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ARS Home » Southeast Area » Raleigh, North Carolina » Food Science and Market Quality and Handling Research Unit » Research » Research Project #438059

Research Project: Improved Processes for the Preservation and Utilization of Vegetables, Including Cucumber, Sweetpotato, Cabbage, and Peppers to Produce Safe, High Quality Products with Reduced Energy Use and Waste

Location: Food Science and Market Quality and Handling Research Unit

2020 Annual Report

1. Enable the commercialization of reduced NaCl fermentation technology by identifying suitable starter cultures, optimizing processing parameters to prevent freezing of the fruits; and develop a shelf-life model that allows processors to rapidly and accurately predict end-use quality. 1a: Develop starter cultures for cucumber fermentations brined with calcium chloride. 1b: Identify parameters for long term storage of fermented cucumbers brined with calcium chloride so that freezing damage of the fruits can be prevented and removal of goods from tanks is facilitated during the winter season. 1c: Develop an accelerated shelf-life model for fermented cucumber pickles. 2. Determine the factors that maximize survival of probiotic bacteria and retention or production of healthful components in pickled vegetables to facilitate the commercialization of new cucumber pickling methods for delivery of live, probiotic, lactic acid bacteria to consumers. 2a: Determine the acid resistance and growth characteristics of probiotic lactic acid bacteria that influence their survival in acidified and fermented cucumbers. Subobjective 2b: Identify suitable methods for the incorporation of probiotic lactic acid bacteria in refrigerated cucumber pickles. 2c: Evaluate production and/or retention of bioactive peptides in fermented cucumbers. 3. Enable new commercial methods for process-ready-fermentation or acidification to convert surplus vegetables at grocery stores and farmers' markets into value-added products with enhanced probiotic content. 4. Integrate sweetpotato genotypes intended for commercial processing with their potential for increased levels of bioactive compounds and high quality food products.

Consumer interest in vegetable products with enhanced health benefits will drive future developments in the fermented and acidified vegetable industry. One major limitation for expansion is the generation of chloride waste and excess water use from traditional preservation technologies that rely on high sodium chloride (NaCl) concentrations. Cucumber fermentation in calcium chloride brine was developed and transferred to commercial processors as an alternative to reduce chlorides in waste waters. Long-term adoption of this reduced NaCl preservation technology requires: a) defining conditions for bulk storage in outdoor tanks to prevent freezing damage in cold climates; b) understanding the microbial ecology of low salt vegetable fermentations so that appropriate starter cultures can be defined; and c) developing a shelf-life model to accurately predict end-use quality. The ability to deliver probiotic bacteria in pickles and to adapt acidification and fermentation technologies to preserve a wide range of surplus vegetables from farms and retail markets will provide new knowledge and technology for processors to engage the growing consumer market interested in healthy eating. For sweetpotatoes, consumer demands for readily available processed products have increased in recent years. Development of new cultivars that are bred for desirable processing characteristics, low acrylamide formation and high bioactive compound content, will benefit sweetpotato processors and farmers and boost the contribution of this nutritious vegetable in the U.S. diet. The proposed research will support developments that broaden the markets for sweetpotatoes, acidified and fermented vegetables and will reduce food and processing wastes.

Progress Report
This is a bridging project for expired project 6070-41000-008-00D. ARS researchers at Raleigh, North Carolina, completed the new project review process July 2020. The bridging project was terminated 7/6/2020 when the new 5 year project (6070-41000-010-00D) was approved and made active. ARS at Raleigh, North Carolina, has been in maximized telework status for the entire reporting period. Progress was made by ARS researchers at Raleigh, North Carolina, on Objective 2c in the form of manuscript completion and submission and on manuscripts related to Objective 4 that describe the sensory properties and consumer acceptability of orange-flesh sweetpotato prepared by various cooking methods. Experimental plans were devised by ARS researchers at Raleigh, North Carolina, to investigate: 1) methods for enhancing gamma aminobutyric acid content in fermented vegetables; 2) microwave assisted thermal processing and high pressure processing for producing high quality, clean-label, shelf-stable acidified pepper products; and 3) polysaccharides in sweetpotatoes that influence the texture attributes of fried products.