Developing a Herbal Drink from Green Asparagus (Asparagus officinalis L.): Effect of Process Parameters on the Quality of the Product

Green asparagus is widely consumed fresh due to its high nutritional value and a low calorie content. However, its short shelf-life due to a high water content causes high postharvest losses. In this study, we aimed to develop an innovative asparagus herbal drink to ease postharvest losses and diversify asparagus-derived products. 
We investigated the effects of process parameters on the quality of the herbal drink from green asparagus. In particular, we determined the optimal length and grinding size for asparagus and selected suitable blanching and drying methods. Analytical responses included the contents of total soluble solids, polyphenol, carbohydrates, and vitamin C, as well as the visual appearance of asparagus samples. 
The length of 5 mm was found suitable for subsequent steps as it facilitated an increase in solute in the asparagus infusion. Microwave blanching and convective drying were selected to achieve high contents of total soluble solids, polyphenol, carbohydrates, and vitamin C in the asparagus infusion. Dried asparagus ground into 1.5–2.0 mm particles was packaged into tea bags. The asparagus infusion subjected to sensory evaluation had a yellowish color, a characteristic asparagus flavor, and a relatively sweet taste. Total soluble solids in the infusion amounted to 26%. 
Our results showed a possibility of developing an asparagus herbal drink which could be a potent product in the commercial market. Therefore, further large-scale studies of the asparagus herbal drink should be carried out to enhance its feasibility in the food industry.