Foam mat drying of fig fruit: Optimization of foam composition and physicochemical properties of fig powder

Abstract

In this study, we report an optimization study on fig foam composition and hot air/microwave‐assisted foam mat drying (FMD) at different conditions to produce fig powder. The effects of foam composition on foam stability and capacity were evaluated. The optimum ratio of fig, egg white, carboxymethyl cellulose, and maltodextrin was determined as 52.9, 28.9, 0.8, and 17.4% (wt/wt), respectively, targeting maximum foam capacity and minimum drainage volume, that is, maximum foam stability. The effects of drying methods and their conditions were investigated on the drying rate of fig foam and physicochemical properties of fig powder. Moisture content, water activity, particle and bulk properties, and hydroxymethylfurfural and total phenolic contents of FMD fig powder were analyzed to understand the effect of drying methods and conditions on the physicochemical properties of fig powder. Practical applications Although fig fruit is generally dried as a whole, the ready‐to‐eat foods in the food market are mostly in powder form. That is why the powdering fig fruit by an appropriate drying method is essential. In this study, we report the foam mat‐dried (FMD) fig fruit powder. The fig foam composition was optimized. The fig foam was dried through hot air and microwave separately. The results showed that the foam capacity and stability of the fig powder highly depend on the foam composition. Microwave drying method was found more efficient than the hot air in the sense of time. Besides, the higher foam thickness provided more hydroxymethylfurfural content in the fig powder. The drying method and conditions were found to be important to produce a high‐quality FMD fig powder.

Usability of soapwort and horse chestnut saponin extracts as foaming agents in foam mat drying of pomegranate juice

“…Similar results on lower drainage with higher stabilization agent concentration were reported by many previous studies. 9,17,28 Therefore, the results are consistent with the literature.…”

“…This finding could be related to the increased viscosity of the liquid phase, which causes difficulties in trapping air in the structure. 28 Soapwort and horse chestnut extracts showed different behaviours depending on the stabilization agents. Whereas lecithin-stabilized foam prepared from soapwort had lower foam density, CMC provided a lower foam density in the foam prepared from horse chestnut extract.…”

“…The highest reduction percentage, 26%, was observed in the samples dried at 70°C; on the contrary, drying at 50°C increased the total monomeric anthocyanin As can be seen in Table 5, spreading thickness did not cause any effect on the chemical composition of the pomegranate juice powder. Varhan et al 28 determined a significant difference in total phenolic content of fig powder spread at 0.5, 0.7, and 1.0 cm. Similar results were also reported by several researchers.…”

Foam mat drying of taro (Colocasia esculenta): The effect of ultrasonic pretreatment and drying techniques on the drying behavior, flow, and reconstitution properties of taro flour

“…In addition, it can be stated that the moisture content values of the taro flours generally have an inverse proportion with the bulk density values. The bulk density values of CHAD and UP + CHAD were also in line with those obtained by Varhan et al (2019) who revealed that the bulk density values of hot air‐assisted foam mat dried fig powders changed between 0.36 and 0.50 g/cm 3 .…”

“…The bulk density values of the foam mat dried taro flour ranged between 462.62 and 529.62 kg/m 3 (Table 2) which were lower than the reported values by Kaushal et al (2012) (0.689 ± 0.010 g/ml) and Njintang and Mbofung (2006) (ranged between 0.55 ± 0.01 and 0.74 ± 0.01 g/ml depending on precooking time [0–90 min] and drying temperature [50–80°C]). The highest bulk density values were observed for CHAD + MOD and UP + CHAD + MOD which are desired because of packaging and transportation costs, smaller container requirements, and the feasibility of shipping and transportation (Çalişkan Koç & Dirim, 2018; Varhan, Elmas, & Koç, 2019). Ultrasonic pretreatment (UP + CHAD and UP + CHAD + MOD) resulted in insignificant ( p > .05) lower bulk and tapped density values compared to CHAD and CHAD + MOD; however, higher bulk and tapped density values were ( p > .05) observed for UP + MOD compared to MOD.…”