Effect of Combined Air-Drying-Osmotic Dehydration on Kinetics of Techno-functional Properties, Color and Total Phenol Contents of Lemon (Citrus limon. v. lunari) Peels

Abstract

Combined osmotic dehydration (sucrose solution: 50-70 % w/w, 30-50°C for 2 h followed by air drying at 40 and 60°C) is an appropriate process for preservation of oil retention capacity, lightness and yellowness of lemon peels (Citrus limon. v. lunari). Incorporation of sugars to lemon cuboids pieces increased drying rate during the first falling rate phase of the air dehydration step and improved their color stability. Osmotic dehydration process allows protective effect against further total phenol loss during air drying: significant loss of total phenol content (70-80 %) was recorded during osmotic dehydration and then it remains constant during air drying at 40 and 60°C. For the investigated temperature of osmotic pretreatment (30-50°C), water retention capacities were reduced by up to 70 % and were maintained constant during air drying.

Osmotic dehydration of cassava bagasse (Manihot esculenta) and its effect as pretreatment on the efficiency of convective drying

“…This agrees with other authors who state that the highest rate of mass transfer and water loss from food during OD occurs during the treatment initial stage (Andreou et al, 2021;Ghanem et al, 2016;Kaushal & Shama, 2016;Dermesonlouoglou et al, 2018). The ANOVA shows that both, the main studied factors -concentration of the osmotic agent and solution: sample ratio-and their interaction significantly affect WL and SG respectively (p-value < 0.05).…”

“…In this regard, Assis et al (2017) highlights that one of the most important factors in the OD study is the material type to be treated, as well as its structure and geometry. Thus, the moisture loss reached in this research in the OD stage is compared with the WL of up to 70 % in the first 10 min of OD, reported by Ghanem et al (2016) when subjecting lemons to a 70 °Brix solution of sucrose.…”

“…The process itself is relatively inefficient to achieve low humidity and in some cases requires long treatment times (Bai et al, 2020;Ferreira et al, 2020;Gutiérrez-Salomón et al, 2021). Various OD studies have shown that the greatest mass transfer occurs in the process initial stage (30-100 min) (Andreou et al, 2021;Ghanem et al, 2016;Kaushal & Sharma, 2016;Dermesonlouoglou et al, 2018). Some authors have proposed OD as an early step of thermal drying, resulting in higher energy efficiency and cost reduction (Abbasi et al, 2012;Sharma & Dash, 2019); with decreases, also, of up to 42 % in drying time, and 31.1 % in the required energy (Andreou et al, 2021;Massolo et al, 2020;Da Costa et al, 2016;Masztalerz et al, 2021).…”

Pretreatment of citrus by-products affects polyphenol recovery: a review

“…However, following osmo-dehydration, drying citrus by-products at 40 or 60 °C, had no significant effect on the TPC. The polyphenol loss took place during osmodehydration was attributed to the osmotic driving force which promotes the migration of soluble phenolic compounds from the peels to the osmotic solution [54]. Future studies should be conducted in order to investigate the exact mechanism being involved in the retention of polyphenols during drying after osmo-dehydration.…”

Microorganism preservation by convective air-drying—A review

“…Such condition is hypothesised to be favourable towards high cell survival of microorganisms [29].Majority of studies and reviews, however, largely revolve around freeze-drying and cryogenic preservation which are both costly [8,15,30,31]. Although convective air drying has been used to preserve many foodstuffs, research on its applicability for bacteria preservation is still limited [32][33][34][35][36]. This paper is aimed to critically review work on preservation of microbes; looking into the factors that will affect the cell viability in convective air drying and to suggest future directions on the use of convective air drying for microbial preservation.…”