Effect of maturity on the moisture sorption isotherm of chili pepper (Mareko Fana variety)

Abstract

The moisture sorption isotherm at three maturity levels of the M a reko Fana chili pepper variety (red, brown and green) has been studied in this paper. The sorption isotherm was determined based on the standard static gravimetric method using a glycerol-water mixture in a relative humidity range of 10–92% at three temperature levels and nonlinear regression analysis was used to select suitable sorption models. The Clasius - Clapeyron equation was implemented to determine the isosteric heat of sorption of the chili pepper using the experimental equilibrium moisture content at different sorption temperature levels. The results showed that the GAB model was well fitted for green chili pepper, while the OSWIN model described well the brown and red chili variant. There was a difference in net isosteric heat between the adsorption and desorption isotherm of chili pepper maturity. For green chili, the maximum value of the net isosteric heat was 18 kJ mol −1 and 20 kJ mol −1 for adsorption and desorption isotherms, respectively and it decreased exponentially as moisture content increased. The desorption heat was higher than the adsorption heat for each maturity of chili pepper which indicated the existence of hysteresis in the sorption process. In comparison to literature data reported for different chili varieties, M a reko Fana has a lower heat of sorption and monolayer moisture content.

Sorption Isotherms and Thermodynamic Properties of Pomegranate Peels

“…Kammoun-Bejar et al [ 32 ] found similar results for orange peels. Other authors also reported that the Peleg model offered a good fit to other more dissimilar agricultural products, such as pepper, papaya or fig [ 15 , 30 , 33 ].…”

“…Thus, an accurate modelling of the sorption isotherms permits to establish the best storage conditions or the estimation of the equilibrium moisture content of the sample in the air drying conditions used and allows for the determination of both the optimum end point of drying, which preserves product quality and saves energy [ 12 , 13 ]. In fact, numerous scientific articles can be found that focus on the estimation of the sorption isotherms of very different agricultural products, such as chia, pepper, cambucci or pumpkin [ 14 , 15 , 16 , 17 ]. The experimental sorption isotherms can be determined using several methods, and the hygrometric method is one of the most commonly applied due to its simplicity and low cost.…”

Importance of integrated CFD and product quality modeling of solar dryers for fruits and vegetables: A review

“…Water activity (αw), is one of the critical criteria in fruit and vegetable handling mechanism to determine microorganism development and the release of toxin that indicates non-enzymatic and enzymatic browning formation in the products. The influence of water activity on fruit and vegetable quality during drying and storage was analyzed in detail in the work of (Getahun et al, 2020a).…”

Two-stage solar tunnel chili drying: Drying characteristics, performance, product quality, and carbon footprint analysis

“…In 2019, Ethiopia produced 313,000 t of dry chili peppers on 175,000 ha of land and found in 3 rd next to India, Thailand and mainland China (FAOSTAT, 2019). The most commonly grown types are the Mareko Fana and Bako Local chili varieties of capsicum Annum L. species (Musie et al, 2015, Samira et al, 2013, Getahun et al, 2020. Mareko Fana is a conical form of fruit that ripens to a dark red appearance and has a high extractable color intensity.…”