QUALITY OF MINIMALLY PROCESSED CACTUS STEMS. EFFECT OF TEMPERATURE AND BROWNING INHIBITORS

Abstract

Minimally processed cactus (Opuntia ficus-indica) cladodes have a shelf-life of 1 to 2 d at room temperature, which can be extended to 7 d at 5 °C. The main drawbacks that shorten the shelf-life of cactus cladodes are browning and mucilage secretion. In this work we evaluated the effect of the addition of ascorbic and/or citric acid on the prevention of browning and on maintaining the quality of minimally processed cladodes in storage at 5° or 10 °C. Vegetable material was tender cladodes of fresh appearance that were sorted, washed with chlorinated water, and spines were removed. Cladodes were cut in dices and the bulk of diced cladodes were divided in four lots that were assigned to treatment with ascorbic acid (AA), citric acid (AC), a mixture of AA y AC, and chlorinated water (control); all these solutions contained 2 g L^-1 potassium sorbate. Diced cladodes of each lot were packed in polyethylene bags, with 250 g each one, and were stored at 5° for 21 d or 10 °C for 14 d. Based on the in-package atmosphere composition (O₂ and CO₂), appearance (browning and mucilage secretion), firmness, color, and microbiological analyses (total plate count, total coliforms, fecal coliforms, yeasts and molds), it was concluded that it is not recommended to use citric acid as browning inhibitor. However, by treatment with ascorbic acid it is feasible that shelf-life of minimally processed cactus cladodes can be extended for up to 11 d at 10 °C and 20 d at 5 °C. Microbiological quality was acceptable according to the Mexican Official Standards (NOM-093- SSA1-1994).