Distribution Analysis of Anthocyanins, Sugars, and Organic Acids in Strawberry Fruits Using Matrix-Assisted Laser Desorption/Ionization-Imaging Mass Spectrometry

Abstract

Anthocyanins, sugars, and organic acids contribute to the appearance, health benefits, and taste of strawberries. However, their spatial distribution in the ripe fruit has been fully unrevealed. Therefore, we performed matrix-assisted laser desorption/ionization, MALDI-IMS, analysis to investigate their spatial distribution in ripe strawberries. The detection sensitivity was improved by using the TM-Sprayer for matrix application. In the receptacle, pelargonidins were distributed in the skin, cortical, and pith tissues, whereas cyanidins and delphinidins were slightly localized in the skin. In the achene, mainly cyanidins were localized in the outside of the skin. Citric acid was mainly distributed in the upper and bottom side of cortical tissue. Although hexose was distributed almost equally throughout the fruits, sucrose was mainly distributed in the upper side of cortical and pith tissues. These results suggest that using the TM-Sprayer in MALDI-IMS was useful for microscopic distribution analysis of anthocyanins, sugars, and organic acids in strawberries.

Novel Blotting Method for Mass Spectrometry Imaging of Metabolites in Strawberry Fruit by Desorption/Ionization Using Through Hole Alumina Membrane

“…MSI has been used to separate various metabolites based on their mass-to-charge ratio (m/z) and to visualize their distribution in tissues. Recently, MSI was adapted for analysis of metabolites in foods and was successfully used for visualization using soft ionization techniques, such as matrix-assisted laser desorption/ionization (MALDI) [9][10][11][12][13][14][15][16][17] or desorption ESI [18,19]. These techniques generally require preparation of thin sections (usually 10-20 µm) of the samples using a cryomicrotome.…”

Application of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging for Food Analysis

“…MALDI-MS imaging emerged in the medial field, especially in the field of cancer science to gain a better understanding of the metabolite dynamics during tumorigenesis [21], and has also been applied to the food field [22]. In food science, MALDI-MS imaging is now widely used to determine the localization of specific substances of interest such as sugars, amino acids, lipids, and polyphenols [23][24][25], or to screen non-target molecular dynamics in breeding or dosing applications. Thus, MALDI-MS imaging is used not only to clarify the localization of substances in food but also to ensure food safety.…”

“…This was the first report indicating that CMC-embedded tissues can be used for MALDI-MS imaging. Especially, foods and/or plant with high water content sometimes need embedding to maintain their shape [24,36]. This approach is also applicable for the discovery of the localization of nutritional factors in plants.…”

“…This study further showed that the sweetness of each part of the strawberry differs according to the constituent substance of that part. Thus, MALDI-MS imaging not only clarified the characteristic patterns of metabolism in strawberries but also provided reference information to guide future strawberry breeding improvements [24].…”

Tissue‐Specific Distribution of Sphingomyelin Species in Pork Chop Revealed by Matrix‐Assisted Laser Desorption/Ionization–Imaging Mass Spectrometry

“…Furthermore, tandem MS (MS/MS) can be used to determine the structure of lipid components such as fatty acids (Enomoto et al., ; Goto‐Inoue et al., ; Hayasaka et al., ). IMS was recently adapted for the analysis of metabolites, proteins, and pesticides in food products, which have been successfully visualized using soft ionization techniques such as MALDI (Enomoto, Sato, Miyamoto, Ohtsuka, & Yamane, ; Enomoto, Sensu, Yumoto, Yokota, & Yamane, ; Yoshimura et al., ; Yoshimura, Goto‐Inoue, Moriyama, & Zaima, ) or desorption ESI (Cooks, Ouyang, Takats, & Wiseman, ; Eberlin, Ferreira, Dill, Ifa, & Cooks, ; Enomoto et al., ).…”