Spray Dried Microcapsules of Essential Oils With Antioxidant Activity

ASENSIO CM; GROSSO AL; LARRAURI M; OLMEDO RH; NEPOTE V; GROSSO NR

Chicago

Congreso; IFT 2016; 2016

IFT

Introduction: There is a growing interest in research, development, and commercialization of sensitive packed food ingredients. Microencapsulation provides protection from adverse environmental conditions and can prolong the shelflife of ingredients. The objectives of this work were to encapsulate mint (M) and oregano (O) essential oils, and to evaluate the antioxidant activity of the microcapsules at two storage temperatures. Method: Hydroxypropyl methylcellulose and maltodextrin were used as wall materials. The core consisted of essential oils (M or O) dissolved at 10% w/w in neutralized peanut oil. Two core/wall ratio were used (1:1 and 1:2). Four emulsions (M1:1, M1:2, O1:1, O1:2) were prepared. A mini spray dryer (B290) was used to obtained the microcapsules. Capsules were stored at 23°C (room temperature, RT) and 6°C (fridge, F) during 90 days. Antioxidant activity assays (DPPH and ABTS), total phenolic content (TPC) and volatile compounds (SPMECG) were measured every 30 days after encapsulation. Experimental design was 8 treatments x 3 repetitions x 4 storage days. ANOVA and FisherLSD test were used for statistical analysis. Significance:Oregano essential oil?s microcapusles presented better antioxidant activity than mint. This activity is better preserved when microcapsules are stored at fridge temperature. a high wall material content of microcapsules lessens the antioxidant activity of the encapsulated compound. Results: Antioxidant activity values and volatile compounds significantly change during storage after theencapsulation process (p˂0.001). At day 0 of storage, O1:1 capsules exhibited the best antioxidant activity in DPPH (IC50 14.1) and ABTS (7.7 mg Trolox/g), followed by O1:2 capsules. No significant differences were found in M1:1 and M1:2 capsules. At the end of the storage (day 90), significant differences werefound between samples and storage conditions (p˂0.001). O1:1F samples had the highest values for DPPH (21.1 IC50), ABTS (7.31 mg Trolox/g), TPC (43.78 mg gallic acid/g), followed by O1:1R, O1:2F and O1:2R. O1:1 carried the highest content of antioxidant volatile compounds (thymol, 4terpineol, and ɣterpinen)at the end of storage (p˂0.05).