干酪介电特性与成熟期及成熟度相关性分析

80 2017, V ol.38, No.01食品科学※基础研究

干酪介电特性与成熟期及成熟度相关性分析

范贵生，王莉莎

（内蒙古农业大学食品科学与工程学院，内蒙古呼和浩特 010018）

摘?要：以半硬质契达干酪为研究对象，对同一加工样品在9 ℃贮存成熟，分别对成熟期0、15、30、45、60、

90、120、150、180 d的干酪样品进行了介电特性和成熟度指标的测定，包括干酪样品总氮（total nitrogen，TN）含

量、pH 4.6可溶性氮（soluble nitrogen，SN）含量及三氯乙酸（trichloroacetic acid，TCA）溶液中SN含量的测定。

测试频率选定为500、915、1 500、2 000 MHz，对测试结果进行了统计分析，建立了干酪介电特性与成熟度指标之间的相关性。结果表明：随着成熟期的延长，干酪水分含量略有减少、水分活度明显降低、pH值先降低后升高、成熟度指数pH 4.6-SN/TN和12% TCA-SN/TN均随成熟期延长而增大；介电常数ε’在所选的测试频率下与成熟期和成熟度指数的变化均呈线性相关关系；介电损耗因数ε’’在所选测试频率范围内，随成熟期的延长和成熟度的增大呈现总体下降趋势，与成熟期和成熟度在500 MHz和915 MHz频率条件下线性相关性极显著（P＜0.01），而在高频

1 500 MHz和

2 000 MHz条件下线性相关性不显著；损耗角正切值变化不明显，表明在测试频率范围介电常数ε’和介

电损耗因数ε’’的变化方向一致，同时变化幅度相近。

关键词：契达干酪；介电特性；频率；成熟度

Correlations of Dielectric Properties of Cheddar Cheese with Ripening Time and Ripening Index

FAN Guisheng, WANG Lisha

(College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China)

Abstract: The dielectric properties and ripening properties of Cheddar cheese samples from the same batch with different ripening times (0, 15, 30, 45, 60, 90, 120, 150 and 180 d) at 9 ℃ were evaluated with respect to total nitrogen (TN), pH

4.6-soluble nitrogen (pH 4.6-SN) and trichloroacetic acid-soluble nitrogen (TCA-SN). The testing frequencies were set

to 500, 915, 1 500, and 2 000 MHz. The obtained data were analyzed statistically to establish the correlation between dielectric properties and ripening indexes. The results showed that as the ripening time increased, the moisture content of the cheese samples decreased slightly and the water activity evidently dropped; the pH decreased from day 0 to day 45 and then increased from day 45 to day 180; the ripening indexes pH 4.6-SN/TN ratio and 12% TCA-SN/TN ratio were increased persistently throughout the ripening time. At all the testing frequencies investigated, the dielectric constant ε’ exhibited a decreasing trend over the ripening period of 180 days, and it had a linear correlation with the ripening time and ripening parameters. With the increase in ripening time and ripening indexes, the dielectric loss factors ε’’ in the frequency range of 500 to 2 000 MHz generally showed a decreasing trend. It had signi?cantly linear correlations with ripening time as well as ripening indexes at 500 and 915 MHz (P?< 0.01). But the linear correlations were not signi?cant at 1 500 and 2 000 MHz.

The loss tangent tanδ did not change signi?cantly during the ripening period at all the testing frequencies. These ?ndings showed that ε’ and ε’’ changed in the same direction to a similar extent.

Key words: Cheddar cheese; dielectric properties; testing frequency; ripening index

DOI:10.7506/spkx1002-6630-201701013

中图分类号：TS252.53 文献标志码：A 文章编号：1002-6630（2017）01-0080-06引文格式：

范贵生, 王莉莎. 干酪介电特性与成熟期及成熟度相关性分析[J]. 食品科学, 2017, 38(1): 80-85. DOI:10.7506/spkx1002-6630-201701013. https://www.wendangku.net/doc/014460665.html,

FAN Guisheng, WANG Lisha. Correlations of dielectric properties of Cheddar cheese with ripening time and ripening index[J]. Food Science, 2017, 38(1): 80-85. (in Chinese with English abstract) DOI:10.7506/spkx1002-6630-201701013.

https://www.wendangku.net/doc/014460665.html,

收稿日期：2016-01-21

基金项目：国家自然科学基金地区科学基金项目（31260382）

作者简介：范贵生（1957—），男，教授，博士，研究方向为农产品加工及贮藏。E-mail：spfgsh@https://www.wendangku.net/doc/014460665.html,