Near infrared spectroscopic and aquaphotomic evaluation of the efficiency of solar dehydration processes in pineapple slices

Abstract

Parallel transformation tests on pineapple slices using two micro drying plants (M1 and M2) operating with solar energy were carried out. Method M1 consisted of an active fan at the top, whose ventilation rate depended on the internal temperature. Method M2 had a continuously working fan at the bottom. The dehydration performance of these two micro-plants was compared by collecting spectra from pineapple slices in reflectance mode (900–1600 nm) at three different times: (0) process start, (1) during the process [48 h] and (2) process end [56 h]. Simultaneously, dry matter, titratable acidity (SH°), pH and aw (water activity) were measured. For these parameters, significant differences ( p < 0.05) were detected between the fresh (t = 0) and the dried product (t = 56). Near infrared (NIR) spectra analysis was carried out according to previously published methods. Spectral data in the wavelength region from 1300 to 1550 nm underwent statistical processing to perform aquaphotomics evaluation and chemometrics methods such as PCA (Principal Component Analysis) and LDA (Linear Discriminant Analysis). The Aquagrams highlighted differences among fresh, half-dried and dried slices where water molecules were highly organized between the water matrix coordinates C1 to C3 at t = 0 and C2 to C6 for the other evaluated times. The PCA could explain about 98% of the total variance in the PC1–PC3 scores plot. And the additional LDA classified the NIR spectra with an accuracy of 100, 98 and 83% for t = 0, t = 56-M1 and t = 56-M2, respectively. Such preliminary results suggest the applicability of Aquaphotomics and chemometrics for the continuous monitoring of fruit drying processes using an adequate NIR probe. Further experiments are already in progress.

An Aquaphotomics Approach for Investigation of Water-Stress-Induced Changes in Maize Plants

“…They are especially significant in the range 1409–1453 nm. The water absorption at 1441 and 1447 nm is important in desiccation processes and abiotic stress [ 35 , 42 ].…”

“…Aquaphotomics analysis of water–light interactions is a new source of information for a better understanding of the biological world. The combination of NIRS and aquaphotomics has already been used for the non-destructive investigation of aqueous and biological systems, for the evaluation of fresh and processed fruits and vegetables quality [ 32 , 33 , 34 , 35 , 36 , 37 , 38 ], plant abiotic stress and diseases [ 39 , 40 , 41 , 42 ].…”

Selection of a Green Contractor for the Implementation of a Solar Power Plant Project

“…Manyako et al [44], in their research, considered the possibility of using energy from solar panels to obtain a large amount of saturated steam, which is used in the production of essential oils from fruits. Cattaneo et al [45] examined the possibility of using a solar power plant in fruit drying processes to increase dehydration. Based on these and similar studies, it can be confirmed that the use of solar power plants contributes to the efficiency of food companies' business operations.…”

Aquaphotomics monitoring of strawberry fruit during cold storage – A comparison of two cooling systems

“…This research aimed to utilize aquaphotomic NIRS for monitoring during cold storage and better understanding of the mechanisms for maintaining freshness, choosing the strawberry fruit as a fruit-model system. The combination of NIRS and aquaphotomics has been already used to monitor aqueous and biological systems non-invasively for various purposes, such as evaluation of fresh and processed fruits and vegetables quality (36)(37)(38)(39)(40)(41)(42), milk quality (43,44), viral infections in plants, bacterial cultures (45,46) and fermentation (47)(48)(49), and physiological monitoring and diagnostics in higher organisms (50)(51)(52)(53)(54)(55). The second aim of the investigation was to compare the effects of different cooling technologies on the preservation of strawberries.…”