Understanding and improving the shelf life of tomatoes

Authors: WANG, KEXIN - Purdue University; Mattoo, Autar; HANDA, AUTAR - Purdue University

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 8/9/2016
Publication Date: 3/31/2017
Citation: Wang, K., Mattoo, A.K., Handa, A.K. 2017. Understanding and improving the shelf life of tomatoes. In: Mattoo, A. and Handa, A., editors. Achieving sustainable cultivation of tomatoes. Burleigh Dodds Science Publishing. Cambridge, UK. p. 315-342.

Interpretive Summary: Postharvest deterioration of the tomato fruit crop is one of the major challenges to the tomato industry, as it leads to huge economic losses at each step of the marketing chain, especially during long distance shipping/transportation. This chapter discusses various strategies that have been utilized to extend tomato fruit shelf life and quality. Natural variation and availability of non-ripening mutants have provided the means to develop tomato cultivars with an enhanced shelf life. However, fruit quality of these cultivars is inadequate in terms of the organoleptic taste attributes. The need to develop tomato cultivars with both improved organoleptic quality and extended fruit shelf life is a need of the times as never before. Molecular breeding and genetic engineering approaches have provided new sets of technologies and tools that should allow molecular dissection of the relationship between shelf life and fruit quality. Transgenic fruits have been developed through introgression of novel genes with a potential for improving quality attributes and longer shelf life. Also, fruit quality is relevant to the well being of consumers since increasing the levels of antioxidants, phytonutrients and other elixirs in fruits, along with a longer shelf life attribute, raise hopes for enhancing human health in addition to increasing marketing prowess for the economic benefit of the farmer, producer and supplier. Understanding the fundamental mechanisms of how plant hormones work, ethylene in particular for fruits, will provide new road maps for future development of long shelf life fruits, and override the inadequacy of attributes not beneficial to human taste and health. The emerging fundamental information from various facets of research are anticipated to provide new ways to maintain desirable tomato fruit quality and overcome the deleterious effect of senescence to enrich the horticulture industry. This book chapter is relevant equally to students, faculty, and scientists in the following areas: horticulture, tomato breeding, molecular biology, biotechnology and plant physiology.

Technical Abstract: Shelf life of ripe tomato fruit is economically very important, from production to the marketing chain, since it determines the cash returns to the grower and the grocer/processor. Shelf life of horticultural edible produce, including tomato, is regulated through myriad physiological, biochemical and environmental processes. Tomato, being a climacteric fruit, undergoes increases in respiration and ethylene production at the onset of ripening, and once the ripening process is initiated cannot be reversed. Ripening of tomato is associated with marked changes in gene expression, regulating the biosynthesis of a large number of catabolic enzymes, including cell wall hydrolases, implicated in fruit softening. Fruit softening leads to the loss of texture and enhanced susceptibility of the fruit to decay-enhancing pathogens. Ripening-associated changes in sugars, acids and volatile compounds determine the organoleptic characteristics of fruits. Ripening-impaired tomato mutants and genetically engineered genotypes characterized by inhibition or slowing down of the ripening process, respectively, have a longer shelf life but fruits from a majority of these cultivars are generally of low quality. Other treatments that increase tomato fruit shelf life include the use of ethylene inhibitors, such as aminoethoxyvinylglycine, and 1-MCP. Postharvest management through modified atmosphere packaging, temperature and humidity control, has provided some control on enhancing the fruit shelf life. A common strategy applied extensively to increasing tomato fruit shelf life is the off-vine ripening of mature green tomato fruit either during transit or marketing-chain. In this chapter we summarize the emerging knowledge on the molecular mechanisms regulating fruit ripening and such information is expected to contribute to devising new methods to prolong tomato fruit shelf life.