Establishment of a comprehensive indicator to nondestructively analyze watermelon quality at different ripening stages

Abstract

Two nondestructive methods based on visible and near-infrared (VIS-NIR) spectroscopy and X-ray image have been used for the evaluation of watermelon quality. The prediction performance based on partial least squares (PLS) by di®use transmittance measurement (500-1010 nm) was evaluated for chemical quality attributes SSC (Rc ¼ 0:903; RMSEC ¼ 0:572% Brix; Rp ¼ 0:862; RMSEP ¼ 0:717% Brix; RPD ¼ 1:83), lycopene (Rc ¼ 0:845; RMSEC ¼ 0:266 mg/ 100 gFW; Rp ¼ 0:751; RMSEP ¼ 0:439 mg/100 gFW; RPD ¼ 1:13) and moisture (Rc ¼ 0:917; RMSEC ¼ 0:280%; Rp ¼ 0:937; RMSEP ¼ 0:276%; RPD ¼ 2:79). The X-ray calibration linear equations developed by extracting the appropriate gray threshold were su±ciently precise for volume (R 2 ¼ 0:986) and weight (R 2 ¼ 0:993). In order to optimize prediction model of watermelon quality in growth period, multivariate multi-block technique factor analysis enabled integration of these traits: chemical information is related to physical information. Applying principle component analysis to extract common factors and varimax with Kaiser normalization to improve explanatory, the comprehensive indicator based on variances was established satisfactorily with Rc ¼ 0:94, RMSEC ¼ 0:244, Rp ¼ 0:93, RMSEP ¼ 0:344 and RPD ¼ 2:00. A comparison of these models indicates that the comprehensive indicator determined only by portable VIS-NIR spectrometer appears as a suitable method for appraising watermelon quality nondestructively on the plant at di®erent ripen stages. This method contributes to infer the This is an Open Access article published by World Scienti¯c Publishing Company. It is distributed under the terms of the Creative Commons Attribution 3.0 (CC-BY) License. Further distribution of this work is permitted, provided the original work is properly cited.

Recent Advances in Nondestructive Analytical Techniques for Determining the Total Soluble Solids in Fruits: A Review

“…It was shown that X‐ray CT scanning could be useful in monitoring the internal changes of peach fruits. Recently, Qi and others () analyzed watermelon TSS at different maturity stages based on X‐ray image and VIS‐NIR spectroscopy (500 to 1010 nm) with PCA‐PLS model. In that study (Qi and others ), the X‐ray calibration linear equations had been developed by extracting the appropriate gray threshold and the prediction model was evaluated with of 0.865, RMSEP of 0.00717, and RPD of 1.83.…”

Influence of Sampling Component on Determination of Soluble Solids Content of Fuji Apple Using Near-Infrared Spectroscopy

“…5 Agricultural products are significantly different from industrial products because of the variation in size, color, shape, and concentration of the chemical component of interest, caused by varied ripening stages, cultivars, origins, seasons, or even orchards, as well as the shelf-life. [6][7][8][9] Such variations lead to differences in light-scattering properties of fruit, and subsequently, the effective optical depth in samples would additionally be changed, affecting model validation performance. Because of the different qualities of Fuji apples from two main production areas (Shandong and Gansu) in China, samples from both these areas were studied to enlarge the variance of the sample sets during chemical-data collection, and thereby improve the reliability of modeling results.…”

Measurement of Soluble Solids Content of Three Fruit Species Using Universal near Infrared Spectroscopy Models

“…The use of near infrared (NIR) spectroscopy to measure the SSC of fruit has been investigated extensively during the last decade because it is a rapid, real-time, reliable and non-invasive technology compared with most instrumental techniques. [1][2][3] A wide variety of fruit have been studied, ranging from apples 4,5 to peaches, 6,7 pears, 8,9 mandarins, 10,11 mangoes 12,13 and watermelon, 14,15 among others.…”