Effect of sequential treatments of fermentation and ultrasonication followed by extrusion on bioactive content of apple pomace and textural, functional properties of its extrudates

Abstract

Apple pomace (AP) is a potential source of phenolic compounds, and most of the phenolics are presented in the bound form. Liberation of these bound phenolics is required to improve their health functionality. In this context, AP was naturally fermented followed by the ultrasonication and microwave drying. Fermentation time (FT), pomace to water ratio (PWR), ultrasonication intensity (UI) and microwave power (MWP) had significant (P < 0.05) effect on total phenolic content (TPC) and antioxidant activity (AA) of AP. At the optimum pretreatment conditions of 24 h FT, 5% (w/v) PWR, 37 W cm À2 UI and 90 W MWP, TPC and AA of AP were 40.3% and 92.9%, respectively, higher than that of the control AP. Extrudates from pretreated AP also had improved textural (hardness, brittleness, crispness) and functional (water absorption index, water solubility index) properties. Pretreatment reduced crystalline fraction amount and enhanced solubility of AP.

Effect of Extrusion Processing Parameters on Antioxidant, Textural and Functional Properties of Hydrodynamic Cavitated Corn Flour, Sorghum Flour and Apple Pomace‐Based Extrudates

“…Higher soluble dietary fiber in raw material indicated higher expansion of extruded products (Table ). Soluble fiber is able to interact sufficiently with starch molecules, and consequently forms a viscoelastic mass that has the ability to expand sufficiently as the extrudate exits the die (Lohani and Muthukumarappan ). Korkerd et al .…”

Effects of ultrasound treatment and concentration of ethanol on selectivity of phenolic extraction from apple pomace

“…Nowadays, the ultrasound-assisted extraction (UAE) is widely recognised as green technique with reduced energy consumption, processing time and low quantity of wastes (Jacotet-Navarro et al, 2016;Chemat et al, 2017aChemat et al, , 2017bKhadhraoui et al, 2018). Particularly, in several works, an application of UAE for recovery of polyphenols from apple pomace has been reported (Virot et al, 2010;Pingret et al, 2012;Lohani & Muthukumarappan, 2016;Chemat et al, 2017b). Obtained extracts were nondegraded and demonstrated high antioxidant activity.…”

Influence of fermentation followed by ultrasonication on functional properties of sorghum extrudates

“…Upon passing through the die of extruder, the elastic matrix retained a higher amount of air/gas, which formed stabled fine air cells in the expanded extrudates when melt was subjected to atmospheric pressure after coming out of the die. Cell wall thickness of the extrudates decreased with presence of more air cells in them, and because of it, extrudates had less hardness, more brittleness, and crispness (Lohani & Muthukumarappan, ).…”

“…In the past few decades, fermentation has been extensively used for ameliorating the functional properties in rice bran (Hegde, Kavitha, Varadaraj, & Muralikrishna, ), legumes (Oboh, Ademiluyi, & Akindahunsi, ), and apple pomace (Lohani & Muthukumarappan, ). It was also reported that the microbial fermentation degraded AA along with TPC in the sorghum (Dlamini et al, ; Svensson, Sekwati‐Monang, Lutz, Schieber, & Gänzle, ) but improved its water solubility index, starch‐protein digestibility, and water absorption index (WAI) (Pranoto, Anggrahini, & Efendi, ).…”

“…Hypothetically, bound phenolics in the sorghum flour will be released because of separation and breaking down of starch and protein using natural fermentation followed by ultrasonication (Zhao, Bean, & Wang, ). Very few authors reported on the effects of the fermentation‐assisted ultrasonication on phenolics in plant materials (Ajila, Brar, Verma, Tyagi, & Valéro, ; Lohani & Muthukumarappan, ). As far as industrial process is concerned, fermentation is already a commercialized technology and ultrasonication is in the process of scaling up.…”