NMR water transverse relaxation time approach to understand storage stability of fresh-cut 'Rocha' pear. (December 2016)

• Record Type: Journal Article
• Authors: Fundo, Joana F.; Galvis-Sanchez, Andrea; Madureira, Ana Raquel; Carvalho, Alexandra; Feio, Gabriel; Silva, Cristina L.M.; Quintas, Mafalda A.C.
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 74(2016)
• Page Start: 280
• Page End: 285
• Publication Date: 2016-12
• Subjects: Molecular mobility -- NMR -- Quality parameters -- Storage -- Fresh-cut pear; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2016.07.050
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: Fresh-cut fruit is an important segment in fruit market due to the increasing demand for healthy/convenient foods. However, processing promotes a decrease in fruits stability with faster physiological and microbiological deteriorations. Food stability is strongly attributed to its molecular dynamics and "water availability". Understanding changes in water location/mobility is of utmost importance, since water dynamics profoundly influences physic-chemical and microbiological quality of foods. Nuclear magnetic resonance spectroscopy (NMR) is a methodology used to study the food constituents' molecular dynamics. The aim of this study is to use NMR to evaluate changes in water mobility that occurred in fresh-cut pear tissues during storage, by measuring the transverse relaxation time ( T 2 ) parameter. Results showed the existence of three water classes in the cells after processing, with T 2 values of 10 ms, 187 ms and 3s for cellular wall, cytoplasm and vacuole, respectively. Also, the obtained results demonstrated that T 2 was affected by processing and storage. Moreover, a relationship between T 2, microstructure and the quality parameters was established. T 2, maximum value increased with pear hardness as well as water activity. On the contrary, a decrease in total colour difference (TCD) was found with T 2 . Results demonstrate the usefulness of the application of NMR relaxometry in food studies. Highlights: A relationship between T 2 (spin-spin relaxation time) and quality parameters of pear was obtained. Processing/storage affected water dynamics evaluated by T 2 . Microscope images support results obtained by nuclear magnetic resonance (NMR) technique. T 2 determinations are relevant to understand food degradation reactions. The usefulness of NMR application in food science studies was demonstrated.