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Plums are nutraceutically rich and have health-promoting properties. To produce high-quality fruits, it is important to monitor them at harvest. This study illustrates the potential of nondestructive laser-induced fluorescence and confocal micro Raman spectroscopy for monitoring the ripening of plums. The fluorescence profile indicates that as fruit ripens, the intensity of the fluorescence of chlorophyll at 685 and 730 nm decreases with increase in the intensity ratio (F685/F730) of these bands. These observations reveal that as fruit ripens, there is a gradual loss of chlorophyll. In order to get further insight into pigment dynamics, the Raman spectra of the fruit were analyzed. The Raman spectra of pre and post-ripe stages of fruits show that as the fruit ripens, there is a prominent increase in the intensity of anthocyanin bands accompanied by subsequent decrease in the intensity of the carotenoid bands. The spectral analysis reveals that the ripening is associated with a decrease in the chlorophyll and carotenoid content with subsequent increase in anthocyanins. The results of this study highlight the utility of laser-induced fluorescence and confocal micro-Raman spectroscopy for the rapid, sensitive, and nondestructive monitoring of plum ripening. [ABSTRACT FROM AUTHOR]

Underutilized fruits like kadam are bio-reserves of numerous biochemical and minerals and have the potential to be used as food alternatives and supplements to fulfill the needs of malnourished populations. The production of quality fruits needs monitoring throughout the growth and ripening in order to build consumer and industry confidence. The nondestructive optical spectroscopic techniques have immense potential to monitor the growth and ripening indices of the fruits. Hence, this study explores the potential of laser-induced fluorescence and confocal micro Raman spectroscopy for the reliable and cost effective monitoring of growth and ripening of kadam fruits. The analysis of the laser-induced fluorescence measurements reveals that the ripening of the kadam fruits may be monitored by analyzing the fluorescence emission of chlorophyll and carotenoids. The decrease in the intensity of chlorophyll fluorescence accompanied by the increase in the intensity of the carotenoid bands is the characteristic fluorescence signature associated with the ripening of the kadam fruits. Hence, upon the ripening of the fruits, the concentration of chlorophyll decreases considerably with the accumulation of carotenoids. This fact is further complimented by confocal micro Raman measurements, which show that as the fruit ripens, the intensity of carotenoid bands increases dramatically. The observed spectral features may be used by the horticulture scientists and nutritionists to monitor the growth, maturity, and ripening of underutilized fruits like kadam in order to maximize the quality and minimize postharvest losses. [ABSTRACT FROM AUTHOR]

Ixora flowers of different cultivars are widely grown for their esthetic values as they have bright, abundant, and beautiful inflorescence. A derivative of plant origin, especially flowers, possesses a broad spectrum of biological activities; therefore, it is important to explore current techniques and protocols for the isolation, identification, and characterization of these substances. This study explores the utility of nondestructive spectroscopic probes for monitoring the composition and bioprocess in ixora flowers. The various cultivars of ixora flowers having dark red, dark pink, light pink, peach, orange, and yellow flowers have been collected, and their absorption, fluorescence, and scattering spectral signatures have been acquired using ultraviolet-visible, laser-induced fluorescence and confocal micro Raman spectroscopy. The pre-processing and spectral analysis reveal that biochemicals present in dark red, dark pink, light pink, orange, and peach ixora flowers include flavonoids, phenolic compounds, anthocyanins, and carotenoids of varying concentrations, while the yellow flowers are abundant in carotenoids. The spectral signatures obtained in this study open new avenues for monitoring the substances of plant origin in a nondestructive, rapid, robust, and sensitive way without high operational costs. [ABSTRACT FROM AUTHOR]

Climacteric fruits such as papaya are characterized by changes in the pigment composition during fruit ripening. Therefore, information on the degree of fruit ripeness with respect to the pigment composition using proper monitoring tools is important to growers for determining the appropriate harvest time associated with best quality. This study is aimed at exploring the applicability of spectroscopic probes such as laser-induced fluorescence (LIF) and confocal Raman microspectroscopy for the nondestructive, extraction free and rapid evaluation of pigment changes associated with the growth and ripening of papaya fruits. The laser-induced fluorescence spectra of the papaya show that as the fruit ripening progresses, there is a decrease in intensity of the chlorophyll bands with a simultaneous increase in intensity of carotenoid bands. This phenomenon can be regarded as a characteristic feature of the ripening of papaya. To obtain additional insight about the carotenoid dynamics during ripening, confocal Raman microspectroscopy has been utilized. The Raman spectra show strong spectral signature of carotenoids in both pericarp and mesocarp whose intensity increases as the fruit ripens. In addition, the bands of carotenoids are more prominent in the spectra of the mesocarp than in the pericarp. These facts are supported by the quantitative estimation of pigments in the papaya fruits by ultraviolet-visible spectroscopy. The determined spectral signatures can be used as indices for effective monitoring of ripening of fruits and commercial application for the phenotyping of important plant parts, screening, grading, shelf life estimation and quality standardization. [ABSTRACT FROM AUTHOR]

This study explores the application of spectroscopic techniques (laser induced fluorescence, Raman and attenuated total reflectance Fourier transform infrared) coupled with principal component analysis for the nondestructive, extraction free and rapid evaluation of biochemical changes associated with ripening of chili peppers at four stages (mature, pre-ripe, ripe and post-ripe). The analysis of the fluorescence spectra of the exocarp of chili pepper shows a decrease in the intensity of chlorophyll bands at 685 and 735 nm and an increase in the intensity of carotenoid fluorescence bands at 490–500 nm and 565–580 nm with progress in the ripening stages. These changes are regarded to be significant phenotypic markers for the ripening of chili peppers. The observed changes in the position of carotenoid bands in Raman spectra at 1004, 1156, 1188, and 1524 cm−1 with increase in their intensity indicating the accumulation of carotenoids and change in the carotenoid composition from β-carotene in the mature chilis to capsanthin in the ripe chilis. In addition, the infrared spectra show changes in the carbohydrates, amide II, amide I and cutin at various stages of ripening. Also, the variation in the position of pectin bands indicates change in its molecular mass with decreasing content. The determined spectral signatures can be used as biomolecular index for effective monitoring of the ripening of chili peppers. The commercial application of noninvasive spectroscopic probes will be advantageous for the phenotyping of economically important plant parts, screening, grading, shelf life estimation and quality standardization. [ABSTRACT FROM AUTHOR]

In the present investigation, attempts have been made to obtain the spectral signature of the fruit jamun and to estimate the changes in biochemical composition that take place in the process of ripening of the fruits. The changes in exocarp, mesocarp, and seed of the fruit in raw and ripe stages have been investigated with the help of label-free, nondestructive, and rapid techniques: laser-induced fluorescence and attenuated total reflectance Fourier transform infrared spectroscopy. For this, the fluorescence spectra of the different parts (exocarp, mesocarp, and seed) of the raw and ripe fruits of jamun excited by 405 nm violet diode laser have been recorded in the spectral region 400–900 nm. The spectrum shows the spectral signature of anthocyanin, flavonoids, carotenoid, and chlorophyll. The observed decrease in the intensity of chlorophyll bands and simultaneous increase in the intensity of anthocyanin and carotenoid bands is regarded as indicator of the ripening of the fruit of jamun. Also, attenuated total reflectance Fourier transform infrared spectra have been recorded in the spectral region 4000–485 cm−1for the identification of functional groups associated with different biochemical altered during ripening process of the fruits of jamun. The analyses of the recorded infrared spectra show the presence of carbohydrates, cell wall components, phenolic compounds, nucleic acid, and amide. The quantitative estimation of the biochemical content in the different parts of jamun fruit during the ripening process has been done through calculating the area of the band by curve fitting. The determined spectral signatures can be utilized for the effective monitoring of jamun fruit. [ABSTRACT FROM AUTHOR]