Effect of Pretreatment Times on the Quality Characteristics of Orange Fleshed Sweet Potato (Ofsp) Flour

Abstract

Orange Fleshed Sweet Potato (OFSP) flour presents a promising alternative to traditional flours, offering enhanced nutritional benefits, particularly in Vitamin A content. This research delves into the drying characteristics of OFSP slices and the subsequent quality of its flour. The primary focus was to ascertain the impact of chemical and hot water blanching pretreatment durations prior to air drying at varied temperatures. The OFSP samples, sourced from a farm, underwent a process of washing, peeling, and slicing to a thickness of 3mm. These samples were then subjected to blanching in hot water and ascorbic acid for durations ranging from 1 to 3 minutes, followed by drying at temperatures of 50, 60, and 70℃. Key drying characteristics, such as drying curves, moisture ratio, and effective moisture diffusivity, were meticulously studied. Quality attributes, including color, water absorption capacity, and swelling index, were also analyzed, with color assessment conducted using a HunterLab colorimeter. Findings revealed that a drying temperature of 70℃ resulted in the shortest drying time. Ascorbic acid pretreatment for 3 minutes retained the highest moisture content across all temperatures. Effective moisture diffusivity values oscillated between 1.081 to 1.171×10-9 m²/s, with samples dried at 70℃ showcasing higher values. Five thin-layer models were employed to interpret the drying curves, with the Page model proving optimal for temperatures of 50oC and 60℃, and the logarithmic model for 70℃. The research underscores that varying combinations of pretreatment, duration, and drying temperature can yield diverse outcomes concerning quality criteria. In the broader context of the food industry, the insights from this study can pave the way for the large-scale production of high-quality OFSP flour, potentially revolutionizing flour-based products with enhanced nutritional profiles.