Effect of Preparation, Microwave and Pressing on Quality of Carrot Powder

Abstract

The experiment was carried out with the aim to study effects of preparation, microwave and pressing on quality of carrot powder. The experiment was conducted at Department of Post Harvest Technology, ASPEE College of Horticulture, Navsari Agricultural University, Navsari, Gujarat during 2021-22. Single strength pressing was done to fasten the drying rate. The experiment was replicated three times using completely randomised design (CRD) with factorial concept and comprised of 18 treatments viz. preparation techniques as Factor-1 ["Shredding" (T1), "Crushing" (T2) and "Slicing" (T3)]; microwave pre-treatments as Factor-2 [Control (M1), Microwave pre-treatment 450 W for 30 seconds (M2) and microwave pre-treatment 450 W for 60 seconds (M3)] and pressing as Factor-3 [without pressing (P1) and pressing (P2)]. After single strength pressing, the samples were dehydrated in mechanical dehydrator using three stage dehydration temperatures (75oC for 2 hours, 65oC for 2 hours and 60oC for about 11-12 hours) till final moisture content of 5.50 ± 1% following by packing. The results of the investigation revealed that best quality carrot powder can be obtained from carrot which was prepared by dehydrating crushed materials by giving microwave for 60 seconds followed by pressing (T2M3P2) and carrot powder obtained from this treatment possess higher rehydration ratio, dehydration ratio and sensory score while lowest drying time, moisture content, water activity, reducing sugars and non-enzymatic browning (NEB). While, the carrot powder which was prepared by dehydrating crushed materials by giving microwave pre-treatment for 60 seconds followed by pressing (T2M3P2) exhibited minimum changes in nutritional as well as sensory attributes during six months’ storage when packed in polypropylene bags of 400-gauge thickness. It can be concluded that carrot powder can be prepared by dehydrating crushed materials by giving microwave pre-treatment for 60 seconds followed by pressing (T2M3P2) and the powder can remain microbiologically safe for storage period of six months.