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Vacuum Frying to Eliminate the Need for Reconditioning After Long-term Cold Storage and to Retain He

time:2017-06-06 source:LianHuibrowse:79

Potatoes are a leading vegetable crop in the world, providing an array of macro- and micronutrients as well as secondary metabolites. Due to their high consumption, potatoes are the greatest source of polyphenols in our diet. Color-fleshed potato consumption has increased by 17 % in the last decade likely due to their health-benefiting properties. Understanding the farm-to-fork operations of potatoes with goals of improvement are critical to maintain their nutritious value. After harvest, potatoes are stored in long-term cold storage (4 – 10 °C) for 2 - 12 months. In order to combat the accumulation of reducing sugars brought upon by the degradation of starch during cold storage, potatoes are reconditioned at 12 – 20 °C for two to three weeks. This process is costly due to the requirement of two different rooms and energy to temperature control both rooms at different temperatures. During reconditioning potatoes experience a break in dormancy leading to sprouting. While white-fleshed cultivars are bred to withstand this reconditioning process, color-fleshed cultivars have not and therefore undergo sprouting during reconditioning, resulting a costly produce-loss. After storage, potatoes are processed in to French fries and potato chips, which make up 51 % of the processed potato market. Potato chips account for 15 % of the total processed potato market (66 % of potatoes are processed). Deep-fat frying causes the formation of the neurotoxin acrylamide and a loss of health-benefiting anthocyanins. To date, no systematic studies have considered processing mitigation strategies to eliminate reconditioning. We sought to utilize vacuum frying to eliminate the need for reconditioning while retaining health-benefiting compounds and reducing toxins. Vacuum frying straight from cold storage yielded a less browned and more yellow, red, or blue potato chip with the same texture and moisture content as the typical reconditioned conventional countertop fried potato chips. Glycoalkaloids were reduced with both frying treatments, even straight from cold storage, but were further reduced with vacuum frying. The glycoalkaloids levels are similar to that of reconditioned conventional countertop fried chips. These results suggest even with prolonged time of frying at reduced temperatures, glycoalkaloids are reduced and have potential for health-benefiting properties. Though cold storage results in excess sugars, we report no differences in acrylamide content in cold stored vacuum fried chips and reconditioned conventional countertop fried chips. However, due to the limit of detection of HPLC, we suggest further confirmation of this data with a more sensitive technique, GC-MS. The reconditioning process increases the risk of sprouting in color-fleshed cultivars which have not yet been bred to withstand this process. A leading factor to the use of color-fleshed potatoes is their health-benefiting anthocyanins. Anthocyanins were better retained in red- and purple-fleshed potato chips which underwent vacuum frying compared to conventional countertop frying, regardless of storage treatment. However, health-benefiting trigonelline was degraded, similar to the findings of the other compound in their family, glycoalkaloids. Together, these findings suggest vacuum frying can be utilized on potatoes straight from cold storage to create comparable quality chips with an improved bioactive profile compared to conventional countertop frying after reconditioning. This research provides evidence vacuum frying can be used straight from cold storage to eliminate reconditioning, thus reducing costs associated with energy, space, and produce loss. Furthermore, vacuum frying could be used to introduce color-fleshed potato chips straight from cold storage both reducing produce loss due to sprouting and retaining health-benefiting compounds. Overall, our research enables improvements to the farm-to-fork process by eliminating reconditioning and with the potential for improved health-benefits in potato chips.