Impact of ethanol treatment on physiological and microbiological properties of fresh white asparagus (Asparagus officinalis L.) spears

- Ethanol solution (50 L L−1) dipping of fresh asparagus spears reduces total bacterial and mould loads.
- Ethanol washing (30 s) has no clear effects on yeast loads.
- Ethanol washing has no effects on water content, spear stiffness, respiration and sugar content.
- Ethanol washing seems to stabilize the antioxidational protection system (vitamin C).
- Ethanol washing in practice can improve asparagus spears quality maintenance and safety.

Fresh and minimally processed white asparagus (Asparagus officinalis L.) spears are very susceptible to microbial spoilage, often accompanied by changes in physiological and textural quality. To prevent economic losses and to guarantee product quality and safety, postharvest handling and processing need to be improved. New environmentally friendly and safe sanitation techniques should be introduced. This study investigates the efficacy of short-term washing in 0.5 L L−1 ethanol solution at 10 °C as disinfectant of asparagus spears. The prevention of microbial spoilage and treatment effects on physiological properties and value adding quality parameters such as respiration, TSS, vitamin C and water content, and texture were evaluated in fresh white asparagus spears in four harvest seasons. Short-term dipping immediately reduced total bacterial counts and mould loads, and retarded their growth during storage. Retardation apparently did not increase with treatment duration. Short-term (30 s) ethanol washing but not longer treatments result in lower tissue water content and less stiff spears; it also reduced respiration and consumption of sugars. It seems to stabilize the vitamin C contents. Hence, short-term washing with ethanol is a promising approach to improve quality maintenance and safety of fresh asparagus spears and can be easily used in processing lines.