Effects of Drying and Roasting to Effectively use a Discarded Part of Asparagus (Asparagus officinalis L.)

Asparagus ( Asparagus officinalis L.) has a characteristic flavor and useful components, although the lower stem is not suitable for eating because it has a fibrous skin like wood, being normally discarded. Therefore, to propose drying and roasting as methods for using the hard lower stem of asparagus, usually discarded, useful components in the asparagus stem after drying and roasting were analyzed. The rutin content was decreased significantly by drying and roasting. The ascorbic and folic acids contents were almost unchanged by drying but decreased by roasting. The fructose content was increased by drying, although glucose was almost unchanged. Both were decreased significantly by roasting. The sucrose content was increased by drying but unchanged by roasting. The increase or decrease in some free amino acids were caused after drying, and most of free amino acids disappeared after roasting. Furthermore, characteristic volatile compounds derived from the Maillard reaction were caused by drying and roasting. Most of the useful components in the hard lower stem of asparagus can be concentrated by drying, and characteristic volatile compounds be added by drying and roasting. Therefore, it is promising that the asparagus stem, an unused resource, is able to be utilized as a useful food material by drying and roasting