Determination of oil and moisture distribution in fried potatoes using magnetic resonance imaging

Abstract

The objective of this study was to examine oil and moisture distribution in fried potatoes using Magnetic Resonance Imaging (MRI) as nondestructive technique and to establish a correlation between moisture content and oil content of fried potatoes with MRI results. In addition, it was aimed to evaluate the effects of frying time, predrying and precoating by hydroxyprophylmethylcellulose (HPMC) on moisture loss and oil uptake of the samples. Coating with HPMC was the best pretreatment to reduce oil uptake. Spin echo (SE) and multislice–multi‐echo (MSME) pulse sequences were used to obtain longitudinal relaxation time (T1) weighted and water suppression images and also spin–spin relaxation time (T2) maps of the samples. Results confirmed that by using different MR imaging sequences, prediction of oil and moisture contents (r > 0.70) and exploring the distribution of oil and moisture within the fried pototaes was possible. Practical applications MRI, as being a nondestructive technique offers advantages compared to conventional methods of moisture and oil content measurements. Moreover, use of spin–spin relaxation time (T2) maps provided further information for moisture and oil distribution on the samples. MR images could also be used to extract information about the microstructure of the sample.

Causal factors concerning the texture of French fries manufactured at industrial scale

“… (Possible) cause Technique(s) Ref. Effort Value Molecular level Moisture profile MRI ( Esveld et al, 2012 ) ( Isik et al, 2018 ) ( Yang et al, 2019 ) ++ +++ T2-NMR imaging Li et al (2020c) +++ +++ XRT (density) Watanabe et al (2008) ++ +++ Drying oven method + + Glass transition DSC ( Kasahara et al, 2002 ) ( Rahimi et al, 2017 ) + +? DMTA Rouillé et al (2010) + ++ Cellular level Case hardening Microscopy Reeve and Neel (1960) + + MRI Ruan et al (1991) ++ ++ Microstructural level Porosity/structure XRT (X-ray tomography) ( Van Koerten et al, 2015 ) ( van der Sman et al, 2021 ) ( Van der Sman et al, 2018 ) ( Van Dalen et al, 2007 ) ++ …”

“… DMTA Rouillé et al (2010) + ++ Cellular level Case hardening Microscopy Reeve and Neel (1960) + + MRI Ruan et al (1991) ++ ++ Microstructural level Porosity/structure XRT (X-ray tomography) ( Van Koerten et al, 2015 ) ( van der Sman et al, 2021 ) ( Van der Sman et al, 2018 ) ( Van Dalen et al, 2007 ) ++ +++ Direct immersion method Kalogianni and Papastergiadis (2014) + ++? UV-VIS CSLM Achir et al (2010) ++ ++ light microscopy Reeve and Neel (1960) + + Corner compactness SEM Sadeghi et al (2021) ++ + Oil adsorption T2-NMR/MRI ( Yang et al, 2020 ) ( Isik et al, 2018 ) ++ ++ Crust level Crust thickness MRI ++ ++ …”

“…Thus NMR can distinguish oil and water, but MRI can not do that. However, by combining NMR and MRI techniques simultaneously one can image both oil and moisture spatial distributions ( Isik et al, 2018 ). However, this requires some water/oil suppression pulsing techniques.…”

Evaluation of the Thermophysical, Sensory, and Microstructural Properties of Colombian Coastal Carimañola Obtained by Atmospheric and Vacuum Frying

“…Understanding the effect of processing conditions on a desirable food is critical; therefore, the microstructure is important to understanding the process of water absorption in fried products [ 20 ]. In the same way, the study of the atmospheric or immersion frying process is important to understand mass transfer, particularly oil absorption in the finished product [ 21 ]; also, current consumer trends require lower fat contents but optimal sensory characteristics.…”