Estimation of the physiological maturity of bell pepper

Abstract

The consumption and popularity of bell pepper (Capsicum annuum L.) are growing, mainly due to its characteristic flavour and the wide variety of colours. 2. Objective Can we use LED induced fluorescence/reflectance spectroscopy to estimate physiological maturity (age) of paprika? 3. Methodology •LEDs are used as light sources •Ocean optics USB 4000 was used as the detector •White, green, yellow, orange and green paprika samples were used •Measurements were taken twice a day •Data were compressed and trained a linear model 4. Results • The most suitable spectral components for different varieties for estimating the physiological maturity is as follows Where, R- diffused reflectance, F xxx fluorescence excited by LED with xxx nm centre wavelength 5. Conclusions •Physiological maturity of a certain part of a fruit can be estimated using LED based optical spectroscopic method •Need to develop more robust imaging application for estimating maturity of a whole fruit 6. Acknowledgment This work was supported by the Swedish Research Council and through a Linnaeus grant to the Lund Laser Centre. Support from International Science Programme, Uppsala University is also gratefully acknowledged. Paprika Sample Suitable combination of Spectra Confidence level Truncatio n RMSE (h) R2 White R, F375 96.9 % 3 27.7 0.96 Yellow F375 98.2 % 3 23.3 0.96 Orange R 98.4 % 3 36.0 0.91 Red F355, F375 97.5 % 4 27.9 0.96 Green R, F375 93.0 % 3 21.2 0. 97 GG420 long pass emission filter 355 nm LED AlGaN 410 nm LED 470 nm LED InGN+Ce:YAG 750 nm LED AlGaAs 850 nm LED AlGaAs 375 nm LED AlGaN 395 nm LED AlGaN UG11 short pass excitation filter Excitation wavelength (nm) Emission wavelength (nm) Spectrometer channels Carotinide Chlorophyll UG 1 350 400 450 500 550 600 650 700 750 800 850 350 450 550 650 750 850 Long pass filter GG420 Excitation source 600 μm collection fiber UG1, UG11 excitation filter Reflectance source Cu housing Sample 30 mm 450 500 550 600 650 700 750 800 Wavelength (nm) Fluorescence intensity Fluorescence spectra ex. at 395 nm LED t=0 min t=3 min t=65 min Chlorophylls a and b and their oxidation products give greenish colours Carotinides gives yellow, orange and deep red colours