Effect of Shallot’s Pretreatment Methods on the Functional Properties of Shallot–Wheat Flour Blends and Quality of their Biscuits

Abstract

Shallots are rich in bioactive compounds and antioxidants. They are, however, susceptible to quality loss during food pretreatments, thereby making careful selection of their pretreatment technique very imperative. This study investigated the influence of shallot powder pretreatment methods (blanching, soaking, and no treatment) on the functional properties of shallot–wheat flour blends and attributes of their biscuits. Pretreated and dried shallot powder was incorporated at 6 g per 100 g of wheat flour in the biscuit recipe. A control sample was prepared from 100% wheat flour. Functional properties (water absorption capacity [WAC], oil absorption capacity [OAC], swelling capacity [SC], and bulk density [BD]) of the flour blends were evaluated. Chemical and physicochemical characteristics of biscuits from various blends were determined using standard methods. A nine-point hedonic scale was used to evaluate the sensory properties of the biscuits using 50 panelists. Data were analyzed using ANOVA at α_0.05. Blanched shallot–wheat flour sample demonstrated the highest WAC (79.00%) and OAC (90.67%), indicating enhanced hydration and emulsification potential. Results of the proximate analysis showed that biscuits containing shallot powder, particularly those prepared with blanched pretreatment, exhibited increased levels of protein (15.67%), fat (10.33%), and ash (4.00%) compared to the control. Mineral analysis results revealed elevated concentrations of iron (10.60 mg/100 g), potassium (340.78 mg/100 g), and phosphorus (425.98 mg/100 g) in pretreated shallot-supplemented biscuits. Vitamins A, C, and E were also significantly improved, with the highest values in the samples supplemented with shallot pretreated by blanching and soaking. The highest antioxidant potentials of the biscuits, as measured by FRAP and total antioxidant capacity, were found in pretreated shallot-supplemented samples. Samples of biscuits supplemented with shallots were within acceptable ranges for taste, aroma, and crispiness, though the control biscuit received the highest overall sensory score. The findings indicate that shallot powder, particularly when blanched prior to application, can serve as a functional ingredient to improve the nutritional quality of baked products without adversely affecting consumer acceptability.