Quality Characteristics of Cakes Produced from Composite Blends of Wheat (Triticum aestivum L.) and ‘Dhawala’ Sweet Potato (Ipomoea batatas) Cultivar Flour

Abstract

Wheat flour (WF) is the main ingredient of bakery items like cakes. Wheat is not grown in Sri Lanka and imported spending a huge number of foreign revenues. Local cultivars of sweet potatoes are not utilized to obtain optimum benefits. Therefore, this study was conducted to identify the suitability of utilizing ‘Dhawala’ sweet potato cultivar as a substitute for wheat in cake production. The yield of the flour obtained from sweet potato (SPF) was 21.47±0.00%. Four cake formulas were produced; A (100% WF/ control), B (60% WF and 40% SPF), C (50% WF and 50% SPF), and D (40% WF and 60% SPF). The density of the cakes incorporated with SPF ranged between 0.51 gcm-3 – 0.57 gcm-1. 40% SPF incorporated cake was chosen as the most consumer-accepted cake using the five-scale hedonic test. Friedman test results revealed a significant relationship between sensory attributes (appearance, aroma, taste, mouth feel, after taste) with consumer acceptability for cake formulas (p < 0.05) except with color. The moisture (17.78±0.01%), fat (15.75%±0.01), total ash (2.70±0.01%), and crude fiber (0.93±0.01%) contents were analyzed using AOAC methods. The total ash (2.70±0.01%) and crude fiber (0.93±0.01%) content of cakes incorporated with 40% SPF were higher than the control (2.30±0.01%, and 0.62±0.01%, respectively)while moisture and fat content of the cake were similar to that of control. Hardness,gumminess, chewiness, adhesiveness, cohesiveness, springiness and, resilience of most consumer accepted cake were 245.00±0.71 g, 160.25±0.78 g, 88.50±0.56 mJ, 0.16±0.08 mJ, 0.85±0.02, 51.48±0.21 mm, and 0.51±0.01 respectively. The β carotene content,polyphenol content, and IC50 value for DPPH radical scavenging of the most consumeraccepted formula were 1.48 mg/100 g, 0.005 mg/ml, and 0.066 mg/ml respectively.Therefore 40% of wheat flour can be substituted with Dhawala sweet potatoes flour in cake production while adding value to the cultivar.