# Quality Improvement of Green Saba Banana Flour Steamed Cake
###### Abstract  
Gluten avoidance is becoming a popular diet trend around the world. In this study, green Saba banana flour (GSBF) was used to produce a gluten-free (GF) steamed cake. The effects of soy protein isolate (SPI) (0%, 10%, 15%) and Ovalette (0%, 3.5%, 7%) on the quality of the cake were investigated. Physicochemical properties of the flours were measured. The viscosity and specific gravity of the batters; as well as the specific volume, weight loss and texture profile of the resulting cakes were determined. Sensory evaluation was performed to compare the acceptance of the cake formulations. The macronutrient and resistant starch content of the cakes were determined. The use of an appropriate level of SPI and Ovalette was found to effectively enhance the aeration of the cake batter and improved the specific volume and weight loss of the cake. The presence of Ovalette was essential to soften the texture of the cake. GF cake supplemented with 10% SPI and 3.5% Ovalette obtained the highest sensorial acceptance. The nutritional quality of this sample was significantly improved, whereby it contained higher protein than the gluten-containing counterpart. GSBF also contributed to the high dietary fiber and resistant starch content of the cake. green banana flour; soy protein isolate; emulsifier; cake; gluten-free; resistant starch; dietary fiber +
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a loss of technological quality and nutritional quality of the final products. As a result, it is of paramount importance to replace proteins from other sources in the GF product formulations to achieve the desirable properties such as to enhance the Maillard browning and flavor formation while cooking; to improve the viscoelasticity of the dough or batter; as well as to improve the structure of the final products by aiding the gelation and foaming process [10]. Green banana flour is known to contain high resistant starch (RS) which is resistant to digestion. Intake of RS has been reported as able to reduce postprandial insulinemic and elevated glycemic responses. Other metabolic health-associated benefits of RS are increasing satiety, reducing fat storage, improving insulin sensitivity, lowering triglyceride and plasma cholesterol concentrations [11; 12]. Through a proper modulation of SCFAs in the human body, the obesity-related metabolic disorders, and their associated diseases, such as type 2 diabetes, hypertension can be prevented [13; 14]. These attractive health benefits have called attention to the development of various food products using green banana flour. [PERSON] et al. (2017) [15] found that the substitution of wheat flour with green banana flour increased the dietary fiber, resistant starch, polyphenol content and antioxidant activity of both layer cakes and sponge cakes. They also found that the particle size of green banana flour affected the nutritional quality of the cakes, where coarse flours yielded cakes with a higher content of dietary fiber, and fine flours yielded cakes with a significantly higher RS content. Another study also disclosed that the fiber content and the antioxidant properties of cake samples were enhanced upon addition of banana flour from 2% to 10%, however, a negative impact on textural and sensory profile was noticed beyond 8% of incorporation [16]. Soy Protein Isolate (SPI) is a highly purified protein that is isolated from soybean. It has good gelling, emulsifying and foaming properties and is often used as a functional ingredient in food industry. SPI was used to replace the protein in GF food such as rice-cassava bread [10] and banana-cassava pasta [17]. SPI could effectively improve the total phenolic content, antioxidant capacities, enhance amino acid profiles and increase the protein digestibility of gluten-free pasta made of mixture of banana flour and cassava flour [17]. Emulsifiers are key ingredients for the successful production of bakery products. They are surface-active, and amphiphilic by nature.