Moisture dynamic sorption isotherms and thermodynamic properties of parchment specialty coffee (Coffea arabica L.)

Abstract

Sorption isotherms represent an efficient and valuable tool for predicting the equilibrium moisture content of foods under different humidities and temperatures; thus, they are useful for determining shelf-life and safe storage conditions. The aims of this study were to determine the sorption isotherms of parchment specialty coffee at water activity values of 0.1−0.8 and temperatures of 25, 30, and 40 °C using the dynamic dew point method. The experimental sorption data were modeled using 12 different equations to represent the dependence of equilibrium moisture content on water activity and temperature. Thermodynamic properties were also obtained from the experimental data. The results showed a type II sigmoid shape according to Brunauer-Emmett-Teller (BET) classification, and the double log polynomial (DLP) equation successfully modeled the effects of temperature on the sorption isotherms, obtaining a good fit (R 2 adj = 0.99 and RMSE = 0.1 % dry basis). The dynamic dewpoint isotherm (DDI) method was advantageous for modelling due to its high availability of experimental data. Thermodynamic analyses showed that the net isosteric heat of sorption, Gibbs free energy, and sorption entropy decreased as equilibrium moisture content increased, and the compensation theory provided evidence that the sorption process was controlled by enthalpy (T β > T hm ).

DFT-calculated IR spectra for spectrum-feature extraction

“…Specifically, if DFT-calculated spectra are a practical complement to experimental measurements, within a spectrum-template database, they must be scalable to meso and macro scales, within reasonable levels of approximation. DFT-calculated IR spectra of a caffeine molecule in vacuum and its spectral-feature enhancements using interpolation and pseudo-broadening procedures, can be utilized as template spectra for feature extraction related analysis of substances containing caffeine, especially quality control of different varieties of coffee [23][24][25][26].…”

“…Emphasized in this study is that spectral-feature extraction is equivalently important for the quality control of foods. A result of this study is an ensemble of template spectra for caffeine IR spectra, which can be applied for spectral-feature extraction associated with practical quality control of coffee, a global problem of importance (see references [23][24][25][26] and references therein).…”

Typha Domingensis Polenleri̇nden Bi̇yoakti̇f Bi̇leşi̇kleri̇n Ekstraksi̇yonunda Geleneksel Ve Ultrasoni̇k Yöntemleri̇n Ardişik Kullanimi

“…The wide peaks between 3600 and 2990 cm -1 were detected in all the samples which were attributed to the stretching vibration of -OH groups in phenols and flavonoids (Kalaichelvi and Dhivya, 2017). The peaks at 2926 and 2852 cm -1 were associated with the -CH stretching vibrations of aromatic rings (Jain et al, 2016;Collazos-Escobar et al, 2020). The peak at 2852 cm -1 was more apparent in the ethanol extracts than in methanol extracts.…”

Sorption Isotherm and Effect of Packaging Materials on Proximate, Organoleptic and Lipid Oxidation Quality of Chicken Nuggets Stored at Two Different Temperatures

“…Sorption isotherm is a critical concept in the field of food science and engineering [2], specifically in the study of moisture absorption by food products such as chicken nuggets. The understanding of this relationship between the equilibrium moisture content of a food product and the water activity of its surrounding environment is essential for predicting the shelf-life of food products, determining their stability, and optimizing their processing conditions [3,4]. By analyzing the sorption isotherm of chicken nuggets, valuable insights into the moisture sorption behavior of this popular food item, which can ultimately inform strategies for improving its quality and extending its shelf-life can be evaluated.…”