Wold J P, Jørgensen K, Lundby F
MATFORSK Norwegian Food Research Institute, As, Norway.
J Dairy Sci. 2002 Jul;85(7):1693-704. doi: 10.3168/jds.S0022-0302(02)74242-2.
The purpose of this paper is to demonstrate the potential of solid-sample fluorescence spectroscopy in nondestructive assessment of light-induced oxidation in different dairy products such as Swiss cheese, cream cheese, and sour cream. Analytical and quantitative spectral properties of fluorescence were elucidated by use of principal component analysis with designed experiments involving different levels of air and light exposure. A significant reduction in fluorescence intensity at approximately 525 nm, and a corresponding increase in the region 415 to 490 nm as a result of illumination was observed on all the products. The effect was ascribed to photodegradation of riboflavin. Variation in two smaller peaks at approximately 620 nm and 630 nm was an interaction effect between exposure to light and air. A pronounced interaction effect between light and air produced intense blue fluorescence and off-flavors on Swiss-like Jarlsberg cheese. High correlations (0.83 to 0.93) between fluorescence spectra and sensory measured off-flavors were obtained for cream cheese. Results indicate that solid-sample fluorescence can be used as a nondestructive and rapid tool to measure the degree of light-induced degradation of riboflavin as well as sensory properties connected to storage of dairy products. Images of fluorescence can be used to visualize the intensity and propagation of this process. The simplicity and rapidity of the method offer rich opportunities for efficient evaluation of factors affecting light-induced oxidation in dairy products, such as packaging materials, light sources, exposure time, and temperature.
本文的目的是证明固体样品荧光光谱法在无损评估不同乳制品（如瑞士奶酪、奶油奶酪和酸奶油）中光诱导氧化方面的潜力。通过主成分分析和涉及不同空气和光照水平的设计实验，阐明了荧光的分析和定量光谱特性。在所有产品上均观察到，光照后在约525 nm处荧光强度显著降低，在415至490 nm区域相应增加。这种效应归因于核黄素的光降解。在约620 nm和630 nm处两个较小峰的变化是光照和空气暴露之间的相互作用效应。光照和空气之间显著的相互作用效应在类似瑞士的贾尔斯贝里干酪上产生了强烈的蓝色荧光和异味。对于奶油奶酪，荧光光谱与感官测量的异味之间具有高度相关性（0.83至0.93）。结果表明，固体样品荧光可作为一种无损且快速的工具，用于测量核黄素光诱导降解的程度以及与乳制品储存相关的感官特性。荧光图像可用于可视化该过程的强度和传播。该方法的简单性和快速性为有效评估影响乳制品光诱导氧化的因素（如包装材料、光源、暴露时间和温度）提供了丰富的机会。
