A non-invasive NMR and MRI method to analyze the rehydration of dried sea cucumber

Abstract

Sea cucumbers possess high-value and bioactive components that have been used for human food and pharmaceuticals in treating a wide number of ailments. Most of the sea cucumber products on the market are dehydrated due to the immediate autolysis that occurs upon removal of the sea cucumber from seawater. Rehydration of the dried products is necessary to obtain sea cucumbers with the highest water content. In this study, a rapid and non-invasive NMR and MRI method was introduced to analyze the rehydration process for dried sea cucumber. The spin-spin relaxation time (T 2 ) weighted NMR signal, obtained by a CPMG pulse sequence and processed by the chemometric method, was used to identify lightly dried and salted dried sea cucumber. The water uptake and distribution during the rehydration process was monitored by NMR 1 H T 2 . Structural changes were analyzed by MRI with T 1 and T 2 weighted imaging. The results indicated that the proper presoaking and rehydration time was 24 and 96 h, respectively, for lightly dried sea cucumber. Good linear correlation during the rehydration process was observed between the NMR parameters and texture profile analysis parameters including the hardness, chewiness, and rehydration ratio of lightly dried sea cucumbers. The NMR and MRI method has the potential to noninvasively analyze the rehydration process of dried sea cucumber.

Effect of temperature–time pretreatments on the texture and microstructure of abalone (Haliotis discus hanai)

“…Water content is another factor that may impact the texture of abalone meat. A good linear correlation during the rehydration process was observed by Geng et al () between NMR parameters (e.g., the individual T 2 relaxation time) and texture profile analysis (TPA) parameters of hardness, chewiness, and rehydration ratio in lightly dried sea cucumbers. NMR imaging also confirmed that presence of water in cooked abalone meat ameliorates texture properties.…”

Water dynamics of turbot flesh during frying, boiling, and stewing processes and its relationship with color and texture properties: Low-field NMR and MRI studies

“…Moreover, magnetic resonance imaging (MRI), the other type of NMR technology, can provide internal structural information of food materials. The combined NMR and MRI method has been successfully used in the analysis of sea cucumber rehydration (Geng et al, ), food and agricultural products (Patel, Khan, & Kar, ), salt and water distribution of heavily salted cod with different presalting methods (Gudjónsdóttir, Traoré, Jónsson, Karlsdóttir, & Arason, ). By using the combined NMR and MRI techniques, one can not only obtain the information of water status and distribution in a nondestructive way but also obtain the visualization of internal structural changes during food processing.…”

Influence of Freezing–Thawing Cycle on Water Dynamics of Turbot Flesh Assessed by Low-Field Nuclear Magnetic Resonance and Magnetic Resonance Imaging

“…In order to describe the status and distribution of water during the process in details, multiexponential fitting of the CPMG relaxation data was applied to obtain T 2 relaxation spectra, and three main water populations were identified (Figure 1b). The population with the shortest relaxation time T 21 Figure 1d), with a range of 147.61-321.42 ms, was ascribed to free water, which was in the place of myofibrils (extra-myofibrillar) [18,27]. The LF-NMR relaxation result of Sardine, tuna and mackerel flesh frozen at −40 °C and stored for 1 day (24 h) has also shown three domains from different pools of protons (i. e. low mobile, medium mobile and high mobile) [20].…”

“…It can not only tell the water distribution in food samples but also provide visual information during the food process. T 1 -and T 2 -weighted MR images (Figure 2a) were used to evaluate changes in water distribution during thawing process in a time course (red color stands for high signal density of water while blue color represents the low signal density of water), which showed success in evaluation of sea cucumber [18]. The water with shorter relaxation time (T 1 ) was almost unchanged in the process because the entrapped water with lower mobility changed a little.…”

“…The parameter of NMR is related to the parameters of flesh quality, such as color, shear force, and thiobarbituric acid-reactive substances (TBARS), which is useful in the evaluation of the quality of food [5,[11][12][13][14][15][16][17]. Magnetic resonance imaging (MRI), the other type of NMR technology, provides the information about the internal distributed status of water in food, which has been employed for food processing and analysis [18]. Therefore, the NMR and MRI are considered as accurate and nondestructive methods for visualizing the internal food structure [19], in the evaluation of the quality of fish products [15,20].…”