The Effects Of Drying Temperature On Sugar Conversion And Aroma Components Of Apricot Fruit

Apricot fruit with rich aroma,sweet and juicy was one of the feature fruit of Xinjiang.Considering that the harvest time was short in apricot,the decay rate of fresh apricot was high and the commodity rate was low,as the traditional products of dried apricot,it will still be the leading products in the industry of apricot in Xinjiang.In this paper,the green ripe stage and full ripe stage of Xinjiang Saimaiti were chosen as the materials,the effects of drying temperatures on sugar conversion and volatile aroma components were studied,this research has an important significance to illustrate the sugar conversion mechanism during the drying process and quality control of the apricot fruit,and then provide a theoretical basis for new technology of dried fruit of apricot.The result as follows:1?The content of glucose was higher than that of fructose content in apricot fruit,and the mainly form of sugar accumulation was sucrose.Hot air drying could promote the conversion of hexose to sucrose,which can be beneficial to accumulate the sugar content in apricot fruit of green ripe stage at 45? and full ripe stage at 40?.The sucrose hydrolysis was enhanced in full ripe stage of apricot fruit under hot air drying at 50?,it was not conducive to accumulate of sugar content.2?The high activity of FRK and HXK can accelerate the consumption and transformation of hexose in fruits.The hot air temperature treatment of 45? and 40? can effectively improve the activity of sucrose synthase and promote the synthesis and accumulation of sucrose in apricot fruit of green ripe stage and full ripe stage,the change of sugar content was the result of the decomposition and synthesis of sugars.3?The activity of PG was first increased and then decreased in the whole period,the higher activity of PG could degrade the pectin molecules into small molecular substances.The activity of cellulose enzymes(cellulase enzyme and ?-glucosidase enzyme)were first increased and then decreased,and those were key enzymes of apricot fruit in ripening and softening,the content of cellulose in two maturity apricot fruit was decreased during the whole drying period.The temperature of 45? and natural drying were beneficial to improve the activity of cellulose enzyme in apricot fruit of green ripe stage and full ripe stage,which could provide the impetus for the ripening of fruit softening and cell wall metabolism.4?By SPME/GC-MS technology,there were identified 134 kinds of compounds from ripe stage of apricot fruit.There were 43,62,54,58 and 67 volatile components at temperature of 40??45??50? and natural drying.The hot air drying sample contained alcohols,aldehydes and ketones.The principal component analysis method was used to evaluate the aroma content and variety in apricot fruits under different drying conditions,which the highest score was 40?,and the aroma quality was the best.Comprehensive consideration,the temperature of 45? and 40? can be beneficial to accumulate the sugar content in apricot fruit of green ripe stage and full ripe stage,which has higher aroma and flavor.