Resource Utilization Of Crawfish Shell And Its Application In Leisure Food

China produces 2.3937 million tons of crayfishes in 2021,which with one million tons of by-products,such as the head,shell and so on.Most of them were just abandoned,resulting in serious environmental pollution and waste of resources.Fried puffed food was popular because of its crispy and delicious,attractive aroma and other characteristics.In this paper,chitin and calcium were added into shrimp shell and the main components of shrimp shell to develop low-glycemic index fried puffed food and calcium-fortified fried puffed food,which improved the added value of low-value shrimp shell and realized the recycling of resources.The main results were as following:(1)Calcium supplement preparation: Herein we describe an effective approach to the preparation of Calcium gluconate and glutamate chelate by using ultrasonic-assisted extraction.Single-factor and response surface methodology was utilized to investigate the effects of D-gluconic acid addition,feed-liquid ratio,ultrasonic time and reaction temperature on the calcium gluconate of calcium glutamate chelate.The results show that the optimum conditions were determined as follows: 4.68 ml D-gluconic acids,30:1 liquid-to-material ratio,32.1 min ultrasonic time and 45℃ reaction temperatures,calcium gluconate yield was 86.38%86.38%,However,according to the reaction of glutamine acid with calcium in shrimp shell at4:1,liquid-to-material ratio 31:1,ultrasonic time 23 min and the reaction temperature60 ℃,the cheating rate of glutamine acid chelated calcium was 93.68%.(2)Shrimp shell powder was added into flour and fried to prepare biscuits.The physical and chemical properties of the biscuits were determined by RVA,GC-MS and in vitro digestion simulation,which effects on oil content,puffing degree,density and color of biscuit were significant.The addition of crayfish shell powder and chitin can clearly reduce the digestibility of starch in biscuits,in which the contents of RDS decreased by 11% and 13%,also SDS decreased by 10% and 15%,while RS increased by 20% and 28%,respectively.The predicted glycerin index decreased with the increase of crayfish shell powder and chitin biscuit,and the biscuits with 10% of crayfish shell powder and chitin biscuit had better sensory performance.(3)Study on calcium-enhanced fried expanded biscuits: acrylamide content in the biscuits by GC-MS and in vitro digestion was used to simulate the biological accessibility of calcium supplements.Calcium supplements could significantly reduce the acrylamide content in fried food.The effects of calcium supplements are calcium gluconate glutamate chelate calcium > Calcium Carbonate.The lowest content of acrylamide in the biscuit was 140μg kg.Through in vitro digestion experiment,it was found that calcium salt in crawfish shell powder had the highest content of calcium dialysate,when the amount of calcium salt added was 0.8%,the calcium dialysate content was as high as 64.83%,which significantly enhanced the efficiency of calcium supplement,and low in acrylamide.Overall comparison,calcium gluconate was the most suitable calcium fortifier,and the 0.8% additive had the greatest significant strengthening effect on crawfish shell powder biscuit.