Effect of storage temperature on ripening and postharvest quality of grape and mini-pear tomatoes

Keri P. Roberts, Steven A. Sargent, Abbie J. Fox

Abstract


Specialty tomatoes have become a staple item in the produce section of many markets. There is little literature available, however, regarding postharvest handling. Field-grown mini-pear ('Red Pear') and grape ('Santa') tomatoes were harvested at breaker/turning stage (10% to 30% red), sorted for uniformity, placed in loosely capped glass vials (n = 4), and stored the same day at 5, 10, 13 or 20C. After 7 days tomatoes stored at 5 or 10C were transferred to 20C for ripening. Pear tomatoes stored at 5C/20C reached the red-ripe stage (lightred + 6 days) in 18 days, while those stored at 10C/20C in 17 days, those stored at 13C in 16 days, and those stored at 20C in 12 days. Grape tomatoes ripened similarly for respective storage temperatures. At red-ripe stage there were no temperature effects on external or internal color for either type. External hue angles ranged from 40 to 45(red-orange); internal color of grape tomatoes was more yellow than pear (83 to 87 and 67 to 75, respectively). However, both pear and grape tomatoes stored at 13C lost about 50% less weight during ripening to red-ripe stage (3.5% and 2.6%, respectively) and were firmer (2.1 and 3.0 N at 2 mm deformation, respectively) than at the other temperatures. Grape tomatoes had a higher respiration rate (RR) at 20C than pear tomatoes, initially at 58 mg*kghr[sup-] and decreasing to 24 mgkg-hr[sup-] by day 11. In contrast, RR for pear tomatoes decreased from 30 to 14 mg*kg-hr[sup-] by day 8. At 13C RR for grape tomatoes decreased from 25 to 18 mg*kghr[sup-] during ripening; that for pear tomatoes was about 5 mg·kg-hr[sup-] lower on respective days. Initial soluble solids contents (SSC) were higher for both tomato types harvested at red-ripe stage than at breaker/turning stage (pear: 4.9 vs. 3.7Brix; grape: 5.1 vs. 4.2Brix, respectively); SSC remained lower for virtually all tomatoes ripened to red-ripe stage, suggesting that these grape and pear tomatoes should be harvested near redripe stage for best flavor. Storage at 5C resulted in about 30% reduction in total titratable acidity (0.41%-pear and 0.34%- grape), whereas those from other treatments maintained similar levels (0.53 to 0.67%).

Keywords


respiration; lycopersicon esculentum; quality; specialty vegetables

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Proc. Fla. State Hort. Soc.     ISSN 0886-7283