Chemical composition of Dracocephalum kotschyi and Origanum majorana hydrosols and their effect as a natural preservative on the quality of fresh-cut broccoli during storage

Abstract

Dracocephalum kotschyi and Origanum majorana hydrosols, as a beneficial by-product of steamed-distilled essential oil (EO), are consumed for treating fresh-cut broccoli. The effect of two independent variables, the concentration of hydrosols (50-100%) and the portion of Origanum majorana hydrosol to the sum of Dracocephalum kotschyi and Origanum majorana hydrosol (0-100%) on maintaining the quality of fresh-cut broccoli (content of moisture, L-ascorbic acid, and total phenolic components, antioxidant activity, textural and color features, and microbiological properties) after 14 days of storage at 4°C was assessed and modeled through response surface methodology. Origanum majorana hydrosol was effective in preserving the firmness, color, and ascorbic acid content of fresh-cut broccoli. Origanum majorana hydrosol was more efficient at reducing the mesophilic and fungal populations, while Dracocephalum kotschyi hydrosol was effective in controlling the psychrophilic and lactobacillus count. Increasing the concentration of hydrosols decreased the mesophilic count; however, it had no considerable effect on the psychrophilic, lactobacillus, and fungal populations of the product. Optimum levels of independent variables considering the microbial and physicochemical properties of the product were 47.9% portion of Origanum majorana hydrosol, 52.1% portion of Dracocephalum kotschyi hydrosol, and 73.93% concentration of hydrosols. A comparison of the optimal and control samples’ characteristics revealed that treatment of fresh-cut broccoli with appropriate concentration and the portion of the hydrosols postponed the microbial spoilage and textural, colorimetric, and nutritional changes of fresh-cut broccoli during 20 days of storage.