Minimally processed cassava leaves: effect of packaging on the microbiological and physical-chemical standards

Abstract

The study presents itself as an alternative for the minimal processing of crushed cassava leaves, a product widely used in the Northern Brazilian cuisine. A Box-Behnken design was used to define the concentration of the sodium hypochlorite solution (NaClO) and the immersion time (t) capable of guaranteeing acceptable levels for thermotolerant coliforms and molds and yeasts in the leaves. The leaves sanitized in this condition were crushed, packed in polyethylene packaging under standard atmosphere (PE-WV) and under vacuum (PE-V); also packed in polyamide packaging under vacuum (PA-V), and stored at 7ºC for 30 days. The following properties were monitored: fresh weight loss, water activity, pH, titratable acidity, soluble solids, instrumental color, chlorophyll a and b, and total phenolic contents. In addition, there were assessed Salmonella spp, coliform at 45ºC, molds and yeasts and psychrotrophic bacteria. The 20 min immersion time and 250 mg/L NaClO solution were defined as the optimal conditions for the sanitization of the leaves and, after that, the leaves were rinsed with water. The behavior of the physical-chemical and microbiological properties indicated that the sanitized and crushed cassava leaves will be suitable for consumption for 24 h when packed in PE-WV; for 7 days when packed in PE-V and for 14 days when packed in PA-V, at 7°C storage.