Improvement of Oxidative Stability of Roasted Peanuts by Edible Coatings and Ultrasonication

Abstract

In this study, an innovative method was developed to improve the shelf life of roasted peanuts. Sonication was combined with edible coating for enhancing the oxidative stability of roasted peanuts. Georgia green runner peanuts were roasted, subjected to sonication and then coated with whey protein isolate (WPI), ZEIN and carboxymethyl cellulose (CMC). Relative to the control, the oxidative stability of roasted-coated samples was improved by 80, 38 and 5% for CMC, WPI and ZEIN coating, respectively, while roastedsonicated-coated samples were improved by 91, 52 and 27% for CMC, WPI and ZEIN coating, respectively. Sonication prior to coating resulted in 11, 14 and 22% improvement beyond the CMC, WPI and ZEIN coatings, respectively. Texture analysis showed there were no significant differences (P < 0.05) in peanut texture between the treated and the control. Color results showed the HunterLab color parameters L, a, and b for most of the treatments did not have significant differences (P < 0.05) compared with the control. PRACTICAL APPLICATIONSEdible coatings used in this study (carboxymethyl cellulose, whey protein isolate and ZEIN) were capable of acting as oxygen barriers to reduce peanut lipid rancidity. This research demonstrated the potential of power ultrasound to remove lipids from the peanut surfaces and improve coating adhesion. The texture and the color of coated peanuts did not change over the storage period. This study indicated that edible coatings in combination with sonication 1 Corresponding 469 provided an alternative way for improving the oxidative stability and eventually the shelf life and quality of roasted peanuts. 470 P. WAMBURA ET AL. 472 P. WAMBURA ET AL.

Antioxidant Containing Gum Cordia Coatings for Control of Peanut Oxidation

“…Similarly 38 to 70% (Min and Krochta 2007;Wambura et al 2008) and higher (Mate et al 1996) increase in shelf life has been reported using WPI coatings. in shelf life of roasted peanuts.…”

“…These coatings are cheaper, environment friendly and continue protection of nuts even after opening the package (Mate et al 1996). However, protection provided by corn zein was very low (Wambura et al 2008). However, protection provided by corn zein was very low (Wambura et al 2008).…”

“…Edible coatings prevent moisture loss and reduce oxygen diffusion in nuts (Quezada-Gallo 2009). Carboxymethyl cellulose (CMC; Wambura et al 2008Wambura et al , 2010Wambura et al , 2011, whey protein isolate (WPI; Mate et al 1996;Min and Krochta 2007;Han et al 2008) and corn zein (Wambura et al 2008) have been reported as coatings to retard the oxidative rancidity in peanuts. Carboxymethyl cellulose (CMC; Wambura et al 2008Wambura et al , 2010Wambura et al , 2011, whey protein isolate (WPI; Mate et al 1996;Min and Krochta 2007;Han et al 2008) and corn zein (Wambura et al 2008) have been reported as coatings to retard the oxidative rancidity in peanuts.…”

Sensory Quality Preservation of Coated Walnuts

“…The solution was allowed to equilibrate at room temperature. Then, glycerol was added as a plasticizer (1.9%), and the solutions were stirred for another 10 min (Wambura and others ; Maftoonazad and Ramaswamy ).…”

“…The same weight of glycerol was added to the solution. It was kept at 90 °C for 30 min in a water bath (Min and Krochta ; Wambura and others ).…”