| Potato（Solanum tuberosum L.）tubers are rich in a variety of minerals,vitamins,and polyphenolic antioxidant active substances,and their fresh-cut products are popular among consumers because of the convenience and freshness.However,excessive storage of potato tubers will affect the quality of fresh-cut products.In this thesis,the potato varieties‘Hua Song No.7’and‘Houqihong’were selected as the experimental materials to explore the effects of different storage periods and 5 g·L-1Oxalic acid browning inhibitor on the quality and physiological changes of fresh-cut potato products during shelf life,to provide theoretical support for fresh-cut potato processing and preservation technology.The main results of this study are as follows:1.The fresh-cut quality and physiological changes of fresh-cut potato products in different storage periods were compared.The results showed that with the extension of storage time of potato tubers,the color a*value,browning index,ethylene release,respiratory intensity,lignin,and sugar content of fresh-cut products increased,while the brightness L*value,hardness,flavonoids,phenols and starch content of slices decreased;The activities of PAL,4CL,C4H,POD and PPO increased with the extension of shelf life.Further correlation analysis showed that chlorogenic acid was the main phenolic substrate causing enzymatic browning of fresh-cut potatoes during shelf life.Moreover,the shelf life of fresh-cut potato products decreased with the extension of tuber storage time.The shelf life was 3 days within 30 days,and 1～2 days for 60 and 90 days.2.The effects of different storage periods on the flavor quality of fresh-cut potato tubers were compared by the electronic tongue,electronic nose,and HS-GC-MS.The results showed that the electronic tongue data analysis indicated that the fresh-cut potatoes without storage and after 30 days of storage were mainly tasted bitter and sour,while the fresh-cut products after 60 and 90days of storage were mainly tasted sweet and salty.With the extension of the storage period of potato tubers,the bitterness of the fresh-cut products decreased and the sweetness increased.Using electronic nose analysis,it was found that the volatile compounds leading to the difference in flavor quality of fresh-cut potato products were mainly alcohols,aldehydes,ketones,and terpenoids.Further study by HS-GC-MS showed that potato volatile flavor substances were mainly composed of 26 kinds of aroma substances,including aldehydes（8）,alcohols（7）,furans（4）,and hydrocarbons（3）,esters（3）,ketones（1）.The ROVA analysis showed that the terrible flavor of fresh-cut potato products during shelf life was mainly caused by the increase in the contents of（2E）-2-Octenal,Heptanal,and Oct-1-en-3-ol.In addition,the reduction of 2-Amylfuran content was also the major reason for the weakening of fresh-cut potato flavor.3.By exploring the effect of Oxalic acid treatment on the shelf-life quality of fresh-cut potatoes,the results showed that compared with the control group,oxalic acid treatment significantly delayed therise of browning index,a*value,ethylene release,and respiratory intensity of fresh-cut potatoes,and reduced its total phenols,flavonoids,glucose,fructose,and sucrose,inhibited the activities of PPO,POD,PAL,and LOX activities,effectively maintained hardness,TSS,starch and ascorbic acid content and induced DPPH scavenging ability and CAT activity,slowing down malondialdehyde accumulation.In addition,Oxalic acid treatment could significantly inhibit the expression of PAL,PPO,and POD genes in fresh-cut potatoes.Therefore,Oxalic acid treatment can delay the surface browning of fresh-cut potato,inhibit the activity of enzymes related to browning,improve its antioxidant capacity and reduce its membrane lipid peroxidation damage,thereby maintaining the sensory quality and nutritional quality of fresh-cut potato during the shelf life and prolong its shelf life. |
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