REDUCTION OF ROASTED PEANUT LIPID OXIDATIVE RANCIDITY BY POWER ULTRASOUND AND EDIBLE COATINGS CONTAINING NATURAL EXTRACTS

Abstract

ABSTRACT The antioxidative potential of jujube extract, pomegranate extract and tocopherol mixed into carboxymethyl cellulose (CMC) solution then coated on roasted and roasted–sonicated peanuts was investigated. The concentration of jujube and pomegranate extracts added into the CMC solution was 1,000 ppm, while synthetic tocopherol was 250 ppm. Antioxidant effect was determined by the measurement of oxidative stability index. After 12 weeks of storage at 35C, the reduction in oxidation was 14.5 and 19.7% for samples roasted–coated with CMC added with extracts of jujube and pomegranate extract, respectively, as compared to uncoated sample (R as a control). Meanwhile, the oxidative stability of samples roasted–sonicated coated with CMC added with extracts of jujube and pomegranate was significantly (P < 0.05) improved by 24.8 and 31.8%, respectively, in relation to the control. However, it was observed that samples with tocopherol did not have any improvement in oxidative stability of the roasted peanuts. Sonication treatment beyond coating improved the storage stability of the samples mixed with jujube extract, pomegranate extract and tocopherol by 10.3, 12.1 and 3.2%, respectively. It is concluded that jujube and pomegranate extracts can control roasted peanut lipid oxidation during storage.PRACTICAL APPLICATIONSThis study showed that a combination of power ultrasound treatment and an edible coating of carboxymethyl cellulose mixed with natural plant extracts can be used for delaying the oxidation of roasted peanuts. The delaying development of oxidation compounds in roasted peanuts is very useful to the peanut industry. This process can be used for the preparation of shelf‐stable peanut products for the purpose of reaching distant markets, to be used during extended storage period. Likewise, the peanuts can be packed without the need to modify the packaging atmosphere or use of expensive packages.