Standard Analytical Methods, Sensory Evaluation, NIRS and Electronic Tongue for Sensing Taste Attributes of Different Melon Varieties.

Németh Németh,Zaukuu Zaukuu,Kokai Kokai,Szentpeteri Szentpeteri,Kappel Kappel,Kovacs Kovacs,Bodor Bodor,Balazs Balazs,Daood Daood

doi:10.3390/s19225010

Németh Németh, Zaukuu Zaukuu + Show 7 more

Open Access

https://doi.org/10.3390/s19225010

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Abstract

Grafting by vegetables is a practice with many benefits, but also with some unknown influences on the chemical composition of the fruits. Our goal was to assess the effects of grafting and storage on the extracted juice of four orange-fleshed Cantaloupe type (Celestial, Donatello, Centro, Jannet) melons and two green-fleshed Galia types (Aikido, London), using sensory profile analysis and analytical instruments: An electronic tongue (E-tongue) and near-infrared spectroscopy (NIRS). Both instruments are known for rapid qualitative and quantitative food analysis. Linear discriminant analysis (LDA) was used to classify melons according to their varieties and storage conditions. Partial least square regression (PLSR) was used to predict sensory and standard analytical parameters. Celestial variety had the highest intensity for sensory attributes in Cantaloupe variety. Both green and orange-fleshed melons were discriminated and predicted in LDA with high accuracies (100%) using the E-tongue and NIRS. Galia and Cantaloupe inter-varietal classification with the E-tongue was 89.9% and 82.33%, respectively. NIRS inter-varietal classification was 100% with Celestial variety being the most discriminated as with the sensory results. Both instruments, classified different storage conditions of melons (grafted and self-rooted) with high accuracies. PLSR showed high accuracy for some standard analytical parameters, where significant differences were found comparing different varieties in ANOVA.

Highlights

Melon is grown on 3.5–3.7 million hectares around the world
Results of ET and near-infrared spectroscopy (NIRS) were evaluated with chemometric methods: Principal component analysis (PCA), linear discriminant analysis (LDA) and partial least square regression (PLSR)
A significant difference was obtained in violaxanthin between Centro and Donatello, and in total carotene Centro distinguished from the two other types and in vitamin C from Celestial variety

Summary

Introduction

Melon is grown on 3.5–3.7 million hectares around the world. Nowadays, a strong increase in production volumes and consumption can be observed in developing countries with highSensors 2019, 19, 5010; doi:10.3390/s19225010 www.mdpi.com/journal/sensorsSensors 2019, 19, 5010 populations [1]. The main argument for melon grafting is the gained increase in tolerance against pests [2], and abiotic stresses [3]. Fruit quality of melon is made up of several factors, like the visual appearance, texture, and the taste and aroma, which are the most important characteristics for consumers [5]. There are studies showing that grafting can influence the soluble sugar content of melon in a negative way. At the late 1940s [6] it was recorded that the Cucurbita moschata rootstock causes weaker texture and aroma in the grafted Honey Dew’ fruits, it established tolerance against fusarium wilt. Grafting did reduce sugar content by 1 Brix◦ in case of watermelon and melon as well in the experiments of international studies [7,8,9]. Compared to 350 melon varieties and found that the vitamin C content of them is between 0.75–35.3 mg/100g

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