Postharvest conservation techniques for purple carrot newly introduced in Brazil

Author(s)

Natalia Dallocca Berno

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2018-11-29

Examining board members

Ricardo Alfredo Kluge; Marcelo Augusto Gutierrez Carnelossi; Magda Andréia Tessmer

• Advisor: Marta Helena Fillet Spoto; Ricardo Alfredo Kluge

Abstract

The cultivation of carrots (Daucus carota L.) occurs in several regions of the world, with annual production exceeding 35 million tons. Purple carrots have recently been introduced in Brazil and have restricted availability due to planting still in expansion. Thus, this vegetable is new for consumers and producers. Postharvest practices are still poorly studied and require more knowledge to enable storage and have a product with physical-chemical and nutritional quality. In this way, the objective of the present work was to study different postharvest technologies for carrot newly introduced in Brazil. First, different storage conditions and their implications on the quality of purple carrots were investigated. The data showed that the losses are directly related to the increase of the storage temperature, that is, the higher temperature induce greater qualitative and quantitative losses. Ambient conditions (25°C and 70% RH) provide increases in metabolic processes, causing greater losses in appearance and bioactive compounds present. Carrots storage at 2°C, besides having a longer shelf life (60 days), maintained the physical-chemical and nutritional quality, with lower losses of phenolic compounds and polyphenols and increase of anthocyanins, flavonols and antioxidant capacity. That way, this is the best temperature for storage of purple carrots. With the storage temperature defined, it was aimed to study different modified atmospheres packaging (MAP) and to identify the one that results in greater maintenance of quality of purple carrots in storage. The MAP in purple carrots inhibited wilting losses and resulted in greater maintenance of appearance and biochemical aspects, as well as prolonged shelf life. In unpackaged carrots, a high wilting index and a loss of fresh weight were observed, with a durability of only 15 days, and lower concentrations of bioactive compounds. Concentrations of O2 between 11% and 12% and CO2 at 0.5% are indicated for the prolonged storage of purple carrots in MAP. Then, the use of different concentrations of chitosan and carnauba wax coatings in the conservation of purple carrots was evaluated. The use of edible coatings in purple carrots is a efficient postharvest technique for the preservation of commercial quality. The coating of 3% chitosan, combined with high relative humidity and low temperature during storage, is more efficient to maintain the quality of purple carrots and increases shelf life by 15 days compared to uncoating carrots. The results showed the importance of knowing postharvest physiology and applying good practices, especially those related to the reduction of plant metabolism, such as the technologies studied. The results could be readily applied by the producers, for extending the shelf life of the newly introduced vegetable to the Brazilian market. (AU)

• FAPESP's process: 14/07779-6 - Characterization of postharvest quality and application of conservation techniques in cultivars of purple and yellow carrots newly introduced in Brazil
• Grantee: Natalia Dallocca Berno
• Support Opportunities: Scholarships in Brazil - Doctorate