Study On Improving Potato Processing And Storage Quality Characteristics By Acetic Acid Pretreatmen

Shredded potato in vinegar is a classic dish in Shandong cuisine,and acetic acid plays an important role in maintaining its crispness after heating.Similarly,cold skewers in Sichuan cuisine are also soaked in white vinegar to improve their crispness after marinated.Our research group previously revealed that one of the targets of acetic acid pretreatment to maintain the hardness of potato in hot working is the gelling of cell wall pectin.In this study,fresh cut potato chips and potato chips were taken as objects to continue to explore the effects of acetic acid pretreatment on the quality of potato products,in order to explore the possibility of acid treatment technology to improve the quality of potato products.in addition,the properties of potato pectin treated with acetic Acid were analyzed,and the concept of cell wall pectin in-situ acid-induced gelation(AIG)was proposed for the first time.In this process,it is found that:(1)Acetic acid pretreatment significantly reduced the cooking loss and starch digestibility of fresh potato slices during short-term storage(7 days),and inhibited the ascorbic acid degradation and oxidation activities.At the same time,the color of fresh potato slices during storage was improved.(2)Acetic acid pretreatment significantly reduced the oil content of potato chips.When the pretreatment time was extended to 4 h,the oil content of potato chips was the lowest(17%).The microscopical observation of the cell structure of potato chips showed that after acetic acid pretreatment,the pectin between cell walls had gelled,and the cell structure was relatively complete with few voids.In addition,the sensory properties of potato chips after acetic acid treatment were significantly improved,with more vivid color and crispiness.(3)Acetic acid pretreatment changed the structural characteristics and thermal stability of potato pectin.In the Fourier transform infrared spectrum,the intramolecular and intermolecular hydrogen bonding between(D-galacturonic acid)Gal A units near 3400 cm-1 where the hydrogen bond absorption strength increased from 50.9 to 70.7 for pectin where AIG in situ occurred was enhanced.The crystallinity of pectin increased from 4.02% to 36.63% after AIG in situ modification.Atomic force microscopy(AFM)showed that the molecular chains modified by AIG in situ were linear,ranging from 0.5 to 4.6 μm in length.Thermogravimetric analysis and rheological analysis showed that the structure of potato pectin was more stable and the heat resistance was enhanced after in-situ AIG.