QUALITY CHANGES ON MINIMALLY PROCESSED PURSLANE BABY LEAVES GROWTH UNDER FLOATING TRAYS SYSTEM

The purslane (Portulaca oleracea L.) is an annual crop with fresh succulent leaves often consumed in salads which contain high levels of biologically active compounds. The innovative cultivation system under floating trays allows obtaining clean, safe and high quality raw material for the minimal processing or fresh-cut vegetables industry. In addition, it is relatively cheap and easy to implement at commercial level, being an efficient system to produce leafy vegetables. There are very scarce studies about the postharvest quality changes of minimally processed baby leaves grown under this cultivation system. The aim of this work was to study the sensory and microbial quality and total antioxidant capacity changes during shelf life of purslane grown in floating trays system with two aeration levels. After manual harvest, the raw material was pre-washed with tap water at 5°C, and subsequently it was washed for 2 min and disinfected by immersion in a solution at 5°C with 100 ppm NaClO at pH 6.5. As control, a 2 min tap water washing at 5°C was done. Then, the purslane was spin dried to eliminate water excess. The final product was packed under passive modified atmosphere packaging in polypropylene baskets, top sealed with a bi-oriented polypropylene and stored up to 10 days at 5°C. The steady state atmosphere within all baskets was 11-13 kPa O₂ and 8-10 kPa CO₂ which was reached after 7 days. The total antioxidant capacity decreased up to 10-20% in all treatments regarding the initial values (11-13 mg ascorbic acid eq. kg^-1 fw). The initial mesophilic counts were 2-3 log cfu•g^-1, and after 10 days at 5°C it remained below the legal limits for safe consumption, without differences among treatments. The sensory quality parameters changes determined a shelf life of 10 days at 5°C. As main conclusion, floating trays were a good system for cultivation of purslane as raw material for the minimal processing industry due to the low initial microbial load, which can avoid or reduce the use of chemical disinfectants and will preserve the overall quality.