背景:在这项研究中,硬糖是用蔗糖生产的,葡萄糖浆和水.它们在不同的温度下煮熟,从135°C变为145°C,间隔为2.5°C。它们储存在不同的储存温度下,分别为25、4、-18和-80℃。在室温下放置的硬糖储存2个月。为了了解硬糖的结晶特性,进行了纵向弛豫时间(T1)和二阶矩(M2)测量的时域(TD)质子核磁共振(1H-NMR)参数。通过Karl-Fischer滴定法测定硬糖的水分含量。还进行了X射线衍射实验作为补充分析。
结果:提高蒸煮温度可显著提高硬糖的结晶度,降低硬糖的含水率(P≤0.05)。此外,储存温度和储存时间对硬糖的结晶度有显著影响(P≤0.05)。T1和M2的结果彼此相关(r>0.8,P≤0.5),并且在145°C的烹饪温度和4°C的储存温度下都产生了最高值(P≤0.05)。T1和M2的值分别为245.9ms和13.0×10-8Hz2,用于145°C的烹饪温度和4°C的储存温度。
结论:这项研究表明,可以通过TD-NMR弛豫法观察和检查硬糖的结晶度,作为常用方法的替代。©2024作者(S)。约翰·威利父子有限公司代表化学工业学会出版的《食品和农业科学杂志》。
BACKGROUND: In this study, hard candies were produced by using sucrose, glucose syrup and water. They were cooked at different temperatures, changing from 135 to 145 °C with an interval of 2.5 °C. They were stored at different storage temperatures, which were 25, 4, -18 and -80 °C. Hard candies placed at room temperature were stored for 2 months. In order to understand the crystallization characteristics of the hard candies, time domain (TD) proton nuclear magnetic resonance (1H-NMR) parameters of longitudinal relaxation time (T1) and second moment (M2) measurements were conducted. Moisture contents of the hard candies were determined by Karl-Fischer titration. X-ray diffraction experiments were also conducted as the complementary analysis.
RESULTS: Increasing cooking temperature increased the
crystallinity and decreased the moisture content of the hard candies significantly (P ≤0.05). Furthermore, storage temperature and storage time had significant effects on the
crystallinity of the hard candies (P ≤0.05). The results of T1 and M2 correlated with each other (r > 0.8, P ≤ 0.5) and both produced the highest value at the cooking temperature of 145 °C and storage temperature of 4 °C (P ≤ 0.05). The values of T1 and M2 were obtained as 245.9 ms and 13.0 × 10-8 Hz2, respectively, for the cooking temperature of 145 °C and storage temperature of 4 °C.
CONCLUSIONS: This study demonstrated that the
crystallinity of hard candies can be observed and examined by TD-NMR relaxometry, as an alternative to commonly used methods. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.