Process Optimization And Quality Evaluation Of Refractance Window Drying Of Orange Citrus Sinensis Pulp Pestil

Abstract

This study focused on investigating drying traits and quality retention of orange pulp using newlineRefractance Window Drying (RWD) method and the effect of pre-treatments using salt and newlinemicrowave power. The effect of RWD temperature (70, 80 and 90 °C) and orange pulp newlinethickness (2mm and 3mm) on drying time, drying rate, moisture content, ascorbic acid and newlinecolour (L*, a*, b* and b*/a*), moisture diffusivity, thermal diffusivity, total sugar, crude newlinefibre, Total phenolic content (TPC), and antioxidant activity were studied. The storage newlinestudy for 75 days was also performed under ambient conditions. The moisture content of newline15-25 % (wb) for intermediate moisture food like orange pestil was achieved within 50 newlineminutes of drying. Drying time for 2mm pulp thickness was 50 min and for the pulp newlinethickness of 3mm the duration of drying obtained was about 60 min which is 20% greater newlinethan 2mm pulp thickness. Salt pre-treated samples (0.5,1.0 and 1.5%) showed better newlinemoisture removal than microwave pre-treated samples (300, 450 and 600W). The moisture newlinecontent of the final product was 18.5% (wb). The maximum drying rate showed an newlineincreasing trend as the salt concentration and temperature increased. Increasing the puree newlinethickness showed a decreasing trend for drying rate. The highest aw (0.83) was noted for newlineT28 (3mm, 300W, 70°C). Lowest aw of 0.47 was exhibited by sample T9 (2mm, 1.5%, newline90°C). The maximum effective moisture diffusivity value (Deff) 9.32x10-10 m2/s was newlineobtained in T36 (2mm, 1.0%, 90 °C). It was found that maximum thermal diffusivity (and#945;) newlinevalue 8.02 x 10 newline-10 newlinem newline2 newline/s was given by T16 (3mm, 600w, 70°C). newlineHighest rehydration ratio of 4.9 was observed for sample T9 (2mm, 1.5 % salt, 90°C). The newlinehighest L* value (62.25) was observed for sample T5 (2mm, 1.0% salt, 80°C). Sample T17 newline(2mm, 450W, 90°C) displayed the highest a* value of 16.07. The sample T5 (2mm, 1.0%, newline80°C) displayed the greatest value, 27.8. The highest value of total sugar 59.41% was newlineobserved for sample T5 (2mm,1.0% salt, 80 °C). The highest fiber c