The comparison of quality and microbiological characteristic of hamburger patties enriched with green tea extract using three techniques: Direct addition, edible coating and encapsulation

• Encapsulation process protects the active ingredients and enhances their stability.
• Green tea extract was utilized in hamburger patties by using different techniques.
• Direct addition, edible coating, encapsulation methods were compared.
• Lipid oxidation and microbial values of the patties were determined during storage at 4 °C.
• Coating of patties and addition of encapsulated extracts lowered the oxidation.

This study was aimed at the comparison of the effects of green tea extract (GTE) added with different techniques (direct addition, edible coating and encapsulation) on quality (particularly oxidative) and microbiological properties of hamburger patties. High molecular weight (1000 kDa) chitosan was utilized as the coating material and chitosan-TPP solution was formed for encapsulation of the extract. At the beginning (day 0) and in the middle of storage (day 4), control patty and the patties including GTE had higher pH values than the coated patties (p < 0.05) probably due to the inhibition effect of coating materials as a barrier on microbiological growth. TBARS value of control patty was higher than the other treatments in each measuring time (on the days 0, 4 and 8). This showed that enrichment of treatments by adding or coating with encapsulated green tea extract solution led to attenuation effect against lipid oxidation. However, TBARS value of all the treatments increased throughout storage, except the treatment coated with 1% (w/w) chitosan solution (p > 0.05). According to microbiological results, there were significant differences among the treatments.