Moisture sorption isotherms and thermodynamic properties of whole black peppercorns (Piper nigrum L.). Issue 1 (November 2015)

• Record Type: Journal Article
• Authors: Yogendrarajah, Pratheeba; Samapundo, Simbarashe; Devlieghere, Frank; De Saeger, Sarah; De Meulenaer, Bruno
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 64:Issue 1(2015:Nov.)
• Page Start: 177
• Page End: 188
• Publication Date: 2015-11
• Subjects: Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2015.05.045
• Languages: English
• ISSNs: 0023-6438

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Abstract</title> <sec> <p id="abspara0010">Adsorption and desorption isotherms for whole black peppercorns (<italic>Piper nigrum</italic> L.) were developed at 22, 30 and 37 °C using standard static gravimetric method. The sorption isotherms exhibited a type III behaviour according to Brunauer-Emmett-Teller (BET) classifications. The equilibrium moisture content (EMC) decreased with increasing temperature at a particular water activity (a<sub>w</sub>). Hysteresis existed over the entire a<sub>w</sub> range at 30 and 37 °C. At 22 °C, an intersection of the curves was found at a<sub>w</sub> closer to 0.75. The goodness of fit of the models was evaluated using several statistical indices and residual plots. The Guggenheim-Anderson-de Boer (GAB) and Peleg models were determined to best describe the experimental sorption data. The monolayer moisture content (<italic>M</italic><sub>0</sub>) were 4.78, 3.56 and 3.49 g/100 g at 22, 30 and 37 °C for adsorption. The maximum isosteric heat of sorption was 28.1 and 73.3 kJ/mol for adsorption and desorption, respectively. The net isosteric heat of sorption and sorption entropy increased with increase in EMC; both curves dropped off exponentially after <italic>M</italic><sub>0</sub>. The Gibbs free energy change for adsorption ranged from 100.6 to 9370.6 J/mol. The black peppercorns can be stored at 22, 30 and 37 °C, by reducing their MC to 10, 8 and 7 g/100 g, respectively, with a<sub>w</sub> below 0.60.</p> </sec> </abstract>