Application of DRIFT-FTIR spectroscopy for quantitative prediction of simple sugars in two local and two Floridian mango (Mangifera indica L.) cultivars in Kenya

Abstract

Background: Mangoes are fruits of nutritional importance in Kenya. The fruits vary in their sugars depending on cultivar type and ripening stage. Current methods of sugar content analysis are based on HPLC methods, which are accurate but expensive and time-consuming. We evaluated the potential of diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy as a rapid tool for quantitative prediction of fructose and glucose sugars in the pulp of Kenyan mangoes. Methods: Principal component analysis and partial least regression models were developed using the first derivative DRIFT spectra (400-4000 cm −1) to predict fructose and glucose sugars. A factorial analysis of variance compared effects of site (three locations), cultivar type (four cultivars), fruit position (inside/outside), and their interactions on fructose and glucose contents. Results: The principal component analysis scores plot using components 1 and 2 explained 75 and 8% of the variance, respectively, with no clear grouping either by sites or cultivars. The PLS range for glucose was R 2 = 0.80, SECV = 0.55, and RPD = 11.52 and fructose R 2 = 0.70, SECV = 0.28, and RPD = 11.52. Site (F (2, 265) = 18.12, p < 0.05, η2 = 0.02), cultivar type (F (3, 256) = 4.44, p < 0.05, η2 = 0.05), and fruit position (F (1, 259) = 7.62, p < 0.05, η2 = 0.03) had a significant effect on glucose content and not on fructose content. However, interactions between these three factors were not significant, p > 0.05. In general, fruits outside the canopy had higher fructose and glucose contents than those within the canopy. Conclusions: DRIFTS coupled with chemometric techniques showed potential for prediction of fructose and glucose contents of mango fruits.

FTIR-DRIFTS-based prediction of β-carotene, α-tocopherol and l-ascorbic acid in mango (Mangifera indica L.) fruit pulp

“…These results are similar to those reported by Ornelas-Paz et al [38]. and Robles-Sánchez et al [39] in 'Manila' and 'Ataulfo' mangos respectively and even for sugars [34]. The increase in β-carotene with ripening stage has been associated with the increase in respiration initiated by the action of ethylene produced (Mercadante and Rodriguez-amaya 1998).…”

“…The average β-carotene, α-tocopherol and l-ascorbic acid contents in the pulp of the four mango cultivars harvested from two fruit position; sun-exposed and within the tree canopy fruits are listed in Table 3. Generally, fruits that are sun-exposed receive higher light intensity with relatively more UV and red light than in other positions [33,34]. Similarly, in this study, better light conditions experienced in sun-exposed fruits resulted in significantly high l-ascorbic acid contents of mango fruits (Fig.…”

Mid-Infrared Spectroscopy as a Valuable Tool to Tackle Food Analysis: A Literature Review on Coffee, Dairies, Honey, Olive Oil and Wine

“…FT-MIR and sampling instrumentation have been evolving over the years. There are three commonly used sample presentation techniques for vibrational spectroscopy: transmission, attenuated total reflection (ATR), and diffuse reflectance (DRIFT) ( Figure 2 ) [ 15 , 16 ]. Transmission spectroscopy is the oldest and most basic technique and, in the case of liquid samples, these are placed in fixed-length transmission cells.…”

“…This technique can result in increased resolution of the spectra and reduced interference from water bands compared to transmission techniques. The DRIFT applications in food analysis are limited, but can be found in some reports on quality of coffee [ 15 , 21 , 22 , 23 ], of rice [ 24 ], and more recently, sugars in mangoes [ 16 ].…”

“…Reis et al reported a series of studies to assess the potential of DRIFT for analysis of the adulteration of pure roast Arabica coffee with coffee husks, spent ground coffee, corn and barley, despite the roasting conditions [ 16 , 22 , 59 ]. PCA and LDA were applied to find out if each one of the studied adulterants, as well as adulterated coffee samples (at adulteration levels ranging from 1 to 66 g/100 g) could be discriminated from pure roasted coffee [ 15 ].…”