Effect of Drying Method on Physical and Chemical Properties of Butternut Squash Flour (Cucurbita moschata Duchesne ex Poiret)
Abstract
Background: Butternut squash (Cucurbita moschata Duchesne ex Poiret) is a type of Cucurbita moschata that is potentially a source of beta-carotene and has high antioxidant activity. The Osmotic Dehydration (OD) pretreatment has been used to retain the colour of dried butternut squash cubes. This study investigated the effects of the drying method, i.e., freeze drying, cabinet drying, And vacuum drying of butternut squash cubes with and without OD pretreatment on the flour characteristics.
Methods: The study was conducted at the Faculty of Agriculture, UNS Surakarta, January 2024. Butternut squash was peeled and cut into 1×1×1 cm cubes. The OD pretreatment was carried out in 15% (w/v) salt solution. The cubes treated with or without OD were then dried, further ground into powder, and sieved to produce flour. The flour’s characteristics tested included moisture, beta-carotene, antioxidant activity, colour, and pasting properties. The data was statistically analyzed with analysis of variance, followed by the Duncan multiple range test at p<0.05 using IBM Statistics 25.
Results: The drying method significantly impacted the characteristics of the butternut squash flour. The moisture, beta-carotene, and antioxidant activity of flour pretreated with OD were lower than those without OD in all drying techniques. The highest L, b, and chroma values were observed in freeze dried and OD samples, and the lowest were in the cabinet dried and non-OD samples. OD pretreatment generated a denser microstructure with fewer cavities; protein and fiber on the starch granule surface were replaced by salt, causing greater starch aggregation, resulting in flour with higher thermal stability than that from non-OD pretreatment.
Conclusions: The drying methods impacted the chemical, physical, and pasting properties of butternut squash flour. Although DO pretreatment reduced the beta-carotene content and antioxidant activity of flour, the treatment improved thermal stability, making it suitable for a wide range of food applications.
