Cellulose crystallinity can be described according to the crystal size and the crystallinity index (CI). In this research, using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) methods, we studied the crystallinity of three different types of cellulose: banana rachis (BR), commercial cellulose (CS), and bacterial cellulose (BC). For each type of cellulose, we analyzed three different crystallization grades. These variations were obtained using three milling conditions: 6.5 h, 10 min, and unmilled (films). We developed a code in MATLAB software to perform deconvolution of the XRD data to estimate CI and full width at half-maximum (FWHM). For deconvolution, crystalline peaks were represented with Voigt functions, and a Fourier series fitted to the amorphous profile was used as the amorphous contribution, which allowed the contribution of the amorphous profile to be more effectively modeled. Comparisons based on the FTIR spectra and XRD results showed there were no compositional differences between the amorphous samples. However, changes associated with crystallinity were observed when the milling time was 10 min. The obtained CI (%) values show agreement with values reported in the literature and confirm the effectiveness of the method used in this work in predicting the crystallization aspects of cellulose samples.
The agroindustry generates substantial quantities of byproducts, particularly in coffee production, which yields significant waste, most notably spent coffee grounds (SCGs). This study explores the potential of SCGs as a versatile resource for applications in both food and nonfood sectors. A comprehensive chemical analysis revealed that SCGs consist of 30.2 wt.% cellulose, 25 wt.% hemicellulose, and 12 wt.% lignin. Morphological characterization was performed using field emission scanning electron microscopy (FESEM). Additional analyses included attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA). ATR-FTIR identified key polysaccharides and oils, whereas TGA offered insights into the thermal degradation behavior of SCGs, confirming the presence of typical plant cell wall components. X-ray diffraction (XRD) patterns revealed low crystallinity, consistent with SCGs’ amorphous structure. Mineral content was assessed using inductively coupled plasma atomic emission spectrometry (ICP-AES) and atomic absorption spectrophotometry (AAS). The results showed that mineral concentrations in SCGs (per 0.01 kg) were within recommended daily intake limits, confirming their safety for potential human consumption. These findings establish SCGs as a valuable lignocellulosic biomass with applications in composite materials. Additionally, it can serve as an organic soil amendment after fermentation to prevent stress on plants. This approach supports effective waste management and advances resource sustainability practices in the agro-industrial sector.
Emulsion stabilization is a broad and relevant field with applications in oil, polymer and food industries. In recent years, the use of solid particles to stabilize emulsions or Pickering emulsions have been studied for their kinetic and physical properties. Nanomaterials derived from natural sources are an interesting alternative for this application. Cellulose nanofibrils (CNFs) have been widely explored as a Pickering emulsifier with potential food applications, however, in some cases the presence of surfactants is unavoidable, and the literature is devoid of an evaluation of the effect of a non-ionic food-grade surfactant, such as polysorbate 80, in the stabilization of a vegetable oil by CNFs. To better assess the possible interactions between CNFs and this surfactant emulsions containing coconut oil, an emerging and broadly used oil, were processed with and without polysorbate 80 and evaluated in their qualitative stability, morphological and physical properties. Fluorescence microscopy, dynamic light scattering and rheology were used for this assessment. Results indicate in absence of the surfactant, emulsion stability increased at higher CNFs content, creaming was observed at 0.15 and 0.3 wt.% of CNFs, while it was not evidenced when 0.7 wt.% was used. After the addition of surfactant, the droplets are covered by the surfactant, resulting in particles with a smaller diameter, entrapped in the cellulosic structure. Rheology indicates a lower network stiffness after adding polysorbate 80.
Color is an important characteristic of food products. This characteristic is related to consumer acceptability. To use the entire rhizome of Curcuma longa (CL) as a food colorant, a novel gel alike stable suspension (CLS) was previously developed using cellulose nanofibers (CNFs). Therefore, the present study was conducted to evaluate the CLS as a color additive on a stirred yogurt. Three concentrations of CLS were studied (0.1, 0.125, and 0.15 wt. %) and compared to yogurt without CLS. The obtained yogurts were characterized through the determination of pH, titratable acidity, syneresis, color and curcumin content after 1, 7, 14, and 21 days of storage. Additionally, rheological and sensory measurements were performed on the samples after one day of storage. Results show that the addition of CLS does not affect the pH and titratable acidity of the samples, but all the yogurts showed an increase in their syneresis during the storage time, showing a breakdown of the gel structure. Furthermore, the CLS suspension has the ability to impart a yellow color to yogurts, a characteristic that was stable during storage. Finally, the addition of 1 wt. % or 1.25 wt. % of CLS allows the development of a yogurt with adequate sensory perception.
Characterizations ofApis mellifera honey produced in Southwest of Antioquia, an important coffee region of Colombia, have not been published in recent years. In the present work, seven samples of honey collected in the mentioned region, were physically (refractive index, specific rotation, density), chemically (moisture content, water activity, pH, free acidity, carbohydrates) and microbiologically (Clostridium, fungi and yeast) analyzed. The results show that the analyzed honeys meet both national (Resolución 1057 of 2010) and International (Codex-Stan 12 of 1981) standards for moisture content, free acidity, sucrose content and microbiological pa-rameters, indicating their good quality. Fructose/glucose ratio,pH and specific rotation values indicate that the samples are blossom honeys.