Investigation of the Physical, Chemical and Antioxidant Properties of Nanoliposomes Loaded with Quinoa Seed Hydrolyzed Proteins

Encapsulation is a process; by which, a susceptible compound is surrounded with a membrane or matrix that is able to release its contents at a controlled speed under certain conditions. In recent years, popularity of adding bioactive compounds to food products has increased. These compounds are usually sensitive to environmental, processing and/or gastrointestinal conditions. Therefore, encapsulation is an appropriate option to protect these compounds against harsh conditions. Nanoliposomes are made from edible compounds and therefore are common for encapsulation, protection and controlled release of bioactive compounds in foods. The objective of this study was to investigate properties of nanoliposomes loaded with quinoa seed protein hydrolysates.

In this study, nanoliposomes loaded with quinoa seed protein hydrolysates (without and with chitosan coating) were assessed for their particle size, zeta potential and antioxidant activity using DPPH radical scavenging and ABTS radical inhibition activity. Furthermore, effects of six weeks of storage in refrigerator conditions were assessed on the stability and properties of nanoliposomes. Hydrolysis was carried out using alcalase and pancreatin enzymes.

Results showed that particle size increased from nearly 22 nm in control sample to 40 and 70 nm in samples with and without chitosan coating, respectively. Moreover, disintegration index in the sample with chitosan coating (No. 2) was improved, compared to control sample with further uniform distributions. Zeta potential changed from -9 MV in control sample to -4 and 26 MV in samples without and with chitosan coating, respectively. Microencapsulation efficiency over six weeks of storage at refrigerator temperature was 40% in sample No. 1 (sample without chitosan coating) and 65% in sample No. 2 (sample with chitosan coating).

Encapsulation of hydrolyzed quinoa proteins using nanoliposome and its coating with chitosan improve various characteristics of nanoliposomes such as particle size, decomposition index and zeta potential, improving particle stability by decreasing its release rate during storage and causing high storage ability of the active compounds in nanoliposome structures.