheless the TPC in test group did not overtake the imposed threshold until the storage time of 36 days. In addition, the lowering aw not only retarded the rate of acidification in SBWN, but also maintained their sensorial qualities during the storage. Therefore, the teehnique for reducing aw and promoting water combination increased storage stability of SBWN, and extended its shelf - life.
作者
白艺朋
郭晓娜
朱科学
周惠明
Bai Yipeng ,Guo Xiaona ,Zhu Kexue ,Zhou Huiming(School of Food Science and Technology, Jiangnan University, Wuxi 21412)
出处
《中国粮油学报》
EI
CAS
CSCD
北大核心
2018年第3期27-33,共7页
Journal of the Chinese Cereals and Oils Association
基金
国家自然科学基金(31371849)
关键词
荞麦半干面
水分活度
横向驰豫
核磁共振成像
保质期
semi - dried buckwheat noodle, water activity, transverse relaxation, magnetic resonance imaging, shelf - life
