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Scholarly Works, Department of Chemistry

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/367

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    Development of a facile and convenient method for sugar determination in low moisture confectioneries and honeys using fourier transform infrared attenuated total reflectance spectroscopy and chemometrics
    Setijadi, Catherine H.; Felix, Jonathan N.; Ellis, Helena C.; Alumbro, Jihan Santanina S.; Bello, Ghalib; Dumancas, Gerard G. (Informa UK Limited, 2020-01-10)
    A method using Fourier transform infrared with attenuated total reflectance spectroscopy and partial least squares (PLS) chemometric analysis to simultaneously quantify the mass percent concentrations of glucose, fructose, and sucrose, commonly found in honey and low moisture confectionery food products, was developed. A three-component full factorial design was generated as a training set (n = 64) to predict the sugar concentrations in a Box-Behnken testing set (n = 16). Analysis of the entire spectral region from 649.99 to 3996.38 cm−1 using Savitzky–Golay signal processing technique and PLS algorithm garnered optimal errors of prediction and better linearity between predicted and measured concentrations in the test set compared to analysis using a specific spectral region from 800 to 1500 cm−1 and using a wide array of signal processing techniques (first derivative, second derivative, moving average, binning, and standard normal variate). The model further detected these sugar concentrations in 3 standard honeys, 12 commercial honey samples, 8 honey adulterants, 13 low moisture confectionery food samples, and 15 unknown honey samples from Louisiana apiaries. Applying principal component and clustering analysis also enabled the discrimination of these honey samples based on their fructose:glucose ratios. Thus, the developed method represents a potentially novel, simple, accurate, nondestructive, and rapid means of quantifying concentrations of glucose, fructose, and sucrose in honey and low-moisture confectioneries in 1–2 minutes.
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    Zein nanoencapsulation enhances the antifungal activity of thymol for postharvest decay control in bananas
    Punelas–Villanueva, Dana C.; Almeda, Ronaniel A.; Chua, Mari Sherlin S.; Tabor, Rico F.; Vidallon, Mark Louis P.; Rodriguez, Evelyn B. (Springer, 2024)
    The current work describes a nanoparticle system-based approach to enhance the antifungal activity of thymol, a ubiquitous natural antifungal phenolic compound, in postharvest control against banana anthracnose. Thymol was encapsulated within the amphiphilic protein zein by high-shear emulsification, yielding highly dispersible thymol-loaded zein nanoparticles with a high encapsulation efficiency (70%). These particles have an average diameter of 300 nm with spherical morphology, smooth interface, and matrix-type internal structure, as supported by comprehensive structural characterization (dynamic light scattering, transmission electron microscopy and atomic force microscopy). Based on a 40-d storage stability test, thymol was effectively retained within the nanoparticles at 4 °C and ambient room temperature (99% and 97% retention, respectively), despite thymol’s instability and volatility. Antifungal activity assessment against Colletotrichum musae, one of the predominant pathogens that cause banana anthracnose, showed a 200- to 300-fold improvement in the in vitro antifungal activity of thymol. Moreover, the application of thymol-loaded zein nanoparticles as a spray component for banana postharvest treatment demonstrated the efficacy of thymol-loaded zein nanoparticles in preventing and delaying the formation of initial symptoms of banana anthracnose. This appears to arise from the thymol-loaded zein nanoparticles depositing as a film on the banana epidermis, as revealed by atomic force microscopy. Overall, this nanoparticle system offers a new avenue for the design of effective antifungal materials with potential applications in combatting postharvest diseases. Graphical abstract: (Figure presented.)
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    Lactational changes in Filipino human milk oligosaccharides reveal maternal secretor status
    Albaladejo, Anthony Salvador B.; Nacario, Ruel C.; Navarro, Baby Richard R.; Lebrilla, Carlito B.; Completo, Gladys C. (Wiley, 2023)
    Background: Breast milk contains human milk oligosaccharides (HMOs), which are the third most abundant solid component and are considered indigestible with no nutritional value to infants. However, HMOs provide protection against pathogens, support gut bacteria, and aid in brain development. This study investigated the relationship between HMOs and secretor status and tracked changes in HMO levels throughout lactation. The study employed a rapid-throughput extraction method, nano-HPLC Chip/TOF-MS analysis, and an annotated HMO structure library for oligosaccharide analysis. Results: Results from the study revealed that 81% of Filipino mothers (N = 155) are secretors, while 19% are non-secretors. The total HMO abundance significantly decreased (p = 0.0001) throughout lactation but was significantly (p = 0.0390) higher in colostrum compared with mature milk. The total fucosylated HMOs had a significantly (p = 0.0460) lower absolute abundance, while the total sialylated HMOs showed a significantly (p = 0.0012) higher abundance in colostrum relative to mature milk. Non-fucosylated neutral HMOs showed no significant (p = 0.1040) difference in abundance between colostrum and mature milk. Conclusion: This is the first comprehensive data on the maternal secretor status of Filipino mothers, showing the decrease in total HMO abundance throughout lactation and differences in the abundances of various oligosaccharide types between colostrum and mature milk.