Nondestructive Quality Screening of Green Tomatoes Using Ethylene Gas

Abstract

The effects of prolonged ethylene exposure on external and internal quality parameters of tomato fruits were studied in order to explore the feasibility of its use as a nondestructive technique for screening immature and inferior quality fruit. `Agriset' and `CPT-5' tomatoes were hand harvested at Stage 1 (green) and held at 20°C and 50 ppm ethylene for 1-7 days. Each 24 hours, fruits reaching Stage 2 (breaker) were removed from C2H4 and transferred to 20°C air for subsequent ripening. Tomatoes were considered at edible maturity upon reaching full red-ripe stage and 4 mm deformation and final quality parameters were determined. For both cultivars, fruits which required prolonged C2H4 exposure to reach Stage 2 had lower overall visual appearance. `Agriset' tomatoes which required short exposure times to C2H4 (1 to 3 days) had somewhat higher quality than those requiring prolonged times (4 or 5 days). Days to reach edible maturity were 9.5 and 7.7, respectively. For the short exposure times, peel color was more intense (higher chroma value), while soluble solids content and total sugars were significantly higher (P = 0.05). Quality of `CPT-5' tomatoes was not adversely affected until requiring 6 or 7 days exposure to C2H4. Days to reach edible maturity decreased from an average of 12.5 to 11.0 for 1 to 5 or for 6 to 7 days exposure, respectively. For fruits requiring 7 days exposure, soluble solids content, total sugars and pH were significantly higher than for those reaching Stage 2 in fewer days. There were no significant differences in titratable acidity or ascorbic acid content for either cultivar.