Physicochemical properties and antioxidant stability of microencapsulated marjoram extract prepared by co‐crystallization method

Abstract

In this study, the physicochemical characteristics of the microencapsulated marjoram extract powders such as entrapment yield (EY), loading capacity (LC), DPPH* radical scavenging activity, thermal characteristics (DSC), chemical structure (FTIR), and surface morphology (SEM) was investigated. Finally, the maintenance yield of total phenolic compounds and antioxidant properties of the co‐crystallized powder were compared with the spray‐dried powders in different conditions (75% relative humidity, artificial light, darkness, and at temperature of 4°C) during 4 months storage. The color and loading capacity of powder samples was significantly affected by concentrations of the extract. The encapsulation efficiency of co‐crystallized products was about 83%. DSC and FTIR graphs indicate lack of interaction between core and matrix components. The surface morphology of particles showed porous structure and the irregular holes among the agglomerates. Also, stability tests indicated a better performance of co‐crystallization process than the spray‐drying in maintaining phenolic compounds during different storage conditions. Practical applications Marjoram has several health benefits and its bioactive components can be used to produce functional foods. However, due to many problems including an unpleasant taste and instability of their polyphenols during storage, use of its liquid extract made is difficult. Encapsulation by co‐crystallization process due to its unique features is a promising method for protection of sensitive bioactive components such as phenolic compounds. Sucrose as a safe and food grade carrier is main matrix in this process and widely used in various food industries. The co‐crystallized Marjoram extract can be used as a source of antioxidants in the production of functional foods, confectionery, chocolate, candy products, and a variety of instant drinks powders.

Stabilization of peppermint polyphenols within crystalline sucrose matrix: Fortification of gummy candy as a food model system

“…These results indicated that the green–yellow color of peppermint aqueous extract had the main effect on the color properties of produced powders by placed them in the sucrose structure. Similar findings have been reported by López‐Córdoba et al (2014) and Sarabandi et al (2019) working with co‐crystallized yerba mate and sweet marjoram extract, respectively.…”

“…Physicochemical stability and functional properties of co‐crystallized powders were influenced by the values of their hygroscopicity (Sarabandi et al, 2019; Sardar & Singhal, 2013). The results showed that increasing concentrations of the extract in crystallized powder caused significant ( p < .05) increase in the moisture absorption of the samples (from 0.35 to 0.52).…”

“…The differential scanning calorimeter (DSC) thermogram of the control sample, extract, and co‐crystallized peppermint extract are presented in Figure 3b. The thermograph of the control sample showed two endothermic peaks around 212.5 and 243.75°C corresponding to the melting point and degradation of sucrose, respectively (Karangutkar & Ananthanarayan, 2020; Sarabandi et al, 2019). The peppermint extract showed a broad peak at 81.25°C, the endotherm transition shape may be due to the diversity from the compounds present in the extract.…”

“…There are multiple health problems associated with an inadequate intake of vitamins, minerals, and antioxidant compounds that the solution to these problems lies in efficient food fortification and improving the nutritional value of fortified products (Ahmad & Ahmed, 2019). Sarabandi et al (2019) encapsulated eggplant peel extract as a natural source of color and antioxidants for the fortification of gummy candy. Sensory evaluation of fortified candy indicated that the addition of 1.5% powder improved the overall acceptability of the product.…”

“…But today, the consumers demand for natural antioxidants has increased due to concerns about the harmful effects of synthetic antioxidants (such as BHA, BHT, TBHQ, and propyl gallate) (Shahidi & Zhong, 2015). In addition, consumers' eagerness is increasingly inclined to consume natural foods that have the least amount of synthetic additives (Sarabandi et al, 2019).…”